Daddy longlegs have been spotted devouring live frogs bigger than themselves in the tropical forests of South America, a new study reports. And this behavior might be more common than scientists expected.

"Finding these animals eating [live] frogs was a complete surprise, we didn't expect them to be able to capture them," study co-author Luís Fernando García, a biologist at the University of the Republic in Uruguay, told Live Science.

When arthropods, the group that includes animals like insects, spiders, centipedes and crustaceans, are observed eating vertebrates, it's typically treated as a rare or isolated phenomenon. But Jose Valdez, an ecologist at Martin Luther University Halle-Wittenberg in Germany who was not involved in the new study, has found that this type of predation — mostly on frogs, lizards, bats and birds — is actually quite common.

In reality, arthropod predation on vertebrates is under-documented, Valdez told Live Science in an email. Valdez's research has found it is most commonly spiders eating frogs, since frogs' soft bodies and thin skin make them relatively vulnerable.

Yet harvestmen (order Opiliones), also known as daddy longlegs, are not technically spiders; they are part of the arachnid class alongside spiders, but they are more closely related to scorpions, so observations like this new study are particularly noteworthy, Valdez said.

In the new paper, published April 21 in the journal Ecology and Evolution, the research team compiled 10 reports in South America of harvestmen eating frogs around their body size. The reports come from field observations in Ecuador and Colombia, scientific papers, and one from the citizen science platform iNaturalist, which lets anyone with a camera upload photos of wildlife and plants.

"The availability of good quality cameras on mobile phones has enormously helped in recording such interactions and making them available to specialists, sometimes through citizen science platforms," Olivier Pauwels, a conservation biologist at the Royal Belgian Institute of Natural Sciences who was not involved in the new study, told Live Science in an email.

Previous anecdotal reports of daddy longlegs eating frogs have been unclear about whether the arachnid had killed the frog or scavenged an already dead amphibian.

"What we found is that they are able to capture frogs, because many frogs were still moving" in these observations, García said, suggesting that the arachnids might be actively hunting frogs.

The researchers don't know exactly how harvestmen capture frogs, since the arachnids are rather slow and don't have venom, García said. They may be hunting sleeping or resting frogs, or grabbing them with their strong front limbs, known as pedipalps, which are similar to the forelegs of praying mantises and can grasp prey.

"The most surprising aspect is how these harvestmen are able to subdue their prey" without venom to chemically immobilize animals, Valdez said. "Instead, they must rely entirely on physical restraint," an impressive feat since some frogs were up to 1.29 times the size of the arachnids eating them, the study found.

"We now have a new field to explore: the feeding and behavior of these animals, which is basically unknown," García said. "We think it is opportunistic behavior, they are generalist predators."

New discoveries about arthropods' diets in the tropics, and their interactions with other species, can help scientists understand how to conserve these ecosystems.

"The fate of some species is often linked to others," Pauwels said.

NASA's Curiosity rover has snapped stunning new photos of giant "spiderwebs" zig-zagging across the surface of Mars. One of these images has revealed never-before-seen, egg-like spheroids covering the sprawling structures — and scientists are struggling to explain them.

Over the last 8 months, Curiosity has been closely examining a series of interconnected rocky ridges, dubbed "boxwork," on the slopes of Mount Sharp, in the Gale Crater. These ridges, which cover an area up to 12 miles (20 kilometers) across, were created billions of yars ago as ancient Martian groundwater seeped beneath the planet's surface. They were first spotted by orbital spacecraft in 2006, but they have remained largely unexplored until now.

The web-like structures should not be confused with the infamous "spiders on Mars" — a series of geological features that are created when carbon dioxide ice sublimates beneath the Red Planet's surface and look like swarming arachnids when viewed from above. (These faux spiders were also recently recreated on Earth, while a similar "wall demon" was also spotted on Jupiter's moon Europa.)

NASA released Curiosity's first boxwork photos in June 2025, shortly after reaching the rocky ridges. But on Monday (Feb. 23), the agency released two more snaps, which showed the structures in much greater detail.

One of these photos, captured Sept. 26 last year, shows off a ground-level view of the ridges, which stand 3 to 6 feet (1 to 2 meters) above Mars' surface. But a second close-up image, snapped on Aug. 21, revealed that some of these ridges are covered in tiny irregular-shaped lumps, or nodules, that have not been seen until now.

These nodules bear a striking resemblance to mini spheroids on the surface of a mysterious "spider egg" rock, which was discovered in the Jezero Crater by NASA's Perseverance rover last year and has an unknown origin. And researchers are also having a hard time explaining exactly how the tiny boxwork "eggs" formed.

"We can't quite explain yet why the nodules appear where they do," Tina Seeger, a planetary scientist at Rice University in Houston who is leading Curiosity's boxwork investigations, said in a statement. "Maybe the ridges were cemented by minerals first, and later episodes of groundwater left nodules around them," Seeger said. But more work is needed to confirm if this is the case.

However, while the nodules and boxwork have an eerily biological appearance, there is no suggestion that they have any direct ties to extraterrestrial life.

Martian spiderwebs

Boxwork is made up of criss-crossing ridges of mineral-rich rocks that litter the surface of Mars. Similar yet smaller structures are found on Earth, predominantly within caves, and form when calcite-rich water flows between rocks that are eventually eroded, much like how stalagmites and stalactites form, according to the National Speleological Society.

However, on Mars, the boxwork was shaped by the fierce winds that scour the planet's surface: "The bedrock below these ridges likely formed when groundwater trickling through the rock left behind minerals that accumulated in those cracks and fissures, hardening and becoming cementlike," NASA representatives previously wrote. "Eons of sandblasting by Martian wind wore away the rock but not the minerals, revealing networks of resistant ridges within."

The team is particularly interested in the patch of boxwork on Mount Sharp because it formed in isolation and is surprisingly high up the mountain's slopes, which has implications for the planet's puzzling watery past.

"Seeing boxwork this far up the mountain suggests the groundwater table had to be pretty high," Seeger said. This hints that the water in this area may have "lasted much longer than we thought," she added.

Researchers hope that further investigation will also shed light on the specific conditions that formed these structures and whether they might have been favorable to any potential ancient Martian microbes.

"These ridges will include minerals that crystallized underground, where it would have been warmer, with salty liquid water flowing through," Kirsten Siebach, a Curiosity mission scientist at Rice University who has also studied the area, previously said. "Early Earth microbes could have survived in a similar environment. That makes this an exciting place to explore."

Uneven terrain

While the latest stage of Curiosity's mission is yielding fascinating results, it is also proving to be one of the hardest to navigate.

The boxwork is arguably the hardest terrain that the car-sized robot has had to traverse since it landed in the Gale Crater in 2012. The rover must balance along the ridges "like a highway" and avoid slipping "down into the hollows" between them, Ashley Stroupe, a systems engineer at NASA's Jet Propulsion Laboratory in Southern California, said in the statement.

The task of controlling the rover has also become increasingly challenging due to a gaping hole in one of the robot's wheels, which was first spotted in late 2024.

"There’s always a solution," Stroupe said. "It just takes trying different paths."

Mars quiz: Is your knowledge of the Red Planet out of this world?

A mysterious, spider-like structure lurking on Jupiter's fourth-largest moon, Europa, may finally have a proper explanation nearly 30 years after it was discovered. The arachnid imposter has also been given a demonic new name.

In March 1998, NASA's Galileo spacecraft — which studied Jupiter and its major moons between 1995 and 2003 — made a close flyby of Europa, a frozen ocean moon often considered one of the most likely places for extraterrestrial life to exist in the solar system. During this flyby, the probe mapped out a roughly 13.7-mile-wide (22 kilometers) impact structure, dubbed Manannán Crater, on the moon's icy surface, and found something strange lurking within it.

Hidden inside a deep pit near the crater's center was a sprawling dendritic shape. The researchers initially believed the dark feature was caused by the extreme gravitational force exerted on Europa by Jupiter, which is responsible for carving multiple fracture lines across the water world's surface. Other experts have since proposed that it was created by eruptions from hydrothermal vents on the floor of Europa's subsurface ocean. However, neither of these explanations fully explain this unusual shape.

But in a new study, published Dec. 2 in The Planetary Science Journal, researchers proposed an alternative explanation: that the Jovian spider formed in a similar way to how dark dendritic patterns on Earth, known as "lake stars," typically do. These features form when snow falls on frozen lakes and water seeps up through tiny holes in the ice.

With this in mind, the researchers used a similar technique to partially recreate the Manannán Crater's mysterious shape in the lab. The study team also finally named Europa's arachnid-like asterisk Damhán Alla, meaning "spider" or "wall demon" in Irish. (Manannán is a Celtic god from Irish mythology, which partly inspired the new name.)

"Lake stars are really beautiful, and they are pretty common on snow or slush-covered frozen lakes and ponds," study lead-author Lauren Mc Keown, a planetary scientist at the University of Central Florida, said in a statement. "It is wonderful to think that they may give us a glimpse into processes occurring on Europa and maybe even other icy ocean worlds in our solar system."

However, rather than water rising through tiny holes, as happens when lake stars form on Earth, Damhán Alla was likely birthed by an asteroid impact — which created a small crack in Europa's icy shell that enabled salty water to seep upward and paint the spider-like pattern on the surface. (This asteroid impact likely happened after the Manannán Crater was already formed.)

The researchers also noted similarities between Damhán Alla and the infamous "spiders on Mars," which are dusty deposits on the Martian surface that look like swarming spiders when viewed from above. These fake arachnids, known as araneiform terrain, form when submerged carbon dioxide ice sublimates, or turns directly into a gas. Mc Keown's team has previously recreated these features on Earth too.

The similarities in shape between Damhán Alla and the spiders on Mars are due to how "fluid flows through porous surfaces," Mc Keown said. In theory, similar spider features could also form on other frozen ocean worlds, such as Saturn's moon Enceladus, Jupiter's other moon Ganymede and the dwarf planet Ceres, which resides in the asteroid belt beyond Mars.

Mc Keown is now setting up a new laboratory, which will focus on studying how these various spider-like features may form on different solar system moons. She hopes to be able to provide valuable insight that could help inform NASA's Europa Clipper mission, which launched in October 2024 and will arrive to extensively study Jupiter's watery moon in 2030.

"The significance of our research is really exciting," Mc Keown said. "Surface features like these can tell us a lot about what's happening beneath the ice. If we see more of them with Europa Clipper, they could point to local brine pools below the surface," she added.

And these pools could be a good place to start looking for signs of extraterrestrial life.

Tiny tropical spiders in the Philippines and the Peruvian Amazon build giant, arachnid-like decoys in their webs to scare off predators, new research shows.

The outsize fake spiders are made of silk; plant debris; and dead, disembodied prey. Some decoys look rudimentary, but others accurately imitate the shape of a spider, according to a study published Nov. 6 in the journal Ecology and Evolution.

The builders of these decoy spiders are the orb weavers Cyclosa inca and Cyclosa longicauda, which measure just 0.1 inch (2.5 millimeters) long. Their spiderwebs are classic wheel shapes made of silk, but inside them lie important clues about spider survival strategies in a world filled with predators.

"They don't just decorate their webs — they meticulously arrange detritus, prey carcasses and silk into a structure that's not only larger than their own body, but clearly resembles the silhouette of a bigger, menacing spider," study lead author George Olah, a conservation geneticist at the Australian National University, said in a statement.

Unlike other orb weavers that build silken tubes to hide inside in their webs, the two Cyclosa spiders invest their time, energy and resources into crafting these decoys. This means the fakes are more than a quirky biological observation, study co-author Lawrence Reeves, an assistant professor at the University of Florida's Medical Entomology Laboratory, said in the statement.

"It illustrates a fundamental evolutionary trade-off in the spider world," Reeves said.

Researchers have known about Cyclosa spiders' strange antics for some time, but the new study is the first time the decoy-building behavior has been formally documented and interpreted.

The spiders turn their webs into "theaters of deception" to stave off would-be attackers, Olah said.

The decoys likely intimidate birds, lizards and other natural predators, prompting them to stay away. They may also provide camouflage for the small Cyclosa spiders, which have the same coloration as their creations and can therefore hide among the plant matter and prey remains.

The decoys may be as effective in defending Cyclosa spiders against predators as the retreats other orb weavers build, explaining why the spiders invest their energy into making them, according to the study. When predators approach the webs, Cyclosa spiders concealed within the decoys shake their abdomen to create vibrations in the fake spiders that make them seem alive.

The spiders do this day and night, the researchers wrote in the study. "When further approached, the spider jumped off from the web to the ground," they noted of a handful of observations in the Peruvian Amazon in 2022, adding that arachnids returned to their webs once the perceived threat was gone.

The decoys may also provide safe places for Cyclosa spiders to lay their eggs, Juan Carlos Yatto, a nature guide in Peru's Tambopata National Reserve who worked with the study's authors, said in a video. The spiders move the contents of their webs to new locations by building a single thread, along which they transport their eggs and all the debris and body parts used for their decoy. In this scenario, the disassembled decoy can camouflage the eggs during relocation, Yatto said.

Other benefits of building decoys could be that they attract prey and strengthen spiderwebs against adverse weather, the researchers wrote in the study. Further research is needed to understand these different advantages, Olah said.

Cyclosa spiders and their strangely decorated webs are featured in the documentary series "The Secret Lives of Animals."

Spider quiz: Test your web of knowledge

Researchers have discovered more than 111,000 spiders thriving in what appears to be the world's biggest spiderweb, deep inside a pitch-black cave on the Albanian-Greek border.

The "extraordinary" colony consists of a colossal web in a permanently dark zone of the cavern, according to a study published Oct. 17 in the journal Subterranean Biology. The web stretches 1,140 square feet (106 square meters) along the wall of a narrow, low-ceilinged passage near the entrance of the cave. It is a patchwork of thousands of individual, funnel-shaped webs, the researchers noted.

This is the first evidence of colonial behavior in two common spider species and likely represents the largest spiderweb in the world, said study lead author István Urák, an associate professor of biology at Sapientia Hungarian University of Transylvania in Romania.

"The natural world still holds countless surprises for us," Urák told Live Science in an email. "If I were to attempt to put into words all the emotions that surged through me [when I saw the web], I would highlight admiration, respect, and gratitude. You have to experience it to truly know what it feels like."

The spider megacity is located in Sulfur Cave, a cavern that was hollowed out by sulfuric acid formed from the oxidation of hydrogen sulfide in groundwater. While the researchers revealed tantalizing new information about Sulfur Cave's spider colony, they weren't the first to see the giant web. Cavers with the Czech Speleological Society discovered it in 2022 during an expedition in the Vromoner Canyon. A team of scientists then visited the cave in 2024, plucking specimens from the web that Urák analyzed before going on his own expedition to Sulfur Cave.

This analysis revealed that two spider species live in the colony: Tegenaria domestica, known as the barn funnel weaver or domestic house spider, and Prinerigone vagans. On their visit to the cave, Urák and his colleagues estimated there were about 69,000 T. domestica and more than 42,000 P. vagans specimens. DNA analyses for the new research also confirmed that these are the dominant species in the colony, Urák said.

Sulfur Cave's spider colony is one of the largest ever documented, and the species involved weren't previously known to assemble and cooperate in this way, Urák said. T. domestica and P. vagans are widespread near human dwellings, but the colony is "a unique case of two species cohabiting within the same web structure in these huge numbers," he said.

Scientists would normally expect barn funnel weavers to prey on P. vagans, but the lack of light in the cave may impair the spiders' vision, according to the study.

The spiders instead eat non-biting midges, which in turn feast on white microbial biofilms — slimy secretions that protect microorganisms against threats in their environment — from sulfur-oxidizing bacteria in the cave. A sulfur-rich stream fed by natural springs flows through Sulfur Cave, filling the cavern with hydrogen sulfide and helping microbes, midges and their predators survive, the researchers wrote in the study.

The spiders' sulfur-rich diet influences their microbiomes, causing them to be significantly less diverse than the microbiomes of spiders from the same two species outside the cave, gut content analyses revealed. Molecular data also showed that the spiders inside the cave were genetically different from their relatives living outside, suggesting the cave-dwellers have adapted to their dingy surroundings.

"Often, we think we know a species completely, that we understand everything about it, yet unexpected discoveries can still occur," Urák said. "Some species exhibit remarkable genetic plasticity, which typically becomes apparent only under extreme conditions. Such conditions can elicit behaviors that are not observed under 'normal' circumstances."

It's important to preserve the colony, despite challenges that might arise from the location of the cave between two countries, Urák said. In the meantime, the researchers are working on another study that will reveal further clues about Sulfur Cave's inhabitants, he added.

There are an estimated 50,000 species of spider living on Earth, from behemoths like the giant huntsman and goliath birdeater, down to the tiniest, the dwarf orb weaver and Patu digua. In this extract from "The Lives of Spiders: A Natural History of the World's Spiders" (Princeton University Press, 2024), author Ximena Nelson looks at the three species with unusual diets — plants, blood and pill bugs.

Vegetarian spider

Scientific name: Bagheera kiplingi

Family: Salticidae

Body length: 1∕5–¼ in (5–6 mm)

Notable anatomy: Males have iridescent green markings on cephalothorax and abdomen

Memorable feature: Primarily vegetarian

A spider is an unlikely vegetarian, but Bagheera kiplingi almost fits the bill. Supplementing its diet with nectar, ant larvae, and nectar-feeding flies, this jumping spider feeds almost entirely on Beltian bodies, the detachable fat and protein-rich leaf tips of Vachellia acacia shrubs.

Bagheera is so dependent on Beltian bodies that it is an obligate resident of Vachellia plants, where it lives in areas that are not well patrolled by the resident Pseudomyrmex ants. There is such host specificity to the plant that the spider’s geographic range is limited by the presence of Vachellia.

Plant mutualisms

Ants can be helpful to plants because they tend to be aggressive and keep herbivorous insects away. Consequently, many plants make an effort to lure ants as bodyguards and keep them around by producing accessible nectar through extrafloral nectaries. This continuous source of food is irresistible to ants, but often is also exploited by spiders, especially wandering spiders that roam to hunt their prey.

This includes many species of jumping spiders, where nectarivory may be a common tactic to obtain a meal with less risk of injury than hunting. Nectarivory can increase spider longevity and reproductive output. Importantly, for the tiny spiderlings, nectar may provide much-needed energy that allows them to hunt prey inevitably larger than themselves. In addition to extrafloral nectar, Vachellia species produce nutritious Beltian bodies to keep Pseudomyrmex ants nearby.

Related: We now know why tarantulas are hairy — to stop army ants eating them alive

The defense put up by the ants is formidable, and few animals can encroach it. Bagheera exploits the mutualism by harvesting the Beltian bodies and extrafloral nectar produced by the acacia without providing defense to the plant. Being able to see ants from a distance, Bagheera largely seems to avoid encounters with them — unless craftily stealing a larva being carried by one.

An unusual diet

Depending on location, plant-derived food accounts for between 60 and 90% of Bagheera’s diet, making this the only near-herbivorous spider known and a rather extreme outlier in a group known for its predatory behavior. As spiders cannot ingest solids, the Beltian bodies must be enzymatically broken down prior to being consumed, which can happen in a matter of minutes. Although this may be an easily available source of food, the spiders appear to need a lot of it to get by: They feed on many Beltian bodies in a single feeding bout, and about 30 Beltian bodies are required to provide the nutrition of a single insect prey.

Vampire spider

Scientific name: Evarcha culicivora

Family: Salticidae

Body length: 1∕8–2∕5 in (3–10 mm)

Notable anatomy: Males have bright-red band under forward–facing eyes

Memorable feature: Specializes in hunting the vectors of Anopheles (malaria) mosquitoes

Living in the Lake Victoria region of Africa, Evarcha culicivora is possibly the pickiest animal on Earth. The media-named "vampire spider" does not feed directly on human blood, but does so indirectly by preying on blood-fed female mosquitoes. In fact, Evarcha actively chooses Anopheles mosquitoes, which are attracted to feed on human blood and are hence vectors of malaria.

By feeding on blood-fed female Anopheles at a time of day when the mosquitoes tend to rest after a blood meal, sexually mature spiders attain a "perfume" that makes them alluring to the opposite sex. This suggests that, unusually, their prey preference may be at least partly driven by sexual selection. As a coup, E. culicivora may play a small role in mitigating the transmission of malaria by preventing mosquitoes carrying the parasite from biting and infecting another person.

An affinity for blood

The vampire spider has an approximate hierarchy of preferences, with blood-fed female Anopheles at the top, followed by other kinds of local blood-fed female mosquitoes, then non-blood-fed female Anopheles, male Anopheles, and finally the most common prey type in its habitat: midges. Juveniles even have an Anopheles-specific method of hunting, which they don’t use for other prey. Odors associated with humans may attract the spiders to houses, where they are likely to encounter the Anopheles, but it is their visual decision-making that we understand best.

Anopheles has a specific resting posture, and Evarcha uses this to differentiate it from other mosquitoes. The spider judges how "fat" the abdomen appears as an indication that it is full of blood. To determine sex, it also looks at how feathered the antennae are, as female mosquitoes have barer antennae.

Paradoxical plants

Aside from houses, a popular hunting spot is on Lantana camara shrubs, where mosquitoes sometimes rest and eat nectar. The spiders also feed on Lantana’s nectar, which gives them a nutrition boost that allows them to hunt prey many times their size. Paradoxically, Evarcha’s prey preference is no longer expressed when the spider is exposed to the dominant volatile compound of Lantana, β-caryophyllene. This is because the plant odors reduce the time Evarcha spends visually assessing its prey. The fact that the spider is prone to identification errors of its preferred prey illustrates a trade-off in Evarcha’s ability to process information when faced with a diversity of stimuli involving multiple sensory modalities.

Woodlice-eating spiders

Scientific name: Dysdera crocata

Family: Dysderidae Females

Body length: Females c. ½–c. 3∕5 in (11–15 mm), males c. 2∕5 in (9–10 mm)

Notable anatomy: Has very noticeable and broad chelicerae

Memorable feature: Specializes in hunting woodlice

Woodlice are terrestrial crustaceans (isopods) with a thick carapace, which they use as a shield when they roll into a ball or cling to a surface to avoid attack. Despite being slow-moving, many species have noxious secretions, making them formidable foes. Some spiders in the genus Dysdera, the most famous being Dysdera crocata, are among the few predators to hunt them.

Pincer, fork and key

Species that specialize in catching woodlice have specially adapted chelicerae. Unlike nonspecialist Dysdera species, these specialists use one of three main tactics to grasp prey: the pincer, the fork, and the key. Each strategy is associated with a particular mouthpart morphology.

Species with elongated chelicerae, like D. crocata, use the pincer approach, rapidly penetrating the unprotected underside of a woodlouse with one chelicera before it can roll up and defend itself, while simply holding the armored side to keep the prey in place. If the woodlouse manages to roll into a ball or cling hard, the spider patiently waits, unmoving and ready, until it gets another chance to attack.

The fork tactic is used by species that have chelicerae with a concave upper surface. Here, attacks consist of quicky grabbing the woodlouse with its first pair of legs, slipping the chelicerae under the isopod, and rapidly biting the underside of the woodlouse before it has time to adopt a defensive posture. The key tactic requires flattened chelicerae. Like fitting a key into a lock, the spiders slide one chelicera between the armored segments of the carapace of the woodlouse, inserting its fang to bite — voilà!

Woodlice gradient

Of the Dysdera species that largely consume woodlice, there is variation in how much they rely on these prey. However, it is likely that all need to eat at least some woodlice to grow and develop quickly, suggesting a metabolic need for this food source. Furthermore, there is a correlation between the level of modification of the chelicerae and woodlouse specialization, with those that are almost obligate specialists having the most strongly reshaped mouthparts. This is matched by behavior, with species with less modified mouthparts exhibiting markedly less prey preference, and by their ability to extract key nutrients from their prey.

Adapted from THE LIVES OF SPIDERS: A NATURAL HISTORY OF THE WORLD’S SPIDERS. Copyright © 2024 by Ximena Nelson. Reprinted by permission of Princeton University Press.

Giant, invasive Jorō spiders have spread across several U.S. states during the last decade. Now, scientists have discovered these palm-size critters are potentially much more tolerant to living in cities than other species and appear to thrive alongside major roads, which could help give them a foothold (or eight) in major cities along the Eastern Seaboard.

Jorō spiders (Trichonephila clavata) are a species of orb-weaving spiders — a group known for creating highly symmetrical, circular webs. Jorōs are easily recognizable thanks to the distinctive yellow bands that adorn their otherwise black legs. They also build unique webs that can be more than 6 feet (1.8 meters) across and appear golden when they reflect sunlight. 

Female Jorōs, which can grow to around 3 inches (7.6 centimeters) across — around double the size of males — also have blue stripes and red patches on their predominantly yellow abdomens. 

After mating in early autumn, female Jorōs lay large, web-bound clusters of up to 400 eggs before dying off at the start of winter, along with the males. When the eggs hatch in spring, the baby spiders create parachute-like webs that enable them to fly up to 100 miles (160 kilometers) away from where they were born. 

Jorō spiders are endemic to Asia, and until recently they were only found in Japan, Korea, Taiwan and China. However, in 2014, researchers spotted several Jorōs in the U.S. near Atlanta, Georgia. Experts believe these invasive individuals were accidentally brought to the U.S. inside a shipping container, according to a 2015 study. 

In the years since, Jorō spiders have quickly multiplied and spread in the U.S. thanks to their ability to widely disperse after birth. They are now found across Georgia, as well as in South Carolina, North Carolina and Tennessee. Additional sightings have also been reported in Alabama, Maryland, Oklahoma and West Virginia, and experts believe they could spread across the entire U.S. East Coast in the future.

Related: What is the deadliest spider in the world?

Since their arrival, researchers have noticed that Jorō webs are often located in close proximity to major highways. This is surprising because the vibrations caused by busy roads normally interfere with spiders' ability to hunt: When smaller critters get trapped in spider webs, they struggle to get free, which alerts the spiders to their presence, but busy roads can drown out these vibrations. Spiders are also very sensitive to vibrations in general.

In a new study published Feb. 13 in the journal Arthropoda, researchers investigated how vibrations impacted Jorō spiders. In the laboratory, the study team used tuning forks to simulate the vibrations given off by highways to see how it impacted the arachnids' ability to hunt simulated prey placed in their webs.

Across 350 trials, vibrated Jorōs attacked simulated prey 59% of the time, while non-vibrated Jorōs pounced on the dummy prey 65% of the time. The trials also showed that the "roadside" spiders were able to maintain a similar healthy body weight to the other spiders, indicating that the vibrations were not impacting them in the long term.

"The spiders seem to be able to make a living there," lead study author Andy Davis, an ecologist at the University of Georgia, said in a statement. They are surprisingly "urban tolerant," he added.

It is unclear what long-term effects Jorō spiders will have on the ecosystems they invade. Last year, researchers revealed that the spiders are unusually shy and non-aggressive toward other spiders. However, without a natural predator seeking them out, their numbers will likely continue to rise, which could help them outcompete other species for resources.  

But whatever their ecological effects, the new findings suggest these arachnid invaders aren't going anywhere anytime soon.

"I don't know how happy people are going to be about it, but I think the spiders are here to stay," study co-author Alexa Schultz, a third-year ecology student at the University of Georgia, said in the statement. And they could end up in places "where you wouldn’t imagine a spider to be," she added.

A strange, yellow, spider-like creature with four near-black eyes and large bulbous claws has been pulled from the depths of the ocean off Antarctica.

The never-before-seen animal is a sea spider — a distant relative of horseshoe crabs and arachnids that live on the ocean floor, eat through a straw-like proboscis instead of a mouth and breathe through their legs.Scientists have discovered more than 1,000 species of sea spiders all over the world.

The newfound species, Austropallene halanychi, was pulled from the ocean floor in the Ross Sea, about 1,870 feet (570 meters) below the surface. In addition to all the other weird things about sea spiders, the new species has large claws that look like "boxing gloves," which it likely uses to grab hold of soft foods like anemones and worms, study co-author Andrew Mahon, a biologist at Central Michigan University, told Live Science. The study was published Nov. 28 in the journal ZooKeys.

A. halanychi's body is about 0.4 inches (1 centimeter) long, but its legs stretch nearly 1.2 inches (3 cm) long. That gives the species the spindly look typical of many sea spiders — though some species can grow much larger, reaching nearly 2 feet (60 cm) wide.

Related: Sea spiders can regrow their anuses, scientists discover

What's more, this new species is likely just a drop in the bucket when it comes to the undiscovered wildlife living at the bottom of the Southern Ocean — an ecosystem home to everything from brightly colored sea stars and otherworldly marine worms to sponges and cold-water coral.

"The benthic environment in Antarctica is an area of science that we need to keep exploring," Mahon said. "There's so much down there that every time we go, we find new things."

To learn more about this environment, researchers drop nets deep underwater to pick up whatever might be hanging around at the bottom. After pulling the nets up, they sort everything they caught and preserve each specimen before shipping them back to labs for further analysis.

But with so many potentially new species to describe, it can take time to go through all the samples. A. halanychi was first pulled up in 2013 by the Nathaniel B. Palmer, a U.S. research vessel. Recently, Mahon and his colleague Jessica Zehnpfennig took it out of storage and identified it as a species new to science by analyzing its body shape and genetics.

Yet researchers may also be running out of time to study the Antarctic seafloor. As the climate keeps changing, warmer waters may threaten the future of some of the species living in this isolated and unique ecosystem, Mahon said. One of the reasons that researchers keep studying the Antarctic seafloor, he said, is to help describe and protect this biodiversity before it’s too late.

Certain male spiders in South America usually give their partners a tasty snack before mating. But in stressful environmental conditions, males may "cheat" in their mating ritual by offering females a useless ball of silk instead of a nutritious meal, a new study has found.

The research shows how spiders may adapt their behavior to reflect changes in their environment.

When a male Paratrechalea ornata spider wants to mate, he'll snag an insect and prepare it for a female, said study co-author Maria Albo, a biologist at the University of the Republic in Uruguay.

Related: Female spiders play dead during sex so males don't have to worry about being eaten

The spider starts by wrapping the insect in silk over and over until it forms a nice, little ball with a juicy treat hidden inside. "And then they start to walk along the river, along the stones," Albo told Live Science.

If a female takes the bait, she'll grab onto the gift with her mouth and slowly digest the silk to reach the food inside. While that's happening, the male mounts the female and they mate.

But some P. ornata males try to mate without going through the hassle of giving a gift. Instead of packaging a piece of food, these males will wrap up something not so tasty, like a leaf or even the leftover bits of an insect they've already eaten.

Albo knew that some males offered "worthless" gifts, but in the new study, published July 27 in the journal BMC Biology, she and her colleagues compared the prevalence of worthless-gift giving in two distinct habitats in Uruguay. One, in southern Uruguay, has a relatively stable climate. The more northern habitat is more affected by El Niño and is a more variable and unpredictable — and, therefore, more stressful — climate for a spider. In addition, the southern habitat had vastly more prey than the northern one did.

The team collected spiders along the river and checked what was inside their silk balls. In the less-stressful, southern population, males carried worthless gifts just 38% of the time. But in the more-stressful, northern population, males had worthless gifts a whopping 96% of the time.

Albo offered a couple of theories that might explain this discrepancy. For one, spiders in the stressful habitat might have to be more focused on survival, because the amount of nearby food is lower. So, the stressed-out males may be more tempted to keep the food to themselves instead of giving it away to females.

In addition, spiders in the stressful habitat were smaller, perhaps as a result of having less food around. So smaller-bodied females may not need any extra food to stay healthy. But larger females in the less-stressful habitat may need the extra food the males provide to produce healthy offspring.

These kinds of gifts given before mating, known as "nuptial gifts," occur in many different animals. In many scorpionfly species, males offer females either a dead insect or a ball of saliva to eat while they mate. Male great gray shrikes (Lanius excubitor) — a species of small, carnivorous bird — often offer their potential mates a dead mouse or lizard. And katydids have combined mating and feeding — as they copulate, the males will also provide the females with a "spermatophylax," a gelatinous ball of nutrients that the females will eat after they've finished mating.

Throughout history, tales of giant spiders have gripped the human imagination — from Arachne, the half-woman, half-spider figure in Greek mythology to J'ba Fofi, the rumored monkey-size spider of the Congolese rainforest and Shelob, the monstrous arachnid who keeps Frodo the hobbit on his toes in "The Lord of the Rings." 

But are there real-life spiders that inspired these stories and myths? What, in fact, is the biggest spider in the world?

While none are quite as enormous as those fictional beasts, the real world contains giant spiders galore. Just take giant huntsman spiders (Heteropoda maxima), which are the world's largest spiders by leg span. Measuring 11.8 inches (30 centimeters) across, these arachnids can reach the size of a dinner plate. 

But another spider species is so large it's closer to the size of a puppy. "If we're talking about the largest species of tarantula, that would be a species called Theraphosa blondi," said Ray Hale, a wildlife lecturer, arachnologist and vice chairman of the British Tarantula Society. "That is, the goliath bird-eating spider."

Related: What is the deadliest spider in the world?

How big is it?

Most spiders can be split into two broad groups, Hale told Live Science: araneomorphs (also known as 'true spiders', a group that includes 90% of spiders on earth) and mygalomorphs. Tarantulas are mygalomorphs, a group that's considered more primitive than true spiders. This means that they have evolved less since ancient times, and have therefore maintained certain features that true spiders have since shed — such as downward-pointed fangs, and their large size. 

This is why tarantulas feature the biggest spiders on Earth, including the West African Hercules baboon spiders (Hysterocrates hercules) — hefty creatures whose legs stretch to about 8 inches (20 cm); and face-size tarantulas Poecilotheria rajaei, which can also reach 8 inches in diameter and are native to Sri Lanka. Even larger are Brazilian salmon pink bird-eaters (Lasiodora parahybana), whose legs can reach 11 inches (28 cm).

But none of these beat goliath bird-eaters, which live in dense rainforest in northern South America. While these spiders have slightly shorter legs than their huntsman cousins, stretching to 11 inches — their weight gives them the edge. 

At 6.17 ounces (175 grams), and with bodies measuring 5.1 inches (13 cm), they are double the weight of their salmon pink relatives, making them the largest spiders in the world by mass. In 2014, an entomologist roaming the jungles of Guyana came across a goliath birdeater that was so big, it rustled the undergrowth and was equivalent in size to a young puppy — though a bit less cuddly, perhaps.

What does it eat?

The goliath bird-eater's name is a bit of a misnomer. "Yes, it is a big spider. Does it eat birds? Not really," said Hale. There are different theories on where the name came from. It was possibly inspired by a 19th-century engraving that showed these arachnids feasting on birds, while Hale said the name came from the accounts of 16th-century explorers to South America who put two-and-two together when they discovered some chicks that had fallen into the silk-lined burrows of this ground-nesting tarantula. 

But Hale noted that while the nocturnal hunters might opportunistically pounce on vulnerable birds — and the occasional mouse — the bulk of their diet is made up of crickets, lizards and frogs. The spiders are near-blind, so they use extremely delicate bristles on their legs and abdomen to sense slight vibrations that guide them to their food. Their prey meet the sharp end of the tarantulas' 1 inch-long (2.5 cm) fangs, which inject a lethal amount of neurotoxic venom, followed by digestive juices that liquefy prey's tissues so that the spiders can slurp it up. 

Goliath bird-eaters have their own predators, including snakes, wasps and humans — who report that the spiders have a delicious prawn-like flavor when roasted in banana leaves. 

Is this spider harmful to humans?

Goliath bird-eaters are more likely to scurry away from a human than attack. And while there's nothing nice about receiving a nip from their needle-like fangs — an experience that's been compared to a wasp sting — their venom isn't potent enough to harm us. "You're not going to die from it. They're not dangerous," Hale said. 

They do, however, have a secret weapon to ward off unwanted attention: By rubbing their hind legs against their abdomens, they release a flurry of hook-shaped bristles called "urticating hairs" that, once airborne, can become lodged in the skin and eyes and cause enough irritation to drive a predator away. That only happens after these spiders have delivered a warning: Threatened tarantulas will rub their front legs together to produce a high-pitched hissing sound that warns uninvited animals away. Called "stridulation," it's loud enough to be heard from up to 15 feet (4.6 meters) away.

And if that's not enough, these spiders can live for an extraordinarily long time. Along with their huge size, female goliath bird-eaters can live for up to 25 years, Hale said. Alongside the other wonders of their biology, this strikingly long lifespan is perhaps another reason that these behemoths deserve our respect and admiration, more than our fear.

There seems to be no ideal number of legs. Humans have two, dogs have four, insects have six and millipedes can have over 1,000. So what made spiders settle for eight legs? 

"I think the best answer and the simplest answer is that spiders have eight legs because their parents did," Thomas Hegna, an assistant professor of invertebrate paleontology at the State University of New York at Fredonia, told Live Science. "But then that gets into sort of a regress, and somewhere this all had to start."

If we follow the succession of eight-legged spider parents back to about 500 million years ago, during the middle Cambrian Period, we arrive at the root of the chelicerate lineage, the group of arthropods that contains spiders. If we go even further back, to 541 million years ago, we find the ocean-dwelling lobopods, the ancestors of all arthropods. 

The name "lobopod" doesn't refer to a single species but rather a large variety of species with rather simple bodies. Basically, they were wormlike creatures with segmented bodies. Each segment featured roughly identical pairs of short, stubby legs, and this pattern continued along the lengths of their bodies. 

Related: What is the deadliest spider in the world?

As the lobopods evolved, they began specializing their legs and fusing body segments. The early chelicerates seem to have fused their small body segments into two big ones: the head and the abdomen. Scientists aren't sure why, but the head kept the legs, and the abdomen lost them. By the time spiders appeared 315 million years ago, they inherited a body plan that was likely already 150 million years old.

It's unclear which environmental pressures, if any, caused chelicerates to settle on their eight-legged arrangement. However, we know a great deal about where their legs came from — and it's weird.

"Those legs are actually part of their mouth," Nipam Patel, a developmental biologist and director of the Marine Biological Laboratory, which is affiliated with the University of Chicago, told Live Science. 

Because spiders, insects, crustaceans and millipedes all evolved from an ancestor that likely had a segmented body with a set of appendages on each segment, these species are just highly modified riffs on that basic plan. According to Patel, all arthropod appendages — including legs, antennae and even mandibles (the jaws) — can be traced back to a stubby lobopod appendage. 

Take a mantis shrimp. It swims with a bunch of little legs on a segmented abdomen. On the cephalothorax (a fused head and thorax) are its walking legs, and then near its mouth are little appendages that not only make up its jaws but also sweep food into its mouth to help it eat. 

Compare that to an insect, whose abdomen doesn't have appendages. But it has six legs on its thorax, while its head and mouth are basically set up like the mantis shrimp's.

Then, there are spiders.

"If you look at a spider embryo, it looks exactly like an insect embryo," Patel said. "Except it only grows the legs on its head. But instead of using those as mouthparts, it uses them to walk."

The reason spiders walk with appendages from their faces goes back to lobopods and the original chelicerate body plan. While modern arthropods are spoiled for specialized appendages, the lobopods were wormlike creatures with many sets of roughly similar appendages. 

Related: What is the largest arachnid to ever live? 

"Initially, all of the legs were the same," Heather Bruce, a research associate at the Marine Biological Laboratory, told Live Science. "But then the first appendages became differentiated for being a sensory appendage, like for sensing and grabbing food."

From that point, the spider's chelicerate ancestors began to diverge from the other groups. In the ancestors of insects and crustaceans, the lobopod's multitasking front appendages lost their grabbing and feeding ability and became specialized sensory structures called antennae. But for chelicerates, those same appendages lost their sensory capabilities and became fangs. 

Meanwhile, chelicerates' second leg pair evolved into a set of grabby appendages called pedipalps; the following four sets of legs remained in their role as walking legs, and all appendages after that were lost. 

Well, not all of them. "Spinnerets evolved from spider legs," Bruce said. "There are really cool fossils in amber of a species that looks to be an ancestor of both spiders and scorpions, so it has some intermediate traits between the two. And on that fossil, there are very clear legs hanging off of the abdomen."

When male spider mites are ready to mate, they strip off the skin of maturing females as part of a freakish mating ritual.

Scientists in Austria uncovered the creepy act for the first time while studying spider mites, the dust speck-size relatives of arachnids such as spiders and scorpions, in their lab. The researchers found that the males would guard the females, which typically reach sexual maturity at 10 days of age, and wait until their potential mates began molting their exoskeletons, according to a study published Friday (June 7) in the journal iScience.

"The males will guard the females for hours," study co-author Peter Schausberger, a zoologist and professor in the Department of Behavioral and Cognitive Biology at the University of Vienna, told Live Science. "The males are able to recognize when the premature females start molting because their exuvia [old, outer skin] turns silvery as air lodges between it and the new skin."

And this is when things get really weird. To make the female ready for mating sooner, the male then slips beneath the female and uses its pedipalps (needle-like mouthparts) to pull the skin off the female. Once the exuvia is removed, the male can insert his aedeagus (reproductive organ) into the female, according to a statement.

Related: Strange love: 13 animals with truly weird courtship rituals

The researchers also noticed that at times the males would use their forelegs to "drum" against the female, perhaps to trigger them to begin the molting process, according to the study. 

"It only takes a couple of seconds for copulation," Schausberger said. "This guarding behavior is high in energy and time, so the males want to ensure that another male doesn't take over a female."

This dedication to ensuring a mate is pivotal for the males, since the "first copulation partner of a female is the one that sires all the offspring," according to a statement.

Interestingly, the researchers discovered that at times the female spider mites would "undress" themselves when it came time for them to molt. However, the females pulled off the skin beginning from their heads, whereas the males would remove the hind part of the skin first.

While this is the first time that this skin-stripping behavior has been recorded in any species, spider mites aren't the only ones that conduct creepy mating rituals in the animal kingdom.

For instance, male butterflies will "penetrate the casing" of a female pupa, the stage in a butterfly's life cycle after it's a caterpillar and cocoons itself into a chrysalis, Schausberger said.

Both of these instances "show that intense mate competition can arise" and that these "sophisticated behaviors are driven by sexual selection even in the tiniest of animals," Schausberger said. 

The scientists hope to expand their research by seeing what happens when males have to contend with rivals during this undressing act.

Black widow spiders in the U.S. are being killed off by an unexpected rival: their invasive relatives, but the motivation behind the highly aggressive attacks is not yet clear, a new study finds. 

The perpetrators, brown widow spiders (Latrodectus geometricus), likely originated in Africa or South America but have since spread to every continent on Earth apart from Antarctica. Brown widows are from the same genus as black widows, of which there are five species, including three that are native to North America: southern black widows (Latrodectus mactans), western black widows (Latrodectus hesperus) and northern black widows (Latrodectus variolus). But unlike black widows, which can all inflict extremely painful and occasionally lethal bites on humans, brown widow bites rarely cause significant harm to people, likely because they inject less venom into their bites despite having venom that is "drop-for-drop" just as toxic, according to the Center for Invasive Species Research (CISR) at the University of California, Riverside. 

In the U.S., brown widow spiders were first spotted in 1935 in Florida, and have subsequently spread across the southern states and into California, according to CISR. Since the invasive species was introduced, southern and western black widow numbers have plummeted, particularly in Florida, where southern black widows have gone "locally extinct" in certain areas.

However, scientists are unsure exactly why this is happening: Other spider species have not been affected by the brown widow's arrival, and there does not appear to be any competition for resources that would force the two widow species to fight one another.

Related: False widow spider preys on baby bat in never-before-seen encounter

In a new study, published Monday (March 13) in the journal Annals of the Entomological Society of America, researchers put solitary brown widows into laboratory tanks with one of three individuals from another spider species — a southern black widow, a red house spider (Nesticodes rufipes) or a triangulate cobweb spider (Steatoda triangulosa), which all overlap with brown widows in the wild — to see how the brown widow reacted to cohabiting with each of the species. 

When paired with the non-widow spiders, the brown widows peacefully cohabited with their tankmates in 50% to 80% of the tests. The rest of the time, one spider would kill and eat the other, but there was little difference between which species would end up victorious.

But when adult brown widows were paired with adult black widows, the invasive species killed and consumed the black widows 40% of the time, the pair peacefully cohabitated together 30% of the time, and in the remaining trials the black widows ended up victorious — but only after defending themselves from an initial brown widow attack. However, when sub-adult individuals of both species were mixed, the brown widows killed and ate their counterparts 80% of the time. Overall, brown widows were six times more likely to kill black widows than the other two spider species. 

In separate experiments, the team also showed that brown widows produce more offspring than black widows and that those offspring begin to reach maturity faster than black widows. This could explain why sub-adult individuals were so adept at killing younger black widows, which in turn would explain why black widow populations are collapsing in areas where brown widows have invaded, the researchers wrote. However, the researchers were surprised at the stark behavioral differences between brown and black widows.

Related: 11 deadliest spiders

"Brown widows are boldly aggressive and will immediately investigate a neighbor and attack if there is no resistance from the neighbor," study co-author Deby Cassill, an ecologist at the University of South Florida (USF), said in a statement. "But the black widows are extremely shy, counterattacking only to defend themselves against an aggressive spider."

The researchers are unsure why the closely related species react so differently to one another and plan to study brown and black widows in other parts of the world, such as Africa, to see if the same trends apply.

"I would love to see if their [brown widows'] behavior and displacement of black widows is something that they have adapted here in North America, or if this behavior is something they exhibit naturally even in areas where they have coevolved with black widows for much longer periods of time," study lead author Louis Coticchio, a doctoral student of conservation biology at USF, said in the statement.

Taking a dead spider's lifeless body and reanimating it as a robot is an idea that would be the stuff of nightmares for most people. But scientists aren't most people. Recently, a team of researchers turned the corpses of wolf spiders into arcade-style claw machines that could pick up and move a variety of objects — including other dead wolf spiders.   

The idea for the mechanized arachnid grippers, or "necrobots," first came about when researchers noticed a dead spider curled up in a ball in a corner of their engineering lab. After looking up why the legs of dead spiders always seem to end up pulled tightly toward their abdomens, the scientists learned that spider joints were controlled through a hydraulic pressure system that fails when the arachnids die. The team then realized that they could reverse engineer this hydraulic system to hijack the spider's corpse and give it a second life as a machine.

By puffing air into wolf spider cadavers, the team found that all eight legs could be simultaneously straightened out and curled up again to create a grabbing motion that could then be used to lift up objects. Wolf spiders — a group that comprises nearly 2,400 species in the Lycosidae family — can carry objects much larger than themselves and have tiny hairs on their legs that give them extra grip. This means the necrobots could pick up a wide variety of objects, including delicate electrical components, irregularly shaped meshes and, yes, dead wolf spiders, the researchers explained in a new study. 

The researchers believe their work could inspire the creation of other necrobots from the corpses or individual body parts of other dead animals. "It's something that hasn't been used before, but it has a lot of potential," senior study author Daniel Preston, an assistant professor of mechanical engineering at Rice University in Houston, said in a statement.

Related: Millions of palm-sized, flying spiders could invade the East Coast, scientists say 

In humans and other vertebrates (animals with backbones), most joints are controlled by antagonistic muscle pairs, which are opposing muscles that pull a joint in different directions. An example of an antagonistic muscle pair in humans is the bicep and tricep: When the bicep contracts and the tricep relaxes, our arm bends at the elbow; when the tricep contracts and the bicep relaxes, our arm straightens out again. 

However, spiders only have a single flexor muscle in their joints that allows them to bend their legs. To straighten their legs again, spiders use a hydraulic pressure system, which involves forcing blood from a chamber near the thorax, known as the prosoma, into the legs. The blood acts as the antagonist to the single flexor muscle and pushes the joint back open. But when the spider dies, there is nothing to push against this muscle, and the joints close.

"When they die, they lose the ability to actively pressurize their bodies," lead study author Faye Yap, a doctoral candidate in mechanical engineering at Rice University, said in the statement. "That's why they curl up."

To transform the wolf spiders into necrobots, the researchers recreated the arachnid hydraulic system, substituting air for blood. The team inserted a needle into the prosoma of a dried-out spider corpse and superglued it in place. When they blew air into the chamber through the needle, the air flow activated the hydraulic system just as a spider's flowing blood would, forcing the legs to straighten. When the air was sucked back out through the needle, the legs returned to their naturally curled-up position.

Normally, spiders control each individual leg through valves that adjust the flow of blood into each limb. The researchers were worried about how this would affect the mobility of their reanimated spiders, as there was no easy way to open the corpses' leg valves. But it turned out that in dead spiders, the valves were permanently stuck in the "open" position, Preston said. This allowed the researchers to control all of a necrobot's legs simultaneously, making them perfect for grabbing objects, he added.

The dead wolf spiders were so well suited to their new task that the researchers were able to create a working necrobot on their first attempt. "We took the spider; we placed the needle in it not knowing what was going to happen," Yap said. "And when we did, it worked the first time, right off the bat." It is extremely rare for engineers to succeed so quickly when doing this type of trial-and-error experiment, she added. 

Further experiments with the necrobots showed that they could reliably lift objects that weighed more than 130% of their own body weight, and occasionally, they could lift even more. However, after around 1,000 cycles of opening and closing their legs, the necrobots became less efficient and showed signs of damage. 

"We think that's related to issues with dehydration of the joints," Preston said. However, the researchers think they can eventually overcome this problem by coating the legs with special polymers, which would extend the life span of the necrobots, he added.

The necrobots have a wide range of potential applications, according to the statement. The team has already shown that the spider grippers can be used to move fragile components in electrical circuits without damaging them, which hints at their usefulness for assisting in the assembly of microelectronics and other small-scale construction projects. And if the scientists can replicate their work with other species, that could further extend the range of projects that could benefit from a necrobot's delicate touch, the team reported in the study. 

Ecologists also could utilize necrobots to collect live insects to study from the wild without damaging them, Yap said. The reanimated spiders are likely to be highly effective tools for capturing insects because their legs have evolved specifically to catch tiny arthropods, and their natural camouflage could help keep them hidden in the field, she added.

Using necrobots instead of mechanical constructs made of metal and plastics  could also help to reduce the waste produced during tool manufacturing. "The spiders themselves are biodegradable," Preston said. "So we're not introducing a big waste stream, which can be a problem with more traditional components."

Wolf spiders are extremely common, widespread and easy to collect, so there would be a cheap and plentiful supply of spider corpses for engineers to transform into necrobots — as long as those engineers aren't arachnophobic, that is.

The study was published online July 25 in the journal Advanced Science.

Originally published on Live Science.

Male wolf spiders (Schizocosa stridulans) that improvise intricate dance moves are big winners in the mating game, wooing females with showstopping tap routines. Now, new research finds that the more complex the dance, the more likely the spiders are to find love. 

The study researchers found that improvised steps benefited the spiders, which live in humid, mostly forested areas worldwide. The ability to bust a complicated move wasn't associated with size or strength in males, but it may hint to females that the male possesses a certain athleticism and grace.

"Females aren't necessarily looking for the biggest male or the loudest male or the strongest male," study co-author Eileen Hebets, a biologist at the University of Nebraska–Lincoln (UNL), said in a statement. "But maybe they're looking for a male that is really athletic and can coordinate all of these different signals into one display."

Feel the noise

S. stridulans are brownish-gray spiders that can grow to be 1.4 inches (35 millimeters) in body length. But behind that drab coloration lies a flashy and flamboyant performer, with mating dances that involve males tapping their forelegs and vibrating their abdomens. Females feel these vibrations and decide whether or not to let the suitor get close enough to mate.

Recent UNL doctoral graduate Noori Choi, a student of Hebets', wondered what exactly the females found so intriguing about the mates that they eventually chose. He analyzed one of Hebets' experiments in which ready-to-mate female spiders were put in a soundproof chamber with one amorous male at a time. The researchers placed the spiders on top of thin filter paper, which easily transmits vibrations, and monitored them with cameras and a laser to detect every last shiver and twitch created by the male's dance.

Related: These male spiders use built-in leg catapults to escape sexual cannibalism

Out of 44 hopeful males, nine spiders were deemed acceptable by the female test subjects. The spiders that successfully mated also had the most complex dances, Choi found.

Getting into a groove

Choi analyzed the complexity of the spiders' dances with computer-science analyses that have been used to quantify the complexity of patterns in data signals, part of the process of data compression. These methods have never before been applied to arachnid vibrations. Previously, Hebets said, scientists looked at features of a spider's dance individually, focusing just on factors like vibration alone, or looked at very basic interactions, such as those between visual signals and vibrations. 

"Now we're at the point, with some really talented people who have quantitative skills, of coming up with computational ways to look at how all of these things might interact, and how the entire package might be important in ways that we would never understand if we were just looking at components A, B or C," Hebets said. 

Males danced with more complexity for heavier females, which are desirable mates because they're likely to be able to bear and take care of large broods of spiderlings, the researchers found. Successful males also amped up their dance complexity as the courtship went on — dances can last up to 45 minutes —which may have indicated that the females were communicating their interest in some way. 

"When you're talking about spiders," Hebets said, "I think that's something people don't tend to appreciate; that signalers are paying attention to the receivers, they're paying attention to their environment, and they're adjusting accordingly."

The complexity of these spiders' moves is the equivalent of a person dancing on a syncopated beat, changing up the tempo, or otherwise making unpredictable artistic choices. These moves didn't correlate with spider size or a male's ability to produce loud vibrations, the researchers reported May 18 in the journal Biology Letters. Instead, the important qualities seemed to be related to vigor and skill, the researchers said. 

Or maybe these males just stood out from the crowd by abandoning preplanned choreography and thinking on their feet.

"There are a lot of studies that show that animals prefer novelty, in some capacity," Hebets said. In the case of the lovelorn wolf spiders, "the males constantly changing things up" might be the best way to catch — and keep — females' attention, she added. 

Originally published on Live Science. 

The term "arachnids" likely conjures up visions of spiders: from creepy, crawly things silently spinning webs in the corner of the room to big, hairy creatures with fangs — the likes of the mythical Shelob or Aragog — stalking you in the dark. But just how big (and ferocious) can these arachnids get? Even better, what was the largest one to have ever lived?

Answering this question is deceptively simple. Arachnids are eight-legged arthropods, which means that this group not only contains spiders but also scorpions and ticks among other, much smaller and rarer groups. Of these, spiders are the most diverse group of arachnids (the 50,000th species was discovered recently, and that number is expected to grow). The problem is that exactly what counts as an arachnid is a bit of an open question.

Arachnids are part of a larger group of arthropods called the chelicerates. The chelicerates are subdivided into smaller groups, with arachnids being one group and horseshoe crabs (in the order Xiphosura) and sea scorpions (Eurypterida) being separate but related to the arachnids.

According to Russell Bicknell, a paleontologist at the University of New England in Australia, this is the traditionally accepted phylogeny. "But a paper came out recently that suggested this is wrong, and suggested that horseshoe crabs and sea scorpions are actually nested within arachnids."

Related: Why do Cambrian creatures look so weird? 

Thomas Hegna, an assistant professor of paleontology at the State University of New York (SUNY) at Fredonia, who was not involved in the new study, told Live Science in an email that the new phylogeny, which is based on molecular analysis, implies some groups of land chelicerates (spiders and scorpions) came before marine ones (horseshoe crabs and sea scorpions). However, despite the fact that this claim is well supported by genetic evidence, it is inconsistent with the fossil record. 

This might seem like paleontological pedantry, but it actually makes a huge difference when it comes to determining the largest-ever arachnid. 

According to the traditional view of the arachnid family tree (ignoring horseshoe crabs and sea scorpions), the largest living arachnid is likely to be a spider. 

There are two spiders that make great contenders for the title of "world's largest spider." The largest known spider by mass is the Goliath Birdeater (Theraphosa blondi), a 6-ounce (170 grams) spider whose body can reach up to 5 inches (12 centimeters) in length, a number that grows to 11 inches (28 cm) when its legs are included, according to the American Association for the Advancement of Science (AAAS). 

If one is to judge the size of a spider instead by the diameter of its leg span, then the largest spider may very well be the Giant huntsman spider (Heteropoda maxima), which has a leg span of about 1 foot (30 cm) in diameter, making it about the size of a dinner plate. Despite its size, this spider wasn't discovered until 2001. 

When we dive into the fossil record, we find that the largest-ever arachnid was likely not a spider, but a scorpion. Brontoscorpio anglicus was a scorpion that lived during the Silurian-Devonian era (between 350 million and 450 million years ago) and reached lengths of nearly 3 feet (1 m) long — five times longer than the longest scorpion alive today. However, the caveat here is that the one example of this species was described from a single fossilized finger, so the animal's actual size is an educated guess. 

Related: Is every spider web unique?

These animals are the largest-known arachnids, both living and extinct, as arachnids are traditionally defined. But if sea scorpions and horseshoe crabs are indeed considered arachnids, as new research might suggest, then the largest living arachnid is no longer a spider, but is instead a horseshoe crab.

The largest living species of horseshoe crab dramatically surpasses the largest living spiders. Tachypleus tridentatus, the largest of this group, can reach sizes of 31 inches (79.5 cm) and weigh as much as 9 pounds (4 kilograms), according to research published in 2017 in the Journal of Asia-Pacific Biodiversity.

As far as the largest-ever species goes, the title would likely go to a member of the now-extinct sea scorpions, a group scientifically known as eurypterids. Fossils suggest that many of these ancient marine predators would even rival humans in size. 

The largest species from this group was Jaekelopterus rhenaniae, a species discovered in 2007 that had claws up to 18 inches (46 cm) long. From the claws, researchers estimated that its body was roughly 8 feet (2.5 m) long, making it not only the largest potential arachnid, but the largest-ever member of the entire group that contains arachnids, the chelicerates. 

Originally published on Live Science.

An invasive spider in the U.K. snagged two bats in its web, and only one bat survived the grisly encounter, thanks to the help of a local resident who freed the entangled creature before it met its doom.

The noble false widow spider (Steatoda nobilis) originally hails from the Madeira archipelago and Canary Islands in the North Atlantic Ocean, but the species is now found in other parts of Europe, as well as in Asia and the Americas. The black widow look-alike reached southern England in 1879 and has since spread toward Scotland and into Wales and Ireland, according to a statement. 

Prior to a new case report, published Feb. 21 in the journal Ecosphere, no spider in the Steatoda genus had ever been observed preying on bats — or any mammal, for that matter. But last July, Ben Waddams, a wildlife artist based in Shropshire, England, snapped photos of several bats trapped in a S. nobilis web at his home. 

Related: Ewwww! Photos of bat-eating spiders 

He shared the snapshots on social media, where they soon drew the attention of researchers at the National University of Ireland (NUI), Galway, Michel Dugon, head of the Venom Systems Lab at NUI Galway and senior author of the study, said in a video. "We actually understood very quickly that this was a first," Dugon said.

"We knew immediately the significance of Ben's discovery and contacted him to collaborate on documenting this in the scientific literature, as this furthers our understanding of this species capabilities as an invasive species," first author John Dunbar, an Irish Research Council postdoctoral fellow in the Venom Systems Lab, told Live Science in an email. 

Based on Waddams' photos, the team identified the spider as a mature female S. nobilis. The bats that fell victim to the spider's trap belonged to a colony living in Waddams' attic, according to the report. The spider had constructed its web directly beneath the entrance to the bat colony's roost, in an area spattered with bat droppings.

In July 2021, Waddams noticed a dead bat pup suspended in this opportunistically placed web, its wings tightly pinned against its silk-wrapped body. The posterior end of the young bat appeared purple and shriveled, suggesting that the spider had been feeding on the animal, the researchers observed. 

The venom of S. nobilis is a potent neurotoxin that carries some of the same toxins as the venom of true black widows (Latrodectus); past research found that the spiders use this venom to immobilize and feed on small vertebrates, including lizards, the authors noted in their report. 

"False widow spiders, just as their close relatives black widow spiders, have extraordinary prey capture techniques and remarkably potent venom, which allows them to capture small vertebrate prey many times larger than the spider itself with surprising ease," study co-author Aiste Vitkauskaite, a researcher at the Venom Systems Lab, said in the statement. 

"In addition to delivering a bite that injects potent neurotoxic venom, the noble false widow can use other strategies to assist in subduing prey," such as slinging sticky silk at them, Dunbar told Live Science in an email. And for large prey, "the spider will attach additional pre-tensioned threads to the prey which allows the spider to effectively hoist the prey off the ground," to keep it out of reach of pests and parasites, he said. 

The remains of the baby bat's body fell to the ground by the next day, but at that time, an adult bat had become trapped in the same web, Waddams noticed. In this case, the bat was still alive and not yet swaddled in silk when he observed the animal, so he scooped the bat from the web and placed it on the adjacent wall. The rescued animal then crawled back up toward its roost. 

The researchers identified the bats as either common pipistrelles (Pipistrellus pipistrellus) or soprano pipistrelles (Pipistrellus pygmaeus), which are two small, superficially indistinguishable bat species found in Britain. 

Pipistrelle bats are protected under the Wildlife and Countryside Act and the Conservation of Habitats and Species Regulations, according to the statement. This means that people can incur fines or prison time if they capture, injure or kill the bats, or if they damage or obstruct access to their breeding or resting places, for instance, according to Natural England and Department for Environment, Food & Rural Affairs.

"This study presents yet another example of the invasive impact by the noble false widow spider on native species," Dunbar said in the statement. In a previous study, published in 2018 in the journal Biology and Environment: Proceedings of the Royal Irish Academy, the team reported that the spider also preys on the viviparous lizard (Zootoca vivipara), a protected species in Ireland.  

"We know they are much more competitive than native spiders, and this further confirms their impact on prey species," Dunbar said.

Species of bat-eating spiders have been identified on every continent except Antarctica, and the arachnids typically prey on small or juvenile insect-eating bats that are unfortunate enough to get snagged in their webs, Live Science previously reported. Now, S. nobilis joins the list of spiders that pose a threat to the fuzzy, flying mammals.   

Editor's note: This article was updated on March 7, 2021 with additional quotes from John Dunbar. The original story was posted on March 3. 

Originally published on Live Science. 

Scientists have created "daddy shortlegs," a stunted version of the common household pest daddy longlegs, by suppressing the genes behind the arachnid's famously elongated limbs.

Daddy longlegs, also known as harvestmen, belong to the class Arachnids — a group of eight-legged invertebrates that includes spiders, scorpions, ticks, mites and horseshoe crabs. There are more than 6,500 species of daddy longlegs in the order Opiliones, each of which is characterized by flexible legs that are several times longer than the individual's body.

In a series of new experiments, a team of researchers mapped the entire genome of Phalangium opilio, the most common species of daddy longlegs, and isolated the genes responsible for their famous long legs. The researchers then turned off the long leg genes in developing embryos, creating individual arachnids with shorter, deformed legs.

Related: 10 amazing things scientists just did with CRISPR

"Our purpose was not just to shorten their legs just for the sake of it," lead author Guilherme Gainett, a graduate student at the University of Wisconsin-Madison, told Live Science. "We wanted to understand more about how these fascinating creatures evolved their alien way of locomotion and body plan." 

Unlike true spiders, daddy longlegs don't use all eight of their legs for walking; instead, they use three pairs for locomotion and the remaining, and longest, pair, they wave around to feel their way around, Gainett added.

Mapping the genome 

The researchers took two years to map all 580 million base pairs of the P. opilio genome, which is around one-sixth the size of the human genome, Gainett said. 

Once that was done, researchers searched the DNA map for genes likely to cause long legs, by comparing the P. opilio genome with the genomes of other insects, such as the fruit fly (Drosophila melanogaster), in which scientists had already figured out which genes code for legs, Gainett said.

The comparison revealed two Hox genes — a group of related genes that code for specific body parts during embryonic development — known as Deformed (Dfd) and Sex combs reduced (Scr), that were tied to leg development in other species.

Switching off the genes 

The researchers were confident that the Dfd and Scr genes played a role in the development of long legs in P. opilio. But it was not clear if both needed to be turned off, or if some combination was sufficient, to change leg shape and size, Gainett said. 

Therefore, the researchers down-regulated these genes in developing embryos to see if the change would interfere with the development of their long legs.

To do this they used a process known as RNA interference, which is inspired by a process living cells use to ward off viruses. When viruses invade cells, a protein structure known as the RISC complex identifies the invaders' double-stranded RNA. The cell can then target and turn off the corresponding messenger RNA (mRNA), single-stranded RNA used to help transcribe or read genes, which viruses use to reproduce within the cell, Gainett said.

However, organisms also produce mRNA to create new proteins. So the scientists repurposed the RISC complex to silence the mRNA of the Dfd and Scr by disguising those genes as viruses. 

"By synthesizing artificial double-stranded RNA matching your gene of interest and injecting it into the embryo, it is possible to interfere with the expression of that gene," Gainett said. 

Deformed legs 

Switching off both the Dfd and Scr genes resulted in individuals with three pairs of shortened "walking" legs. They also changed shape.

"When the Hox genes are down-regulated these leg appendages transform into short food-manipulating appendages called pedipalps," Gainett said.

In addition to being much shorter than their normal legs, pedipalps have six segments, instead of the usual seven in regular legs; pedipalps also lack special joints known as tarsomeres, which give their legs the flexibility needed to properly move around and help sense the world around them, Gainett said.

However, not all the embryos' legs became shorter. The fourth pair of legs still grew to their usual length. "This is because the fourth pair of legs likely requires the input of a third Hox gene to set up their fate," Gainett said. "This is something that we are currently investigating," he added.

Some of the deformed embryos hatched with their shortened legs, but they all died before reaching adulthood, Gainett said.

Understanding arachnids 

The findings help shine light on one of the most unusual body plans in the animal kingdom, Gainett said. "They [daddy longlegs] have been around for far longer than we have, around 400 million years, and to me, it is just amazing that we can make inferences about how animal morphologies evolved long ago and understand a bit more about the creatures we share our planet with," he added.

Gainett hopes that the findings could also lead to breakthroughs in understanding other arachnid body parts.

"I think future studies have the potential to clarify how other unique structures of arachnids are formed, such as the chelicera [fangs in spiders]," Gainett said.

The study was published online Aug. 4 in the journal Proceedings of the Royal Society B.

Originally published on Live Science.

Spiderwebs are astonishingly complex constructions for objects that are so delicate. Even if webs don't literally spell out the words "terrific" and "radiant" like those in the book "Charlotte's Web" do, each is nonetheless an intricate engineering marvel. 

Building these strong yet ephemeral traps is a process that follows patterns shared among spider species. But is there room for individual variation that makes one species' web — or one individual spider's — recognizably different from another's? Are all webs identical, or is every spiderweb unique? And what factors cause spiders to vary their silky webs?

Related: Is it OK to throw house spiders outside?

There are approximately 48,000 known spider species worldwide, and while all spiders have silk-producing organs, known as spinnerets, and can produce several varieties of silk, not all spiders spin webs and lie in wait for their prey. Some spiders actively hunt for food, but they still use silk for making wind-sailing balloons, egg sacs or tiny "houses" to hide in, according to the Burke Museum of Natural History and Culture in Seattle. Other spiders use silk to build ingenious traps and tools, such as throwing nets, oxygen-holding nets for breathing underwater, web slingshots, silk-sealed leaf pockets for catching frogs, and silk pulleys capable of lifting lizards or small mammals.

Picture a spiderweb, and you might imagine a wheel-like structure with a spiral and spokes radiating outward from the center. These are known as orb webs, and they are made by fewer than 10% of known spider species, said Samuel Zschokke, an arachnologist in the Section of Conservation Biology at the University of Basel in Switzerland, where he researches and visualizes spiderweb construction. Orb webs are ideal for catching flying insects because they provide a wide area for prey capture and are nearly invisible, according to the Australian Museum in Sydney. 

And while they all may look very similar, no two are exactly alike.

Spiders that build orb webs typically follow a similar construction plan and create a similar shape. They begin with a few threads that center on a single point, in a "Y" shape; the spider then establishes a frame around the "Y," connecting a few more threads in the middle. "Then they make more threads from that middle to the frame — these are the so-called radii, or, spokes, if you're comparing it to a wheel," Zschokke told Live Science.

At this point, the spider moves to the middle and builds what is known as an auxiliary spiral from the inside out. This is a placeholding structure made of non-sticky silk. Once this temporary spiral is finished, the spider crafts a new, sticky spiral by working toward the center from the outer frame. When that spiral is finished, the spider removes the auxiliary spiral, Zschokke explained.

Related: 21 totally sweet spider superlatives

To some extent, all orb webs resemble each other, but there are details that differ between species. For example, spiders in the Cyclosa genus install a "decoration" in the middle of their webs made of prey leftovers and bits of leaves, which the spider may use as camouflage, Zschokke said. Other orb weavers incorporate a zig-zag structure into the web center, known as a stabilimentum. And while most orb-weavers produce webs that are perpendicular to the ground, some, such as Leucauge dromedaria, spin webs that are oriented horizontally, according to the Atlas of Living Australia.

Webs spun by spiders that are not orb weavers may look messy or haphazard by comparison. These web types include funnel webs, sheet webs, mesh webs and tangle webs, according to a study published in 2013 in the journal PeerJ.

An orb web's physical location can also influence what it looks like, Sebastian Echeverri, an arachnologist with the American Arachnological Society, told Live Science in a message on Twitter. 

"Even if the central pattern of the web is essentially the same between individuals, the lines of silk that anchor it to the environment will have to be different," Echeverri said. An orb-web spider that builds a web in flexible grass faces different construction challenges than a spider from the same species that spins its web in a tree; though those spiders would still follow the same basic construction plan, their webs would look somewhat different, Echeverri said.

Recently, researchers observed individual orb-weaving spiders in the species Uloborus diversus as they built webs — one per day, over several days. Those webs were similar but not identical, even when conditions stayed the same, day after day, the scientists reported May 25 in bioRxiv, a preprint website. 

In the study, which was not peer reviewed, the scientists said they captured small differences in the webs by tracking changes in the spider's position, but that didn't reveal why the spider varied its technique. Pinpointing the sensory cues that motivate slight changes in the spider's web spinning would require "a more detailed understanding of the spider's behavior," the researchers reported in the study.

Under the influence

Some very distinctive and unusual web variations in orb weavers have sprung from circumstances that most spiders usually don't encounter in nature: exposure to stimulants, sedatives and psychedelics. Since the late 1940s, scientists have manipulated spiders into designing webs that diverged wildly from the usual patterns by feeding the arachnids a smorgasbord of mind-altering drugs.

A 1971 study published in the journal Behavioral Science documented more than two decades of such experiments beginning in 1948, when H. M. Peters, a professor of zoology at the University of Tübingen in Germany, decided that he wanted his lab spiders to build their webs at a time that was more convenient for humans than the spiders' preferred pre-dawn schedule. 

So Peters gave the spiders amphetamines, reported study author Peter Witt, who in 1971 was a pharmacologist with the North Carolina Department of Mental Health in Raleigh. Witt collaborated with Peters in the spider experiments, and the two scientists co-authored a landmark 1949 study documenting how the Tübingen spiders responded to amphetamines.

Related: How do spiders make silk?

While stimulants didn't affect what time the spiders chose to spin their webs, "the webs were built in a way which seemed distorted beyond the range of variations in the geometric pattern which had been observed up to that time," Witt wrote, adding that "it took only a few days to prove that the phenomenon was reproducible." 

The 1948 discovery fueled Witt's curiosity about spiders' web spinning and what it could tell scientists about the ways that drugs alter behavior, and he continued investigating how drugs affected behavior in spiders and in people, according to a biography published in 2013 in the journal Archives of Environmental Health). In more than two decades of research, Witt and other scientists found that different drugs prompted different web-building techniques. 

For example, dextroamphetamine, a stimulant that is used to treat narcolepsy and ADHD, led to "irregular radius and spiral spacing," according to the 1971 study. Scopolamine, a medication for motion sickness, "caused wide deviation of spiral spacing distinctly different from amphetamine." By comparison, spiders that were given the hallucinogenic drug lysergic acid diethylamide — LSD — produced "unusually regular webs," Witt reported.

Decades later, researchers at NASA's Marshall Space Flight Center in Huntsville, Alabama revisited these experiments by dosing European garden spiders (Araneus diadematus) with caffeine, benzedrine, marijuana and the sedative chloral hydrate, according to a 1995 report published in the journal NASA Tech Briefs. Photos of the resulting webs revealed that caffeine was the biggest structural disrupter, the web's signature spokes and spirals replaced with a seemingly random hodgepodge of strands, according to the study.

While spiders normally don't build webs that are so dramatically distinctive (and wonky) without chemical assistance, they do craft a fresh web every night or so. That means a spider can produce about 100 to 200 webs over the course of its lifetime, depending on the species, so there's bound to be at least some variation from web to web — even if it isn't quite as extreme as a web spun by a spider that's high caffeine, Zschokke said.

"If you look close enough, each web will be somewhat different," he said.

Originally published on Live Science.

Many residents of Victoria, Australia, evacuated their homes to avoid disastrous floods last week — and upon their return, they found the land, trees and road signs coated in thick veils of shimmering spider silk, according to news reports.

Heavy rains and strong winds triggered flash floods in the Australian state last week, leaving tens of thousands of residents without power, The Guardian reported; two people died when their vehicles became inundated by the floodwaters. The Victoria State Emergency Service had issued flood warnings beforehand, specifically urging residents to evacuate from the Traralgon Creek area, located in the rural Gippsland region of Victoria, according to tweets from Darren Chester, the member of Parliament representing Gippsland.

As the residents of Gippsland evacuated their homes, local arachnids also fled for higher ground. Using a behavior called "ballooning," spiders clambered atop vegetation and flung fine silk threads into the wind; as the threads caught air, the spiders got plucked from their perches and lifted to safety, CNN reported.   

Related: 21 totally sweet spider superlatives 

"When we get these types of very heavy rains and flooding, these animals who spend their lives cryptically on the ground can't live there anymore, and do exactly what we try to do — they move to the higher ground," Dieter Hochuli, an ecologist at the University of Sydney, told CNN affiliate 7News. "This is a surprisingly common phenomenon after floods," he said, adding that sheetweb spiders — a family of arachnids in the genus Stiphidiidae — likely spun the abundance of silk.

When thousands of spiders balloon at the same time, their many silk threads can merge to form a "remarkable carpet of silk, called gossamer, covering shrubs or fields," according to the Australian Museum. Given how much gossamer accumulated in Gippsland, it's possible that millions of spiders took to the air to escape the floods, Ken Walker, a senior insects curator at Museums Victoria, told The Age, a Victoria-based newspaper.  

"To me, it's absolutely beautiful. A silken blanket that undulates throughout vegetation," Walker said. "It also shows the literally tens of thousands, if not millions, of spiders at ground level. Without spiders, we'd have plagues of insects," he added.

Local councillor Carolyn Crossley told BBC News that she noticed the "beautiful" sheets of spider silk while assessing flood damage in the area on Monday night (June 14). "The fact that it didn't separate — it was like these spiders had coordinated to make this incredible landscape art installation or something," she said. Crossley had witnessed this ballooning phenomenon before but never to such a dramatic extent, she said.

The billowing mats of spider silk should disintegrate sometime this week, BBC News reported. Meanwhile, Gippsland continues to recover from the severe flash floods.

Originally published on Live Science.

Ogre-faced spiders hang from their webs, and like gymnasts, they flip backwards to snatch flying insects from the air. To hear their prey coming, the spiders "listen" for the flap of tiny wings using a special organ in their spindly legs, a new study has found.

The organ looks like a patch of parallel slits cut into the spider's exoskeleton; located near the tip of each leg, each slit measures between 0.0000003 and 0.000007 inches (10-200 nanometers) in length. These tiny slits contain nerve cells that detect minute changes in pressure caused by sound waves rippling through the air; the organ then sends this information to the brain. 

Thus equipped, ogre-faced spiders (Deinopis spinosa) can hear sounds up to 6.5 feet (2 meters) away and pick up frequencies between 100 and 10,000 hertz, according to a new study, published Oct. 29 in the journal Current Biology. Humans can hear sounds between about 20 and 20,000 hertz, for context.

"It's very alien to us because we don't have a sensory system like this," said study author Jay Stafstrom, a postdoctoral researcher studying sensory biology at Cornell University. 

Humans, of course, use their eardrums to detect sounds, but spiders don't have eardrums. That said, Stafstrom and his colleagues suspected that the ogre-faced spider might rely on some form of hearing to snag flying prey from the air — and the new study supports that suspicion. 

Related: 21 totally sweet spider superlatives

The authors found that certain sounds sent the spiders flipping; as if on cue, the arachnids would hear the sound and perform a sudden half-backflip as if launching toward a passing bug. Ogre-faced spiders can be found in forested regions of Australia, Africa and parts of the United States, including Florida, according to Cosmos Magazine; the teeny spiders, which measure less than an inch (1.5-2.5 cm) in length, hide among palm fronds and other vegetation and use their nimble acrobatics to catch moths, mosquitoes and flies that fly past.

The flip is "ballistically rapid, it's very quick … and they're surprisingly accurate," in terms of enabling the spider to catch prey on the fly, Stafstrom told Live Science. "From such a tiny little spider, with a tiny little brain, it's very impressive."

In general, ogre-faced spiders are better known for their impressive vision than their hearing. "They've got the biggest eyes of any spider," Stafstrom said. The spiders hide from predators throughout the day, camouflaged to blend in with the plants they live on. At night, the arachnids emerge and use their two huge, night-vision eyes to spot crawling insects on the ground below. To catch the creepy-crawlies, the spiders hang suspended from a web near the ground and ensnare bugs in a tiny, stretchable net that they hold between four legs.

The spiders deploy the same net to catch flying insects, but they contort their bodies backwards to aim the net upward, rather than lurching down toward the ground. It wasn't initially clear, however, if the spiders relied on their night-vision to aim the net at flying prey.

In a previous study, published 2016 in the journal Biology Letters, Stafstrom set out to determine whether ogre-faced spiders even needed their eyes to capture flying insects. He blindfolded the spiders using dental silicone, a kind of opaque plastic, and found that they could no longer capture crawling prey from the ground, but they could still pluck flying insects right out of the air. Clearly, they were relying on some other sense besides vision, Stafstrom said.

In the new study, Stafstrom and his co-authors played different sounds for the spiders to see if any would trigger their signature backflip. When exposed to low-frequency sounds, between 150 Hz and 750 Hz, the spiders lurched backwards and stretched their nets as if to catch a bug. These low-frequency sounds mimic the wingbeat patterns of various flying insects, the authors noted. The authors found that no sounds of any frequency caused the spiders to aim forward toward the ground, confirming that the spiders use their vision, not hearing, to catch crawling prey.

Related: Creepy, crawly and incredible: Photos of spiders

Compared with low-frequency sounds, high-frequency tones did not send the spiders somersaulting. However, electrical recordings of the spiders' brain cells revealed that specific groups of brain cells, or neurons, react to high frequencies, specifically between 1,000 Hz and 10,000 Hz; the sensory organ in the spiders' legs reacted to the same range of sounds. The authors speculate that, since flying insects don't flap their wings at such high rates, the spiders might also listen for the high-pitched call of predator birds.

"It might be an early warning sign, that a bird that could end your life may be in the vicinity," Stafstrom said. "We're really interested in knowing, 'Can these spiders hear bats?'" he added, but the study didn't include frequencies high enough to mimic most bat chirps.

While the study of spider hearing remains quite new, several other arachnid species can also hear sound, Stafstrom noted. 

For instance, jumping spiders sense and respond to sounds more than 9.8 feet (3 m) away, Live Science previously reported. Jumping spiders have pressure-sensitive leg hairs that respond to the movement of air particles around them. Ogre-faced spiders also have these special leg hairs, and jumping spiders have the same sensory organ in their legs as the ogre-faced does. 

"We suspect that both spiders are using both systems," but that has yet to be confirmed, Stafstrom said.

With the discovery that ogre-faced spiders use their hearing to capture prey, Stafstrom and his team now wonder how well the spiders can discern which direction a given sound is coming from. They plan to place the spiders in an arena and play sounds from various angles, to see whether the spiders change up their acrobatic routine to aim their net in the corresponding direction.

Originally published on Live Science. 

A newfound spider species wears a striking red-and-white pattern on its back that resembles the grin worn by Batman's long-standing nemesis, the Joker. The resemblance is so uncanny that the researchers who described the arachnid named the species after actor Joaquin Phoenix, who portrayed the tormented, smiling villain in the 2019 film, "Joker."

Ironically, the colorful spider belongs to a genus that was named for the late punk rock icon Lou Reed, who famously wore black and rarely smiled.

Scientists discovered Loureedia phoenixi in Iran; it's the first Loureedia spider to be identified outside the Mediterranean region, they reported in a new study. The genus, first described in 2018, now includes four species.

Related: Incredible photos of peacock spiders 

On the backs of the male L. phoenixi spiders, a splash of vivid red stands out against a background of white, much like the Joker's unnerving smile contrasts with his white facial makeup, the scientists wrote in the study. Though, you'd need magnification to see it clearly, as the spider's body measures only about 0.3 inches (8 millimeters) long and is covered in tiny hairs.

In fact, spiders in this family — Eresidae — are known as velvet spiders because they sport dense, velvety coats, said lead study author Alireza Zamani, an arachnologist and doctoral candidate in the Biodiversity Unit at the University of Turku in Finland. Velvet spiders are especially interesting to arachnologists because some have unusual habits, such as cooperating to build communal nests and collectively caring for their young, Zamani told Live Science in an email.

Discovering Loureedia spiders is challenging, because the arachnids are active aboveground only for a three-week period each year.

"These spiders spend most of their lives in their subterranean nests," Zamani said. Males leave their burrows to hunt for females, "usually from late October to mid-November," and spiderlings come to the surface when they leave their mother's nest, he explained.

So far, scientists have collected and described only male Joker spiders. But the search will continue for the elusive females, targeting locations where males have been found.

"Ideally, if you have enough time and patience, it would be interesting to track
a wandering male. He should know how to find the female better than anyone else," Zamani said. "This way, you would also have the chance of observing and photographing the actual mating behavior, which has not been documented for any Loureedia species yet," he added.

The findings were published in the June issue of the journal Arthropoda Selecta.

• Weird and Wonderful: 9 Bizarre Spiders
• Creepy, crawly & incredible: Photos of spiders 
• In photos: Fish-eating spiders around the world

Originally published on Live Science.

In this episode of Life's Little Mysteries, we'll take a closer look at mysterious arachnids with more legs and eyes than you can count on one hand: spiders.

How long have spiders been around? How many different spider species are there, and which species are the most dangerous to humans? Listen to Life's Little Mysteries 25: Mysterious Spiders, to find out! 

We'll also hear about tiny, colorful peacock spiders, and how the males' elaborate courtship dances protect them from being eaten ... not by predators, but by the much-bigger females.

Co-hosts: Jeanna Bryner and Mindy Weisberger

Guest: Kimberly Hickock, reference editor for Live Science and Space.com

Listen to Life's Little Mysteries 25: Mysterious Spiders below or on Audioboom, or subscribe on Apple Podcasts and Spotify, so you don’t miss out on new episodes.

Follow us on Facebook and Twitter for even more Life's Little Mysteries, and catch up on the latest Life's Little Mysteries articles. You can also join the conversation in our forums, where you can pose Life's Little Mysteries questions of your own, or even suggest topics for upcoming podcast episodes. 

Originally published on Live Science.

AUSTIN, Texas — Male peacock spiders have the ultimate challenge to contend with when it comes to mating: The much larger females would rather kill and eat the male than have sex with him. But the males might have a clever trick up their sleeve, or abdomen, rather. 

New research presented here on Jan. 4 at the Society of Integrative and Comparative Biology meeting suggests that the intricate and colorful designs on the male's abdomen make him look like a predator, which may stop the female from attacking and eating him and therefore give him a chance to mate. 

Male peacock spiders (in the Maratus genus) are well-known for their elaborate courtship dance. The male hops around directly in front of a female, waving his fabulous butt in the air like he just don't care. Some of these displays are particularly interesting because the designs on the males' flipped-up abdomens look like the faces of their predators, such as wasps and mantises. 

Related: See Stunning Images of Flashy Peacock Spiders

The natural response of these spiders when they see something scary, like a predator, is to freeze and closely watch the potential threat. So, male peacock spiders might be flipping up their flashy rears in front of a female to scare her stiff and stop her from eating him. 

"Humans, however, are really excellent at seeing faces where there aren't faces," said Olivia Harris, a biologist at the University of Cincinnati and lead author on the study. To figure out if humans are seeing patterns that aren't really there, Harris used machine learning to compare images of the spiders' abdomens with images of the spiders' predators. 

The photos were taken by Jurgen Otto, an Australian scientist and photographer, who has created the most comprehensive collection of pictures of peacock spiders and information about the Maratus genus. After training the computer to distinguish between spiders and other invertebrates, Harris had the computer classify different images as either spider, mantis or wasp. The machine did a pretty good job, reaching as high as 95% accuracy, she said; but the vast majority of the machine's mistakes occurred because it misclassified the spider abdomen as a mantis or a wasp. The abdomen designs of some of the spider species, such as Maratus aquilus, look so much like a mantis face that the computer never got it right and always categorized it as a mantis.

The male spiders may use their misleading abdomens to stop a female in her tracks, but "there has to be some moment when the male clues in the female or gets close enough that the female figures out [he's] not something to be scared of," Harris said. "That's important because copulation for these spiders involves female involvement. There's no forced copulation." The male just needs the female to freeze and watch his display long enough to convince her that she likes it. That could be why, after startling the female, some males lift a leg on either side, slightly obscuring the image on his abdomen, as if signaling to the female, "But look, I'm actually a great male! Aren't I pretty?"

"The [males] are always taking a risk, because the females are much larger and will totally eat him," Harris said. So the next step in this research, she said, is to observe spider-mating behavior in the lab to determine if the males of peacock spider species that have predator-mimicking displays get attacked less often than the species that don't.

• 21 Totally Sweet Spider Superlatives
• In Photos: 7 New Species of Peacock Spider
• Incredible Photos of Peacock Spiders

Originally published on Live Science.

Editor's note: This article was updated at 12:37 p.m. to reflect a correction about the accuracy of the computer: It was correct 95% of the time, not 65%. This article was also updated on Jan. 13, 2020 to correct "moths and mantises" to "wasps and mantises."  

Southeastern Colorado will soon be experiencing the pitter-patter of little feet — tens of thousands of them — as thousands of male tarantulas begin their annual migration to the prairies to find a mate.

Beginning in late August, Oklahoma brown tarantulas (Aphonopelma hentzi, also known as Texas brown tarantulas) will begin their trek through the La Junta, Colorado, area, a journey to undisturbed grasslands that typically lasts through early October, according to a report by The Gazette, a newspaper that serves Colorado Springs.

Female tarantulas hunker down in their prairie burrows for most of their lives, but the males walk for up to 1 mile (2 kilometers) to find a mate, according to CNN. However, this epic migration will look more like a steady trickle of spiders than a dense carpet of hairy brown bodies, as the tarantulas aren't social and usually travel alone, Mario Padilla, head entomologist at the Butterfly Pavilion, a nonprofit invertebrate zoo in Westminster, Colorado, told CNN.

Related: Creepy, Crawly & Incredible: Photos of Spiders

Oklahoma brown tarantulas are fuzzy, brownish spiders; females' bodies measure 3 inches (7.6 centimeters) long and weigh about 0.7 ounces (20 grams), while males are somewhat smaller, according to the U.S. Fish and Wildlife Service (FWS). 

The spiders produce venom to subdue their prey, though the toxins are not harmful to people. However, tarantulas' sharp fangs can pierce human skin, and bites can lead to bacterial infection. Tarantulas also defend themselves by brushing off stinging hairs on their abdomen, which can irritate a person’s skin, eyes and respiratory tract, FWS says.

Males typically embark on a female-finding trek when they reach sexual maturity at around 10 years old, CNN reported. And the spiders' first migration is also their last; while males may remain active through the fall, nearly all of them will be dead by November, according to a fact sheet posted on Colorado State University's Western Colorado Entomology (WCI) website. 

The spiders are most active at dusk in the hour before sunset, and tarantula enthusiasts hoping for a glimpse of the leggy travelers will find plenty of amorous arachnids on Highway 109 on the Comanche National Grassland, according to a recommendation by a La Junta tourism site.

• In Photos: Tarantulas Strut Their Stuff
• In Photos: Spiders Hatched from Web Towers
• In Photos: The Spectacular Migration of Monarch Butterflies

Originally published on Live Science.

In Australia — where else? — a large spider recently demonstrated the dominance of arachnids over puny mammals, as it chowed down on an unfortunate pygmy possum.

Southern Tasmania resident Justine Latton shared her husband's photos of the gruesome meal on June 14 in the Facebook group Tasmanian Insects and Spiders. He captured the images at a lodge in Tasmania's Mount Field National Park while doing light repair work, Latton said yesterday (June 18) on the radio program "Tasmania Talks."

Members of the Facebook group identified the arachnid as a huntsman (also known as a giant crab spider); these large, long-legged spiders in the Sparassidae family live all over Australia. In the photo, the huntsman hangs head-down from a door hinge and grips its prey by the neck. The dead marsupial — which appears to be a pygmy possum, according to commenters — dangles limply from the huntsman's mandibles. [In Photos: A Tarantula-Eat-Snake World]

The animal commonly known as a possum in North America (actually an "opossum," which belongs to a different order) can grow to be as big as a cat; were that the case here, the spider would easily be the size of a large dinner plate. But pygmy possums (Cercartetus lepidus) are the smallest possums in the world, measuring about 2 to 3 inches (5 to 7 centimeters) long and weighing about 0.2 ounces (7 grams), according to Tasmania's Parks and Wildlife Service.

On average, a huntsman spider's leg span can reach up to 6 inches (15 cm), while their bodies measure about 0.7 inches (2 cm) long, the Australian Museum reported.

Latton's husband was conducting repair work at the lodge when he noticed the spider lurking on the door just above his co-worker's head, Latton told "Tasmania Talks." The two captured the spider in an empty ice-cream container and released the huntsman outside the lodge; the arachnid skedaddled and left its possum meal behind, Latton said.

Huntsman spiders are ambush predators, and they use their large and powerful fangs to deliver venomous bites. Spiders are commonly thought to suck the liquids from their prey; in reality, they vomit digestive fluid onto their meals, chew the saturated flesh and then slurp up the dissolved nutrients, Rod Crawford, curatorial associate of arachnids at the Burke Museum in Seattle, wrote on the museum website.

Huntsman spiders' usual prey includes many types of insects, reptiles and even other spiders. But it shouldn't come as a surprise that small mammals are also occasionally on the menu. Numerous spider species worldwide are known to eat bats, and researchers recently recorded the first evidence of tropical spiders preying on mouse opossums, in the Peruvian Amazon, Live Science previously reported.

• Goliath Birdeater: Images of a Colossal Spider
• In Photos: The Amazing Arachnids of the World
• In Photos: Tarantulas Strut Their Stuff

Originally published on Live Science.

Don't freak out, but you probably have a few dozen arachnids grinding up on the tiny shafts of hair lodged inside your face, quietly gorging themselves on your natural oils.

OK, you can freak out if you want. But there's nothing wrong with you. These tick-like arachnids are known as face mites (in the genus Demodex) and, according to a skin-tingling new video created by the folks at KQED San Francisco, they live a peaceful life buried in the facial pores of most human adults. (The mites are not found on babies, and they are thought to be transmitted through motherly contact.)

These creepy-crawlies are eight-legged, mostly transparent and microscopic in size, measuring about 0.01 inches (0.3 millimeters) apiece, according to an NPR article accompanying the new video. They live near the roots of facial hair follicles on both men and women, hidden away inside your pores. [10 Reasons Why Humans Are So Gross]

What's the draw of these cramped living quarters? Consider it easy access to an all-you-can-slurp buffet of sebum — the waxy oil your face excretes to keep hydrated. Sebum is produced by glands tucked inside your pores, near the bottom of your hair follicles; Demodex mites seek out this greasy meal ticket by burrowing face-first into those pores, where they sleep by day. At night, when you're asleep, they crawl onto the surface of your skin to mate. That's right — there's a nightly mite party on your face, and you're not invited.

Given their dietary preferences, face mites are attracted to the greasiest pores on your body, including those around the cheeks, nose and forehead. According to a study published in 1992 in the journal Clinical and Experimental Dermatology, infested follicles can hold a half-dozen mites at once, with room for many more. Each mite can live for about two weeks. These mites pose no known threats to humans, unless they amass in truly huge numbers, sometimes leading to a disease called demodicosis, or demodectic mange. In humans, demodicosis can cause a red or white sheen to form on the skin, and it is often associated with a decline in immune-system response, Kanade Shinkai, a dermatologist at the University of California, San Francisco, told NPR.

But the condition is rare, Shinkai said, and most people live peacefully with their face mites until old age. Just think, in your lifetime, your nose could serve as the family home to hundreds of generations of grease-swilling, nocturnal-partying arachnids. If the thought doesn't fill your pores with pride, consider one last silver lining: You probably won't ever have to clean up after your Demodex houseguests. As KQED points out in the video, face mites have no anus, instead storing their poop in their bodies for the full duration of their brief lives. Now that's just good manners.

• In Photos: Amazing Arachnids of The World
• Body Bugs: 5 Surprising Facts About Your Microbiome
• The 10 Most Diabolical and Disgusting Parasites

Originally published on Live Science.

White-armored Stormtroopers in the "Star Wars" movies are practically identical and nearly impossible to tell apart. That uncanny similarity recently inspired a team of scientists who had discovered a new spider genus; the arachnids were so alike each other in size and markings that the researchers named them after the helmeted troops, calling the creatures Stormtropis.

These eight-legged Stormtroopers belong to a family dubbed bald-legged spiders, which are native to South America and Central America.

Like the Stormtroopers, the spiders "are very similar to each other, with some capacity for camouflage"; the sci-fi soldiers and the newfound spiders are also alike in being somewhat clumsy, according to the study. However, there is no evidence (yet) that the spiders, like their movie namesakes, are terrible at hitting moving targets with a blaster. [9 Animals with 'Star Wars'-Inspired Names]

Stormtroopers are a common sight across the Empire's conquered worlds in the "Star Wars" universe, and Colombia's bald-legged spiders turned out to be surprisingly numerous, too. Though the arachnids had never been reported in that country before, the study authors described two species in two previously known genera — Paratropis, Anisaspis — and four in the newfound Stormtropis genus. All the newly described species were scattered across a diverse range of habitats in Colombia.

Male Stormtropis spiders have just two claws on their feet, while other bald-legged spiders have three claws. Stormtropis males also lack the group's signature leg spines and have genitals that are more elongated. Female Stormtropis spiders' genitals have a tubular "neck" and an overall mushroom shape, which also differs from the typical shape found in bald-legged spiders.

Some of the newfound female spiders unexpectedly demonstrated a previously unknown behavior: digging burrows in soil, the researchers reported.

One Stormtropis species — S. muisca — was collected in the central Andes at an altitude of 11,155 feet (3,400 meters) above sea level, making that creature the highest-dwelling bald-legged spider species confirmed to date, the authors wrote.

However, S. muisca's cousins may live even higher than that. The scientists gathered evidence of other bald-legged spider species living at altitudes as high as 13,123 feet (4,000 m), but that data is yet to be published, according to the study.

The findings were published online today (March 14) in the journal ZooKeys.

• Creepy, Crawly & Incredible: Photos of Spiders
• Chewbacca to Jabba the Hutt: 10 Real 'Star Wars' Beasts in the Animal Kingdom
• Incredible Photos of Peacock Spiders

Originally published on Live Science.

Super spiders

Spiders are incredibly diverse creatures. They can be the size of the period at the end of the sentence… or the size of your face. They can live in deserts, in the tropics, in Siberia and even underwater. They can be docile or deadly, ground-dwelling or web-spinning.

To highlight the incredible accomplishments of arachnids, biologist Stefano Mammola of the University of Turin and his colleagues rounded up 99 of their most mind-boggling records in a publication in the open-access journal PeerJ. It's a wide-ranging list, but we've picked 21 of our favorite entries and paired them with pictures of the spiders that deserve a little bit of recognition. These records might just make you see arachnids in a whole new light.

Largest fossil spider

Now here's a new twist on Jurassic Park: The largest fossil spider ever found comes from the middle of that era, some 163 million to 174 million years ago.

The species is Mongolarachnidae jurassica. Found fossilized in Inner Mongolia, China, this species had a body length of 0.7 inches (1.65 centimeters) and legs up to 2.4 inches (6 cm) long.

Oldest fossil spider

Spiders are eight-legged old souls. These arachnids have witnessed the breakup of Pangaea, the rise and fall of the dinosaurs, and the expansion and retreat of the polar ice caps. The oldest fossilized spiders date back around 300 million years, with the trophy for oldest going to a species called Palaeothele montceauensis. Discovered in Montceau-les-Mines, France, the fossil shows an impression of a spider about 0.5 inches (1.2 centimeters) long.

Biggest family

The prize for most unwieldy family reunions goes to … Saltidicae! This group, better known as the jumping spiders, includes more than 6,000 individual species. Jumping spiders are a fascinating bunch. They have the best vision of any spiders and often put on fantastic mating displays, complete with snazzy dances. One fuzzy little jumping spider in England even learned to jump on command.

Most star-studded names

They'll never know it, but a group of "smiley-face spiders" found in the Caribbean now boasts star-studded monikers.

Researchers and students at the University of Vermont gave six new species of Spintharus spiders names to honor those who had stood up for human rights and warned about climate change. These spiders are known for their distinctive markings, which look a bit like a happy face. The arachnid-honored individuals? Figure them out from these scientific names: Spintharus davidattenboroughi, S. barackobamai, S. michelleobamaae, S. davidbowiei, S. leonardodicaprioi, and S. berniesandersi. (The researchers also named one species, Spintharus skelly, after a pet cat.)

Largest web

The Darwin's bark spider (Caerostris darwini) spins its webs across rivers, ponds and lakes, trawling for the insects that flutter over water. By necessity, these webs can be huge — up to 30 square feet (2.8 square meters) in area and some 82 feet (25 m) across. That's a lot of work for a little spider: Females measure about an inch (2.5 cm) in body length, and males just a quarter of an inch (6 millimeters).

The webs are also extremely tough and elastic, researchers have found. A 2010 study revealed that the spider's silk is about twice as stretchy as other related spiders that spin smaller webs. It was also 10 times more resistant than Kevlar to breaking from being stretched.

Longest leg span

Heteropoda maxima, the giant huntsman, is sometimes considered the largest spider on Earth. These spiders, found in Laos, are more spindly than the Goliath bird-eater, but regularly boast leg spans of at least a foot (30 cm). This dinner-plate-sized arachnid doesn't spin webs; instead, it chases down its prey, delivering a venomous killing bite. Fortunately, the venom isn't very dangerous to humans, causing only minor pain and swelling.

Smallest spider

A little less terrifying than the bird-eater or the huntsman is Patu digua, the smallest spider on record. This pipsqueak is only 0.01 inches (0.37 millimeters) in total length, according to a 1977 paper in American Museum Novitates. The spiders are so small that studying them is a challenge, according to that paper. A light microscope isn't strong enough to allow researchers to see their most diminutive features, so scanning electron microscopy must be used instead.

Longest fangs

The longest fangs-to-body-size award goes to Myrmarachne spiders. Remember the Salticidae jumping spiders and their enormous family tree? Well, Myrmarachne occupy one of the weirder branches. These spiders look almost exactly like ants, an adaptation that helps them avoid spider-loving predators. Male Myrmarachne spiders also have enormous fangs, longer than their head and thorax put together.

Largest venom glands

Most spiders have some form of venom, but very few are actually dangerous to humans; spider venom is generally injected in tiny amounts into insects or other small prey, so hurting people isn't the point. The Phoneutria genus of Brazilian wandering spiders is an exception. Their venom is capable of killing a human, in part because their large venom glands pack a lot of punch. Their venom glands can be up to 0.4 inches (10.2 mm) by 0.1 inches (2.6 mm) in size. But wandering spiders don't typically inject all their venom at one time, so the chance that a bite will actually kill a person is low.

Heaviest spider

With a common name like the Goliath bird-eater, it's no surprise that Theraphosa blondi weighs in as the most massive spider on the planet. These spiders have been known to grow as large as 6 ounces (170 grams), with a leg span up to 1 foot (30 cm) and bodies the size of a clenched fist. Goliath bird-eaters are capable of eating birds, but since they hunt mostly on the ground, their main prey are large earthworms — though they'll chow down on frogs and insects, too.

Smallest web

The smallest spiders build the smallest webs. According to Mammola and his colleagues, Symphytognathidae spiders hold the record for smallest webs built. This group includes the probable smallest spider in the world, Patu digua. These spiders weave webs that are less than 0.4 inches (10 mm) wide.

Most dangerous (to humans)

Spiders rarely bite humans. In fact, researchers reported in 2013 that most of the reported spider-bites are actually simple rashes, skin infections or bites from other arthropods. "You really have to work to get bitten by a spider, because they don't want to bite you," the lead author of that study told Live Science at the time.

Still, it'd be wise to steer well clear of the Sydney funnel-web spider (Atrax robustus), an Australian native that can kill a human with a mere 0.2 milligrams of venom per kilogram of the victim's weight. Only about 17 percent of A. robustus bites involve a large injection of venom, though, according to a 2005 review paper; another denizen of Down Under, the Australian funnel-web spider (Hadronyche cerberea) might be more dangerous in reality, as 75 percent of its bites involve big venom doses. The good news is that there is an antivenom treatment for both.

Least venomous

While the vast majority of spiders couldn't hurt a human if they wanted to, most still boast venom for subduing prey. The exceptions are two spider families: Holarchaeidae and Uloboridae. According to Mammola and his co-authors, Holarchaeidae spiders (there are only a couple known species) have venom glands, but there is no opening in them, making them essentially vestigial. Uloboridae, or hackled orb weavers, puke digestive enzymes all over their prey to digest them instead of injecting them with venom.

Shiniest

The crab from Disney's "Moana" has nothing on the jumping spider Cosmophasis umbratica. Females of this tropical spider species are rather plain, but males are dressed to the nines. Their black, white and yellow markings all reflect ultraviolet light. In other words, they're the living version of one of those velvet blacklight posters that were so popular in the 1970s.

Scientists have found that the intensity of a male C. umbratica's shine communicates something to females about his quality as a mate. The shine is risky, though; researchers have also found that predators, such as the jumping spider Portia labiate, cue in to the ultraviolet reflections when pouncing on their prey.

Longest-living

It's rare to track a given spider throughout its life span, but at least one Australian arachnid lived to an impressive 43 years of age. The spider, a trapdoor spider (Gaius villosus), which unwittingly participated in a research project that started in 1974, probably died when a parasitic wasp broke into her burrow, scientists reported in May 2018.

While Number 16, as scientists knew her, was the longest-living spider individual, different species usually get credited as the most likely to reach retirement age. Hickmania troglodytes, the Tasmanian cave spider, likely lives for multiple decades, and some tarantulas make it to age 30 in captivity.

Most eggs

Not to haunt your dreams or anything, but the spider Nephila pilipes can lay more than 3,000 eggs at once — perhaps as many as 9,700, according to a 2002 paper in the journal Oikos. The largest egg mass sampled in that study weighed a quarter of an ounce (6.9 grams). That's the weight of a standard packet of bread yeast, for comparison's sake.

The very fecund spider at hand is a golden orb-web spider found in Asia and Australia. The males grow to only about 0.2 inches (5 mm) in body length, while those egg-laying females can be nearly 2 inches (50 mm) long.

Fastest attacker

Trap-jaw spiders are tiny, but deadly. Their chelicerae, the little claw-like appendages by a spider's mouth, are capable of snapping shut on prey in a fraction of a second. The fastest recorded, a species of Zearchaea, completed its attack in a stunning 0.00012 seconds. (It took high-speed videography to even see what was happening.)

Trap-jaw spiders, known scientifically as Mecysmaucheniidae, live in New Zealand and South America. They get their jaw power from adaptions in their muscles and muscle attachments that essentially make their jaws act like a coiled spring, poised to explode with energy when triggered.

Fussiest spider

Evarcha culicivora is probably the pickiest eater of the spider world. This jumping spider from East Africa prefers to chow down only on female mosquitoes that have recently drunk their fill of blood.

This preference for a meal with a meal inside has made E. culicivora quite interesting to scientists, because blood-feeding mosquitoes from the genus Anopheles are the vector for the spread of malaria, which kills more than a million people each year. Some researchers have suggested that the spiders might be one way to control the population of Anopheles mosquitoes.

Coldest-living

It doesn't seem possible that much of anything lives in Oymyakon, Russia, much less spiders. But 55 different species call this tiny, insanely frigid town home. Oymyakon is barely south of the Arctic Circle and is the site of the coldest temperatures ever recorded outside of Antarctica. In 2013, the town's weather hit negative 98 degrees Fahrenheit (negative 72 degrees Celsius), its official low. In January 2017, USA Today pointed out that the temperature in Oymyakon at the time was down to negative 88 F (minus 67 C), which is colder than the average temperature on Mars.

The spiders that live in Oymyakon are hardy steppe and forest species, according to a 2004 paper in the journal Arthropoda Selecta. They are typically rather unassuming-looking creatures like Arctella lapponica, a little brown spider also known as a meshweaving spider, or Philodromus alascensis, a spindly species that is part of a family known as the running crab spiders.

Weirdest

Mammola and his colleagues crowned Argyroneta aquatica the spider species with the strangest habitat, but we're feeling confident in calling this spider the weirdest all around. Better known as the diving bell spider, A. aquatica is the only spider to live a completely aquatic lifestyle.

The spider breathes underwater thanks to special hairs on its abdomen that repel water and trap air, making it possible for the spider to swim without drowning. It also creates a "diving bell" out of spider silk and air bubbles from the surface, which provides a safe base of operations underwater. These two adaptations allow the spiders to hunt small fish and underwater invertebrates, molt, mate and lay eggs, all underwater, according to a 2011 paper in the Journal of Experimental Biology. Within days of emerging from their eggs in their mother's diving bell, hatchlings head out into the world, spinning tiny new diving bells of their own.

Oldest spider web

The oldest spider web ever preserved comes from a 110-million-year-old chunk of amber from San Just, Spain. This incredible fossil holds 26 gossamer threads of spider silk and three unfortunate spider victims. Trapped in the strands are a mite, a small fly and a wasp. The spider creator of the web wasn't preserved, but paleontologists suspect it may have been something like today's orb web spiders, which weave webs in the classic circular shape.

She was known only as Number 16 by the researchers who studied her. Little about her behavior or appearance was out of the ordinary. But Number 16 was special — she was the oldest known spider in the world.

Number 16, a trapdoor spider (Gaius villosus), was first spotted as a wee spiderling in 1974, and appeared in arachnid research surveys conducted at a site in Australia's North Bungulla Reserve, through 2016. As the years rolled by, the spider lived on — through Watergate, the release of the first IBM personal computer, and the debut of the World Wide Web.

But scientists recently discovered that Number 16 had died.

They pronounced her deceased at 43 years old, making her the longest-lived spider to date and unseating the previous record-holder — a 28-year-old tarantula in the Theraphosidae family — which lived and died in captivity, researchers wrote in a study published online April 19 in the journal Pacific Conservation Biology. [10 Things You Didn't Know About Spiders]

"To our knowledge this is the oldest spider ever recorded," study lead author Leanda Mason, a doctoral candidate at the School of Molecular and Life Sciences at Curtin University in Perth, Australia, said in a statement.

"Her significant life has allowed us to further investigate the trapdoor spider’s behaviour and population dynamics," Mason added.

Hidden underground

For more than four decades, Number 16 didn't see much more than the inside of her underground lair. Trapdoor spiders build and maintain individual burrows, lining their tunnels with silk and constructing protective lids; they ambush their insect prey from behind these camouflaged doors. The spiders enlarge the holes to fit their bodies as they molt and grow, and when females are brooding spiderlings, they reinforce their burrows' openings with mud plugs for extra protection, according to the study.

The spiders are very possessive of their burrows, and won't move into a neighbor's abandoned tunnel, the researchers wrote. Scientists who study these arachnids in the wild track populations — and follow individual spiders like Number 16 — by checking in on burrows, and noting which ones still have a spider inside.

When the males reach sexual maturity, at about 5 years old, they leave their burrows to find a mate and seal the entrances behind them. But once females dig their burrows, that's where they stay all their lives. Even if a spider's burrow is damaged, the spider will opt for repairing it rather than seeking a new home that was built by someone else, the scientists reported.

Number 16 was part of the first group of spiderlings that study co-author Barbara York Main, a now-retired arachnologist formerly with the University of Western Australia,  observed building their burrows decades ago. (York, who first began the survey, tracked the trapdoor spiders for 42 years.)

Year after year, Number 16 inhabited her underground home. But on Oct. 31, 2016, the researchers found grim evidence suggesting that the spider was dead — and that she probably had a violent end.

A parasitoid wasp had pierced the lid of her lair, and the burrow was falling into ruin, they wrote. Number 16 had likely been attacked and parasitized, a gruesome process in which a wasp implants its egg in a living spider. Then, once the wasp larva hatches, it consumes the spider from the inside out over a period of weeks.

Number 16 may have suffered a grisly ending, but her lengthy life provided researchers with decades of valuable data on the habits and biology of trapdoor spiders, and shows that long-term studies can uncover big surprises about the natural world. 

Original article on Live Science.

A hapless cricket gets the horror-story treatment in a chilling new GIF of a trapdoor spider on the attack.

The GIF, posted on gfycat by user jm610228 but originally taken by Nashville, Tennessee-based arachnid enthusiast Andrea van Veggel, shows a cricket moseying by what looks to be a large mound of mud … only to have that mud open up like a clamshell, to reveal a shiny, fat spider (think Thing from "The Addams Family"). The oversize arachnid grabs the passing cricket, and the hidden burrow closes. The spider in the GIF is a female African red trapdoor spider, a species in the Ctenolophus genus, van Veggel told Live Science. It lives with her in a bear-shaped cookie jar filled with dirt, for all its burrowing needs. "She makes one [a burrow] and goes all the way to the bottom of the jar, which is filled completely with dirt," van Veggel said. [Beastly Feasts: Amazing Photos of Animals and Their Prey]

Van Veggel's Facebook page features several videos of the trapdoor spider, as well as many other arachnids in her collection.

African trapdoor spiders are part of a group called mygalomorphs, which have downward-pointing fangs, said Joe Ballenger, an entomologist who runs the website Ask an Entomologist. Tarantulas are another example of mygalomorphs. By contrast, jumping spiders, wolf spiders and other familiar garden species are araneomorphs, distinguished by their inward-pointing fangs.

Although African trapdoor spiders are common pets among exotic-animal enthusiasts, not much is known about their natural ecology in the wild, Ballenger told Live Science. It's not uncommon for animals in the pet trade to be poorly studied in their natural environment, he said. Sometimes, new species are even discovered in aquariums or cages, simply because people who trap and trade animals from the wild aren't usually biologists.

What is known is that African trapdoor spiders live in grassland environments in Africa, where they dig flask-shaped tunnels and cover them with "lids" made of silk, dirt and vegetation. This lid makes them quite different from other trapdoor spiders that use a similar method of ambush hunting. The ravine trapdoor spider (Cyclocosmia truncata), for example, plugs its burrow with its own abdomen, which ends in a flat disc lined with grooves, making it look nearly identical to an Oreo.    

According to the Continental Neoichnology Database at Ohio University, African trapdoor spiders rarely venture from their burrows once they've dug in. They're mostly active at night, making them largely invisible pets. But they're also good housekeepers: When they need to excrete waste, they climb to the door and projectile-poop to keep the feces far from their dwelling.

Original article on Live Science. 

Scientists have discovered a new species of wandering spider that looks like it has two red fangs and lives mostly in grottos and old mines in Baja California Sur. The Sierra Cacachilas wandering spider (Califorctenus cacachilensis) is a relative of the aggressive and very venomous Brazilian wandering spider (Phoneutria fera). But though the new species, like most spiders, does have venom, it does not appear to be dangerous to humans. (A report in 2007 suggested the Brazilian wandering spider's venom can cause an uncomfortable, hours-long erection in men who are bitten.)

"I got bit while handling a live specimen of Califorctenus cacachilensis and I'm still alive," Jim Berrian, a field entomologist at the San Diego Natural History Museum and one of the spider's discoverers, said in a statement. [Goliath Birdeater: Images of a Colossal Spider]

Cave dwellers

The Sierra Cacachilas wandering spider is part of the Ctenidae family of spiders, which encompasses more than 500 species of spiders that hunt their prey by chasing them down. But very few of this group — a baker's dozen, before the latest discovery — are known from Mexico.

Berrian and some colleagues were doing fieldwork at Rancho Las Canvas in the Sierra de Las Cacachilas on the Baja peninsula in 2013 when they noticed a large exoskeleton that had been shed by a molting spider and was clinging to a rock overhang. The carapace had eyes arranged in three rows, with two on top, four in the middle and two on the bottom. That pattern is common throughout the Ctenidae family. The researchers knew that Ctenidae spiders are typically nocturnal, so they returned that night to the rock grotto where they found the exoskeleton to collect live specimens.

Berrian showed the spiders to Maria Luisa Jimenez, an expert on Baja California Sur spiders, who is a researcher at the Centro de Investigaciones Biológicas del Noroeste.

"In all my experience over the years collecting spiders on the peninsula, I had never seen a spider this large," Jimenez said in the statement. "I suspected that something new was waiting to be described."

Wandering spider

An analysis of the spiders' anatomy revealed the specimens to be a new species. More were later found in mine shafts scattered around Baja California Sur. The spiders are dark brown, with dirty yellow opistosomas (the most posterior section of the spiders' body). They have bulging brown mouthparts, or chelicerae, each of which features a small, red protuberance called a condyle at its base; the effect is as if the spider has two tiny crimson fangs. The spiders' total body length can reach up to an inch (27 millimeters), and their spindly legs can be nearly twice that.

The new spider is closely related to two other genera of Ctenidae spiders, Thoriosa and Trogloctenus, the researchers reported March 2 in the journal Zootaxa. All look similar, and Trogloctenus is another cave-dweller ("trog" comes from the Greek for "hole").

Despite its menacing look, and notorious relatives, the new wandering spider isn't especially dangerous, the researchers said.

"We haven't analyzed the toxicity of the venom," Berrian said, "but most wandering spiders are not as dangerous as the Brazilian wandering spider."

Original article on Live Science. 

Three new species of massive, furry "birdeater" spiders have been discovered, with dozens more stricken from the grouping.

In a new paper published in the open-access journal ZooKeys, researchers cleaned house on the genus Avicularia, a group of hairy tarantula spiders that was, in the words of lead study author Caroline Sayuri Fukushima, "a huge mess."

Fukushima, a researcher at the Instituto Butantan in São Paulo, Brazil, and her colleagues sorted out the genus, which was first described in 1818. They narrowed the number of Avicularia species from more than 50 to 12, including three new species of Avicularia that hadn't been noted before. They named one of these species after Maria Sibylla Merian, a naturalist born in 1647 who famously painted an illustration of an Avicularia spider eating a bird. [See Amazing Photos of Goliath Birdeater Spiders]

"This illustration gave origin to the name of the genus and the popular name birdeater spiders," Fukushima told Live Science in an email. "People [in] that time did not believe in her observations, saying that a spider eating a bird was a female fantasy. But now we know she is right!"

A tangled web

Over the years, other scientists added more and more spiders to the genus, but no one ever had a good sense of what made a tarantula an Avicularia, other than that they are large and fuzzy, and live in trees, feasting on everything from insects to bats to small birds. Most Avicularia species grow around 5 or 6 inches (12 to 15 centimeters) in length, and many are popular pets for tarantula enthusiasts. [Ewww! See Photos of Bat-Eating Spiders]

"The reasons to do this work were the necessity of solving the many problems of the genus (which were causing confusion to other genera, too), but also the chance to do something hard, big, important and new regarding tarantula taxonomy," Fukushima wrote.

And hard it was. The project took years, Fukushima said. The researchers had to track down ancient specimens from museums around the world, puzzling out original descriptions in Latin, French, Dutch, Portuguese and German. The scientists compared the anatomical characteristics of these old identifications with those of spiders from modern zoos and museums.

Naming new spiders

Untangling the mess of Avicularia required creating a new genus, Ybyrapora, to encompass certain Brazilian spiders that dwell in rainforest trees, the scientists said. Researchers also moved two species of Caribbean spider that were previously in the Avicularia genus to a new genus called Caribena. Finally, the scientists established a new genus called Antillena for a species of Dominican Republic tarantula identified in 2013 as Avicularia rickwesti. The spider is large and mostly reddish, with a distinctive red "oak leaf" pattern on its black abdomen.

The discoverers of A. rickwesti wrote in the journal Zoologia at the time that the species was quite different, anatomically, from other Avicularia spiders, but noted that it didn't fit in any other genus, either.

The researchers also named three new species of spider in the Avicularia genus. One, A. caei, is found only in Brazil. Another, A. lynnae, can be found in Ecuador and Peru. A. merianae, found only in Peru, was given its name in honor of the naturalist Merian.

"Despite her great work for natural science, she is poorly recognized when compared with male naturalists of that time," Fukushima explained.

Original article on Live Science. 

A colossal spider

Imagine a spider as big as a child's forearm that weighs as much as a puppy. That's how huge the South American Goliath birdeater — arguably the world's largest spider — can be. Entomologist and photographer Piotr Naskrecki encountered one while he was on a nighttime stroll in the rainforest of Guyana, and at first he thought it was a small, hairy mammal. Here's a brief look at the fearsome eight-legged beast — arachnophobes beware! [Read full story on the Goliath spider encounter]

Spider in the hand

The South American Goliath birdeater (Theraphosa blondi) is the world's largest spider, according to Guinness World Records. Itslegs can reach up to one foot (30 centimeters) and it can weight up to 6 oz. (170 grams).

Defense mechanisms

The spider has three lines of defense. By rubbing its legs against its abdomen, it produces a cloud of tiny, barbed hairs that get in the eyes and mucous membranes and cause extreme pain and itching for days. It has two-inch-long fangs strong enough to pierce a mouse's skull. And it can make a hissing sound by rubbing its hairs together, which sounds like pulling Velcro apart.

"Birdeater"

Despite its name, the Goliath birdeater doesn't usually eat birds (although it's definitely capable of doing so.) Instead, it eats whatever it can find on the ground — usually earthworms, frogs, or other small invertebrates, injecting venom into its prey with its lengthy fangs. The spider does not pose much of a threat to humans, though a bite would be "like driving a nail through your hand," Naskrecki said.

Guyana specimen

Naskrecki encountered this specimen, a female, on a trip to Guyana, and captured her to take back with him. She is now stored in a museum. Naskrecki has only seen a total of three birdeaters in his career.

Scaring off predators

The Goliath birdeater has plenty of ways to scare off potential predators, including a behavior called stridulation in which it rubs the bristles on its first two legs and pedipalps together to create a hissing sound. The spider can also strike a spooky pose by arching the first two pairs of its legs back and "hinging back the fangs," so it's in perfect bite mode, according to the Natural History Museum. If that weren't enough, the Goliath can flick barbed hairs from its abdomen at potential enemies — the hairs can irritate the skin of such foes.

Growing up

The spiders take about two to three years go mature. And being a type of tarantula, the Goliath birdeater continues to molt into adulthood; that allows the creepy-crawlies to regenerate damaged or lost limbs, according to the Natural History Museum.

Up-Close

Here, a close-up look at a Goliath birdeater tarantula. The beast can grow as long as a child's forearm and weigh more than 6 oz. (170 grams), according to Naskrecki.

Huntsman Spider

Some sources say the giant huntsman spider, due to its sprawling leg span, is bigger than the Goliath birdeater. The huntsman's legs, rather than bending vertically relative to the body, have twisted joints that allow the legs to spread out forward and laterally sort of like a crab, according to the Australian Museum.

When Peter Parker's "spidey sense" starts tingling, it's warning him about danger nearby. Real spiders are known for their ability to detect close-up threats, but a new study suggests that they can also sense sounds that are much farther away.

Tiny jumping spiders, which depend primarily on their vision to catch prey and evade predators, were thought to be capable of sensing only the sounds produced nearby, the study authors wrote.

But the researchers found that the spiders could also sense and respond to sounds coming from distances more than 9.8 feet (3 meters) away — no small feat for a creature that measures just 0.04 to 0.98 inches (1 to 25 millimeters) and lacks ears and eardrums. [Creepy, Crawly and Incredible: Photos of Spiders]

"Hearing in spiders is really different from the way that our own ears work," study lead author Paul Shamble, a biologist who conducted jumping-spider research with colleagues at Cornell University but is now at Harvard University, told Live Science.

"Instead of eardrums that respond to pressure, spiders have these extraordinarily sensitive hairs that respond to the actual movement of air particles around them," Shamble told Live Science. "Though they differ in size and number, these specialized 'hearing' hairs are found across virtually all spider species."

Shamble and his colleagues discovered by chance that this "hearing" was even more sensitive than anyone suspected.

The researchers wired a jumping spider's brain with electrodes — a technique that Shamble helped to pioneer at Cornell in 2014 — to record how the spiders processed visual signals. And then something unusual occurred.

Shamble recalled in a statement that the researchers had set up a speaker so they could hear when the spider's neurons fired, which produced a distinctive popping sound. As one of the scientists moved away from the table, his chair squeaked — and they heard the sound of the spider's neuron firing.

"He did it again, and the neuron fired again," Shamble said.

This was surprising, Shamble explained, because in behavioral experiments with other jumping spiders, once objects moved about 12 inches (30 centimeters) away, the spiders seemed to stop responding to them. [Weird and Wonderful: 9 Bizarre Spiders]

"Also, until now, most biologists relied on a set of simplifying assumptions to understand how creatures like this could respond to sounds," Shamble added. "Those assumptions suggested that if you were more than about a meter [3 feet] away from the sound source, the signal would be so small that it would be undetectable. Since this matched the behavior that people had observed, this seemed to work."

However, a jumping spider in a Cornell laboratory was proving those assumptions wrong. Shamble clapped his hands near the spider. The neuron fired. And it kept firing in response to his clapping, even after he had moved outside the room, to a distance of 16 feet (5 m) from the spider.

The researchers conducted further tests and found that touching the sensory hairs on jumping spiders' forelegs triggered the neurons that responded to sounds, suggesting that these hairs were picking up audio signals even over distances of several meters.

"This brings up all kinds of new ideas and questions — from what might they be using this hearing for, to the neurobiology of how they process all this information," Shamble said. "Just imagine if you assumed that cats could not hear, and then one day you found out that they could — it would change everything about how you thought about their lives!"

As to what comes next — you could say that the scientists who study these spiders will be all ears.

The findings were published online Oct. 13 in the journal Current Biology.

Original article on Live Science.

The twists and turns of a scorpion's underground burrows are generally inaccessible to anything that isn't a scorpion — including scientists. That is, until now.

Researchers used an unusual method to model the lairs of these underground arachnids, finding out that the subterranean refuges built by different species are surprisingly similar, even when the scorpions inhabit different environments.  

The scientists investigated the burrow construction of three species from two different genera of the Scorpionidae family, to understand how the scorpions were benefiting from their tunnels' structural designs. The scorpions lived in three locations — the Negev desert in Israel, and the Kalahari Desert and the Central Highlands, both in Namibia — where variations in soil composition and hardness could affect the types of tunnels the critters constructed. [Photos: Modeling Scorpions' Lairs in 3D]

Despite notable differences in the dirt the scorpions were digging through — silty soil in the Negev, sandy and loamy soil in the highlands, and sand dunes in the Kalahari — the scorpion species in all three locations built lairs with features that were common across all the burrow structures.

First, the scientists spent three days measuring the temperature and moisture levels at different points along the burrows. The temperatures taken inside the scorpions' tunnels matched that of the soil around it. Tunnel soil also held more water than soil at the surface, likely providing the arachnid with relief from hot, dry conditions, the researchers suggested.

Extracting a tunnel in 3D

Being unable to enter the scorpions' tunnels themselves, the researchers did the next best thing — they brought the tunnels to the surface. By pouring molten aluminum into 43 burrow openings (after first capturing the scorpions that built them) and allowing the metal to cool, they were able to extract the tunnels as 3D shapes.

They then compared the tunnel models and found that all of them had a horizontal entry platform that could be used like a front porch; a minimum of two spiral bends, likely to keep out predators and restrict surface air flow; and a chamber at the tunnel's end where the scorpion could rest and feed — and where females also perform courtship rituals, mate and deliver their young.

Burrow architecture should be recognized as complementary to the animals' biological needs, "performing functions its body would otherwise have to do on its own, like maintaining a comfortable temperature or improving ventilation," study co-author Berry Pinshow, a professor of physiological ecology at Ben-Gurion University of the Negev in Israel, said in a statement.

As biologists continue to explore still-unanswered questions about burrowing scorpions and how they live, these findings suggest that their burrowing behavior and the architecture they produce deserves closer investigation as well. The similarities between the species' burrows is especially interesting, the authors noted in the study, and hints that structural parallels may be found in the burrows of other scorpion species as well.

The findings were published online June 16 in the journal The Science of Nature.

Original article on Live Science.

Almost a spider

A computed tomography (CT) image of a 305 million-year-old arachnid that is almost, but not quite, a spider. This arachnid lived alongside true spiders in what is now France, but did not have the silk-spinning spinnerets that define spiders.

Researchers reported the discovery of this new arachnid, Idmonarachne brasierii, on Wednesday, March 30 in the journal Proceedings of the Royal Society B. The fossil was discovered decades ago, but because its front half was buried in rock, researchers did not unlock its secrets until they used a CT scanner to peer inside. [Read the full story on the "almost spider"]

Arachnid ancestor

Idmonarachne brasierii, the 305 million-year-old spider relative, has spiderlike mouthparts and legs. But its abdomen is segmented, unlike modern spiders', and it lacks spinnerets. This spider lived alongside some of the oldest known true spiders, but none of its descendants are alive today. Spinnerets may have been the adaptation that made true spider so successful and diverse, study researcher Russell Garwood of the University of Manchester told Live Science.

Myth and legend

Idmonarachne brasieri gets its name from Idmon, the father of Arachne, who in Greek myth was turned into a spider by the goddess Athena. The species name is in honor of Martin Brasier, a paleobiologist at the University of Oxford who died in 2014. Here, a computed tomography image of the "almost spider."

Scanning an Almost-Spider

A side view of I. brasieri, which was found fossilized in iron carbonate in the Montceau-les-Mines in France. The arachnid is about 0.4 inches (10 millimeters) long. Arachnids are the most diverse group of animals after insects, according to study researcher Russell Garwood, but little is known about their origins and relationships. They were among the first terrestrial organisms, adopting a land-based lifestyle at least 420 million years ago. Few terrestrial rocks from that era are preserved, making early arachnid fossils rare.

My, What Sharp Fangs You Have

A computed tomography image of the fangs of 305 million-year-old Idmonarachne brasierii. Arachnid species can be differentiated by their mouthparts, and it took a CT scan to see the details of the fossilized fangs of this ancient spider relative. The fangs are very spiderlike, researchers reported March 30 , 2016, in the journal Proceedings of the Royal Society B.

Arachnid 'arms'

The pedipalps of Idmonarachne brasierii. These appendages look like an extra pair of legs alongside the arachnid's head, but they were used more like arms. These pedipalps are very spiderlike, positioning this arachnid close to spiders in the arachnid family tree. But the absence of spinnerets and a segmented abdomen mark this arachnid as not quite a spider.

Almost Spider - 7

This image shows a "slice" of the I. brasieri fossil in cross-section. Soon after the arachnid died, the mineral iron carbonate precipitated out around it. The arachnid corpse rotted away, leaving behind a three-dimensional void, seen in black.

A new fossil found in France is almost a spider, but not quite.

The arachnid, locked in iron carbonate for 305 million years, reveals the stepwise evolution of arachnids into spiders. Dubbed Idmonarachne brasieri after the Greek mythological figure Idmon, father of Arachne, a weaver turned into a spider by a jealous goddess, the "almost spider" lacks only the spinnerets that spiders use to turn silk into webs.

"It's not quite a spider, but it's very close to being one," said study researcher Russell Garwood, a paleontologist at the University of Manchester in the United Kingdom. [See Images of the Fossilized 'Almost Spider']

Locked in rock

Arachnids are an ancient group with murky origins, Garwood told Live Science. The creatures were among the first land-dwellers, adopting a terrestrial life at least 420 million years ago. There are very few rocks laid down on land from that time, so little of arachnids' early history is preserved, Garwood said. And figuring out arachnid evolutionary relationships from DNA is likewise difficult because arachnids diversified so early, leaving few traceable evolutionary changes in their genes.

The oldest known spider fossil comes from the Montceau-les-Mines, a coal seam in eastern France. That spider was 305 million years old. The newfound fossil from the same time period reveals that these ancient spiders lived alongside not-quite-spider cousins. 

The 0.4-inch-long (10 millimeters) arachnid was discovered decades ago, but no one could make much of it, because the front half of the fossil is buried in rock. Computed tomography unlocked the mystery by allowing Garwood and his colleagues to peer inside the rock at the arachnid's walking legs and mouthparts, which are important for identifying the genus and species of this kind of creature.

Long-lost cousin

The arachnid turned out to have had spiderlike mouthparts and legs. But unlike true spiders, it lacked spinnerets. It also had a segmented abdomen, rather than a fused abdomen, which modern spiders have.

"We're looking at a line of spiderlike arachnids that haven't survived but must have split off before 305 million years ago," Garwood said.

Members of an earlier arachnid branch, called the Uraraneida, known from 385-million-year-old fossils, were also spiderlike in appearance, Garwood said, but had a long, tail-like structure called the flagellum that disappeared before I. brasieri branched off the family tree. Uraraneida did not have spinnerets, but did have structures called spigots that could have excreted silk. As a result, the researchers said they suspect that I. brasieri might have produced silk, too, just without the spectacular weaving abilities that spinnerets allow.

The researchers said they plan to examine other fossils to get a better understanding of the rise of spiders. Very little is known about how spiders and other arachnids, such as scorpions and harvestmen, fit together in a family tree, Garwood said.

"Arachnids as a whole are an incredibly successful group," he said. "They're the most diverse group of living organisms after insects. They're really, really successful — but we have a very limited understanding of how they are related to each other."

Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

Spiders are known as clever predators, trapping and stalking their insect prey. But many species round out their diets with a little roughage.

There are at least 95 recorded instances of spiders eating plant products, according to a new review in the Journal of Arachnology. Spiders chow down on everything from nectar to sap to small fruiting bodies, wrote the study's leader, Martin Nyffeler, a research fellow in conservation biology at the University of Basel in Switzerland, and colleagues.

"Such a large diversity of plant types, plant taxa and plant materials being used as food by spiders is novel," Nyffeler told Live Science.

Even the most plant-loving spiders can't survive on a vegetarian diet alone, the researchers wrote, but spiders might be more resilient in times of food shortages if they eat plant food as well as prey. [See Photos of Amazing Plant-Eating Spiders from Around the World]

Plant food

About 60 percent of reported incidents of spiders eating plants have been jumping spiders (Salticidae), the largest family of spiders. These spiders live all over the world, and their plant-eating behavior has been observed on every continent except for Antarctica (where the spiders don't live) and Europe (where they live but haven't shown their habit of eating leafy greens). In about 75 percent of reported cases, spiders were observed eating nectar, and field tests of spiders have found that 20 percent to 30 percent have fructose in their guts — an ingredient in nectar — the researchers wrote.

For some jumping spiders, getting nectar is a sticky business, Nyffeler wrote in another study published March 6 in the journal Peckhamia. Ants also eat nectar, so spiders have to scurry in when ants aren't present in order to get nectar without a battle. They may also have to outrun or outjump ants if challenged, Nyffeler said. One genus, Peckhamia, even mimics ant behavior to sneak in for a sweet treat.

Nectar is only one portion of the potential spider diet, though. Some spiders bite into leaves to feed on plant sap. The South American spider Anelosimus rupununi has been seen biting into mango leaves in Venezuela to suck the sap, for example. Spiders even eat the solid parts of the plants — though they have to inject small pieces with digestive fluids to liquefy them, just as they do with insects. In particular, a colorful jumping spider from Central America, called Bagheera kiplingi, eats almost exclusively Beltian bodies, which are sugar-rich nubs that grow on acacia plants. 

Even weirder, some spiders feed on honeydew, which is a sugary liquid secreted by insects such as aphids that are also feeding on plants. Two species of jumping spiders, Myrmarachne foenisex and Myrmarachne melanotarsa, have been seen "milking" honeydew from insects called coccids. [Check Out Incredible Photos of Peacock Spiders]

Spiders seem to have all the enzymes they need to break down plant material, the researchers wrote, except for exinase, which breaks down the outer covering of pollen. But some spiders have been seen eating pollen, perhaps by piercing its outer shell. Spiders may also consume pollen, seeds and spores that accidentally get captured in their webs, the researchers wrote.

A balanced diet

About 80 percent of spider plant-eating occurs in warmer regions of the world, perhaps because plants secrete more nectar in warmer spots, Nyffeler and his colleagues wrote. They found evidence of more than 60 plant-eating spider species, but many more species may do the same, they added.

Most spiders cannot survive on plants alone, Nyffeler said. In lab studies, scientists have fed spiders vegetarian diets, like pollen or nectar alone, and have found that the spiders fail to molt or they have stunted growth. A possible exception is the largely herbivorous species B. kiplingi, Nyffeler said. But one laboratory study found that when B. kiplingi spiders were fed only plant matter, they died after a few weeks, too.

Nevertheless, plants may be an important part of the spider diet, Nyffeler said.

"The ability of spiders to derive nutrients from plant materials is broadening the food base of these animals; this might be one of several survival mechanisms helping spiders to stay alive for a while during periods when insect prey is scarce," he wrote in an email to Live Science. "Furthermore, enriching the spiders' diets with plant materials leads to a more diverse diet, a process considered to be advantageous from a nutritional point of view, since diet mixing is optimizing a balanced nutrient intake."

More studies need to be done to understand how different categories of plant food contribute to spider diets, how spiders digest plant foods and how frequent plant-eating is under natural conditions, Nyffeler said.

Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

If you think an erection lasting more than 4 hours is a problem, try one lasting more than 99 million years.

That's how long the penis of a newly discovered arachnid fossil has been standing at attention. The harvestman, a spider relative also known as a daddy longlegs, was encased in amber during the Cretaceous in what is now Myanmar. Its distinctive penis, with a heart-shaped tip and a bit of a twist at the end, was erect at the time.

"It was very surprising to see the genitals, as they are usually tucked away inside the harvestman's body," said Jason Dunlop, the curator of the arachnid, millipede and centipede collections at the Museum für Naturkunde in Berlin, who reported the discovery online Jan. 28 in the journal The Science of Nature. [See Images of the Preserved Harvestman Arachnid with Erect Penis]

Amorous arachnids

Arachnid genitals are varied. Some spiders, for example, have grasperlike pedipalps that they use to pass a sperm bundle to females. Male orb-web spiders can detach their pedipalps and leave them behind inside a mate in order to escape their cannibalistic female sex partners. 

Harvestmen, on the other hand, have extendable penises that are similar to mammal penises. When not in use, these organs are stashed inside the body. [7 Amazing Bug Ninja Skills]

The new harvestman specimen belongs to an ancient species called Halitherses grimaldii. A private collector sent it to Dunlop and his colleagues. Harvestman fossils are rare — only 38 have ever been found, the researchers wrote in their new paper — but harvestman genitals are even more elusive. This is the first amber specimen visibly preserving the structure of the penis, Dunlop told Live Science in an email.

"These penis details (shape, form of the tip, etc.) are very important for saying where this amber species fits in the harvestman family tree," he said. "In fact, we couldn't find an exact match in terms of penis shape with any living species."

As a result, the researchers propose that the spider belonged to a previously unknown (and now extinct) family of harvestmen. The team is investigating several other new species found in Burmese amber, but none of those are preserved with visible genitals, Dunlop said.

An undignified death

The spider penis extends more than half a millimeter from the lower abdomen of the harvestman. The arachnid's round body is about 2 millimeters long and sits atop spindly legs. The glans of the penis is heart-shaped. From it protrudes an additional structure called the stylus, which curves and twists to the right.

There was no female trapped alongside the erect harvestman. It's possible that the arachnid was mating when the amber enveloped him, but that the female was nearby and escaped, or wasn't preserved. Or maybe the erection was no fun at all.

"In harvestmen, the penis is sometimes pushed out by increasing blood pressure," Dunlop said. "Maybe as the animal struggled when it got caught in the sticky tree resin, its blood pressure rose and the penis was pushed out accidentally?"

Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

Scientists have unearthed a monstrous new arachnid lurking in the woods of southwest Oregon — and it's a beast.

The new daddy longlegs species, dubbed Cryptomaster behemoth, towers over other creatures of its kind. And like its cousin, the equally elusive Cryptomaster leviathan, the new species is incredibly difficult to find, because it hides out beneath the logs and leafy debris that blanket the forest floor.

The Cryptomaster leviathan was discovered in 1969 at one location in the coastal town of Gold Beach, Oregon. The mysterious creature belonged to one of the most diverse suborders, called Laniatores, which contains at least 4,100 species. (Daddy longlegs belong to the arachnid order commonly known as harvestmen, so-called because they often emerge during the fall months during the harvest.) [In Images: 4-Eyed Daddy Longlegs Helps Explain Arachnid Evolution]

Though the 0.15-inch-wide (4 millimeters) body of the creature is relatively small compared to that of tarantulas or other arachnids, the daddy longlegs towers over other creatures in its Laniatores suborder. As a result, its discoverers gave it the species name leviathan, after the serpentlike sea creature that prowls the deep in the Bible. The genus name Cryptomaster is a nod to the creature's elusive and reclusive nature.

For 40 years, little else was known about C. leviathan. But in recent years, researchers have found more of these elusive creatures at multiple locations, including some as far off as the Cascade Mountains in southwest Oregon.

That led James Starrett, an entomologist at San Diego State University, and his colleagues to suspect there may be other undiscovered species in the Cryptomaster genus. The researchers set out on an expedition to the region, on a hunt for new Cryptomaster species.

New monster lurking

This hunt led them to the discovery of a completely new daddy longlegs species, also relatively huge, called Cryptomaster behemoth. (The behemoth, like the leviathan, is a biblical beast.) Both have the unusually short legs characteristic of arachnids of the Laniatores order.

One of the main differences between the two species is that C. leviathan sports two teensy, fully erect spines pointing upward on its penis. The purpose of those spines isn't clear.

Interestingly, both the C. leviathan and C. behemoth speciescome in two forms: a larger and a smaller one.

But exactly why remains a mystery.

"The basis for these two forms is unknown — the different forms can be found in both sexes, in both species and from the same localities. Additionally, the two forms are not genetically divergent," the researchers wrote in the paper, which was published online Jan. 20 in the journal Zookeys.

The team also extracted DNA from the legs of multiple animals from each species. Interestingly, the C. leviathan has relatively little genetic diversity, though the creature shows up in a wide range of habitats. By contrast, C. behemoth seems to have a more restricted range, yet has much more genetic diversity than does C. leviathan. The genetic analysis also revealed that the big and small versions of each species don't differ genetically, so some other factor must explain the size difference.

The new species reveal how much genetic diversity can be found within a relatively tiny area, the scientists wrote.

"This research highlights the importance of short-range endemic arachnids for understanding biodiversity, and further reveals mountainous southern Oregon as a hot spot for endemic animal species," the researchers wrote.

Editor's Note: This article was updated to correct James Starrett's affiliation; he is at San Diego State University, not at the University of California, Riverside as was stated.

Follow Tia Ghose on Twitterand Google+. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

It's eight-legged, furry and a very cool shade of cobalt blue. What is it? A tarantula, of course!

While tarantulas aren't normally associated with the color blue, many of these critters have a distinct cobalt hue, which is produced by tiny structures located on the animals' hairy bodies and appendages. Known as photonic nanostructures, the itsy-bitsy structures reflect blue light, turning a creepy-crawly arachnid into something resembling an eight-legged Cookie Monster.

Scientists have known about the tarantula'slight-scattering hairs for some time, but a recent study took a closer look at the nanostructures that make so many spiders in the family Theraphosidae appear blue. The study found that the blue-reflecting nanostructures are unlikely to have evolved as a result of sexual selection, which is often responsible for the bright colors that distinguish closely related species. (The vividly colored peacock spiders provide an excellent example.) [Goliath Birdeater: Images of a Colossal Spider]

Tarantulas, on the other hand, are largely nocturnal and they don't appear to use their coloration for mating purposes, the researchers found. Instead, the scientists hypothesized that the tarantula's blue hue may be a result of natural selection. In other words, being blue helps certain tarantula species survive in their environments.

To back up this hypothesis, the new study notes the presence of blue-reflecting nanostructures across many species of tarantulas that are not closely related. And these nanostructures are quite distinct from one another (i.e., they don't look the same under a microscope) in various genera of tarantula, a finding that suggests  the structures developed independently many times over the course of the tarantula's long evolution, said study lead author Bill Hsiung, a postgraduate student in biology at the University of Akron in Ohio.

Why so blue?

To learn more about the tarantula's coloring, Hsiung and his colleagues first looked at digital images of the critters to create a phylogenetic tree— a chart that shows the evolutionary relationships between related species. They charted the evolutionary history of tarantulas from 53 genera (the family Theraphosidae contains more than 100 genera in total) and found that at least 40 of these genera had almost the exact same blue coloration. By contrast, only 12 genera of tarantulas were found to have green coloring.

"These blues are so specific. They're pretty much the same hue. I think this wavelength was selected specifically for communicating with potential predators or prey — though we don't know that," Hsiung told Live Science. Ecological studies of tarantula behavior will need to be conducted to confirm that hypothesis, he added.

But why blue, specifically? If a tarantula can use its nanostructures to appear blue, then presumably it could also use similar nanostructures to appear to be a different color — like yellow or green, the scientists said. Yet green, in particular, is not this critter's color of choice. Blue-reflecting nanostructures, on the other hand, evolved independently at least eight times in different species, the researchers found.

This preference for blue could be a result of the tarantula's typical habitat. They often live on the floor of rainforests and other heavily vegetated areas, where the light spectra consist mostly of green colors, Hsiung said.

"If they were green, and the predators and prey in their environments evolved to see green and are very sensitive to the green spectrum, then the [tarantulas] would appear very bright," Hsiung said. "And being too bright in an environment is not a good thing. Maybe blue is a good trade-off — different enough from the background to be seen, but not too bright."

Structural differences

After sorting dozens of tarantula images, Hsiung and his colleagues decided to get their hands on a few live specimens. The researchers obtained eight blue tarantulas that are indigenous to distinct geographic locations, including Singapore, India, Chile and Brazil. They examined the creatures' light-scattering photonic nanostructures, or "structure colors," using high-powered microscopes. What they found surprised them. [Photos: The World's Creepiest Spiders]

"We discovered not just one kind of nanostructure but at least two or three different kinds of nanostructures that produce the same blue colors," Hsiung said. "Previously only one kind of nanostructure had been recorded as producing blue color in tarantulas, but we found that there are other types."

Structure colors like those of the blue-hued tarantulas are not uncommon in nature. Many species of birds and insects also get their colors from nanostructures, rather than the pigments that color the hair and skin of many animals (like humans). However, the tarantula's structure color differs from those of birds and bugs in an important way — it isn't iridescent. That is, the spider's blue color doesn't seem to change when you look at it from different angles.

"These blues have this low iridescence to them, so they're very consistent in their appearance as you look at them from different angles. That's pretty unusual for structural colors," Todd Blackledge, a biology professor at the University of Akron and one of the co-authors of the new study, told Live Science.

The iridescence of structure colors is a problem for those who want to use these light-scattering structures in the real world, Blackledge said. Photonic nanostructures could be used to color things like electronic screens and even clothing, but only if the iridescent properties can somehow be tamed. (A tablet screen that constantly changes colors just won't cut it.)

And taming structural colors is something that Hsiung is very interested in doing. These nanostructure-produced colors offer several advantages over colors created by pigments, Hsiung said.

"Structure colors are usually brighter, and [they] won't fade over time as long as their nanostructures are still intact. These are advantages that people want to use to make color displays for phones, or pigments you can use in your cosmetics or in your clothes. Iridescence is a big constraint in those applications because we usually don't want color to change when we change our viewing angle," Hsiung said.

The tarantula's blue hues could inspire new, non-iridescent structure colors, according to Hsiung, who noted that these colors would not only be brighter and less likely to fade than pigment-based colors, they'd also be better for the environment.

"We can decrease waste and use more eco-friendly materials to produce structure colors, unlike the current dyes [used to make pigments]," Hsiung said.

To produce different structure colors, researchers just need to change the spacing between one nanostructure and the next (which changes the way the structures scatter and absorb light). Producing different pigments is a totally different process in which an entirely new material must be made for every color you want to create, Hsiung said. And sometimes, the materials used to make the pigments that color fabrics and other materials are toxic, he added.

But don't expect to buy a pair of nanostructure-colored bluejeans anytime soon. Hsiung said the structure colors of the future are still too cutting edge to be economically viable for consumers. But the tarantula study brings researchers a step closer to harnessing the power of these tiny light-reflecting formations, he said.

The tarantula study was published Nov. 27 in the journal Science Advances.

Follow Elizabeth Palermo @techEpalermo. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

In a deep, dank cave in Brazil, a pale, blind creature lurks, never venturing out to feel the sun.

No, it's not a monster; it's Smeagol (SMEE-guhl), or Iandumoema smeagol, a newly discovered species of arachnid named for the infamous, goblinlike character (also known as Gollum) from the "Lord of the Rings" trilogy. But I. smeagol isn't a hobbit gone haywire — it's a harvestman, or a member of the Opiliones order of arachnids. Researchers recently found the creature in its underground lair, a limestone cave in southeastern Brazil, and described it for the first time today (Nov. 18) in the journal ZooKeys.

You may know harvestmen as "daddy longlegs," those spiderlike critters that crawl all over the yard during the summer months. But harvestmen aren't spiders and are more closely related to other arachnid orders, such as Solifugae (camel spiders) and Scorpionida (scorpions). [Images: 4-Eyed Daddy Longlegs Help Explain Arachnid Evolution]

Scientists have discovered several species of harvestmen that make their homes underground. (It's a good place to hide out if you don't possess an invisibility-inducing ring like in "Lord of the Rings.") But I. smeagol is the only known harvestman in the genus Iandumoema that is completely eyeless, and therefore completely blind.

The arachnid's blindness is an example of troglomorphism, or a physical adaptation that results from living in the constant darkness of caves. Troglomorphisms such as blindness and loss of pigment are observed in many species of cave-dwelling animals, such as the olm (Proteus anguinus), a pale, eyeless salamander that inhabits the limestone caves of southern Europe.

Like the olm, the Smeagol harvestman has a pale yellowish coloring, a result of its reduced amount of melanistic pigmentation (the pigments that give terrestrial species their darker hues). In 2008, another team of researchers discovered a similar-looking harvestman in the limestone caves of Minas Gerais, a state in southeastern Brazil (the same state where the new Smeagol harvestman was discovered). But unlike I. smeagol, the cave-dwelling species I. setimapocu has a pair of pale-colored eyes.

What really sets I. setimapocu apart, however, is the creature's elongated, spindly legs. This harvestman's name means, roughly, "long legs" in the language of the indigenous Tupi people of Brazil, and some of its legs are nearly 1.5 inches (3.8 centimeters) long. However, the Brazilian arachnid's lengthy appendages are stumpy when compared to those of certain harvestman species in other parts of the world. A cave-dwelling harvestman in Laos, for example, has legs that measure more than 13 inches (33 cm) long. Extra-long legs are another adaptation to life underground that may help these critters feel their way around in the dark.

The Smeagol harvestman is just one of the various many-legged critters newly described by cave-exploring scientists this year. In June, a group of researchers in Croatia stumbled upon a species of centipede with 33 pairs of legs, Geophilus hadesi, which they named for Hades, the mythological god of the underworld.

Follow Elizabeth Palermo @techEpalermo. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

Photographers and researchers from around the world are teaming up to share spectacular (and sometimes skin-crawling) photos of one of Halloween's most popular mascots: spiders.

But even if they're not your favorite animals, spiders do capture the spirit of the season, and these eight-legged beauties happen to be very cooperative models, according to the folks who started Arachtober, the group devoted to sharing spider-themed photos on social media.

Arachtober started in 2007 as a friendly exchange between two Flickr-using macrophotographers, Joseph Connors IV and Ashley Bradford. (Macrophotography is the art of capturing magnified images on film.) Both Connors and Bradford happened to have a lot of spider pictures saved up, and they figured October, the month of Halloween, would be a good time to share the photos with their followers on Flickr. [Arachtober in Action: Amazing Photos of Spiders from Around the World]

The photographers began by posting a spider picture each day during the week of Halloween, but they quickly realized they had enough photos of arachnids to post a spider photo each day for the entire month of October. And with that, Arachtober was born. (The name came from another Flickr-using spider lover, Jenn Forman Orth.)

"We haven't done much to promote the group's existence, so in the early days [of the group], most new members [of the Flickr group] were friends with another member. This helped build a very friendly group of people from around the world," Connors and Bradford told Live Science in an email.

Over the past eight years, the group has steadily gained more followers, and it got a leg up from entomologist and Wired.com contributor Gwen Pearson (also known as @bug_gwen on Twitter) in 2013, when she wrote a few articles that mentioned Arachtober.

Now, what was once an itsy-bitsy Flickr group with just four members has grown to include more than 160 spider groupies. This year, the group has also gained traction on Twitter, where spider lovers are keeping up the tradition of posting a photo a day of an arachnid, accompanied by the hashtag #Arachtober.

#SpidersRule

Sean McCann, a field researcher at Thompson Rivers University in British Columbia, Canada, and a professional macrophotographer, is one of the people contributing photos to #Arachtober this year via Twitter. His reasons for doing so mesh with the original purpose of the group, which Connors and Bradford said was to "have fun" and hopefully raise awareness about the awesomeness of spiders. [5 Spooky Spider Myths Busted]

"I think sharing on social media can inspire people to think about the wonderful diversity of life we have all around us, even in the city, and perhaps that inspiration can lead to some change in their outlook," McCann told Live Science in an email. Specifically, McCann said he hopes his photos get more people out into nature to "appreciate the living world."

Catherine Scott, a postgraduate student in the Department of Behavioral Ecology at the University of Toronto, Scarborough in Canada, has also jumped on the #Arachtober bandwagon. She thinks October is a great time to appreciate spiders, because they are abundant this time of year in North America.

"It's also the month of Halloween, so it's a great opportunity to try to shift from spiders being spooky and scary to spiders being beautiful and fascinating," Scott told Live Science in an email.

Changing the conversation about spiders is something Scott focuses on all year long. Many of her tweets focus on spider behavior and ecology, with an aim toward dispelling common myths about these animals. She thinks spiders' reputationas venomous threats to humans is "unfortunate" and "undeserved," though she admits that, before she started working with the eight-legged critters, she was a bit afraid of them.

"Knowledge quickly shifted my fear to fascination, and I hope that by sharing knowledge about spiders, others can experience the same switch," Scott said.

Bradford described a similar conversion that occurred when she started working up close with spiders — an experience she said helped her get over the reaction a lot of us have of feeling "creeped out" whenever a spider is around.

"Once I could see how varied they are, how beautiful or even cute some of them can be, and I could watch their movements through that macro lens, they became something to admire rather than fear," she said. "So I admire them with my camera and then share those images, hoping that others will see what I see and admire them, too."

If you don't believe that spiders can be adorable, just have a look at the oh-so-charming peacock spider, Maratus personatus, whose mating dance must be seen to be believed.You can also check out the many other beautiful spiders of the world on Arachtober's Flickr page or by searching the #Arachtober hashtag on Twitter.

Follow Elizabeth Palermo @techEpalermo. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

It's October, and for photographers on the photo-sharing site Flickr that can mean only one thing: It's the perfect time to share amazing pictures of spiders! Members of the Arachtober group have been posting their best spider shots on the site for eight years, and this year some members have also begun sharing their photos with the hashtag #Arachtober on Twitter. Here are some of the coolest shots of the eight-legged critters from the photographers and researchers who participate in this yearly photo exchange. [Read the full story about Arachtober]  (All photos used with permission.)

Halloween Weaver

Tropical orb-weaver, Eriophora ravilla

"This species is very common where I live [in Texas], so I end up taking many photos of them. Females can reach an inch long with webs that can span several feet. My dad got a surprise one morning when he nearly walked into one that had been built across the doorway overnight. There is a lot of variety in the coloration and pattern of this species. They are also much more colorful when they are young, often having a bright green patch on their abdomen. It took me a long time to realize those were the same species. Happy Halloween!" [Credit: ©Joseph Connors IV]

(Egg)cellent Shot

Silver Argiope, Argiope argentata

"I watched these guys' mother for three months in my backyard. She never moved her orb web more than a few feet. In that time, I saw her regrow two missing legs, which can be done when spiders molt. She produced a number of egg sacks, so I got to see new babies several times. Spider babies are one of my favorite subjects. They are really cute at around 2 millimeters [0.08 inches] each. As adults, the females can measure over an inch long." [Credit: ©Joseph Connors IV]

Bright Green Jumper

Green lynx, Peucetia viridans

"Because of their bright green color, I really enjoy finding these. When I do, they are generally quite cooperative subjects. They are often found blending in on green leaves. These spiders hunt during the day by jumping at their prey. They are found in the southern United States down through Central America." [Credit: ©Joseph Connors IV]

Excellent Subject

Golden silk orb-weaver, Nephila clavipes

"Commonly known as the 'banana spider,' this species helped get me into nature macro photography because they are excellent subjects. They are large, colorful, easy to find and mostly hold still for photos. Their webs can span several feet. They are found in the southeastern U.S. as well as Central and South America." [Credit: ©Joseph Connors IV]

Camouflage Crabs

Crab spider, family Thomisidae

"These spiders can be found worldwide, and are probably the type I most often find. They do not build webs, but instead wait to ambush prey, often on flowers. Their colors and patterns vary and usually provide great camouflage; some species can even change color over several days. When I can find one on a flower with contrasting color, that can make a great photo." [Credit: ©Joseph Connors IV]

Spitting Skulls

Spitting spider (Scytodes sp.)

"Unlike most spiders, these only have six eyes, which makes their faces look like skulls to me. Their common name comes from their method of catching prey by spitting sticky venom. I have never been spit at, but I read they can spit more than 10 times their body length (so maybe a few inches). I always find them on vinyl siding at my grandparents' house [in Louisiana], living between the slats. They come out to hunt at night." [Credit: ©Joseph Connors IV]

A Scary Surprise

Southern black widow, Lactrodectus mactans

"Found in a web at the bottom of a friend's shower curtain in Alexandria, Virginia. He knew I like photographing spiders, so he gave her to me. I was nervous to have her out, free on my table, but then I found she moved slowly. I learned that black widows have very poor eyesight, and so they don't care to wander much. They find a corner they like, set up house and stay there." – Ashley M. Bradford [Credit: ©Ashley M. Bradford]

Marbled Wonder

Marbled orb-weaver, Araneus marmoreus

"I regularly stalk the woods of Huntley Meadows Park [in Fairfax County, Virginia] with my camera, and spotted this bright beauty between two trees near the beginning of a boardwalk leading out into wetlands. She's a richly colored adult female of the species, and her orange and black legs make me think of Halloween." – Ashley M. Bradford, [Credit: ©Ashley M. Bradford]

Jolly Green Jumper

Magnolia green jumper, Lyssomanes viridis

"After years of seeing photos of these and thinking they must be some exotic tropical species, I was surprised to start finding them right in my own backyard. This one is a tiny juvenile, and as you can imagine, they blend in well with foliage. They are jumping spiders, which hunt on foot rather than making webs. Their eyesight is better than other species', and they tend to look right at you when they notice you notice them, making for photographs like this one." – Ashley M. Bradford [Credit: ©Ashley M. Bradford]

Smiley-Faced Wanderer

Orchard orb-weaver, Leucauge venusta

"Another one found at my local park and wetlands. These spiders are common throughout the entire eastern half and into the center of the U.S. — from up into Canada to down in Florida. They are a beautiful green color, and their silvery abdomens have pretty patterns of yellow, green and red. The red markings are distinctive, forming a smiley face on the bottom, visible even on the smallest young." – Ashley M. Bradford [Credit: ©Ashley M. Bradford]

Feisty Fellow

Jumping spider, Habronattus agilis

"I found this feisty fellow on a wooden railing near the shore. You can tell he's an adult male because he has 'boxing gloves' – those are his palps [or pedipalps]. On juvenile and female spiders, the palps are thin, looking like a pair of small legs. As with most other jumping spiders, he was very attentive to my presence." – Ashley M. Bradford [Credit: ©Ashley M. Bradford]

Tiny Surprise

Cobweb spider, Theridion frondeum

"I was surprised to find this exotic-looking spider right in my own suburban backyard and immediately brought her in for a photo shoot. She's in the same family of spiders as both the harmless common house spider, as well as the infamous black widow. They are all cobweb spiders, which means they build a messy and disorganized web." – Ashley M. Bradford [Credit: ©Ashley M. Bradford]

Stunning Jumper

Jumping spider, Habronattus americanus

"I think my favorite spider image that I have shared so far is this picture of Habronattus americanus — just a stunning little jumping spider found in western North America. It is a gorgeous animal, and definitely as pretty as the peacock jumpers of Australia. If people realize they can find these things almost in their backyards (I found this one at a regional park near Victoria, B.C., in Canada), well, that has got to be some motivation to go out and explore!" — Sean McCann [Credit: ©Sean McCann]

Twiggy

Long-jawed orb-weaver, family Tetragnathidae

"After a long photo session this long-jawed orb-weaver decided she'd had enough of me and tried to hide by becoming another twig on this branch. Is it just me or do these creatures totally resemble a squid when they fold up their long legs like this?" — Scott Tucker [Credit: ©Scott Tucker]

Secret Hideout

Hent's orb-weaver, Neoscona crucifera

"This weaver had a nice web below. She retreated to this leaf on my pear tree [outside of Denver, Colorado] to hide." — Scott Tucker [Credit: ©Scott Tucker]

Rainbow Spinner

Orb-weaver

"When I was shooting this I saw the translucence of the backlit spider, and the rainbow silk was a bonus from the morning sun backlighting its web." — Scott Tucker [Credit: ©Scott Tucker]

The Lair

Grass spider, Agelenopsis sp.

"Just behind this beauty is her cave in this leaf. Moments later she shot back in there." — Scott Tucker [Credit: ©Scott Tucker]

Jumpy Little Guy

Bold jumping spider, Phidippus audax

"This bold jumping spider was elusive, to say the least. Every time I got close enough to try and shoot macro he went undercover. Amazingly, he was sharing these same leaves as territory with a long-jawed orb-weaver — that could have been the reason he was so skittish. (Fall color backdrop compliments of nature.)" — Scott Tucker [Credit: ©Scott Tucker]

Guardian of Rainbows

Orb-weaver, Metellina segmentata

"This is an orb-weaver type spider. The species is Metellina segmentata, and this is a female sitting in the center of her perfect orb web [in County Down, Northern Ireland]. I love how these spiders give the photographer an opportunity to take a picture of a natural history subject next to the abstract image that the web makes in the low angle sun." — Conall McCaughey [Credit: ©Conall McCaughey]

Sunlit Spider

Sheet web spider, (possibly) Linyphia triangularis

"I love to get the morning sun behind the web and find some colored rainbows due to the refraction of the sunlight in the spider silk strands." — Conall McCaughey [Credit: ©Conall McCaughey]

Spider Selfie

Crablike spiny orb-weaver, Gasteracantha elipsoides

"I didn't know I had also taken a selfie until I pulled up the image on my computer…this is a female crablike spiny orb-weaver. They are about 0.38 inches (8-10mm). She will spin a new web every evening and stand head downward near the center. The male is much smaller at 0.06-0.12 in. (2-3mm)." [Credit: ©Mary Wolf]

Pink-Toed Beauty

Pinktoe tarantula, Avicularia avicularia

This pinktoe tarantula is native to Central and South America but can commonly be found in pet stores. The photo comes from Daniel Thombs, an Arachtober member who typically photographs native species in Rhode Island, in the northeastern United States. [Credit: ©Daniel Thombs]

Center of Attention

Orb-weaver

"Orb-weavers create perfect spiral webs, but the centers are often in a geometric pattern for stability. This is a very young spiderling, so it appears to be about the same size as the center [of the web], which is often small in itself." – Daniel Thombs [Credit: ©Daniel Thombs]

Big Appetite

Cobweb spider, Theridon sp.

"[The cobweb spider] generally lives under some form of protection and creates sticky, erratic webs rather than the perfectly flat, ornate ones of the orb-weavers. In this web, it managed to catch a fly many times larger than itself." – Daniel Thombs [Credit: ©Daniel Thombs]

Scallywag Spider

Pirate Spider, Mimetus notius

"[The pirate spider] occurs near (and eats) other spiders — primarily cobweb and orb-weavers, since they stay put and aren't travelers like wolf spiders, crab spiders, etc." – Daniel Thombs [Credit: ©Daniel Thombs]

Trashy Arachnid

Trashline orb-weaver, Cyclosa conica

Trashline orb-weavers like this one reuse the bodies of their prey to camouflage themselves on their webs. More information about these savvy spiders can be found on Bug Eric, the blog maintained by entomologist Eric R. Eaton. [Credit: ©Daniel Thombs]

Crossing Paths

Cross spider, Araneus diadematus

"Saw this one outside around 8 p.m. and knew I had to try and get a shot." – Daniel Thombs [Credit: ©Daniel Thombs]

Action Shot

Dimorphic jumper, Maevia inclemens

A jumping spider takes on an unfortunate fly. [Credit: ©Daniel Thombs]

Follow Elizabeth Palermo @techEpalermo. Follow Live Science @livescience, Facebook & Google+.

Most people likely wouldn't react well to being surprised by a venomous spider, but recently, scientists at Booderee National Park, on the southern coast of Australia, were excited when a highly venomous funnel-web spider showed up unannounced.   

Many species of funnel-web spiders, named for their funnel-shaped webs, are indigenous to Australia, but only one of these species, the Sydney funnel-web spider, is known to live in Booderee National Park.

Sydney funnel-webs (Atrax robustus) are ground-dwelling spiders with highly venomous bites that, before the development of an anti-venom, posed a serious medical risk to humans. Funnel-webs, including Atrax robustus, were believed to be responsible for at least 13 deaths in Australia before the anti-venom became available, in 1981. [Creepy, Crawly & Incredible: Photos of Spiders]

But the spider found along Australia's southern coast by scientists from the Australian National University (ANU) wasn't Atrax robustus. In fact, it might be a brand-new species of funnel-web spider, said Thomas Wallenius, a biologist at ANU's Research School of Biology and one of the scientists who uncovered the arachnid.

"It's remarkable that we have found this other species in Booderee National Park. It shows we still have a lot to learn about what's out there in the bush," Wallenius said in a statement.

The nearly 2-inch-long (50 millimeters) specimen is fairly large for a funnel-web spider, the researchers said. And unlike the Sydney funnel-web, this critter lives inside of fallen trees, not in underground burrows. This suggests that the newfound spider belongs to the genus Hadronyche, which consists of funnel-web spiders that are saproxylic, or dependent on dead or decaying wood for survival.

When Wallenius found the spider, it was burrowed in its "lair," a long web inside of a rotten log. 

"They build a silk-lined burrow inside the hollow log, which can be up to 2 meters [6.6 feet] long. She had probably been living in there for 25 to 30 years," Wallenius said.

That's right: Funnel-web spiders aren't just potentially deadly; they also live for an eerily long time. A study presented at the 22nd International Congress of Entomology in 2006 states that captive funnel-web spiders have a maximum life span of two decades.

The discovery of the (perhaps) previously unknown species of funnel-web spider comes on the heels of another exciting finding by ANU researchers. Last week, an ANU biologist discovered a rare, red-fanged funnel-web spider belonging to the species Atrax sutherlandi in Australia's Tallaganda State Forest. This area, like Booderee National Park, is located in the southeastern state of New South Wales. 

ANU ecologist Mark Wong uncovered the red-tinted arachnid while searching for funnel-web spiders under a rotting piece of wood.

"Almost instantly, the spider had rushed out of her silken lair with her legs raised and fangs greeting me with glistening venom," Wong told Live Science in an email interview last week. "Taken aback by her colors, I knew there and then this was something special."

While some members of the A. sutherlandi species have a bit of red tint on their bodies, this was the first time Wong and his fellow researchers had observed a specimen with red fangs.

The discovery of both the blood-hued funnel-web spider and its cousin, the log-dwelling spider in Booderee National Park, are part of a large study of biodiversity in New South Wales. The state is also home to many species of peacock spiders, which are much less venomous than funnel-web spiders, and arguably a whole lot cuter (some of them even dance).

Follow Elizabeth Palermo @techEpalermo. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

Like a mindless zombie controlled by a menacing overlord, the spider scampers back and forth, reinforcing its silky web. Not long from now, the subservient arachnid will be dead, its web transformed into a shelter for the spawn of the creature that once controlled it, according to a new study.

No, this isn't science fiction; it's the somewhat terrifying (but very real) tale of the orb-weaving spider Cyclosa argenteoalba and the parasitic wasp Reclinervellus nielseni, two species that carry out a strange relationship in Hyogo prefecture, Japan.

Together, the wasp and the spider provide a perfect example of host manipulation — an ecological process in which one species (the parasite) and its young (the parasitoids) manipulate the behaviors of another species (the host) to their advantage. [Zombie Animals: 5 Real-Life Cases of Body-Snatching]

Just how a parasite turns its host into a zombielike slave varies from species to species, and sometimes, researchers aren't sure what the mechanism is that makes a host do its parasite's bidding. That's the case for the orb-weaving spider and parasitic wasp of Japan. Researchers in that country want to find out how R. nielseni controls C. argenteoalba. Does it use a neurotoxin, or perhaps some kind of hormone?

But to solve that mystery, scientists first need to answer another question: What, exactly, does the wasp make the spider do?

Walking dead

The manipulative relationship between the wasp and the spider begins when a female wasp attacks the orb weaver in its web. She deposits her egg onto the back of the spider's abdomen but doesn't kill it. Firmly attached to the spider, the egg develops into a larva, which eventually does kill its host, but not before the spider serves it as a slave throughout the early stages of development, said Keizo Takasuka, a postdoctoral fellow at Kobe University's Graduate School of Agricultural Science in Japan and lead author of a new study exploring the relationship between R. nielseni and the orb weaver. [Watch the Zombie Slave Spider Do the Wasp's Bidding (Video)] 

Over the past several years, Takasuka has headed to the Shinto shrines of Hyogo prefecture to collect spiders enslaved by the parasitic larvae of R. nielseni.

"I looked for already-parasitized spiders in shrines … because the spiders prefer to construct webs particularly in artificial structures and stone materials," Takasuka told Live Science in an email. He's not sure why the spiders prefer the shrines, but he said these arachnids can also be found in other habitats.

In the lab, Takasuka and his colleagues observed the behaviors of the parasitized spiders — mainly the precise way in which the arachnids built their webs — and then compared this behavior with that of orb-weaving spiders that weren't controlled by parasitoids.

The zombie slave spiders tended to build a particular kind of web, one that was quite different from the webs created by parasitoid-free spiders, the researchers found. First, the parasite-ridden spiders took apart their old webs (some even abandoned them altogether), and then they started building new ones that resembled the web an orb weaver would build if it were about to molt, or shed its exoskeleton (something spiders do in order to grow).

Rest in peace

Known as a "resting" web, the pre-molting web is distinct from the spiral-shaped web the spider usually weaves to catch prey. When molting, the spider is soft-bodied, vulnerable and unable to eat. So it stays huddled in the center of the resting web, which has no "capture" areas to snag prey but is instead outfitted with fibrous thread decorations (FTDs), which are strands of silk meant to make the web stand out. [Goliath Birdeater: Images of a Colossal Spider]

You might think that spiders would want to keep their webs inconspicuous, but a molting spider's web is under constant threat from flying birds and other, larger animals. If the web is visible to these animals, they will be less likely to crash into it, and the spider will be more likely to survive the molting process. With that in mind, the spider adorns its home with extra strands of ultraviolet (UV) light-reflecting silk, which passersby are not likely to miss.

The resting web, a safe haven during times of transformation, is the perfect place for a wasp larva to transition into the pupal phase (the stage of transformation in which the insect envelopes itself in a cocoon). An orb weaver's resting web can keep its occupant safe for about two days, which is how long it typically takes the spider to molt. But a web that lasts only two days isn't going to cut it for R. nielseni, which needs to remain ensconced in the spider's web for at least 10 days once it has wrapped itself up in a cocoon.

"[The] cocoon web has to endure falling debris, the elements and animal strikes for a long time — at least four to five times longer than [a] resting web," Takasuka said.

That's why R. nielseni doesn't just direct its host to build a resting web; it instructs the spider to build a superstrong resting web, one chock-full of reinforced threads that hold the web — and the wasp-filled cocoon at its center — in place for long stretches of time, the researchers found.

Using a tensile machine, Takasuka and his colleagues tested the breaking forces (how much force a material can handle before breaking) of the radius and frame silks used to construct a so-called "cocoon" web and found that they were at least 2.7 times greater than the breaking forces of the silks that made up both the orb and the resting webs of C. argenteoalba.

Horrifying hormones

When a zombie spider is finished doing its parasitoid's bidding, it returns to the center of the web, but its ordeal is far from over. With its UV light-reflecting, reinforced shelter in place, the wasp larva no longer needs the spider, so it slaughters it. After chucking the spider's corpse off the web, the larva spins itself a comfy cocoon and hunkers down for nearly two weeks to complete its metamorphosis.

The parasitic wasp's ability to manipulate its host in such a specific and subtle way is not unique. In Costa Rica, another parasitic wasp, Hymenoepimecis argyraphaga, ups the horror by depositing its eggs inside of its host arachnid (Plesiometa argyra), which builds a cocoon-worthy web before being consumed from the inside out by larvae.

And, in Brazil (as well as other countries), there are fungi that infect many species of ants, turning these insects into a host of zombies. The ants climb to the highest point they can find and then die as fungal stalks shoot through their skulls, dispersing the fungus' spores into the wind.

In the case of the fungi-entranced ants, scientists know that the fungi actually release a cocktail of chemicals into the ants' brains, inducing them to do the fungi's bidding. But entomologists are still actively studying the ways that wasps and other insect parasites might control their hosts.

Takasuka suspects that, in the case of R. nielseni and C. argenteoalba, the mechanism controlling the spider's web-strengthening preferences is somehow related to the hormone that is naturally released in the spider just before molting. This hormone is what motivates the spider to start building a resting nest. In the near future, Takasuka hopes to study the chemicals present in the larvae to determine how those chemicals might be related to the resting-web hormone and others.

The researchers' study was published today (Aug. 5) in The Journal of Experimental Biology.

Follow Elizabeth Palermo @techEpalermo. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

This story was updated at 3:12 p.m. ET.

If you don't think spiders are super-cute, then you've probably never seen Maratus personatus perform its very elaborate, oh-so-adorable mating dance.

The males of this newly described species of peacock spider get seriously groovy when wooing lady spiders, and, luckily for arachnophiles, one biologist thinks their dance moves are worthy of recording (and then setting to funky music). Jürgen Otto, a mite biologist and peacock spider enthusiast at the Australian Department of Agriculture in Sydney, maintains a YouTube channel devoted to sharing the mating dances of these spiders in a way that even arachnophobes can appreciate.

Otto's most recent YouTube video features the leg clapping and pedipalp shaking of one M. personatus, or Blueface peacock spider — a species first discovered back in 2013. Otto and his colleague, David Hill, a spider researcher in South Carolina, described this little critter for the first time last week (July 28) in the open-access journal Peckhamia. [See Incredible Photos of Peacock Spiders]

There are a lot of reasons why M. personatus could be called cute. For one thing, it's tiny. Males are only about an eighth of an inch long (they range in size from 0.15 to 0.18 inches, or 3.84 to 4.59 millimeters). Then there's the whole superhero mask thing they have going on; males have a blue band encircling their heads that contrasts nicely with the black-and-white stripes lining the rest of the body.

Add to all that some big, bulbous eyeballs and what you get is a spider that anyone could love. It also doesn't hurt that Blueface is so small that its fangs can't pierce human skin, rendering it completely harmless to humans, Otto told Live Science in an email. However, if the spider's appearance doesn't win you over, its dance moves certainly will.

To get a female to notice him, a Blueface male raises one set of legs over his body while scuttling back and forth in front of his love, Otto and Hill found in their study of the newfound spider. The male's front appendages, or pedipalps, move rapidly as he tries to enchant the female with his slick moves. Unlike some peacock spiders, M. personatus doesn't resort to belly dancing (otherwise known as fan extending) to get the girl. If his dance doesn't attract a female, he has his attractive coloring — which is also meant to help him lure the ladies — to fall back on.

But the elaborate mating dances of peacock spiders aren't just cute: They're downright incredible, Otto told Live Science in 2013.

"People associate complex behavior usually with large animals, usually vertebrates [animals with backbones], so it is very unexpected to see a similar behavior in much smaller invertebrates, in particular spiders that most people hate so much," Otto said in the Live Science interview.

The biologist said he first became interested in recording the behaviors of these spiders after hiking in bushland near Sydney, where all eight of the 40 known species of peacock spiders live (the other species are endemic to other parts of Australia). Otto was surprised by the nimbleness with which the small spiders jumped. It wasn’t until later that he learned of their awe-inspiring mating rituals and decided that someone ought to film them.

Earlier this year, Otto co-authored a report describing two more species of peacock spiders, Maratus jactatus and Maratus sceletus. Nicknamed Sparklemuffin and Skeletorus, respectively, these two colorful arachnids exhibit some pretty awesome dance moves of their own. A male Skeletorus even adds a little something extra to the courtship dance — he flexes a leg as if showing off his muscles, Otto told Live Science in February.

Editor's Note: This story was updated to correctly list the number of known peacock spider species as 40 (including Blueface) and to acknowledge that only eight of these species reside in the bushland near Sydney.

 Follow Elizabeth Palermo @techEpalermo. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

Spiders can dance on water like tiny ballerinas pirouetting across a slippery stage. But unlike a ballet, this arachnid dance routine isn't just for show, a new study finds.

Researchers discovered that spider dancing (also known as spider sailing) is a part of the "ballooning" process — a popular method of transportation for many species of spiders. When ballooning, spiders typically climb to the top of a plant, stick their spinnakers into the air and shoot out a long strand of silk, which catches a breeze and hoists the silk (and the spider) into the air.

But unlike a person riding in a hot air balloon, a ballooning spider has no control over the route it takes or the spot where it touches down. And sometimes, it lands right on top of a body of water. Previously, researchers assumed a ballooning spider that landed on water was a lost cause, according to study lead author Morito Hayashi, team leader of the zoology department at the Natural History Museum of London. [See photos of spiders "sailing" and "dancing" on water]

"We thought that if terrestrial spiders landed on water it was very unlikely that they'd be able to balloon [again], and they'd all die," Hayashi told Live Science. "But now we have to change that idea, because they actually can disperse across the water."

To find out more about how the spiders stay afloat, Hayashi and his team examined 325 adult spiders belonging to 21 different species. All of the spiders had "water-resistant legs" that allowed them to get wet without sinking below the watery surface. While each species had its own signature dance routine, the researchers found that all species tended to use a series of six different postures to stay afloat and move across the surface of the water.

One of these postures was "sailing," in which the spider reacted to a gust of (artificial) wind by raising its legs up like sails. Sailing spiders were able to slide over the water without creating any turbulence, the researchers found.

"The movement is very smooth. It's almost like they're skating on the water," Hayashi said.

Other spiders take a different approach to sailing, raising their abdomens into the air like sails. This pose makes it look as though the sea-worthy spider is doing a handstand on top of the water, Hayashi said.

Some spiders performed a move that the researchers call "anchoring," in which the critter releases silk onto the surface of the water to slow itself down or to stay in one spot. Spiders that wanted to "come ashore" also used anchors, attaching silk to floating objects and then walking across the silk until they reached their new floatation device. [Creepy, Crawly & Incredible: Photos of Spiders]

These postures, and several others, help stranded spiders stay alive, the researchers said. And that's a very good thing, not just for the spider, but for the entire ecosystem that the spider inhabits, according to Hayashi, who said that many of the species that exhibit these water-dancing behaviors play an important role as predators in their respective environments. This predatory role becomes even more essential when a spider is one of the first creatures to inhabit an environment (for instance, a newly burned forest or the land surrounding a recently erupted volcano).

"Spiders are the first colonizers among animals coming to a new or newly created habitat. They come very quickly and become the top predators," said Hayashi, who explained that such predators are needed to control the populations of insects that also typically colonize such habitats. 

The study explains how spiders have been able to colonize such places, even when it means crossing a body of water, according to Todd Blackledge, abiology professor at the University of Akron in Ohio, who was not involved in the study.

"Their insights are a nice example of how keen observation of natural history combines with science to [help us] learn about the natural world," Blackledge told Live Science in an email. "There is still a huge element of risk and randomness involved but these behaviors provide spiders with much better control over their dispersal than we knew about before."

Blackledge also said that he has observed spiders propelling themselves across the water over "quite long distances." However, it isn't yet clear just how long a spider can keep sailing over a body of water, said Hayashi, who noted that he and his team are trying to answer that question now.

The researchers are also exploring whether or not sailing spiders are affected by the saltiness of the water. If they're not bothered by salt water, then it's possible that these remarkable arachnids could quite literally sail the high seas.

The study was published today (July 2) in the journal BMC Evolutionary Biology.

Follow Elizabeth Palermo @techEpalermo. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

You probably already knew that spiders are extraordinary creatures when they're on land. But a new study finds that these critters are also quite remarkable when they're on the water. Researchers in the United Kingdom recently published a study that found that many species of spiders can actually "sail" across water, using only their body parts and silk to propel themselves forward. (All images courtesy of Alex Hyde) [Read full story about the 'sailing' spiders]

Sea legs

In this photo, a Linyphiid spider sails across the water using its legs. Researchers from the University of Nottingham and the Natural History Museum of London found that spiders who sailed this way were able to travel long distances without creating turbulence.

Taking off

This Tetragnathid spider is also using its legs as sails. Morito Hayashi,  team leader of the zoology department at the Natural History Museum of London and lead author of the new study, told Live Science that such spiders look as though they're "skating" over the water.

Making moves

Some of the spiders in the study, such as this Linyphiid spider, sailed using their abdomens instead of their legs.

Preparing for take off

This Tetragnathid spider assumes a "handstand" postion in order to sail using its abdomen.

Safety first

Here, a Tetragnathid spider uses its silk as anchor. The silk drags through the water, slowing the spider down or bringing it to a halt. The researchers also observed some spiders using their silk to "anchor" themselves to a floating object.

Follow Elizabeth Palermo @techEpalermo. Follow Live Science @livescience, Facebook & Google+.