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In Photos: Spiders Hatched from Web Towers

Mysterious structure

Nobody knows exactly what this structure is or who made it.

(Image credit: Troy Alexander / Tambopata Research Center)

While volunteering in the Peruvian Amazon, graduate student Troy Alexander discovered a strange web formation underneath a tarp.

Circle and spires

The weird structure was first spotted on the underside of a tarp near the Tambopata Research Center in the Peruvian Amazon.

(Image credit: Troy Alexander / Tambopata Research Center)

The formation, about 0.8 inches (2 centimeters) across, had a strange spire in the middle encircled by picket-fence like posts.

Slime mold?

a yellow slime mold

(Image credit: Image courtesy of Audrey Dussutour)

Experts guessed it could have been a slime mold, a structure made by moths, or a defense made by spiders, but everyone was stumped.

Return to the scene

(Image credit: Jeff Cremer /

So several months later, a team of researchers returned to the site to study the structures. After putting them in a glass, they found baby spiders hatched from the strange structures.

Spider eggs

spider hatched from strange formation

(Image credit: Jeff Cremer /

The mystery was solved: The web towers were used for spider eggs, from which tiny, less than 1 mm spiderlings emerged.

Still unknown

tiny spider hatchling

(Image credit: Jeff Cremer /

But it's still not clear what species of spider made the webs or what the picket-fence circle is for.

Ant defense?

spider hatchling

(Image credit: Jeff Cremer /

One possibility is that the fence is a defense against ant invaders eating or damaging the eggs, or the spikes lure mites as tasty snacks for the hatchlings.

Tia is the managing editor and was previously a senior writer for Live Science. Her work has appeared in Scientific American, and other outlets. She holds a master's degree in bioengineering from the University of Washington, a graduate certificate in science writing from UC Santa Cruz and a bachelor's degree in mechanical engineering from the University of Texas at Austin. Tia was part of a team at the Milwaukee Journal Sentinel that published the Empty Cradles series on preterm births, which won multiple awards, including the 2012 Casey Medal for Meritorious Journalism.