Picky Eaters

Predatory insects can balance their diet by selective foraging for fat and protein, according to a new study in the Jan. 7 issue of the journal Science.

Researchers created short-term nutrient imbalances then monitored the feeding behavior of three invertebrate predators. The animals adjusted their feeding to correct the specific nutrition deficit.

Each predator species used a different technique. Beetles selected among foods of different protein and fat composition to compensate for nutrient imbalances. Wolf spiders ate more when the available food (either protein-rich or lipid-rich fruit flies) could correct the nutrient imbalance.

Finally, the web-building desert spiders, shown here, compensated for nutrient imbalances by selectively extracting more of the nutrients they lacked from the prey caught in their webs.

These findings contrast past theories of predator feeding and suggest that fine-tuned dietary regulatory mechanisms are involved in day-to-day feeding behavior of at least some predatory insects.

-- LiveScience Staff

Image © Science, courtesy of Mor Salomon