Novel 'bone collector' caterpillar wears its prey

What happened

Scientists in Hawaii Thursday announced the discovery of a carnivorous caterpillar they call the "bone collector" due to its practice of decorating its silk-spun shell with body parts from arthropods it eats or scavenges.

The caterpillars use their carefully curated mélange of dead insect parts to hide from the spiders in whose webs they reside, the researchers said in the journal Science.

Who said what

The few species of meat-eating caterpillars "do lots of crazy things, but this takes the cake," said study author Dan Rubinoff, an entomologist at the University of Hawaii at Manoa. "No other caterpillar is stupid enough to live in a spider's web," because "spiders eat caterpillars," and no others wear body parts. The bone collectors have only been found in spider webs in a six-square-mile area of Oahu, and Rubinoff's team has seen only 62 of them in 20 years of searching.

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The caterpillars prefer to eat struggling insects trapped in their host web or parts left behind by the spider, but they will hunt if need be, even other bone collectors. "That's why we never find more than one caterpillar per web," Rubinoff told USA Today.

What next?

As the species awaits a formal scientific name, "its common name, 'bone collector,' will do" for now, The Washington Post said. But its "current slice of paradise may be at risk" from "invasive ants and parasitic wasps," The New York Times said. "Scientists worry the caterpillars are on the verge of going extinct just as they've been discovered," USA Today said.