Study: Caterpillars rely less on microbiome than other animals

Aug. 22 (UPI) -- A new study has shown that caterpillars have significantly less bacteria and fungi inhabiting their gut than other animals.

Scientists at the University of Colorado Boulder say that the microbiome caterpillars do have serves no real role aside from causing disease.

The study, published today in the Proceedings of the National Academy of Sciences, found that caterpillars might not need microbes, a discovery that could lead to new understanding about the extent and role of resident microbial communities in animals.

"In the microbiome field, there's this prevailing assumption that all animals have a resident microbiome," Tobin Hammer, a doctoral candidate in CU Boulder's Department of Ecology and Evolutionary Biology, said in a press release. "When I started the project, I was not expecting it to turn out this way."

Researchers collected fecal samples from caterpillars in Colorado, Arizona, New Hampshire, Massachusetts and Costa Rica, and extracted DNA from the droppings and from a leaf plant the caterpillar eats.

They found that, compared to other animals, caterpillars had roughly 50,000 times fewer microbes.

Most of the microbial DNA that was found inside the caterpillars matched the microbes found on the plant leaf, which showed the microbes were primarily ingested from their surroundings.

"Caterpillars operate fundamentally differently than a lot of other animals," Hammer said.