Genes Shared With Viruses Protect Caterpillars from Parasitic Wasps

A newly identified gene family named “parasitoid killing factor” is found in both insect-infecting viruses and their hosts, although researchers can’t yet tell where they originated.

Written byAnnie Melchor

| 4 min read

Save for Later

close up of yellow and brown striped caterpillar on a strawberry

Listen with Speechify

0:00

4:00

ABOVE: The cotton bollworm (H. armigera) is one of the species discovered to have parasitoid killing factor genes.
© ISTOCK.COM, TOMASZ KLEJDYSZ

tI’s a scene straight out of your worst nightmare: dozens of tiny, milky larvae wriggle out of their still-living caterpillar host, leaving behind the scarred, gaping holes from whence they emerged. The larvae belong to a type of wasp called parasitoids, whose young dine on the flesh of hosts their parents pick out for them.

But research published Thursday (July 29) in Science suggests that not all caterpillars infected with parasitoid wasps will meet the same grisly end. The study identified a new family of proteins—parasitoid killing factors (PKFs)—that kill parasitoid larvae. PKF genes were found in several large double-stranded DNA viruses that infect lepidopteran insects (moths and butterflies), but also within the genomes of several Lepidoptera species themselves, suggesting that the genes have been swapped between viruses and ...

Interested in reading more?

close up photograph of brown and yellow caterpillar on a strawberry

The Scientist ARCHIVES

Become a Member of

Receive full access to more than 35 years of archives, as well as TS Digest, digital editions of The Scientist, feature stories, and much more!

Join for free today

Already a member? Login Here

Meet the Author

Annie Melchor
Stephanie "Annie" Melchor got her PhD from the University of Virginia in 2020, studying how the immune response to the parasite Toxoplasma gondii leads to muscle wasting and tissue scarring in mice. While she is still an ardent immunology fangirl, she left the bench to become a science writer and received her master’s degree in science communication from the University of California, Santa Cruz, in 2021. You can check out more of her work here.
View Full Profile