A single gene in a caterpillar virus sends its victims running for the treetops, where they die and their bodies liquefy, sending an ooze of virus particles on their brothers and sisters below.

This species of baculovirus infects only gypsy moth caterpillars, essentially turning them into zombies. It stops the caterpillars from molting and sends them up into the tree leaves during the day (a behavior they normally save for the cover of darkness), where they die among the leaves as they wait to molt.

“They die there, and then they melt within hours after they die, and they are dripping virus down onto the leaves below,” said study researcher Kelli Hoover, of Pennsylvania State University. “We knew before that this behavior benefits the virus, but we didn’t know how it was causing the behavior.”

The viral gene, named egt, interferes with the caterpillar’s molting hormone and sends the caterpillars crawling upward.  The virus multiplies fiercely in almost every cell of the caterpillar’s body. When the caterpillar dies among the leaves, it undergoes a natural liquefaction process in which its exoskeleton disintegrates. Each drop of caterpillar goo contains millions of viruses.

Birds even help disperse the virus; when they scarf a caterpillar snack from the leaves, they bash it on branches to remove some of its hair. Slow-motion video shows this action not only dispenses of hair, but also expels droplets of liquefied caterpillar. The virus can even survive in the gut of the birds, to be rained down like viral bombs from above in their feces.

http://www.livescience.com/15962-zombie-caterpillar-virus.html

Thanks to Mr. C for bringing this to the attention of the It’s Interesting community.