Caterpillar Gets More from Its Food When Predator Is On the Prowl

ScienceDaily (July 11, 2012) — Animals that choose to eat in the presence of a predator run the risk of being eaten themselves, so they often go into a defensive mode and pay a physical penalty for the lack of nutrients.

But that's not so for the crop pest hornworm caterpillar, a study shows.

While other animals increase metabolism and stop growing or developing during a defensive period, hornworm caterpillars slow or stop eating but actually keep up their weight and develop a little faster in the short term. Ian Kaplan, a Purdue University assistant professor of entomology; Jennifer S. Thaler, an associate professor of entomology at Cornell University; and Scott H. McArt, a graduate student at Cornell, noticed that hornworm caterpillars ate 30 percent to 40 percent less when threatened by stink bugs but weighed the same as their non-threatened counterparts.

"It was a little puzzling. If you're going to shut down, there should be a cost associated with that," said Kaplan, who studied the caterpillars as a postdoctoral researcher at Cornell. "We usually think that you can either grow really fast and not defend yourself, or defend yourself but pay a physical penalty. That wasn't happening here."

Continued: http://www.sciencedaily.com/releases/2012/07/120711150540.htm