Friday Cat-erpillar Blogging: Damage Dispersal

Pieris rapae caterpillar

Cabbageworms, Pieris rapae

Caterpillar feeding damage on plants is often easier to find than the caterpillars themselves. Some caterpillars only feed on plants at night, then hide off the plant during the day. Others change location after each feeding bout. Why? Entomologists have hypotheses. One centers around food quality. Another is focused on avoiding enemies. When caterpillars feed, the leaves are damaged. The plant responds by producing or releasing defensive chemicals to protect the wounded tissue. These plant chemicals can be toxic to the caterpillar or reduce the quality of the food.

Alternatively, Caterpillars can be food for predators or parasitoids. These enemies can focus on feeding sites, caterpillar frass or chemicals emitted from the plant to find the caterpillar. By moving away from a recent feeding site, a caterpillar can be more difficult to find. Pieris rapae, the imported cabbageworm, will change locations between feeding bouts, sometimes moving almost 1 meter in a day within a single plant. The reasons possibly have to do with both plant quality and enemies.

About jjneal

Jonathan Neal is a retired Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
This entry was posted in behavior, by jjneal, Caterpillar Blogging, Environment. Bookmark the permalink.

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