These plants are evil, they’re savage, they’re going to take over the world…so…..I welcome my plants that turn predators into cannibals overlords.
When does a (typically) vegetarian caterpillar become a cannibalistic caterpillar, even when there is still plenty of plant left to eat?
When the tomato plant it’s feeding on makes cannibalism the best option.
“It often starts with one caterpillar biting another one in the rear, which then oozes. And it goes downhill from there,” says University of Wisconsin-Madison integrated biology Professor John Orrock, author of a new study published July 10 in Nature Ecology & Evolution that examines how plants, in defending themselves from insect predation, can encourage insects to become cannibals.
“At the end of the day, somebody gets eaten,” he says.
It started when Orrock wondered whether a tomato plant could ever taste so horrible that an herbivore that would typically munch on its green leaves would instead turn to its buddy and begin to consume him or her instead.
“Many insects are known to become cannibalistic when the going gets tough,” says Orrock.
So Orrock, his postdoctoral researcher Brian Connolly, and Anthony Kitchen, an undergraduate student in the lab, devised a set of experiments to test their idea using tomato plants and a species of caterpillar called the beet armyworm.
“Beet armyworms are important agricultural pests, in part because they can feed on a variety of plants,” Connolly says. “And early, influential work describing plant responses to herbivore attacks used tomato and beet armyworm. We build on that work here.”
When does a (typically) vegetarian caterpillar become a cannibalistic caterpillar, even when there is still plenty of plant left to eat? When the tomato plant it’s feeding on makes cannibalism the best option, report investigators.