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Butterfly Co-Evolution

December 27, 2007

Plants of the cabbage family evolved a toxic herbicide to ward off pests. But some insects evolved a way around it.

Transcript

BOB HIRSHON (host):
Butterflies vs. Cabbages. I’m Bob Hirshon and this is Science Update.

Many people enjoy the pungent taste of mustard or wasabi. But to insects, the chemical compound that gives these condiments their bite can be deadly. The toxin is found in plants of the cabbage family, which evolved this defense mechanism about 85 to 90 million years ago. But according to evolutionary biologist Christopher Wheat of Penn State, a group of butterflies called the Pierinae quickly evolved the ability to break down the deadly toxin.

CHRISTOPHER WHEAT (Pennsylvania State University):
Using molecular techniques, we found that the butterflies appeared shortly after the plants they eat appeared.

HIRSHON:
He says the ability to consume these plants made it possible for the butterflies to exploit new areas. This allowed them to evolve into many more species in comparison with a closely related group of butterflies that lacks the ability to detoxify the plants. I’m Bob Hirshon, for AAAS, the science society.