Saturday, August 29, 2009

How a Bad Plant Stays Bad

The Venus flytrap, with its spike-like teeth and snapping jaws, is a carnivorous wonder of nature that appeals to the dark side of our imaginations.

Researchers at the University of Wisconsin, curious about how and why the "snap trap" flytrap evolved, have delved into the ecological background of the plant and combined the data with new computer modeling.

The Venus flytrap can trace its roots back 65 million years, when the snap trap carnivorous plants diverged from the sundew plant, which catches bugs by trapping them in a sticky goo.

Today there are only two living "snap trap" species – the Venus flytrap and an aquatic plant called a waterwheel that eats tiny invertebrates. The flytrap is an advance over its sticky trap cousins because the snapping jaws can catch larger, and therefore more nutritious, insects, the researchers said.

"As the insects get larger, you have to change your tactics," said botanist Don Waller. "The snap trap is one way to do that."

In addition to being unique, the Venus flytrap is also a very efficient killer, the researchers noted. It has hinged, jaw-like leaves, teeth, and digestive glands that are recessed for protection against a struggling fly. It also has sensitive trigger hairs on the inside surface of each leaf, and the leaves can snap shut in a fraction of a second. And outside of horror movies, the Venus flytrap cannot grow large enough to threaten much more than flies.

"The physiological demands of capturing and digesting larger and larger prey limits how big the plants can get – even the largest leaves on an average Venus flytrap are … an inch or less across," the researchers said.

The paper on the flytrap appears in the August issue of the journal New Phytologist.

By Jim Dawson
Inside Science News Service
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