How does the Venus flytrap know when to snap?
This drawing of a Venus flytrap is from William Curtis (1746-1799), was a trained pharmacist living in London, whose greater interest was the study of flora and insects. He maintained a large garden where he grew beautiful exotic plants. He began publishing the Curtis Botanical Magazine in 1787.
What happens if you touch a Venus flytrap with a stick? How can carnivorous plants tell the difference between insects and rocks or dirt?
You can probably get a Venus flytrap to close its mouth. But your stick won’t fool the plant altogether. Each “trap” of a Venus flytrap opens and closes like a clamshell.
Each trap can close only half a dozen times over the course of its lifetime – so it has to be particular about what it decides to digest. In fact, the traps are designed to ensure that only worthwhile prey will trigger digestion.
The Venus flytrap has delicate hairs on the inside of its flat leaves. These hairs must be bent or disturbed twice in a short period of time for the plant to close. The teeth of the trap are spaced far enough apart to allow very small bugs to escape.
Once the outer leaves have closed, the Venus flytrap must be continuously stimulated by its struggling prey – or it will abort the digestive process. If there is indeed live prey in the plant, the trap seals around the insect and secretes its digestive juices.
So even if you could get a plant to close around a piece of rubber or a rock, it wouldn’t digest it. If the Venus flytrap does successfully absorb its prey, it’ll be open for business again…a few days later.
