Wednesday, April 6, 2011
How many times can a Venus Fly Trap open and close?
Carnivorous plants are really interesting but we may some misconceptions on how a venus fly trap works.
The traps consist of two clamshell-like halves, lined with guard hairs and very small nectar glands. In their resting position the traps are held open at 45°-60°. A healthy plant may have from 3 to 12 or more traps.
The interior surface of each leaf is filled with microscopic digestive glands, giving the leaf surface a fine bumpy appearance. Each inner leaf half usually has three small delicate trigger hairs in a triangular pattern. Most of the time, for the trap to close, any one of these trigger hairs must be touched twice, or any two hairs touched one after the other. In very warm temperatures one touch may be enough. The longer the period between the two stimuli the slower the closure. The best closing response seems to happen when both stimuli occur within 40 seconds. Each trap will close about 10 times before it will no longer respond.
The time delay for trap closure seems to have some survival advantage. A single stroke caused by a brisk breeze or raindrop will not make the plant spend unnecessary closure energy on non-food. The double stroke will often allow prey to enter the center of the trap and be better positioned for capture. If the trap captures non-organic matter or misses its prey, it will open usually within 24 hours. A trap may take 3 to 5 days to digest completely entrapped prey.