The Carnivorous Plant FAQ v. 12

Q: Exactly how do these plants capture prey? Answer #5--snap traps

A: We know of snap traps in only two closely related plants--Dionaea muscipula and Aldrovanda vesiculosa.

In the snap trap (sometimes called bear trap or spring trap), the leaf has two lobes that are splayed widely apart. Foraging or exploring insects wander into the trap, and trigger it by stimulating a the nearly invisible trigger hairs on the trap walls. Dionaea muscipula has only a few of these hairs on each leaf lobe, while Aldrovanda vesiculosa has many more.

Triggered, the trap snaps shut, making a little prison for the creature. The little animal runs back and forth, and in doing so stimulates those trigger hairs again and again. This causes the plant leaves to tighten, seal, and then release digestive enzymes. The prey dies by suffocation.

For a more detailed discussion of these traps, see my pages on Dionaea traps and Aldrovanda traps.

Much like in suction traps, we can only speculate on the evolution development of a snap trap. Most commonly, scientists suggest that snap traps might have evolved from sticky traps, and to support such claims will note those species of Drosera that have leaves that curl over prey. This could very well have been the case. If so, it would suggest that Aldrovanda evolved from Dionaea. Who knows?

Now what a surprise I have for you!

The FAQ link is VERY scary. It shows gif animations I made in, oh, about 1990, and which are really sleazy. But I have a fondness for them, so I just can't bear to remove them from the FAQ.

Strap yourself in and go ahead to the next FAQ entry...

Page citations: Lloyd, F.E. 1942; Rice, B.A. 2006a.

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Revised: 2018
©Barry Rice, 2018