What mechanism do Venus flytraps use to capture prey?

Venus flytraps use a snap-trap mechanism to capture prey. Their leaves are divided into two hinged lobes that rapidly close when an insect stimulates sensitive trigger hairs on the inner surface.

The trap is not activated by every touch. Typically, prey must touch two trigger hairs in succession within about 20 seconds, or stimulate one hair twice quickly. This threshold helps the plant avoid wasting energy on raindrops, dust, or other accidental disturbances. Once triggered, the lobes can close in roughly one-tenth of a second under suitable conditions.

The initial closure is not the entire digestive process. If the trapped arthropod continues moving, repeated stimulation causes the lobes to seal more tightly. Digestive glands then release enzymes, and the plant absorbs nutrients from the prey. Cilia along the edges form a partial barrier, while gaps can allow very small prey to escape.

Sticky traps belong to sundews and butterworts, suction traps characterize bladderworts, and pitfall traps are used by pitcher plants. The Venus flytrap is unusual because its rapid snap trap is shared naturally with only one other carnivorous-plant genus, Aldrovanda.