Triggerhaare

Triggerhaare, or trigger hairs, are specialized mechanosensory structures on the inner surfaces of the traps of Dionaea muscipula, commonly known as the Venus flytrap. The term is used in German botany to refer to these sensory hairs that detect tactile contact and initiate prey capture.

Each trap lobe hosts several trigger hairs along its midline. They are slender outgrowths of epidermal tissue connected to underlying sensory cells. When a hair is bent, it transmits a mechanical signal to the plant’s electrical system.

Deflecting a trigger hair typically generates an electrical impulse. A single contact is usually insufficient to close the trap; two stimuli within a short time window trigger a cascade of action potentials that cause the lobes to snap shut in a fraction of a second, trapping the prey.

After capture, the trap seals and secretes digestive enzymes. The prey is broken down by digestive fluids over several days, allowing the plant to absorb nutrients. Once digestion is finished, the trap reopens and returns to its resting state, ready to capture again.

Triggerhaare are an adaptation to nutrient-poor environments. They help the plant decide when to expend energy on closing the trap, and their response is highly specific to mechanical stimulation by prey rather than other stimuli. The Venus flytrap is native to subtropical wetlands of the southeastern United States, though related species possess similar hairs.