Venus flytrap trigger hairs are micronewton mechano-sensors that can detect small insect prey

Area of Science:

• Plant biology
• Biophysics
• Insect-plant interactions

Background:

• Venus flytraps (Dionaea muscipula) possess specialized trigger hairs for prey detection.
• These hairs generate action potentials (APs) in response to mechanical stimuli, initiating trap closure.

Purpose of the Study:

• To quantify the mechanical sensitivity thresholds of Venus flytrap trigger hairs.
• To investigate the effect of temperature on trigger hair sensitivity and adaptation.
• To determine if common prey, like ants, meet the sensitivity requirements for triggering the trap.

Main Methods:

• Controlled mechanical stimulation of trigger hairs to measure deflection, angular velocity, and force thresholds for AP generation.
• Variable temperature experiments to assess desensitization and response to consecutive stimuli.
• Recording of natural ant-insect interactions with trigger hairs.

Main Results:

• Trigger hairs generate APs for deflections >2.9°, angular velocities >3.4°/s, and forces >29 µN.
• Hair desensitization occurs with rapid, consecutive stimulations, and this effect is more pronounced at lower temperatures.
• Even small insects, such as ants, exceed the sensitivity thresholds of the trigger hairs.

Conclusions:

• Venus flytrap trigger hairs are highly sensitive mechanoreceptors, capable of detecting the movement and force exerted by small insects.
• Temperature significantly influences the adaptation properties of trigger hairs, suggesting a role in seasonal prey capture efficiency.
• The sensitivity thresholds confirm that typical prey readily trigger the Venus flytrap's prey capture mechanism.