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

Venus flytraps detect moving insects via highly sensitive, action potential (AP)-producing trigger hairs, which act as high-sensitivity levers, crucial for prey capture and digestion. Controlled stimulation revealed that they can trigger APs for deflections >2.9°, angular velocities >3.4° s –1 and forces >29 µN. Hairs became desensitized and subsequently responded to fast consecutive stimulations; desensitization increased at lower temperatures. Recording of ant trigger hair contact events revealed that even small insects exceed the hairs’ sensitivity threshold. Walking ants can slightly bend Venus flytrap sensory hairs and induce an action potential (AP) in vivo. The minimal deflection angle able to fire an AP and other properties of these trigger hairs are described and quantified.