SCIENTISTS REVEAL MECHANISM BEHIND VENUS FLYTRAP'S RAPID SNAP

Scientists have identified the mechanism that allows the Venus flytrap to close around prey within a second of an insect making contact with its leaves. A series of experiments found that hair-trigger detection causes cells on the outer surface of the leaf to soften rapidly, prompting the trap to flip shut. The research resolves a question that defeated Charles Darwin, who believed the plant must contain a muscle to move so quickly. Plants possess neither muscles nor nerves.

Dr Yoël Forterre, a physicist at the French National Centre for Scientific Research (CNRS) and Aix-Marseille University, served as senior author of the research. The team immobilised Venus flytrap leaves using dental glue, allowing the trap to be triggered whilst remaining stationary for measurement purposes. Venus flytraps carry three trigger hairs on each lobe of their trapping leaves, and bending those hairs produces an electrical signal that spreads across both sides of the trap within one-tenth of a second. The researchers used an instrument called a nanoindenter — a fine metal tip — to measure the pressure and stiffness of the leaf's outer surface following activation.

Those measurements confirmed that the outer surface of the leaf softens immediately once the trap is triggered. Forterre noted that the system is so finely calibrated that introducing any outside disturbance, such as a drop of water, causes the trap to close and reopen the following day. When an insect is caught, the plant must digest it and dissolve its skeleton, a process that takes several weeks. Forterre described it as surprising that plant cell walls can alter their mechanical properties so rapidly.