Snaring secrets of the Venus flytrap

While “speed” is not a word most people associate with the plant kingdom, the Venus flytrap closes its v-shaped leaves in just one-tenth of a second – fast enough to accomplish a feat thousands if not millions of backyard barbecuers fail at each summer: snaring a fly. So how can a plant pull this off? By storing and releasing elastic energy, according to Gordon McKay Professor of Applied Mathematics and Mechanics Lakshminarayanan Mahadevan. Mahadevan likened the Venus flytrap’s hinged leaves to a plastic lid that is bowed in one direction and then suddenly pops the other way. While waiting for prey, the plant’s leaves are bowed outward, opening the hinged trap. When an insect touches the hairy triggers located inside of the trap, the plant moves water in the leaves, changing their curvature and suddenly snapping them closed. “It is a relatively simple mechanism, but the plant is actively controlling it,” Mahadevan said. The plant then excretes digestive enzymes that break down the meal, providing nutrients that the plant cannot get from the poor, boggy soil where it grows naturally. The research, published in the Jan. 27, 2005 issue of the journal Nature, was conducted largely while Mahadevan was at the University of Cambridge before coming to Harvard in 2003.