How Venus Flytraps Snap Shut
Charles Darwin called the Venus flytrap one of the most wonderful things in the world yet, over 150 years later, researchers are still struggling to explain how the plant closes its traps so quickly. But now we think we know the answer. Previously scientists had suggested that the rapid closure of the traps occurs when special 'motor cells' deflate, rather like a balloon popping, which brings the two halves of the leaf together. But even this wouldn't account for the speed with which the process takes place. To solve the problem a team of researchers in France, the US, and the UK used high-speed photography, capable of capturing 400 frames a second, to track what happens during the tenth of a second the trap takes to close. The photos have revealed that the flytrap 'snaps' from a convex shape to a concave shape very quickly, just like a broken tennis ball turned inside out that can rapidly be 'popped' from one stable shape to another. This is achieved by the arrangement of cells and fibres within the wall of the leaf, although precisely how the arrival of a potential meal inside the trap triggers the shape change, the scientists haven't yet worked out.