Nature really knows its stuff. I think the movement of the plant by applying outside pressure seems to be because of predators (herbivores) or plagues, if they close when some of these animals come in contact with the plant, they would be swept by the leaves. Thank you for posting this interesting article, I have always wondered about these types of plants and what other plants might be out there that we haven't discovered yet. Without a doubt, nature is a great thing to wonder about.