High-speed video shows how water lily beetles sprint on water
These critters move fast, and now we know how they do it.
Water lily beetles are little speed demons, flitting from one pad to another at half a meter (1.6 feet) per second. Now, thanks to a study conducted by Stanford bioengineering assistant professor Manu Prakash and his students, the secret to its mode of flight has been unraveled. Turns out the insects (Galerucella nymphaeae) perform a routine before their flight, wherein they step on the water before lifting their legs one by one so that only their tips touch the surface. They then raise their middle legs high up in the air while their wings flap, making it look like they're sprinting across the surface.
Their bodies move up and down with the beating of their wings, so much so that they probably feel "as though [they are] on a pogo stick." But they remain stable throughout their flight, because the water's surface acts like some sort of a magnet sticking to their four remaining legs. The team had to video their lab beetles while they darted to and fro inside their aquariums, as well as create mathematical models to figure out the physics behind their movements. It's a very complicated process, as you can tell, but it pays off for the little guys: Prakash says this mode of flight is "one of the fastest-known locomotion strategies on the surface of water."
Now that we know how they move, we wouldn't be surprised if someone somewhere decides to make a robotic version of the creature. Until that happens, you can watch some real, living water lily beetles ski across water in slow motion below.
