Waterlily beetles skim across the surface of the water as part of their everyday lives, but the process is too quick to see without high-speed cameras. In the wild, the tiny creatures seem to just disappear off the surface of water, leaving behind just a ripple.
Researchers from Stanford University carefully recorded the beetles using cameras designed to show their flitting movements. Investigators learned the tiny insects utilize their wings on the water in a fashion similar to the way humans use water skis.
As they prepare to take flight, the beetles lift each leg in turn, before setting them back down on the water. They then lift their middle legs, angling their heads upward toward the sky. Wings are unfurled with a couple flaps before the appendages are moved quickly in a figure-eight pattern to produce forward motion. This all happens without the insect losing contact with the surface, as water tension supports the weight of the insect.
As the beetles lift off the water surface, they travel just over 1 mile per hour. While this does not seem fast, it is equivalent to a human traveling more than 300 miles per hour. This motion creates significant ripples upon the water, which researchers compared to potholes on a busy road.
"The surface tension forces are so large compared to this little thing, but it has the capacity to fly at half a meter per second on the surface of water without ever detaching from the water's surface. It's one of the fastest-known locomotion strategies on the surface of water," Manu Prakash said.
By studying videos of the insects in action, researchers were able to show that each step of the process served to reduce friction between the animal and the water. At the small scales at which these creatures live, the surface tension of water can have a major effect on the world around it.
Waterlily beetles usually live in ponds, lakes and streams across North America, and typically measure around 0.2 inches in length. These insects are capable of flying as well as skimming water. Investigators theorize the creatures may cruise along the water while foraging for food.
Analysis of the flight patterns of waterlily beetles was profiled in the Journal of Experimental Biology.
