Engineers Take Cues from Beetles to Make a Super-Efficient Robo-Boat

Water Bug Electrodes propel this boat by breaking the surface tension of water Courtesy Sang Kug Chung/University of Pittsburgh

Dolphins are elegant swimmers, but waterlily leaf beetle larvae take first place for the simplest stroke. The insect just arches its back to manipulate a basic physics principle that lets it glide across water. Now engineers have borrowed this technique to make a tiny boat that could autonomously patrol water reservoirs for months on just a watch battery.

The larva's efficiency relies on surface tension, the force that causes water molecules to stick together. By arching its body, the larva disrupts the water's tension in such a way that the bug moves forward. Sung Kwon Cho, an engineer at the University of Pittsburgh, decided to harness the tension, like the beetle does, to move an inch-long boat. But instead of making a bendable craft, Cho attached a Teflon-coated electrode to the plastic boat's stern.

Video courtesy Sang Kung Chung, Kyungjoo Ryu, and Sung Kwon Cho

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Tags

Science, Susannah F. Locke, beetles, boats, electrodes, inspired by nature, june 2009, robots, teflon