From ABC News in Science, 5 March 2014:
The hairy legs of water striders are artfully designed to strike a balance between the water capillary action and gravity, Chinese researchers have discovered.
They found the spacing of the insect’s leg hairs fits a formula that takes into account the contact angle of the hairs and fluid mechanics to ensure maximum load-carrying capacity and floating stability.
The results, reported today in Proceedings of the Royal Society A not only provide an insight into the remarkable ability of these insects, but has implications for the design of miniature rafts and water strider-inspired robots that can float stably and move easily across water.
Nature abounds with examples of water-repelling surfaces such as the lotus leaf and insects’ wings that have already inspired a number of technological advances.
“Many researchers have tried to understand how the hairy structures render legs or wings of some insects water repellent from the point of view of surface physics and chemistry,” says Professor Huiling Duan, of the Department of Mechanics and Engineering Science at Peking University.
Previous research had suggested these hairy surfaces were superhydrophobic, hence their ability to repel water.
“In fact, water repellency of hairy surfaces depends on the size, spacing and orientation of the hairs in micro-scale,” says Duan. Read more.