How those pond skaters skim across water

Ever wondered how insects like water striders walk on water or skim across the surface of ponds, rivers and oceans? Scientists in the United States have the answer.

Rather than move by creating waves, as some researchers had thought, the insects use one of their three sets of hairy legs like oars to create vortices or spirals in the water that propel them forward at speeds of up to 150cm a second.

Professor John Bush of the Massachusetts Institute of Technology and his colleagues said tiny waves were created but they were not the main driving force.

"The momentum transfer is primarily in the form of subsurface vortices," Professor Bush says in the science journal Nature.

The researchers uncovered the secret of the water striders, or pond skaters, by using sophisticated tracking and a high-speed video camera.

They also created a mechanical water strider, called Robostrider. It is made out of a drinks can, with stainless steel wire legs and an elastic band and pulley as its middle legs.

- REUTERS