Wednesday, August 25, 2010

Water Strider or Pond Skater

Water striders on the still water at the edge of the Thames River in London, Ont.
Much of the following information was found on a U of T (University of Toronto) Web page.

Today's picture features water striders, the familiar semi-aquatic bugs often sighted gliding across the surface of the Thames River at the water's edge where the current is slow and the water almost still. These bugs have a novel body form that allows them to walk on water. According to the U of T, this was not always the case.

To achieve this gliding ability required the evolution of a unique arrangement of the legs, with the mid-legs greatly elongated. Scientists at the U of T's Department of Ecology and Evolutionary Biology have discovered the gene behind this evolutionary change, the Hox gene.

U ot T research scientists found it not only lengthened the mid-legs but shortened the hind-legs, creating an unusual body form that allows water striders to glide on the water surface. They glide along taking advantage of the water's surface tension. They apply just the right amount of force as they skate along. If too much energy was used, they would break the surface tension.

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