Unidentified species of Pond Skater or Water Strider, order Gerridae. Sorry, not a good picture - he was on the pond, I was on dry land... Need a bigger lens.
"Gerrids... are known to communicate by detecting and generating ripples in the water's surface. Both sexes use the ripples created by insects trapped in the surface tension to locate their prey." http://www.earthlife.net/insects/gerrom
There are three main frequencies found in ripple communication: 25 Hz as a repel signal, 10 Hz as a threat signal, and 3 Hz as a courtship signal. An approaching gerrid will first give out a repel signal to let the other water strider know they are in its area. If the other gerrid does not return the repel signal, then the bug knows it is a female and will switch to the courtship signal.