Scanning a sunlit pond floor for crayfish, I was distracted by seven dark spots gliding in a tight formation. Six crisp oval shadows surrounded a faint, less distinct silhouette. The shapes slid slowly and then, with a rapid motion, accelerated before slowing to another glide. I can remember seeing this pattern as a child, in my first explorations of pond life.
Water strider shadows are far larger than the insects casting them. To visualize the surprising proportion of legs to body, it may help to think in human scale. For mathematical simplicity, picture a six-foot-tall man lying flat on the water surface. Imagine that attached near his hips he has a pair of seven-foot-long, stick-skinny legs pointing back at a 45 degree angle. Just forward of these spindles he has another pair pointing forward at a 45 degree angle; these are nine feet long. A pair of three-foot-long arms point forward and each has a single claw protruding from the palm. » Continue Reading.