From the brushy river bank on this warm September afternoon, I stare into the pool of stagnant water that the sluggish river has bypassed. The more I stare the more I see aquatic life on and above the water, including the gangly-legged insects that catch my attention. They look like giant mosquitos moving on top of the water, though they are not much longer than half an inch.
They are water striders, though the name doesn’t exactly fit what they are doing, for there is no striding happening here if striding means taking long steps. No, the water strider is gliding, scooting, skimming, skating or any other similar words that could describe its rapid propulsions across the water’s surface.
Nature has provided the water strider with short front legs to grab and hold prey. But wait, there are four more legs, much longer legs. The middle two legs push the insect forward, while the two hind legs provide steering.
I watch the water striders scoot forward a few inches on the water’s surface, which in turn is only a few inches above the tannish, silty backwater bottom. The insect suddenly stops and skates in a different direction. A thin membrane created by water surface tension, combined with delicate hairs on the strider’s feet, keep this insect atop the water.
Some striders race toward ripples, which at first baffled me until I later learned that the ripples can either be the sign of prey in distress—an easy meal—or a female strider ready to mate. I stand motionless, drawn to the striders’ movements as much as the striders are drawn to the ripples. Meal or mate.
Later, I was puzzled why my photos of the water striders showed six blobs below each leg. The slightly oblong shadow spots were many times larger that the strider’s six feet. Then, Annie Dillard in “Pilgrim at Tinker’s Creek” solved the mystery for me. Wrote Dillard, “I watch the water striders skate over the top of the water, and I watch the six dots of shade—made by their feet dimpling the water’s surface—slide dreamily over the bottom silt.”
The dots are dimples. All day long the water strider dimples the water. Taking life in stride on the river’s edge.
I loved this, Dave.