A quick flick of movement across a calm spot on the water brought a water strider to my attention. Although they might resemble spiders with their with spindly legs and dark bodies, they are actually members of the order Hemiptera
(half wing) or “true bugs.” Their remarkable ability to skate so adroitly across the surface always makes me stop and watch for a little while. In clear water I often see their shadows gliding along the bottom before I ever see the actual insects.
Their ability to stand on the water without sinking or even getting wet stems from the fact that they are covered in microscopic hairs that allow them to take advantage of surface tension. The depression made by their middle legs pressing down into the surface film give them something to push against. Their front legs are short and held under their heads to grab any unfortunate insect or spider that happens to make waves on the water's surface. Then, in true bug fashion, they inject the victim with digestive juices before consuming it.
Not only do vibrations sound their dinner bells, but they allow these critters to communicate; different frequencies having different meanings. One warns others away from an individual's territory. If that is ignored, the male assumes it is a female. He then gives the courtship signal, and if the female isn't in the mood she gives the repel signal.
From personal experience I can say it is unwise to capture and hold onto them. The bite was not pleasant at all, and it left a black and blue spot on my palm for days.