Broad-shouldered Water Striders Still Active
If you see what look like miniature water striders skating on the surface of a stream or pond, you may have come upon an aggregation of Broad-shouldered Water Striders, a different family of water striders from the ones we commonly see. They are tiny (2-6 mm) and very fast-moving, zipping here and there with the speed of a bullet, staying on top of the surface film, or surface tension, that is created by the attraction of water molecules. Adaptations to this mode of travel include non-wettable hairs at the ends of their legs that don’t disrupt the surface tension, and claws that are located a short distance up the outermost section of their legs rather than at the end of their legs, so as not to break this film.
Broad-shouldered Water Striders are often found in the more protected areas of a stream, where they tend to congregate in large numbers. Members of a common genus, Rhagovelia, are known as “riffle bugs” and are often found below rocks that are in the current. Broad-shouldered Water Striders locate their prey (water fleas, mosquito eggs and larvae, etc.) by detecting surface waves with vibration sensors in their legs. There can be up to six generations a summer (photo shows that they are still mating at the end of October). Broad-shouldered Water Striders spend the winter hibernating as adults, gathering in debris at the edge of the water or beneath undercut banks.
Naturally Curious with Mary Holland 
What Other Naturally Curious People Are Saying