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Rock River water walkers

Water striders on the Rock River eat misquito larvae and feed fish. Here's more from Wikipedia: Water striders are among the most recognizable aquatic insects. Most species have long, slender bodies covered with thick, velvety, water-repelling hairs. Some species have shorter and rounder bodies. They have large prominent eyes and are usually dark brown to black in color. Some have stripes on their bodies. Others have yellow on top of the head. Many water striders are very small (6/100 inch) and others are relatively long (1-1/2 inches). Females are generally larger than males. Water striders have two short forelegs, two long middle legs and two long hind legs. The middle and hind legs are used for locomotion. Each leg is covered with thousands of microscopic, water-repelling hairs to keep them dry. Wet legs would break through the surface of the water, causing the water strider to sink. The hairs have grooves that trap air, increasing buoyancy and water resistance. Scientists use the term “superhydrophobic” to describe how the hairs repel water. There is an air cushion between water striders feet and the water surface. The purpose of this cushion is to create stability and maintain balance even in rainstorms. There are claws above the foot instead of at the end, so the water surface does not break.

Where does it live?

Scientists believe there are about 500 water strider species worldwide. They estimate 45 to 60 species live in North America. Aquarius remigis is the scientific name for one species commonly found in eastern North America. Water striders spend their entire lives on the water’s surface. They can be seen on lakes, ponds and calm parts of rivers and streams. Five water strider species roam the ocean. These insects, known as sea skaters, are the only true marine insect. Their scientific name is Halobates. They have adapted to life on the open seas in warm areas of the Atlantic, Pacific, and Indian oceans. Often, they are seen on tide pools or in debris that has washed ashore.

What does it eat?

Water striders are generally predators. They survive by capturing and feeding on other creatures. They eat newly hatched tadpoles and mosquito larvae that float to the surface. They often eat dead insects. Sea skaters depend on finding floating fish eggs and other sources of protein. Water striders eat land-dwelling insects that drop into the water. When insects drop they are caught on the water’s surface. As they struggle, they send “communication ripples” over the surface. Water striders detect these ripples through sensory receptors on the tips of their legs. They dart quickly to grab the insect prey with their strong front legs. Because they are “true bugs,” water striders are able to swing their beak forward from its resting position on the underside of the body. The beak is used to pierce the prey and inject it with digestive juices. The juices dissolve and liquefy internal organs allowing the water strider to suck out nourishment.

How does it defend itself?

Water striders are eaten by birds, fish, frogs,and aquatic insects. They are especially vulnerable when mating. One defence against predators is camouflage. Resting on floating leaves and vegetation lets water striders blend into their surroundings. Their large prominent eyes help them avoid predators.

Glen Loyd lives in Madison and spends many days with family in Rock County. He is a former public information officer for Wisconsin Consumer Protection, publishes a weekly consumer protection blog and is a regular guest on radio consumer protection programs. Glen is a community blogger and is not a part of The Gazette staff. His opinion is not necessarily that of the The Gazette staff or management.