Water Bug, an insect that lives in or on lakes, ponds, streams, or the ocean. Water bugs have piercing mouthparts through which they suck the body juices of fish, frogs, tadpoles, salamanders, and insects. Some species of water bugs can inflict painful wounds on human beings. A few species feed on plants. Water bugs fly chiefly at night and are attracted by lights.

The water boatmanThe water boatman has flattened legs for swimming.

The giant water bug, or electric-light bug, up to four inches (10 cm) long, is attracted to artificial light. It feeds on small fish and insects. The smaller giant water bug, which grows to 1 1/2 inches (3.8 cm) long, preys on small fish. The female secretes a gluelike substance with which it cements the eggs to the male's wings, where they eventually hatch.

Where do Giant Water Bugs Live?

Like other water bugs, giant water bugs live in freshwater ponds, streams, and lakes. These bugs are very strong swimmers, but they spend most of their time sitting and waiting for prey. They catch insects, tadpoles, salamanders, frogs, and fish. Giant water bugs are the largest of all true bugs.

The back swimmer, about one-half inch (1.3 cm) long, has a torpedo-shaped body. As the name indicates, it swims upside-down; it uses its hind legs as oars to propel itself through the water. It has abdominal cavities in which it traps air, allowing it to remain submerged for up to six hours. It preys on aquatic insects and tadpoles.

Which True Bug Swims on Its Back?

A backswimmer does! This bug paddles across the water, using its back legs like the oars of a boat. Like a water scorpion, a backswimmer can also fly.

A backswimmer can stay underwater for several hours at a time. Usually, it rests just below the surface. But sooner or later, it needs air. A backswimmer has tiny hairlike growths on its body. It pushes these out so they are above the surface of water. This causes air to flow beneath the surface. The backswimmer traps the air in a bubble under its wings. The bug then breathes in the air through its breathing holes.

A backswimmer’s enemies include fish and birds. But this true bug’s colors help it hide from predators. The backswimmer’s belly is light-colored, like the sky. And its back is dark, like the bottom of a pond. So predators often can’t see a backswimmer from below or above.

The water boatman is about the same size as the back swimmer. Its middle and hind legs are flattened and are used in swimming. It feeds on algae, which it scrapes into its mouth with its front legs.

Do Water Boatmen Live on Boats?

Water boatmen don’t live on boats. However, like backswimmers, they are very comfortable in the water. In fact, water boatmen carry their own air supply with them as they swim. They keep the air under their wings and all around their bodies.

Unlike other true bugs, a water boatman has a soft beak. The bug cannot use its beak to stab its food. Instead, a water boatman uses its short front legs to collect algae (AL jee) and the remains of dead animals and water plants. The bug then sucks on what it has gathered.

A water boatman uses its middle and back legs for swimming. The bug can also fly out of water. Like many true bugs that live in the water, it is often attracted by lights that are near a lake or pond.

The water scorpion breathes through a tube at the rear of its abdomen, which it thrusts above the surface. It lies in wait for victims, then seizes them with its front legs and kills or paralyzes them with a fluid injected through its beak. A sticklike type of water scorpion grows to three inches (7.5 cm) long. Another type, broad and flat, grows about three-fifths of an inch (1.5 cm) long. Water scorpions seldom fly.

Which True Bugs Walk on Pond Bottoms?

Water scorpions walk very slowly on pond bottoms. Some look very much like small sticks. They don’t swim very well. But these bugs can fly. If their pond dries up, water scorpions can fly for miles to find a new home.

A water scorpion eats insects, tadpoles, small fish, and salamanders. The bug grabs its prey with its strong front legs. Then the water scorpion uses its beak to stab its victim and to suck out the victim’s body fluids. Because a water scorpion looks like a stick, its victim may not even see it coming.

A water scorpion doesn’t have gills to breathe oxygen from water, as a fish does. Instead, it has a breathing tube on its abdomen. The bug uses its tube like a straw to suck in the air. To do this, the bug climbs up a water plant and lifts its breathing tube above the water.

The water strider lives on the surface of the water, gliding about on its long, spidery middle and hind legs. Its feet are covered with hairs that repel water. Water striders break the surface of the water only as hatch-lings and when laying eggs. A water strider has a slender body from one-tenth to four-fifths of an inch (3 to 20 mm) long, depending on the species. Many water striders have no wings.

Which Water Bugs Skate?

Water striders can move quickly along the water’s surface. These true bugs look as if they are “skating” on water. They don’t sink because of the way they spread out their long, thin back legs. Their weight is spread over a large area, so these bugs can actually slide along the surface of water.

Water striders are about 3/4 inch (19 millimeters) long. Many live on freshwater ponds and streams. These bugs use waves to find food. When insects fall in the water, they make tiny ripples. Water striders feel the ripples with their feet. They skate to the source and stab their victims with their beaks.

Some species of water striders live on the ocean. In fact, they are the only insects that can live their entire lives on the ocean. These bugs skate around and feed on dead fish and other animals they find.

Water bugs form the suborder Heteroptera of the true-bug order, Hemiptera. Giant water bugs form the family Belostomatidae; back swimmers, Notonectidae; water boatmen, Corixidae; water scorpions, Nepidae; water striders, Gerridae.