Colin Milkins/Oxford Scientific Films
Water boatmen have a grayish, elongated, oval body, 3 to 12 mm (0.13 to 0.5 in) long. They have a conical beak and a broad head with large eyes. Adults have short, flattened front legs; long, slender middle legs; and oarlike hind legs fringed with fine hairs that aid in swimming. Eggs are attached to aquatic vegetation as they are laid. Nymphs develop through five growth stages, or instars, and have incomplete metamorphosis.
Like all aquatic bugs, water boatmen lack gills; they breathe air when at the surface of the water. They frequently carry an air bubble on their body surface or under their wings, and draw oxygen from this bubble while they are underwater. Water boatmen can swim rapidly, but they spend long periods clinging to vegetation. Males stridulate, or chirp, to attract mates by rubbing their forelegs against their head.
Water boatmen occur most commonly in ponds and along the edges of lakes, although a few species inhabit the brackish waters of estuaries. Most water boatmen eat algae and minute aquatic organisms. Some are predaceous and feed on mosquito larvae and other small aquatic animals; in this way, they help to control aquatic pests. In turn, they are important prey for many larger aquatic animals. Their broad beak or mouth allows them to ingest solid food particles as well as liquids; other true bugs are able to ingest only liquids. Unlike many other aquatic bugs, water boatman will not bite people.
Water boatmen are sometimes confused with backswimmers, which are generally larger bugs that swim upside down and deliver a painful bite. Water-boatmen eggs are used as food in Mexico and some other parts of the world. Eggs are collected from aquatic plants, dried, and ground into flour.
Scientific classification: Water boatmen make up the true bug family Corixidae, suborder Heteroptera, order Hemiptera.