True Bugs

The water boatmen (family Corixidae) are common aquatic bugs that swim in the water column of lakes and ponds. The hind legs of water boatmen are oar-like in appearance, being long and flattened, and are used for underwater locomotion. Water boatmen do not have gills for the exchange of respiratory gases—they must breath head-first at the surface, although most species can carry a small bubble of air as they swim underwater. Most species of water boatmen are herbivorous, but some others are predators of other aquatic invertebrates. Water boatmen are an important food source for some species of wildlife, such as ducks. The water boatman (Arctocorixa alternata) is a common and widespread species in North America.

The backswimmers (family Notonectidae) are also aquatic bugs. The especially elongate hind legs of these insects are used for swimming, which the backswimmers accomplish while in an upside-down position—hence, their common name. Backswimmers must breath at the surface, but unlike the water boatmen these insects must break the surface abdomen first in order to obtain air. Backswimmers are predators of other aquatic invertebrates, and are themselves an important food for larger species. The backswimmer (Notonecta undulata) is a common and widespread species.

The giant water bugs (family Belostomatidae) include the world's largest bugs, one species of which can attain a most-impressive length of 3.9 in (10 cm). Giant water bugs are oval in shape, with a rather flattened body, and are often a shiny brown color. The front legs are large and strong and are used to grasp their prey, which can include other aquatic insects, as well as small fish, tadpoles, and even frogs and salamanders. Giant water bugs sometimes leave their aquatic habitat and fly about, possibly for the purposes of dispersal. At such times these insects are attracted to lights, where they are sometimes known as electric light bugs. Giant water bugs can inflict a painful bite, and should be handled with care—these insects are sometimes known as toebiters. The giant water bug (Lethocerus americanus) is a widespread species in North America, and can reach a body length of more than 2.4 in (6 cm).

Water scorpions (family Nepidae) are another group of predacious aquatic bugs, with long, scissor-like front legs adapted for fiercely grasping their prey of insects and other creatures. Water scorpions can inflict a painful bite.

Water striders (family Gerridae) are semi-aquatic insects, living on the water surface. The long-legged body of water striders is suspended aloft by surface tension, made possible by the structure of their "feet," which are covered with fine hairs that are not easily wetted. In parts of the southern United States, these insects are known as "Jesus bugs" because of their ability to walk on water. Water striders run and skate over the surface of ponds and lakeshores, hunting terrestrial arthropods that fall onto their two-dimensional habitat, and aquatic insects as they come to the surface to breathe. Water striders have odoriferous scent glands, which may be a deterrent against predation by fish. The water strider (Gerris remigis) occurs commonly throughout much of North America.