Although many people think of large cockroaches when they think of water bugs, a true water bug is classified under the order Hemiptera. Hemiptera comprises the order of insects known as true bugs, which includes more than 50,000 different insect species, and true water bugs are aquatic species belonging to this order, such as the giant water bug, the water scorpion and the water boatman.
Giant Water Bug
The giant water bug, also known as the “electric light bug” and the “toe-biter,” is the largest true bug in the United States, with adults reaching lengths of more than 2 inches. Due to its flat, brown, oval-shaped body, it often gets mistaken for a beetle or a cockroach. These bugs are predators that consume a wide range of prey including other aquatic insects, tadpoles and crustaceans, and sometimes even fish, salamanders and other amphibians. The giant water bug has a short, pointed beak underneath its head that it uses to pierce its prey and inject toxin that both paralyzes its victims and causes its insides to liquify. This bug then sucks the liquified guts through its beak like a straw. Using this method, the giant water bug is able to capture and eat animals up to 50 times its own size.
These members of the water bug group are not scorpions at all, but aquatic insects with two pairs of wings and grasping forelimbs that resemble a scorpion’s pincers. It also has a long breathing tube sticking out from its tail section that resembles a scorpion’s stinging tail. The water scorpion has a small head with large eyes that project to the side. This insect belongs to the sub-order Heteroptera, which includes insects with anterior wings that are stiffened to provide protective wing cases for the membranous posterior wings beneath.
Water boatman are the largest group of aquatic true bugs. They’re small, slightly flattened and elongated bugs with dull mottled coloring. They have hairs on their two pairs of hind legs, and the hind-most legs have oar-shaped feet that allow them to paddle, as well as single-segment forelegs that are shaped like a scoop. They are similar in appearance to backswimmers, for which they are sometimes mistaken. Water boatman feed mainly on algae and other plant material. They can often be seen swimming in groups on open water such as ponds.
Similar in appearance to the water boatman, the backswimmer can be distinguished by wings that are lighter in color than the legs and the lack of scoop-shaped forelegs. Most notably, backswimmers can be distinguished by the habit that gives them their name -- swimming on their backs. Another thing that sets them apart from water boatmen is that they are carnivorous hunters, with prey and eating habits very similar to those of the giant water bug.
- Orkin: Difference Between a Waterbug and a Cockroach
- Animal Planet: Wild Animals: Insects: Water Bug
- Galveston County Master Gardeners: Beneficials In the Garden: Giant Water Bug
- MDCOnline: Backswimmers
- Northern State University: Invertebrates: Water Scorpions
- Texas A&M Agrilife Extension: Water Boatman
Jean Marie Bauhaus has been writing about a wide range of topics since 2000. Her articles have appeared on a number of popular websites, and she is also the author of two urban fantasy novels. She has a Bachelor of Science in social science from Rogers State University.