The Lethocerus americanus, commonly known as the giant water bug, is a member of the Hemiptera order. This aquatic bug, which breathes air through a short tube that sticks out of the water, is one of the largest insects in the United States and Canada. Most giant water bugs are about 1.5 inches long; however, some species may grow to 4 inches in length. Because giant water bugs are attracted to light, they often are seen under street and house lights and commonly are mistaken for cockroaches and beetles.
Because the brown or tan giant water bug has an oval-shaped and relatively flat body, the bug often is incorrectly identified as a beetle. The bugs have a pointy, short beak under the head and overlapping wings at the lower end of the abdomen that resembles an "X." The front legs have hook-like claws to grab and hold prey. Their hind legs hold onto vegetation, while their powerful front legs snatch approaching prey.
With a lifespan of a year or more, giant water bugs live in low-current water, such as streams and ponds that have vegetation. They use surface plants to lie in wait for their prey. Giant water bugs can eat an animal up to 50 times their size, making them formidable hunters of small fish, tadpoles, salamander and birds. The giant water bug uses its sharp beak to pierce prey and inject a toxin, which first paralyzes the prey and then converts its internal parts into liquid so the water bug can suck up its meal.
The bite of a giant water bug is not severely toxic to humans, but they are painful, and the injected substance can cause extreme swelling of the bitten area. A known nickname of the giant water bug is "toe biter" because of its pesky bite.