Coastal BC Insects: Giant Water Bug

Giant Water Bug

Giant Water Bug

Wayne and I have lived at our float cabin on Powell Lake since 2001 and this is the first time I’ve seen a Giant Water Bug (Lethocerus americanus). The only other time was when I was in high school. A boy friend stationed in Vietnam knew I was putting together an insect collection for a biology class, hence he sent me an unusual “present” in the mail.

Giant Water Bugs are common in the United States and Canada. They are found in among bottom vegetation in ponds and lakes. It is the region’s largest aquatic insect, up to 2 3/8” long and 1” wide (60mm x 25 mm). Flying, it has a wingspan of 4 1/8” (110 mm). When flying, they look a lot like bats. I wonder if that was what I saw the other night skimming over the water.

Giant Water Bugs eat fish, tadpoles and other insects. It has a large beak to pierce its prey and injects digestive juices. Once the innards are dissolved, the bug sucks the contents out, leaving a husk behind, not a pretty thought. And if you handle one, the bite is painful.

The two front legs are used for grasping prey. The four hind legs are fringed and designed for powerful swimming.

Females lay eggs in late spring and early fall. Nymphs hatch in two weeks, but few survive due to cannibalism and other aquatic predators. If disturbed, they may play dead or fight back with their beak and caustic saliva.

With a nickname of "Toe Biter," I got close enough to take some pictures from various angles but wasn’t tempted to get give it a touch. -- Margy

References: Bugs of British Columbia (Lone Pine Publishing, 2001) by John Acorn and Ian Sheldon and National Audubon Society Nature Guides: Wetlands (Alfred A. Knopf, 1997) by William A Niering