THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION

Aquatic Invertebrates in Pacific Northwest Freshwater Wetlands
An Identification Guide and Educational Resource

Belostamatidae are some of the largest insects found in fresh waters. The three genera in North America are Lethocerus, Abedusand Belostoma. They are typically found in ponds, ditches, and stream pools among debris and vegetation or floating with their hind end at the water's surface, where they capture air in specially adapted straps at the end of their abdomen. Adults may also be attracted to lights some distance away from the water. Males of some species carry the eggs glued to their backs to protect those eggs from predation. Belostomatids prey on aquatic animals including insects, fish, and amphibians. Their aggressive habits earned them the nickname "toe biters", as they can inflict a painful bite.

Giant water bugs have broad, oval, slightly flattened bodies; short antennae; and strong raptorial front legs. The hind legs have claws, and there are short straplike breathing appendages at the tip of the abdomen. The wingtips have numerous veins running through them.

Size: large to xlarge
Identifying feature(s): large size, raptorial front legs, egg-shaped body
Habitat: wetlands; pools and margins of streams
Tolerance to pollutants: tolerant

Lethocerus: hind legs are more broad and flat than the middle legs; two claws are present at the end of each raptorial front leg; body is elongate and up to nearly 3".

Belostoma: hind legs are similar to the middle legs; the raptorial front legs have only a single claw at the end of each; body is oval and up to only about 1.5" in length.