Species Abedus herberti

Giant water bug

Toe biter

2 subspecies

2-3cm, depending on population and habitat

Robust, deep brown bugs. Wide, broadly rounded, oval body. A pair of short, rounded air straps protrude from the back end of the abdomen. The air straps exhibit a triangular patch of longer hairs about halfway down the length that distinguishes it from the closely related A. indentatus. Hind legs flattened, fringed with short hairs, and mottled brown and black. Forelegs raptorial, also mottled brown, black, ending in a single claw. Underside of abdomen almost entirely covered in a dense mat of short hairs. Large, dark eyes and long, pointed beak present on small, broad head. Antennae very short and bristle-like.

Adults may have a light stripe running down the middle of the thorax that extends under the wings. This stripe is visible as an unbroken line down the center of the body in the nymphs exhibiting this characteristic.

Arizona, Utah, New Mexico, USA; northern Mexico

Freshwater streams, especially in montane areas. They often inhabit intermittent streams, so they are isolated to individual rock pools (tinajas) during dry periods when streams do not exhibit overland flow.

Found year-round in streams. Main mating season occurs during the summer, especially prior to and during the monsoons.

All water bugs are predators. Abedus herberti eats other insects, small fish, small tadpoles, and will become cannibalistic when other food is scarce.

Males attract females by creating patterns of ripples in the water. They then mate many times, the female laying 1-4 eggs after every copulation. Females lay their eggs (sometimes over 100) on the backs of their mates. The father then cares for his brood until they hatch by carrying them to the surface periodically and performing a behavior called brood pumping underwater. Eggs typically take less than 3 weeks to hatch. Once hatched, the nymphs develop through 5 instars before molting into adults. These bugs are long lived and can live well over a year if the conditions are favorable.

This species is flightless and has to move overland to travel between streams. This has led to isolated populations in the Sky Islands of Arizona and northern Sonora that could eventually develop into new subspecies or species over time.

Adult bugs hold an air store under their wings that they use to respire when they are submerged. Nymphs hold their air store externally using a dense mat of hairs on the underside of the abdomen.

The bite of this insect is known to be painful, though not otherwise dangerous.

Abedus is a difficult genus in which to identify species without a microscope for close examination. A. heberti is similar in appearance to most other Abedus species, but it is most similar to Abedus indentatus. A. indentatus is typically only found in California

FINN, DS, BLOUIN, MS, AND LYTLE, DA (2007). Population genetic structure reveals terrestrial affinities for a headwater stream insect. Freshwater Biology 52: 1881–1897. View online

MENKE, AS (1960). A taxonomic study of the genus Abedus Stal (Hemiptera, Belostomatidae). University of California Publications in Entomology 16: 393-439.

MENKE, AS (1979). The semiaquatic and aquatic Hemiptera of California (Heteroptera: Hemiptera). Bulletin of the California Insect Survey 21: 1-166. View online

SMITH, RL (1974) Life history of Abedus herberti in central Arizona (Hemiptera: Belostomatidae). Psyche 81: 272-283. View online

SMITH, RL (1979) Paternity assurance and alterd roles in the mating behavior of a giant water bug, Abedus herberti (Heteroptera: Belostomatidae). Animal Behaviour 27: 716-725.

USINGER, RL (1968). Aquatic Hemiptera, pp. 182-228 IN USINGER, RL (ed.), Aquatic Insects of California, with Keys to North American Genera and California Species. Third Printing, Berkeley and Los Angeles, University of California Press. View online

Identifying American water bug genera