Synonyms and other taxonomic changes
Belostoma griseum
Benacus griseus
Lethocerus grisea
Explanation of Names
griseus is Latin for "gray." This is the masculine form, since Lethocerus is a masculine noun (griseum is the neuter form, which matches the neuter noun Belostoma, and grisea is the feminine form - probably originally used to match Belostoma, which looks like a feminine noun, but isn't).
Identification
According to John T. Polhemus:
"This species can be separated from L. americanus... by the evenly curving anterior margins of the eyes; L. americanus has more bulging eyes. The best key character of griseus is the pad of "fur" rather than a groove on the inner face of the fore femur; griseus is the only Lethocerus species with this feature."
in
L. griseus, anterior margin of eye is evenly curved, posterior margin of eye is at an oblique angle to body axis, and eye is broadly triangular with rounded corners; outer margin of hind tibia broadly curved; width of first hind tarsal segment greater than least interocular distance [all of these features are visible in the close-up image of
L. griseus by schming
here; compare with the image of
L. americanus by Tony Thomas
here]
L. griseus also has no groove in the anterior margin of the fore femur, but this feature is rarely visible in photos
Range
Massachusetts west to Michigan; south to Florida and Texas
Habitat
In ponds and other bodies of still, shallow water
Food
Any animal small enough to grab with their front legs: insects, small fish, tadpoles, frogs - even small birds. Once they have a hold on their prey, they inject enzymes with their strong beak that kill it and start the digestion process (bugs can't chew- they have to feed by the equivalent of drinking through a straw).
Life Cycle
During their breeding season the adults fly around looking for mates and for places to breed.
Eggs are laid near the water in vegetation and on other objects. The nymphs have no wings, but otherwise are similar to the adults, and, like them, live in the water.
Remarks
Adults breathe air (they have a snorkel-like breathing tube at the tip of their abdomen), so they tend to float at the surface or hide in shallow areas within reach of the surface.
Like many predatory bugs, these have a very painful bite. If you're wading or swimming in their habitat, closed-toe foot-wear is a good idea just in case you step on one.
During their flights in the mating season they often get disoriented by electric lights and end up circling them in large numbers. This can lead to mass invasions of artificially lit outdoor spaces near water.
A similar, but even bigger species is considered a delicacy in Thailand, and the North American species have been served in restaurants catering to Thai immigrants in the US.
See Also
in L. americanus, anterior margin of eye is bulging, posterior margin of eye is perpendicular to body axis, and eye is globose or almost spherical; outer margin of hind tibia almost straight; width of first hind tarsal segment less than or equal to least interocular distance
L. americanus also has a groove in the anterior margin of the fore femur, but this feature is rarely visible in photos
in
L. uhleri, the middle and hind legs are distinctly banded (see
U. of Florida image)
Belostoma species are much smaller (20-30 mm) with less elongate bodies
Internet References
Giant Water Bugs photos of all life stages, description, biology, distribution, many references, and a key to Florida species of Belostomatidae (Paul Choate, U. of Florida)
key to species of
Lethocerus and
Belostoma in Michigan (Ethan Bright, U. of Michigan)
The invasion of the giant water bug. A newspaper article about one mass invasion in the Tampa Bay area of Florida: "
Customers stomp and cringe as swarms cover a Pasco shopping plaza. They're huge, creepy - and crunchy in sauce."
Contributed by
Chuck Entz on 5 February, 2006 - 7:55pm
Additional contributions by
Robin McLeodLast updated 20 May, 2006 - 11:40pm
