Belostomatidae

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Belostomatidae
Abedus indentatus male with eggs on its back
Abedus indentatus male with eggs on its back
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Infraorder: Nepomorpha
Family: Belostomatidae
Subfamilies and genera

Belostomatinae

Abedus
Belostoma
Diplonychus
Hydrocyrius
Limnogeton
Poissonia
Sphaerodema
Weberiellia

Lethocerinae

Lethocerus
Benacus
Kirkaldyia

Horvathiniinae

Horvathinia

Belostomatidae is a family of insects in the Order Hemiptera, known as giant water bugs or colloquially as toe-biters. They are the largest insects in the order Hemiptera, and occur worldwide, with most of the species in North America, South America and East Asia. They are typically encountered in freshwater streams and ponds. Most species are relatively large (2 cm or more) with some of the largest, such as Lethocerus, exceeding 12 cm, and nearly reaching the dimensions (length and mass) of some of the larger beetles in the world. Giant water bugs are a popular food in Thailand.

Contents

[edit] Habits

Lethocerus sp. found in Florida and Montana
Lethocerus sp. found in Florida and Montana

Bugs of the family Belostomatidae are fierce predators which stalk, capture and feed on aquatic crustaceans, fish and amphibians. They often lie motionless at the bottom of a body of water, attached to various objects, where they wait for prey to come near. They then strike, injecting a powerful digestive saliva with their mouthparts, and sucking out the liquefied remains. Their bite is considered one of the most painful that can be inflicted by any insect (the Schmidt Sting Pain Index excludes insects other than Hymenoptera); the longer the bug is allowed to inject its saliva, the worse the resulting bite, and as the saliva liquefies muscle tissue, it can in rare instances do permanent damage. Adults cannot breathe under water, and must surface periodically for air.[1] Occasionally when encountered by a larger predator, such as a human, they have been known to "play dead" and emit a fluid from their anus.[1] Due to this they are assumed dead by humans only to later "come alive" with painful results.[1]

Belostomatids show parental care and the eggs of many species are laid on the male's wings and carried until they hatch. The male cannot mate during this period. The males invest considerable time and energy in reproduction and females take the role of actively finding males to mate. This role reversal matches the predictions of R. L. Trivers' parental investment theory.

In some areas belostomatids are considered a delicacy, and can be found for sale in markets. They are often collected for this purpose using large floating traps on ponds, set with black lights to attract the bugs. Adults fly at night, like many aquatic insects, and are attracted to lights during the breeding season.

Male (red tag) and female (blue tag) copulating
Male (red tag) and female (blue tag) copulating

[edit] Reproduction

Males attract the females doing a series of periodic movements near water surface generating ripples in the water known as display pumping. Before a female begins ovipositing the eggs, she mates with the male. Then a series of intercalated series of matings and ovipositions occur, females ovipositing 1-4 eggs in each ovipositing bout. An egg batch can have more than 100 eggs so a couple may copulate more than 30 times before female oviposits all the egg batch. This increases male confidence of paternity, a condition thought necessary for the origin of paternal care. There are two substrates of oviposition, females of species pertaining to the ancestral subfamily (Lethocerinae) oviposit on emergent vegetation. On the other hand, Belostomatinae females oviposit on the males' dorsum. The male will raise the eggs exposing them to air periodically to discourage the growth of fungus and maintain the viability of the eggs, or conduct a series of movements below the water known as brood pumping that increases the amount of oxygen diffusion. The eggs will hatch in approximately three weeks but their hatching time will decrease as temperature rises.

[edit] In Asian cuisine

In various parts of southeast Asia, the species Lethocerus indicus is used as food, or as a source of extracts. (See Lethocerus indicus)

[edit] Notes

  1. ^ a b c A. C. Huntley (1998). Lethocerus americanus, the "toe biter". Dermatology Online Journal 4 (2): 6. 

[edit] References

  • P. J. Perez-Goodwyn (2006). Taxonomic revision of the subfamily Lethocerinae Lauck & Menke (Heteroptera: Belostomatidae). Stuttgarter Beiträge zur Naturkunde, Serie A (Biologie) 695: 1–71. 
  • D. R. Lauck (1962). A monograph of the genus Belostoma (Hemiptera), Part I. Introduction and B. Dentatum and Subspinosum groups. Bulletin of the Chicago Academy of Sciences 11(3): 34–81. 
  • D. R. Lauck (1963). A monograph of the genus Belostoma (Hemiptera), Part II. B. Aurivillianum, Testaceopallidium, Dilatatum, and Discretum groups. Bulletin of the Chicago Academy of Sciences 11(4): 82–101. 
  • D. R. Lauck (1964). A monograph of the genus Belostoma (Hemiptera, Part III. B. Triangulum, Bergi, Minor, Bifoveolatum, and Flumineum groups. Bulletin of the Chicago Academy of Sciences 11(5): 102–154. 
  • A. S. Menke (1960). A taxonomic study of the genus Abedus Stål (Hemiptera, Belostomatidae). University of California Publications in Entomology 16(8): 393–440. 
  • R. L. Smith (1974). Life history of Abedus herberti in Central Arizona. Psyche 81: 272–283. doi:10.1155/1974/83959. 
  • R. T. Schuh & J. A. Slater (1995). True Bugs of the World (Hemiptera:Heteroptera): Classification and Natural History. Cornell University Press. 
Benacus deyrolli
Benacus deyrolli


[edit] External links