{{Short description|Family of true bugs}} {{Automatic taxobox | fossil_range = {{fossil range|230|0|Late Triassic to present}} | image = Belostomatidae HuntingtonVT.jpg | image_caption = ''Lethocerus americanus'' | taxon = Belostomatidae | authority = Leach, 1815 }}
'''Belostomatidae''' is a family of freshwater hemipteran insects known as '''giant water bugs''' or colloquially as '''toe-biters''', '''Indian toe-biters''', '''electric-light bugs''' (because they fly to lights in large numbers), '''alligator ticks''', or '''alligator fleas''' (in Florida). They are the largest insects in the order Hemiptera.<ref name=PerezGoodwyn2006>{{cite journal |author=P. J. Perez-Goodwyn |year=2006|title=Taxonomic revision of the subfamily Lethocerinae Lauck & Menke (Heteroptera: Belostomatidae) |journal=Stuttgarter Beiträge zur Naturkunde |series=Serie A (Biologie) |volume=695 |pages=1–71}}</ref> There are about 170 species found in freshwater habitats worldwide, with more than 110 in the Neotropics, more than 20 in Africa, almost as many in the Nearctic, and far fewer elsewhere.<ref name=Thorp2015>{{cite book | editor1=J.H. Thorp | editor2=D.C. Rogers |year=2015 | title=Thorp and Covich's Freshwater Invertebrates: Ecology and General Biology | publisher=Elsevier | pages=954–955 | volume=1 | edition=4 | isbn=978-0-12-385026-3 }}</ref> These predators are typically encountered in freshwater ponds, marshes and slow-flowing streams. Most species are at least {{convert|2|cm|in|abbr=on|1}} long, although smaller species, down to {{convert|0.9|cm|in|abbr=on}}, also exist. The largest are members of the genus ''Lethocerus'', which can exceed {{convert|12|cm|in|abbr=on|round=0.5}} and nearly reach the length of some of the largest beetles in the world.<ref name=PerezGoodwyn2006/><ref name=Haddad2010>{{Cite journal |last1=Haddad |first1=V. |last2=Schwartz |first2=E.F. |last3=Schwartz |first3=C.A. |last4=Carvalho |first4=C.N. |date=2010|title=Bites caused by giant water bugs belonging to Belostomatidae family (Hemiptera, Heteroptera) in humans: A report of seven cases |journal=Wilderness & Environmental Medicine|volume=21|issue=2 |pages=130–133|doi=10.1016/j.wem.2010.01.002|pmid=20591375 |doi-access= }}</ref><ref name=Schuh1996>{{cite book |author1=Randall T. Schuh |author2=James Alexander Slater | year=1996 | title=True Bugs of the World (Hemiptera:Heteroptera): Classification and Natural History | publisher=Cornell University Press | pages=111–114 | edition=2 | isbn=978-0801420665 }}</ref> Giant water bugs are a popular food in parts of Asia.<ref name=Mitsuhashi2017>{{cite book| author=Mitsuhashi, J. | title=Edible Insects of the World | year=2017 | publisher=CRC Press | isbn=978-1-4987-5657-0 }}</ref>
The oldest fossil member of this family is ''Triassonepa'' from the Late Triassic-aged Cow Branch Formation of Virginia and North Carolina, United States.<ref>{{Cite journal |last1=Criscione |first1=Julia |last2=Grimaldi |first2=David |date=2017-11-01 |title=The oldest predaceous water bugs (Insecta, Heteroptera, Belostomatidae), with implications for paleolimnology of the Triassic Cow Branch Formation |url=https://ui.adsabs.harvard.edu/abs/2017JPal...91.1166C |journal=Journal of Paleontology |volume=91 |issue=6 |pages=1166–1177 |doi=10.1017/jpa.2017.48 |bibcode=2017JPal...91.1166C }}</ref>
== Morphology == [[File:Giant water bug (Belostomatidae), Vohimana reserve, Madagascar (13569458513).jpg|thumb|The largest Hemiptera in the world are ''Lethocerus'' (''L. oculatus'' shown)<ref name=Schuh1996/>]]
Belostomatids have a flattened, obovoid to ovoid-elongate body, and usually the legs are flattened.<ref name=Schuh1996/> The head features two large compound eyes, but lacks ocelli, contrasting with many hemipterans. Short antennae are tucked in grooves behind the eyes. A short breathing tube can be retracted into its abdomen.<ref name=":0">{{Cite book|title=An Introduction to the Aquatic Insects of North America|last=Merritt|first=R.W.|publisher=Kendall/Hunt Company|year=2008|location=Dubuque, Iowa}}</ref> Adults cannot breathe under water, so must periodically place the breathing tube at the surface for air (similar to a snorkel).<ref name="huntley"/>
Their hind tarsi have two apical claws. The frontal legs are modified into raptorial appendages that they use to grab their prey, except in the African ''Limnogeton'', which has "normal" forelegs and is a specialized snail-eater.<ref name=Schuh1996/> Once caught, the prey are stabbed with their proboscis and a powerful proteolytic<ref>{{cite journal | pmid=16844394 | year=2006 | last1=Swart | first1=C. C. | last2=Deaton | first2=L. E. | last3=Felgenhauer | first3=B. E. | title=The salivary gland and salivary enzymes of the giant waterbugs (Heteroptera; Belostomatidae) | journal=Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology | volume=145 | issue=1 | pages=114–122 | doi=10.1016/j.cbpa.2006.05.010 }}</ref> saliva is injected, allowing the Belostomatid to suck out the liquefied remains.<ref name=Haddad2010/> Wing pads can be seen from the dorsal view. While the members of the subfamily Lethocerinae can disperse by flying,<ref name=PerezGoodwyn2006/> other species, including ''Abedus herberti'', have a greatly reduced flight apparatus and are flightless.<ref name=Thorp2015/><ref>{{cite journal| author1=Phillipsen. I.C. | author2=Kirk, E.H. | author3=Bogan, M.T. | author4=Mims, M.C. | author5=Olden, J.D. | author6=Lytle, D.A. | year=2015 | title=Dispersal ability and habitat requirements determine landscape-level genetic patterns in desert aquatic insects | journal=Molecular Ecology | volume=24 | issue=1 | pages=54–69 | doi=10.1111/mec.13003 | pmid=25402260 | bibcode=2015MolEc..24...54P | s2cid=1391038 }}</ref> Giant Water Bugs exhibit muscle regression as they develop from nymphs to adults, adapting their musculature for a more energy-efficient predatory lifestyle, which may influence their hunting strategies and ecological interactions.<ref>Perez Goodwyn, Pablo J. “Muscle Regression in Belostomatid Bugs (Heteroptera: Belostomatidae).” Aquatic Insects, vol. 23, no. 1, 2001, pp. 23–32, https://doi.org/10.1076/aqin.23.1.23.4927 </ref>
==Subfamilies and genera== ''BioLib'' lists three extant subfamilies and a number of fossil taxa:
===Belostomatinae=== Auth. Leach, 1815 # ''Abedus'' Stål, 1862 # ''Appasus'' Amyot & Serville, 1843 # ''Belostoma'' Latreille, 1807 # ''Diplonychus'' Laporte de Castelnau, 1833 (synonym ''Sphaerodema'' Laporte, 1833) # ''Hydrocyrius'' Spinola, 1850 (synonym ''Poissonia'' Brown, 1948) # ''Limnogeton'' Mayr, 1853 # ''Weberiella'' De Carlo, 1966 * Fossil genera
===Horvathiniinae=== Auth. Lauck & Menke, 1961; South America # ''Horvathinia'' Montandon, 1911
===Lethocerinae=== Auth. Lauck & Menke, 1961 # ''Benacus'' {{Au|Stål, 1861}} # ''Lethocerus'' {{Au|Mayr, 1853}} (includes ''Kirkaldyia'' {{Au|Montandon, 1909}})
===Fossil taxa=== subfamily Stygeonepinae Popov, 1971 † # ''Aenictobelostoma'' Polhemus, 2000 † # ''Belostomates'' Schöberlin, 1888 † # ''Lethopterus'' Popov, 1989 † # ''Manocerus'' Zhang, 1989 † # ''Scarabaeides'' Germar, 1839 † # ''Triassonepa'' Criscione & Grimaldi, 2017 †
== Habits == [[File:Abedus herberti.jpg|thumb|Male ''Abedus herberti'' with eggs on his back]]
===Feeding and defense=== Belostomatids are aggressive predators that stalk, capture, and feed on fish, amphibians, as well as aquatic invertebrates such as snails and crustaceans. The largest species have also been found to capture and feed on baby turtles and water snakes.<ref name="BBC Nature article">{{cite web|url=https://www.bbc.co.uk/nature/13500857|title=BBC Nature - Giant water bug photographed devouring baby turtle|work=BBC Nature}}</ref> 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 venomous digestive saliva with their rostrum. Although their bite is excruciatingly painful, it is of no medical significance.<ref name="huntley">{{cite journal |author=A. C. Huntley |year=1998 |title=''Lethocerus americanus'', the "toe biter" |journal=Dermatology Online Journal |volume=4 |issue=2 |pages=6 |url=http://escholarship.org/uc/item/4cb2q8wg/letho.html|pmid=10328676 }}</ref> Occasionally, when encountered by a larger animal or a human, they have been known to "play dead" and most species can emit a fluid from their anus.<ref name=Schuh1996/><ref name="huntley"/> Due to this, they are assumed dead by humans only to later "come alive" with painful results.<ref name="huntley"/>
===Breeding=== [[Image:Abedus roems.jpg|thumb|Male (red tag) and female (blue tag) ''Abedus'' copulating]]
Belostomatids show paternal care and these aspects have been studied extensively, among others involving the North American ''Belostoma flumineum'' and the East Asian ''Lethocerus (Kirkaldyia) deyrollei''. In species of the subfamily Belostomatinae, the eggs are typically 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 the subfamily Lethocerinae, the eggs are laid on emergent vegetation and guarded by the male.<ref>{{cite book |author=Robert L. Smith |date=1997 |chapter=Evolution of paternal care in the giant water bugs (Hemiptera: Belostomatidae) | editor=Jae C. Choe | editor2=Bernard J. Crespi |name-list-style=amp |title=The Evolution of Social Behavior in Insects and Arachnids Sociality |url=https://archive.org/details/evolutionsocialb00choe |url-access=limited |pages=[https://archive.org/details/evolutionsocialb00choe/page/n124 116]–149 |publisher=Cambridge University Press |isbn=978-0-511-72195-3 |doi=10.1017/CBO9780511721953.007}}</ref>
==In Asian cuisine== {{See also|Entomophagy}} thumb|Fried giant water bugs at a market in Thailand Belostomatids can be found for sale in markets mainly in Southeast Asia involving the species ''Lethocerus indicus''.<ref name=Mitsuhashi2017/> In Southeast Asia 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.
==References== {{Reflist}}
==Further reading== *{{cite journal |author=D. R. Lauck |year=1962 |title=A monograph of the genus ''Belostoma'' (Hemiptera), Part I. Introduction and ''B. Dentatum'' and ''Subspinosum'' groups |journal=Bulletin of the Chicago Academy of Sciences |volume=11 | issue = 3 |pages=34–81}} *{{cite journal |author=D. R. Lauck |year=1963 |title=A monograph of the genus ''Belostoma'' (Hemiptera), Part II. ''B. Aurivillianum'', ''Testaceopallidium'', ''Dilatatum'', and ''Discretum'' groups |journal=Bulletin of the Chicago Academy of Sciences |volume=11 | issue = 4 |pages=82–101}} *{{cite journal |author=D. R. Lauck |year=1964 |title=A monograph of the genus ''Belostoma'' (Hemiptera, Part III. ''B. Triangulum'', ''Bergi'', ''Minor'', ''Bifoveolatum'', and ''Flumineum'' groups |journal=Bulletin of the Chicago Academy of Sciences |volume=11 | issue = 5 |pages=102–154}} *{{cite journal |author=A. S. Menke |year=1960 |title=A taxonomic study of the genus ''Abedus'' Stål (Hemiptera, Belostomatidae) |journal=University of California Publications in Entomology |volume=16 | issue = 8 |pages=393–440 |url=https://archive.org/details/a-taxonomic-study-of-the-combined}} *{{cite journal |author=R. L. Smith |year=1974 |title=Life history of ''Abedus herberti'' in Central Arizona |journal=Psyche: A Journal of Entomology |volume=81 |pages=272–283 |doi=10.1155/1974/83959 |issue=2 |doi-access=free }}
==External links== {{Commons category|Belostomatidae}} {{Wikispecies|Belostomatidae}} * [https://web.archive.org/web/20071020145657/https://www.zoo.org/factsheets/giant_waterbug/giantWaterbug.html Factsheet from zoo.org] * [https://web.archive.org/web/20040928233804/http://www.colostate.edu/Depts/Entomology/courses/en507/papers_1995/cito.html Sex role reversal] * [https://archive.today/20121211130508/http://www.dbc.uci.edu/~pjbryant/biodiv/hemipt/Toebiter.htm Toebiters] * [https://web.archive.org/web/20080102172641/http://whatsthatbug.com/toe_biter.html Pictures of a Giant Water bug from whatsthatbug.com] * [http://entomology.ifas.ufl.edu/creatures/misc/bugs/giant_water_bugs.htm ''Lethocerus, Abedus, Belostoma'' spp.] on the University of Florida / Institute of Food and Agricultural Sciences Featured Creatures Web site * [http://www.mister-toad.com/photos/inverts/Lethocerus_eating_frog_01.html Giant Water Bug Feeding on Frog]
{{Hemiptera|3}} {{Taxonbar|from=Q8356884}} {{Authority control}}
Category:Belostomatidae Category:Nepomorpha Category:Heteroptera families Category:Taxa named by William Elford Leach Category:Edible insects Category:Extant Late Triassic first appearances