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Riffle bugs; Temporal range: Tithonian–Present PreꞒ Ꞓ O S D C P T J K Pg N
	Microvelia macgregori
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hemiptera
Suborder:	Heteroptera
Superfamily:	Gerroidea
Family:	Veliidae; Amyot & Serville, 1843

Veliidae is a family of gregarious predatory insects in the suborder Heteroptera. They are commonly known as riffle bugs, small water striders, or broad-shouldered water striders because the segment immediately behind the head is wider than the rest of the abdomen. Species of the genus Rhagovelia are also referred to as ripple bugs.

Veliidae have a specialized body plan that allows them to walk on water and are neuston. The family Gerridae is another closely related group that is also neuston and both are in the superfamily Gerroidea. Veliidae are smaller however, between 1.5 and 6 mm (0.059 and 0.236 in). They can be found on ponds, near lake shores, and in rivers worldwide. Some species can also be found on plants near water, in salt water or in mud flats.

Description

Veliidae are very similar to Gerridae. The most consistent characteristic used to separate these two families are internal genitalia differences, however external cues are usually sufficient to tell the families apart.

A general description is as follows: an oval to elongate body covered with hydrofuge hairs. Wings can be present or absent; when present the wings range from well devolved to vestigial. The four segmented antennae is longer than the head and readily visible. The antennae is non-aristate. The eyes are usually large, but there are no ocelli.^[1]

Males and females can be differentiated by the fore tibiae. Males have smaller tibiae with a grasping comb, as opposed to the larger plain female tibiae.^[2]

Distribution

Veliidae is the largest gerromorphan family and has almost 1173 species and 66 genera.^[3] The present distribution of these species points to two centers of origin: one in the Indo-Malayan region and another on the shores of the Caribbean Sea.^[4] The geographical distance between these points is probably due to continental drift. And now they are present across all continents (except Antarctica).

Life cycle

Like all Heteroptera, the Veliidae go through an egg, nymph and adult stage. They have four or five nymphal instars.^[5] Both the adults and nymphs live together gregariously, in loose communities and can often be found in large groups. Eggs are usually laid underwater, attached to the stream bed, rocks or plant material and held together by a gelatinous substance. In most species females lay under 30 eggs. Nymphs are very similar to adults, but have one segmented tarsus on mid and hind leg as opposed to the adults' two. Some species prefer rapids or riffles in streams but many prefer calmer water.^[6]

Behaviour

Veliidae can walk on water because they take advantage of the high surface tension of water and have hydrophobic legs that distribute their weight across more water.

Although Gerridae typically have longer legs, Veliidae also have legs that spread out the weight over a relatively large area. Thousands of hydrofugal hairs also coat the entire body, mitigating potential problems incurred by water contact: air bubbles, trapped among the tiny hairs if the insect is submerged, lift the insect towards the surface again.

Taxonomy

The following genera are recognised in the family Veliidae:^[7]

Adriennella Poisson, 1942
Aegilipsicola J.Polhemus & D.Polhemus, 1994
Aegilipsovelia J.Polhemus, 1970
Aenictovelia Polhemus, 1979
Altavelia Polhemus, Molano, Morales, Moreira & Floriano, 2019
Angilia Stål, 1865
Angilovelia Andersen, 1981
Aphrovelia J.Polhemus & D.Polhemus, 1988
Aquulavelia Thirumalai, 1999
Arcantivelia Solórzano Kraemer & Perrichot, 2014
Austromicrovelia Andersen & Weir, 2003
Balticovelia Andersen, 2000
Baptista Distant, 1904
Barbivelia Andersen & Weir, 2003
Brechivelia D.Polhemus & J.Polhemus, 2004
Callivelia Polhemus, 2021
Carayonella Poisson, 1948
Chenevelia Zettel, 1996
Cylicovelia J.Polhemus & Copeland, 1996
Drepanovelia Andersen & Weir, 2001
Electrovelia Andersen, 1998
Entomovelia Esaki, 1930
Euvelia Drake, 1957
Eyarinella Zettel & Laciny, 2021
Fijivelia J.Polhemus & D.Polhemus, 2006
Geovelia Zimmermann, 1984
Gracilovelia Poisson, 1955
Haldwania Tamanini, 1955
Halovelia Bergroth, 1893
Haloveloides Andersen, 1992
Hebrovelia Lundblad, 1939
Husseyella Herring, 1955
Lacertovelia Andersen & Weir, 2001
Lathriovelia Andersen, 1989
Macrovelia Tamanini, 1947
Mangrovelia Linnavuori, 1977
Menuthiasia Poisson, 1952
Microvelia Westwood, 1834
Microveloidella Poisson, 1952
Microvelopsis Andersen & Weir, 2001
Millotella Poisson, 1948
Neoalardus Distant, 1912
Nesidovelia Andersen & Weir, 2001
Neusterensifer J.Polhemus & D.Polhemus, 1994
Nilsvelia Cassis, Hodgins, Weir & Tatarnic, 2017
Ocellovelia China & Usinger, 1949
Ocheovelia J.Polhemus & D.Polhemus, 2006
Ochthecorisa Montrouzier, 1864
Oiovelia Drake & Maldonado-Capriles, 1952
Pacificovelia Andersen & Weir, 2003
Papuavelia D.Polhemus & J.Polhemus, 2000
Paravelia Breddin, 1898
Perittopus Fieber, 1861
Petrovelia Andersen & Weir, 2001
Phoreticovelia D.Polhemus & J.Polhemus, 2000
Platyvelia J.Polhemus & D.Polhemus, 1993
Plesiovelia Tamanini, 1955
Polhemovelia Zettel & Sehnal, 2000
Pseudovelia Hoberlandt, 1951
Rhagovelia Mayr, 1865
Rheovelia D.Polhemus & J.Polhemus, 2004
Shaverdinia Zettel & Laciny, 2021
Starmuhlneria Poisson, 1964
Steinovelia J.Polhemus & D.Polhemus, 1993
Stridulivelia Hungerford, 1929
Strongylovelia Esaki, 1924
Submicrovelia Poisson, 1951
Tanyvelia J.Polhemus & D.Polhemus, 1994
Tarsovelia J.Polhemus & D.Polhemus, 1994
Tarsoveloides Andersen & Weir, 2001
Tenagovelia Kirkaldy, 1908
Tetraripis Lundblad, 1936
Thirumalaia Zettel & Laciny, 2021
Tonkouivelia Linnavuori, 1977
Tubuaivelia J.Polhemus & D.Polhemus, 2008
Velia Latreille, 1804
Velohebria Stys, 1976
Veloidea Gould, 1934
Xenobates Esaki, 1927
Xiphovelia Lundblad, 1933
Xiphoveloidea Hoberlandt, 1951

References

^ Herson, John (1 May 2015), "Labouring families in the Famine's aftermath, 1852 onwards", Divergent paths, Manchester University Press, pp. 133–165, doi:10.7228/manchester/9780719090639.003.0006, ISBN 9780719090639
^ Moreira, F.F.F.; Nessimian, J.L.; Rúdio, J.A.; Salles, F.F. (2010). "New species and new records of Veliidae from Espírito Santo State and adjacent Minas Gerais State, Brazil, with notes on nomenclature (Insecta: Heteroptera: Gerromorpha)". Journal of Natural History. 44 (45–46): 2761–2801. Bibcode:2010JNatH..44.2761M. doi:10.1080/00222933.2010.512423. S2CID 84489928.
^ "Veliidae on ITIS".
^ "Water-striders (Hemiptera: Gerridae, Veliidae, etc.)" (PDF). escholarship.org. Retrieved 11 December 2018.
^ Cheng, Lanna; Fernando, C. H. (1971). "Canadian Science Publishing". Canadian Journal of Zoology. 49 (4): 435–442. doi:10.1139/z71-067.
^ Henry, Thomas J. (2009), "Biodiversity of Heteroptera", Insect Biodiversity, Wiley-Blackwell, pp. 223–263, doi:10.1002/9781444308211.ch10, ISBN 9781444308211
^ "Veliidae". www.gbif.org. Retrieved 28 May 2024.