Cybister

{{Short description|Genus of beetles}} {{Automatic taxobox | image = Cybister fimbriolatus UMFS 3.jpg | image_caption = ''Cybister fimbriolatus'' | display_parents = 2 | taxon = Cybister | authority = Curtis, 1827 | subdivision_ranks = | subdivision = }} [[File:Cybister lateralimarginalis (DeGeer, 1774) male.jpg|thumb|''Cybister lateralimarginalis'']] [[File:Cybister & Dytiscus larva.png|thumb|Comparison of ''Cybister'' and ''Dytiscus'' larvae]] '''''Cybister''''' ('kybistētēr' = diver, tumbler), is a genus of beetle in family Dytiscidae. They are found in much of the world, including all continents except Antarctica.<ref name=Miller2016>{{cite book| author1=Miller, K.B. |author2=J. Bergsten | title=Diving Beetles of the World: Systematics and Biology of the Dytiscidae | year=2016 | pages=131–132 |publisher=JHU Press | isbn=978-1-4214-2054-7 }}</ref><ref name="Roberts 1905">{{cite journal |url=https://www.biodiversitylibrary.org/page/8083456#page/124/mode/1up |title=The Distinctive Characters of the Eastern Species of the Genera Dytiscus and Cybister |last=Roberts |first=C H |year=1905 |journal=Journal of the New York Entomological Society |volume=13 |pages=103–107 }}</ref> As of 2024 there are 98 species and 9 additional subspecies among four subgenera in the genus.<ref name="catalogue">{{cite web |last1=Nilsson |first1=Anders N. |last2=Hájek |first2=Jiří |year=2024 |title=A World Catalogue of the Family Dytiscidae or the Diving Beetles (Coleoptera, Adephaga) |url=http://www.waterbeetles.eu/documents/W_CAT_Dytiscidae_2024_new.pdf |edition=1.I.2024}}</ref>

== Description== Adult ''Cybister'' have broad hind legs with unequal tarsal claws (the inner claw being smaller and sometimes absent) and a fringe on the outer margin of the tarsus.<ref name=":0">{{Cite web |title=Genus Cybister |url=https://bugguide.net/node/view/14512 |access-date=2023-03-02 |website=bugguide.net}}</ref> They range in length up to 43 mm (''C. bimaculatus'' from the Afrotropics).<ref name=":1">{{Cite journal |last1=Arce-Pérez |first1=Roberto |last2=Novelo-Gutiérrez |first2=Rodolfo |last3=Fery |first3=Hans |date=2021-11-04 |title=Cybister (s. str.) poblanus sp. n. from Mexico and notes on other species of Cybistrinae (Coleoptera: Dytiscidae) |url=https://mapress.com/zt/article/view/zootaxa.5061.2.5 |journal=Zootaxa |language=en |volume=5061 |issue=2 |pages=323–339 |doi=10.11646/zootaxa.5061.2.5 |pmid=34810625 |issn=1175-5334|url-access=subscription }}</ref> Adult males of the North American species have several ridges on the coxae of the hind legs, forming a stridulatory device.<ref name=":1" />

Larvae have a frontal tooth on the head and lack cerci. North American species can grow up to 80 mm long.<ref name=":0" />

== Ecology == ''Cybister'' live in lentic (still fresh water) habitats that have vegetation.<ref>{{Cite web |last=Liao |first=Wenfei |date=2018-08-19 |title=Cybister, an Immigrant in Finland |url=https://wenfeiliao.wordpress.com/2018/08/19/cybister-an-immigrant-in-finland/ |access-date=2023-03-02 |website=Wenfei's Blog |language=en}}</ref>

Like other diving beetles, ''Cybister'' are predatory. Larvae of ''C. japonicus'' prey on insects (mainly Odonata nymphs and the backswimmer ''Notonecta triguttata'') in their first two instars, while third-instar larvae prey on vertebrates (tadpoles and fish).<ref>{{Cite journal |last=Ohba |first=Shin-Ya |date=2009-06-01 |title=Ontogenetic Dietary Shift in the Larvae of Cybister japonicus (Coleoptera: Dytiscidae) in Japanese Rice Fields |journal=Environmental Entomology |language=en |volume=38 |issue=3 |pages=856–860 |doi=10.1603/022.038.0339 |issn=0046-225X|doi-access=free |pmid=19508796 |hdl=10069/25389 |hdl-access=free }}</ref> Larvae of ''C. rugosus'' feed on both invertebrates and vertebrates in all instars.<ref>{{Cite journal |last1=Yamasaki |first1=Shun |last2=Watanabe |first2=Kohei |last3=Ohba |first3=Shin-ya |date=2022 |title=Larval feeding habits of the large-bodied diving beetle Cybister rugosus (Coleoptera: Dytiscidae) under laboratory conditions |url=https://onlinelibrary.wiley.com/doi/10.1111/ens.12510 |journal=Entomological Science |language=en |volume=25 |issue=2 |doi=10.1111/ens.12510 |issn=1343-8786|url-access=subscription }}</ref>

== Importance == ''Cybister chinensis'' (sometimes misidentified as ''C. japonicus'') is used in a game in Korea. The water beetle game (''mul bang gae nori'') is played in an oval, water-filled tank with vertical flanges along its inner edge and prizes on the tank rim. The game is played by dropping a ''C. chinensis'' through a funnel into the center of the tank, after which it swims towards the edge of the tank and stops in one of the slots formed by the metal flanges. If a prize is above this slot, the player wins it.<ref>{{Cite journal |last=Pemberton |first=R. W. |date=1990 |title=The Korean water beetle game |url=https://www.researchgate.net/publication/345258341 |journal=Pan-Pacific Entomologist |volume=66 |issue=2 |pages=172–174}}</ref>

The swimming behaviour of ''C. lateralimarginalis'' has inspired (biomimetics) the design of a legged underwater robot.<ref>{{Cite journal |last1=Kim |first1=Heejoong |last2=Lee |first2=Jihong |date=2017 |title=Design, swimming motion planning and implementation of a legged underwater robot (CALEB10: D.BeeBot) by biomimetic approach |url=https://linkinghub.elsevier.com/retrieve/pii/S0029801816305133 |journal=Ocean Engineering |language=en |volume=130 |pages=310–327 |doi=10.1016/j.oceaneng.2016.11.006|bibcode=2017OcEng.130..310K |url-access=subscription }}</ref>

==List of species== ===Subgenus ''Cybister'' Curtis, 1827=== * ''Cybister alluaudi'' Guignot, 1936 * ''Cybister bengalensis'' Aubé, 1838 * ''Cybister buqueti'' Aubé, 1838 * ''Cybister cardoni'' Severin, 1890 * ''Cybister celebensis'' Sharp, 1882 * ''Cybister cephalotes'' Sharp, 1882 * ''Cybister chinensis'' Motschulsky, 1854 * ''Cybister cinctus'' Sharp, 1882 * ''Cybister cognatus'' Sharp, 1882 * ''Cybister concessor'' Guignot, 1947 * ''Cybister confusus'' Sharp, 1882 * ''Cybister crassipes'' Sharp, 1882 * ''Cybister crassiusculus'' Régimbart, 1895 * ''Cybister dejeanii'' Aubé, 1838 * ''Cybister dytiscoides'' Sharp, 1882 * ''Cybister ellipticus'' LeConte, 1852 * ''Cybister explanatus'' LeConte, 1852 * ''Cybister extenuans'' (Walker, 1858) * ''Cybister favareli'' Guignot, 1936 * ''Cybister fimbriolatus'' (Say, 1823) * ''Cybister fumatus'' Sharp, 1882 * ''Cybister godeffroyi'' (Wehncke, 1876) * ''Cybister gracilis'' Sharp, 1882 * ''Cybister gschwendtneri'' Guignot, 1935 * ''Cybister guerini'' Aubé, 1838 * ''Cybister guignoti'' Gschwendtner, 1936 ** ''Cybister guignoti pseudosenegalensis'' Guignot, 1936 * ''Cybister hypomelas'' Régimbart, 1892 * ''Cybister janczyki'' Mouchamps, 1957 * ''Cybister javanus'' Aubé, 1838 * ''Cybister laevis'' Falkenström, 1936 * ''Cybister lateralimarginalis'' (De Geer, 1774) ** ''Cybister lateralimarginalis ponticus'' Sharp, 1882 ** ''Cybister lateralimarginalis torquatus'' (Fischer von Waldheim, 1829) * ''Cybister lewisianus'' Sharp, 1873 * ''Cybister limbatus'' (Fabricius, 1775) * ''Cybister loxidiscus'' Wilke, 1920 * ''Cybister natalensis'' (Wehncke, 1876) * ''Cybister nebulosus'' Gschwendtner, 1931 * ''Cybister occidentalis'' Aubé, 1838 * ''Cybister pectoralis'' Sharp, 1882 * ''Cybister pederzanii'' Rocchi, 1979 * ''Cybister poblanus'' Arce-Pérez, Novelo-Gutiérrez, & Fery, 2021 * ''Cybister reichei'' Aubé, 1838 * ''Cybister rugosus'' (W.S.Macleay, 1825) * ''Cybister rugulosus'' (Redtenbacher, 1844) * ''Cybister schoutedeni'' Gschwendtner, 1932 * ''Cybister semiaciculatus'' Schaufuss, 1887 * ''Cybister senegalensis'' Aubé, 1838 * ''Cybister straeleni'' Guignot, 1952 * ''Cybister tibialis'' Sharp, 1882 * ''Cybister tripunctatus'' (Olivier, 1795) ** ''Cybister tripunctatus africanus'' Laporte, 1835 ** ''Cybister tripunctatus lateralis'' (Fabricius, 1798) ** ''Cybister tripunctatus temnenkii'' Aubé, 1838 * ''Cybister ventralis'' Sharp, 1882 * ''Cybister weckwerthi'' Hendrich, 1997 * ''Cybister wittmeri'' Brancucci, 1979 * ''Cybister yulensis'' Guignot, 1956

===Subgenus ''Megadytoides'' Brinck, 1945=== * ''Cybister marginicollis'' Boheman, 1848

===Subgenus ''Melanectes'' Brinck, 1945=== * ''Cybister alemon'' Guignot, 1948 * ''Cybister aterrimus'' Régimbart, 1899 * ''Cybister basilewskyi'' Guignot, 1950 * ''Cybister bellicosus'' Guignot, 1947 * ''Cybister bimaculatus'' Aubé, 1838 * ''Cybister blotei'' Guignot, 1936 * ''Cybister brevis'' Aubé, 1838 * ''Cybister burgeoni'' Guignot, 1947 * ''Cybister convexus'' Sharp, 1882 * ''Cybister danxiaensis'' Jiang, Zhao, Mai, Jia & Hendrich, 2023 * ''Cybister dehaanii'' Aubé, 1838 * ''Cybister desjardinsii'' Aubé, 1838 * ''Cybister dissentiens'' Mouchamps, 1957 * ''Cybister distinctus'' Régimbart, 1878 * ''Cybister ertli'' Zimmermann, 1917 * ''Cybister feraudi'' Guignot, 1934 * ''Cybister griphodes'' Guignot, 1942 * ''Cybister immarginatus'' Fabricius, 1798) * ''Cybister insignis'' Sharp, 1882 ** ''Cybister insignis caprai'' Guignot, 1949 ** ''Cybister insignis purpureovirgatus'' Guignot, 1946 * ''Cybister irritans'' (Dohrn, 1875) * ''Cybister longulus'' Gschwendtner, 1932 * ''Cybister lynceus'' J.Balfour-Browne, 1950 * ''Cybister mesomelas'' Guignot, 1942 * ''Cybister mocquerysi'' Régimbart, 1895 * ''Cybister modestus'' Sharp, 1882 * ''Cybister nigrescens'' Gschwendtner, 1933 * ''Cybister nigripes'' Wehncke, 1876 * ''Cybister operosus'' Sharp, 1882 * ''Cybister owas'' Laporte, 1835 * ''Cybister papuanus'' Guignot, 1956 * ''Cybister pinguis'' Régimbart, 1895 * ''Cybister posticus'' Aubé, 1838 * ''Cybister procax'' Guignot, 1947 **''Cybister procax vicinatus'' Mouchamps, 1957 * ''Cybister prolixus'' Sharp, 1882 * ''Cybister semirugosus'' Harold, 1878 * ''Cybister siamensis'' Sharp, 1882 * ''Cybister smaragdinus'' Régimbart, 1895 * ''Cybister sugillatus'' Erichson, 1834 * ''Cybister sumatrensis'' Régimbart, 1883 * ''Cybister thermolytes'' Guignot, 1947 * ''Cybister vicinus'' Zimmermann, 1917 * ''Cybister vulneratus'' Klug, 1834 * ''Cybister zimmermanni'' Mouchamps, 1957

===Subgenus ''Neocybister'' K.B. Miller, Bergsten & Whiting, 2007=== * ''Cybister festae'' Griffini, 1895 * ''Cybister puncticollis'' (Brullé, 1837)

=== Subgenus unknown ===

* ''Cybister parvus'' Trémouilles, 1984

===Fossil species=== These seven extinct species are known only from fossils: * †''Cybister agassizi'' Heer, 1862 * †''Cybister atavus'' Heer, 1862 * †''Cybister fractus'' Riha, 1974 * †''Cybister imperfectus'' Riha, 1974 * †''Cybister mancus'' Riha, 1974 * †''Cybister nicoleti'' Heer, 1862 * †''Cybister rotundatus'' Riha, 1974

==References== {{Reflist}}

==External links== *[https://web.archive.org/web/20071001081744/http://www.faunaeur.org/full_results.php?id=119194 ''Cybister'' on Fauna Europaea] *[http://bugguide.net/node/view/14512 ''Cybister'' on BugGuide.Net] * [http://insects.tamu.edu/research/collection/hallan/test/Arthropoda/Insects/Coleoptera/Family/Coleoptera1.htm Synopsis of the described coleoptera of the world]

*{{Commons-inline}} *{{Wikispecies-inline}}

Category:Dytiscidae genera Category:Dytiscidae