''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are predators of Collembola and other small arthropods. Adults have a protrusible labium with a sticky tip used in prey capture. To overcome the rapid escape of Collembola, the labium is protruded at high speed (1-3 ms in ''Stenus comma'') by hemolymph pressure, and immediately withdrawn (withdrawn in 30-40 ms in ''Stenus comma''), pulling the prey within the range of the mandibles. However, the labium tip does not easily stick to preys covered in scales or setae or that have a large body size. ''Stenus comma'' is more likely to catch such preys by lunging forward and grabbing them directly with its mandibles rather than using its labium. ''Stenus'' species are also known for "skimming" on the water surface using their pygidial gland secretions that act as a

surfactant Surfactants are chemical compounds that decrease the surface tension between two liquids, between a gas and a liquid, or interfacial tension between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming ...

and rapidly propel the beetle fast forward, a phenomenon known as the Marangoni effect. ''Stenus comma'' has been seen to achieve a velocity of 0.75 m/s, and to cover a distance of up to 15 m if the secretion is continuous.

Selected Species

* ''

Stenus adelops ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' Casey, 1884 * '' Stenus adspector'' Maklin, 1852 * ''

Stenus advena ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are pred ...

'' (Casey, 1884) * ''

Stenus agnatus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' (Casey, 1884) * ''

Stenus alacer ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' Casey, 1884 * ''

Stenus alpicola ''Stenus alpicola'' is a species of rove beetle in the genus ''Stenus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (o ...

'' Fauvel, 1872 * ''

Stenus alveolatus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' Casey, 1884 * ''

Stenus amabilis ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' (Casey, 1884) * '' Stenus amicus'' Casey, 1884 * '' Stenus amplifacatus'' Benick, 1921 * ''

Stenus angustus ''Stenus angustus'' is a species of water skater in the beetle family Staphylinidae The rove beetles are a family (Staphylinidae) of beetles, primarily distinguished by their short elytra (wing covers) that typically leave more than half of t ...

'' Casey, 1884 * '' Stenus animatus'' Casey, 1884 * '' Stenus annularis'' Erichson, 1840 * '' Stenus arculus'' Casey, 1840 * '' Stenus argus'' Gravenhorst, 1806 * '' Stenus arizonae'' Casey, 1884 * '' Stenus artus'' Casey, 1884 * '' Stenus austini'' Casey, 1884 * ''

Stenus bakeri ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' Bernhauer, 1910 * ''

Stenus biguttatus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' (Linnaeus, 1758) * ''

Stenus bilentigatus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' Casey, 1884 * ''

Stenus bipunctatus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' Erichson, 1839 * ''

Stenus biwenxuani ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are pred ...

'' Tang & Li, 2013 * ''

Stenus caenicolus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' Notman, 1919 * ''

Stenus californicus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are preda ...

'' Casey, 1884 * ''

Stenus callosus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are preda ...

'' Erichson, 1840 * ''

Stenus canadensis ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' (Casey, 1884) * ''

Stenus canaliculatus ''Stenus canaliculatus'' is a species of rove beetles native to Europe.Norman H. Joy, , 1932 ''A Practical Handbook of British Beetles ''A Practical Handbook of British Beetles'' is a two-volume work on the British beetle fauna, by Norman H. ...

'' Gyllenhal, 1827 * ''

Stenus capucinus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' Boheman, 1858 * ''

Stenus cariniceps ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are preda ...

'' Maklin, 1852 * ''

Stenus carinicollis ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are preda ...

'' Casey, 1884 * ''

Stenus carolinae ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are preda ...

'' Casey, 1884 * ''

Stenus carolinus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are pred ...

'' Bernhauer, 1917 * ''

Stenus chalybeus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are pred ...

'' Boheman, 1858 * ''

Stenus chapini ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are pred ...

'' Blackwelder, 1943 * ''

Stenus colon ''Stenus colon'' is a species of water skater, Genus ''Stenus'', in the beetle family Staphylinidae The rove beetles are a family (Staphylinidae) of beetles, primarily distinguished by their short elytra (wing covers) that typically leave mor ...

'' Say, 1834 * ''

Stenus colonus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are pred ...

'' Erichson, 1840 * ''

Stenus comma ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' LeConte 1863 * ''

Stenus convictor ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are preda ...

'' Casey, 1884 * ''

Stenus corvus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are pred ...

'' Casey, 1884 * ''

Stenus costalis ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are preda ...

'' Casey, 1884 * ''

Stenus croceatus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus ''Agrilus'' is comparable in size). They are predato ...

'' (Casey, 1884) * ''

Stenus cubanus ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are pred ...

'' Blackwelder, 1943 * ''

Stenus cubensis ''Stenus'' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genus in the kingdom Animalia, with some 2700 known species worldwide (only the beetle genus '' Agrilus'' is comparable in size). They are preda ...

'' Bernhauer, 1910 * ''