Stenus
Introduction '''''Stenus''''' is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genera 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Collembola, the labium is protruded at high speed (1-3 ms in ''Stenus comma'') by hemolymph pressure, and immediately withdrawn (withdrawn in 30-40 ms in ''Stenus comma''), pulling the prey within the range of the mandibles.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 prey covered in scales or setae or that have a large body size. ''Stenus comma'' is more likely to catch such prey 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 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 mif the secretion is continuous.
Selected Species * ''Stenus adelops'' Casey, 1884* ''Stenus adspector'' Maklin, 1852* ''Stenus advena'' (Casey, 1884)* ''Stenus agnatus'' (Casey, 1884)* ''Stenus alacer'' Casey, 1884* ''Stenus alpicola'' Fauvel, 1872* ''Stenus alveolatus'' Casey, 1884* ''Stenus amabilis'' (Casey, 1884)* ''Stenus amicus'' Casey, 1884* ''Stenus amplifacatus'' Benick, 1921* ''Stenus angustus'' 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'' Bernhauer, 1910* ''Stenus biguttatus'' (Linnaeus, 1758)* ''Stenus bilentigatus'' Casey, 1884* ''Stenus bipunctatus'' Erichson, 1839* ''Stenus biwenxuani'' Tang & Li, 2013* ''Stenus caenicolus'' Notman, 1919* ''Stenus californicus'' Casey, 1884* ''Stenus callosus'' Erichson, 1840* ''Stenus canadensis'' (Casey, 1884)* ''Stenus canaliculatus'' Gyllenhal, 1827* ''Stenus capucinus'' Boheman, 1858* ''Stenus cariniceps'' Maklin, 1852* ''Stenus carinicollis'' Casey, 1884* ''Stenus carolinae'' Casey, 1884* ''Stenus carolinus'' Bernhauer, 1917* ''Stenus chalybeus'' Boheman, 1858* ''Stenus chapini'' Blackwelder, 1943* ''Stenus colon'' Say, 1834* ''Stenus colonus'' Erichson, 1840* ''Stenus comma'' LeConte 1863* ''Stenus convictor'' Casey, 1884* ''Stenus corvus'' Casey, 1884* ''Stenus costalis'' Casey, 1884* ''Stenus croceatus'' (Casey, 1884)* ''Stenus cubanus'' Blackwelder, 1943* ''Stenus cubensis'' Bernhauer, 1910* ''Stenus curtus'' Casey, 1884* ''Stenus delawarensis'' Casey, 1884* ''Stenus dispar'' Casey, 1884* ''Stenus dissentiens'' Casey, 1884* ''Stenus dives'' Casey, 1884* ''Stenus dolosus'' Casey, 1884* ''Stenus dyeri'' Blackwelder, 1943* ''Stenus edax'' Notman, 1920* ''Stenus ellipticus'' Casey, 1884* ''Stenus eriensis'' Casey, 1884* ''Stenus erythropus'' Melsheimer, 1844* ''Stenus exasperatus'' Benick, 1925* ''Stenus exploratus'' Fall, 1926* ''Stenus falli'' Scheerpeltz, 1933* ''Stenus femoratus'' Say, 1834* ''Stenus flavicornis'' Erichson, 1840* ''Stenus floridanus'' Casey, 1884* ''Stenus fraternus'' (Casey, 1884)* ''Stenus frigidus'' Falls, 1926* ''Stenus fulvoguttatus'' Notman, 1920* ''Stenus gemmeus'' Casey, 1884* ''Stenus gibbicollis'' Sahlberg, 1880* ''Stenus gilae'' Casey, 1884* ''Stenus gratiosus'' Casey, 1884* ''Stenus gravidus'' Casey, 1884* ''Stenus haitiensis'' Blackwelder, 1943* ''Stenus hirsutus'' Casey, 1884* ''Stenus hispaniolus'' Blackwelder, 1943* ''Stenus hubbardi'' Casey, 1884* ''Stenus immarginatus'' Mäklin, 1853* ''Stenus incertus'' Casey, 1884* ''Stenus incultus'' Casey, 1884* ''Stenus indigens'' Casey, 1884* ''Stenus ingratus'' Casey, 1884* ''Stenus inornatus'' Casey, 1884* ''Stenus insignis'' Casey, 1884* ''Stenus integer'' Casey, 1884* ''Stenus intrusus'' Casey, 1884* ''Stenus juno'' (Paykull, 1789)* ''Stenus juvencus'' Casey, 1884* ''Stenus laetulus'' (Casey, 1884)* ''Stenus leviceps'' Casey, 1884* ''Stenus limatulus'' Benick, 1928* ''Stenus liupanshanus'' Tang & Li, 2013* ''Stenus luctuosus'' Casey, 1884* ''Stenus luculentus'' Casey, 1884* ''Stenus lugens'' Casey, 1884* ''Stenus lutzi'' Notman, 1920* ''Stenus maritimus'' Motschulsky, 1845* ''Stenus megalops'' (Casey, 1884)* ''Stenus mendax'' Casey, 1884* ''Stenus meridionalis'' (Casey, 1884)* ''Stenus militaris'' Casey, 1884* ''Stenus minor'' Casey, 1884* ''Stenus montanus'' Casey, 1884* ''Stenus monticola'' Casey, 1884* ''Stenus morio'' Gravenhorst, 1806* ''Stenus mundulus'' Casey, 1884* ''Stenus murphyanus'' Bernhauer, 1917* ''Stenus nanus'' Stephens, 1833* ''Stenus neglectus'' Casey, 1884* ''Stenus nimbosus'' Casey, 1884* ''Stenus nitescens'' (Casey, 1884)* ''Stenus noctivagus'' Casey, 1884* ''Stenus obstrusus'' Casey, 1884* ''Stenus occidentalis'' Casey, 1884* ''Stenus odius'' Blackwelder, 1943* ''Stenus pacificus'' Casey, 1884* ''Stenus papagonis'' (Casey, 1884)* ''Stenus parallelus'' Casey, 1884* ''Stenus pauper'' Casey, 1884* ''Stenus pauperculus'' Casey, 1884* ''Stenus perexilis'' Notman, 1920* ''Stenus personatus'' Benick, 1928* ''Stenus pertinax'' (Casey, 1884)* ''Stenus pettiti Casey, 1884* ''Stenus pinguis'' (Casey, 1884)* ''Stenus placidus'' Casey, 1884* ''Stenus plicipennis'' (Casey, 1884)* ''Stenus pluto'' Casey, 1884* ''Stenus pollens'' (Casey, 1884)* ''Stenus pterobrachys'' Gemminger & Harold, 1868* ''Stenus pudicus'' Casey, 1884* ''Stenus pugetensis'' Casey, 1884* ''Stenus pumilio'' Erichson, 1839* ''Stenus punctatus'' Erichson, 1840* ''Stenus punctiger'' Casey, 1884* ''Stenus ranops'' Casey, 1884* ''Stenus renifer'' LeConte, 1863* ''Stenus retrusus'' (Casey, 1884)* ''Stenus rugifer'' Casey, 1884* ''Stenus sayi'' (Casey, 1884)* ''Stenus scabiosus'' Casey, 1884* ''Stenus schwarzi'' Casey, 1884* ''Stenus sculptilis'' Casey, 1884* ''Stenus sectator'' Casey, 1884* ''Stenus sectilifer'' Casey, 1884* ''Stenus semicolon'' LeConte, 1863* ''Stenus shoshonis'' Casey, 1884* ''Stenus similiatus'' Blatchley, 1910* ''Stenus simplex'' Casey, 1884* ''Stenus solutus'' Erichson 1840* ''Stenus sphaerops'' Casey, 1884* ''Stenus strangulatus'' Casey, 1884* ''Stenus stygicus'' Say, 1834* ''Stenus subtilis'' Casey, 1884* ''Stenus tacomae'' Casey, 1884* ''Stenus tahoensis'' Casey,1884* ''Stenus tarsalis'' Ljungh, 1804* ''Stenus tenuis'' Casey, 1884* ''Stenus terricola'' Casey, 1884* ''Stenus teter'' Notman, 1920* ''Stenus texanus'' Casey, 1884* ''Stenus torus'' Benick, 1925* ''Stenus trajectus'' (Casey, 1884)* ''Stenus tristis'' Casey, 1884* ''Stenus tuberculatus'' Casey, 1884* ''Stenus utenis'' Casey, 1884* ''Stenus vacuus'' Casey, 1884* ''Stenus venustus'' Casey, 1884* ''Stenus verticosus'' Casey, 1884* ''Stenus vespertinus'' Casey, 1884* ''Stenus vestalis'' Casey, 1884* ''Stenus vexatus'' Casey, 1884* ''Stenus vicinus'' Casey, 1884* ''Stenus villosus'' Casey, 1884* ''Stenus vinnulus'' Casey, 1884* ''Stenus vista'' Sanderson, 1946* ''Stenus zunicus'' Casey, 1884
References