Ranatra is a genus of slender predatory insects of the family Nepidae, known as Water mantis, water scorpions or water stick-insects.www.itis.gov/ There are more than 140 Ranatra species found in freshwater habitats around the world, both in warm and temperate regions, with the highest diversity in South America (almost 50 species) and Asia (about 30 species, reviewed in 1972Lansbury I (1972) A review of the Oriental species of Ranatra Fabricius (Hemiptera-Heteroptera: Nepidae). Transactions of the Royal Entomological Society of London, vol. 124, no. 3. 287-341.). Fewer are found elsewhere, but include several African, some in North America, three from Australia and three from the Palearctic, notably the relatively well-known European R. linearis. Since Ranatra belongs to the family Nepidae which in turn belongs to the order Hemiptera, Ranatra are considered "true bugs".
These brown insects are primarily found in stagnant or slow-moving water like ponds, marshes and canals, but can also be seen in streams. Exceptionally they have been recorded from hypersaline lakes and brackish lagoons.
Biology The front legs of bugs in Ranatra are strong and used to grasp prey. They typically eat other insects, tadpoles and small fish, which they pierce with their proboscis and inject a saliva which both sedates and begins to digest their prey. They are sit-and-wait predators that reside among water plants and position themselves head-down with their grasping legs extended out to surprise passing prey. At least one species will also swim in open water at night to catch zooplanktonic organisms. Like other members in the family they have a long tail-like siphon, or breathing tube, on the rear end of their body. The adult body length is generally depending on the exact species, and females average larger than males of the same species. The siphon is typically almost the same size, but varies from less than half the body length to somewhat longer. Two of the largest species are the East Asian R. chinensis and South American R. magna. Ranatra do have wings and they can fly.
The adults are active year-round, except in extreme cold. Their eggs are positioned on plants just below the water surface, but in some species they can be placed in mud. The eggs typically take two to four weeks to hatch and the young take about two months to mature.
Among the four genera in the subfamily Ranatrinae, Austronepa and Goondnomdanepa are restricted to Australia. Cercotmetus from Asia to New Guinea resembles Ranatra, although the former has a distinctly shorter siphon.
Species The Global Biodiversity Information Facility lists:Global Biodiversity Information Facility: Ranatra Fabricius, 1790 (retrieved 12 January 2021)
Ranatra absona Drake & De Carlo, 1953 Ranatra acapulcana Drake & De Carlo, 1953 Ranatra adelmorpha Nieser, 1975 Ranatra aethiopica Montandon, 1903 Ranatra akoitachta Nieser, 1996 Ranatra ameghinoi De Carlo, 1970 Ranatra annulipes Stål, 1854 Ranatra attenuata Kuitert, 1949 Ranatra australis Hungerford, 1922 i c g b (southern water scorpion) Ranatra bachmanni De Carlo, 1954 Ranatra bilobata Tran & Nguyen, 2016 Ranatra biroi Lundblad, 1933 Ranatra bottegoi Montandon, 1903 Ranatra brasiliensis De Carlo, 1946 Ranatra brevicauda Montandon, 1905 Ranatra brevicollis Montandon, 1910 i c g b Ranatra buenoi Hungerford, 1922 i c g b Ranatra camposi Montandon, 1907 Ranatra capensis Germar, 1837 Ranatra cardamomensis Zettel, Phauk, Kheam & Freitag, 2017 Ranatra chagasi De Carlo, 1946 Ranatra chariensis Poisson, 1949 Ranatra chinensis Mayr, 1865 Ranatra cinnamomea Distant, 1904 Ranatra compressicollis Montandon, 1898 Ranatra costalimai De Carlo, 1954 Ranatra cruzi De Carlo, 1950 Ranatra curtafemorata Kuitert, 1949 Ranatra denticulipes Montandon, 1907 Ranatra digitata Hafiz & Pradhan, 1949 Ranatra diminuta Montandon, 1907 Ranatra dispar Montandon, 1903 Ranatra distanti Montandon, 1910 Ranatra doesburgi De Carlo, 1963 Ranatra dolichodentata Kuitert, 1949 Ranatra dormientis Zhang et al., 1994 Ranatra drakei Hungerford, 1922 Ranatra ecuadoriensis De Carlo, 1950 Ranatra elongata Fabricius, 1790 Ranatra emaciata Montandon, 1907 Ranatra fabricii Guérin-Méneville, 1857 Ranatra falloui Montandon, 1907 Ranatra feana Montandon, 1903 Ranatra fianarantsoana Poisson, 1963 Ranatra filiformis Fabricius, 1790 Ranatra flagellata Lansbury, 1972 Ranatra flokata Nieser & Burmeister, 1998 Ranatra fusca Palisot, 1820 i c g b (brown waterscorpion) Ranatra fuscoannulata Distant, 1904 Ranatra galantae Nieser, 1969 Ranatra gracilis Dallas, 1850 Ranatra grandicollis Montandon, 1907 Ranatra grandocula Bergroth, 1893 Ranatra hechti De Carlo, 1967 Ranatra heoki Tran & Poggi, 2019 Ranatra heydeni Montandon, 1909 Ranatra horvathi Montandon, 1910 Ranatra hungerfordi Kuitert, 1949 Ranatra incisa Chen, Nieser & Ho, 2004 Ranatra instaurata Montandon, 1914 Ranatra insulata Barber, 1939 Ranatra jamaicana Drake & De Carlo, 1953 Ranatra katsara Nieser, 1997 Ranatra kirkaldyi Torre-bueno, 1905 i c g b Ranatra lanei De Carlo, 1946 Ranatra lansburyi Chen, Nieser & Ho, 2004 Ranatra lenti De Carlo, 1950 Ranatra lethierryi Montandon, 1907 Ranatra libera Zettel, 1999 Ranatra linearis (Linnaeus, 1758) i c g Ranatra longipes Stål, 1861 Ranatra lualalai Poisson, 1964 Ranatra lubwae Poisson, 1965 Ranatra machrisi Nieser & Burmeister, 1998 Ranatra macrophthalma Herrich-Schäffer, 1849 Ranatra maculosa Kuitert, 1949 Ranatra magna Kuitert, 1949 Ranatra malayana Lundblad, 1933 Ranatra mediana Montandon, 1910 Ranatra megalops Lansbury, 1972 Ranatra mixta Montandon, 1907 Ranatra moderata Kuitert, 1949 Ranatra montei De Carlo, 1946 Ranatra montezuma Polhemus, 1976 Ranatra natalensis Distant, 1904 Ranatra natunaensis Lansbury, 1972 Ranatra neivai De Carlo, 1946 Ranatra nieseri Tran & Nguyen, 2016 Ranatra nigra Herrich-Schaeffer, 1849 Ranatra nodiceps Gerstaecker, 1873 Ranatra nodioeps Gerstaecker, 1873 Ranatra obscura Montandon, 1907 Ranatra occidentalis Lansbury, 1972 Ranatra odontomeros Nieser, 1996 Ranatra oliveiracesari De Carlo, 1946 Ranatra operculata Kuitert, 1949 Ranatra ornitheia Nieser, 1975 Ranatra parmata Mayr, 1865 Ranatra parvipes Signoret, 1861 Ranatra parvula Kuitert, 1949 Ranatra pittieri Montandon, 1910 Ranatra protense Montandon Ranatra quadridentata Stål, 1862 i c g b Ranatra rabida Buchanan White, 1879 Ranatra rafflesi Tran & D.Polhemus, 2012 Ranatra rapax Stål, 1865 Ranatra recta Chen, Nieser & Ho, 2004 Ranatra robusta Montandon, 1905 Ranatra sagrai Drake & De Carlo, 1953 Ranatra sarmientoi De Carlo, 1967 Ranatra sattleri De Carlo, 1967 Ranatra schuhi D.Polhemus & J.Polhemus, 2012 Ranatra segrega Montandon, 1913 Ranatra signoreti Montandon, 1905 Ranatra similis Drake & De Carlo, 1953 Ranatra siolii De Carlo, 1970 Ranatra sjostedti Montandon, 1911 Ranatra spatulata Kuitert, 1949 Ranatra spinifrons Montandon, 1905 Ranatra spoliata Montandon, 1912 Ranatra stali Montandon, 1905 Ranatra sterea Chen, Nieser & Ho, 2004 Ranatra subinermis Montandon, 1907 Ranatra sulawesii Nieser & Chen, 1991 Ranatra surinamensis De Carlo, 1963 Ranatra texana Hungerford, 1930 Ranatra thai Lansbury, 1972 Ranatra titilaensis Hafiz & Pradhan, 1949 Ranatra travassosi De Carlo, 1950 Ranatra tridentata Poisson, 1965 Ranatra tuberculifrons Montandon, 1907 Ranatra unicolor Scott, 1874 Ranatra unidentata Stål, 1861 Ranatra usingeri De Carlo, 1970 Ranatra varicolor Distant, 1904 Ranatra varipes Stål, 1861 Ranatra vitshumbii Poisson, 1949 Ranatra wagneri Hungerford, 1929 Ranatra weberi De Carlo, 1970 Ranatra williamsi Kuitert, 1949 Ranatra zeteki Drake & De Carlo, 1953
Data sources: i = ITIS, c = Catalogue of Life, g = GBIF, b = Bugguide.net
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