Water bugs (Heteroptera: Gerromorpha, Nepomorpha) of the Caucasus ecoregion

The Caucasian fauna of water bugs (Heteroptera: Gerromorpha, Nepomorpha) is reviewed based on data originating from literature survey, museum and private collections, and extensive field sampling. The diversity of Caucasus ecoregion is quite significant with 77 species and subspecies framed within 25 genera (17 in Nepomorpha, 8 in Gerromorpha), and 13 families (8 in Nepomorpha, 5 in Gerromorpha). Micronecta anatolica anatolica Lindberg, 1922, Sigara iranica Lindberg, 1964, S. samani tigranes Jansson, 1986, Velia kiritshenkoi Tamanini, 1958, and Gerris asper (Fieber, 1860) are reported for the first time from Georgia, M. anatolica anatolica, Notonecta maculata Fabricius, 1794, Mesovelia thermalis Horvath, 1915, and Gerris lacustris (Linnaeus, 1758) represent new records for Armenia, and Microvelia macani Brown, 1953 is new for Azerbaijan. A chorological and similarity analysis highlighted the connections with and between adjacent countries, with Caucasus ecoregion having the highest similarity of the water bug fauna with Turkey, whereas Iran and Russia (European territory) have the lowest. The largest number of shared species/subspecies was found between the Caucasus and Turkey (64 taxa), while the lowest was between Iran and Russia (40 taxa). Our results indicate that the Caucasus represents a composite of various faunal elements of different origin, ranging from Caucasian endemics to Afrotropico-Indo-Mediterranean and Holarctic.