Zaika V.V. 2018. [Stoneflies (Plecoptera) of the Us River basin in the Western Sayan mountains, Russia] // Euroasian Entomological Journal. Vol.17. No.1: 18–25 [in Russian, with English summary].
Tuvinian Institute for Exploration of Natural Resources of SB RAS, Inernationalnaja Str. 117A, Kyzil 667007 Russia.
ABSTRACT. 23 stonefly species, Alaskaperla longidentata (Rauser, 1965), Arcynopteryx dichroa (McLachlan, 1872), A. amurensis (Zhiltzova, 1978), A. polaris (Klapalek, 1912), Alloperla deminuta (Zapekina-Dulkeit, 1970), A. rostellata (Klapalek, 1923), Amphinemura borealis (Morton, 1894), Capnia ahngeri Koponen, 1949, C. pigmaea ? Zetterstedt, 1840, Diura nanseni (Kempny, 1900), D. majuscula ? (Klapalek, 1912), Isoperla asiatica (Rauser, 1968), I. altaica (Samal, 1939), I. eximia (Zapekina-Dulkeit, 1975), I. lunigera (Klapalek, 1923), Megarcys ochracea (Klapalek, 1912), Nemoura arctica (Esben-Petersen, 1910), N. nigrodentata ? Zhiltzova, 1980, Paraleuctra zapekina Zhiltzova, 1974, Pictetiella asiatica Zwick et Levanidova, 1971, Skwala compacta (McLachlan, 1872), Suwallia teleckojensis (Samal, 1939) and Taenionema japonicum (Okamoto, 1922) were found during 2013-2016 in the typical rithral zones of the middle reaches of the Us River and the Buyba River. Isoperla altaica, one of the largest species of the Perlodidae family, and Suwallia teleckojensis of the family Chloroperlidae, were the most widespread. The reproduction period of Isoperla altaica lasts from the first 10 days of July until the third decade of August, and in Suwallia teleckojensis it coincides with the flight period of Chloroperlidae in the second decade of August. According to the Sørensen-Czekanowski Index, the similarity between stonefly faunas of the Western Sayan mountains and the Mountain Altai is 0.56, the Northern Altai is 0.64, and the Upper Yenisei is 0.59. The Western Sayan mountains present a faunal barrier which determines the differences in the faunas of the basins along the southern macroslope between the rivers flowing to the north and to the south. The occurrence of Arcynopteryx amurensis in the south-east Siberian rivers is of particular interest since it was previously known only from the Far East.
KEY WORDS: Plecoptera, fauna, of Us River basin, Western Sayan.