Composition of the Fauna and Pattern of Biotopic Distribution of Bugs (Heteroptera) in the Vicinity of Pevek (Chukotka Autonomous Okrug)

The species richness in the order Heteroptera declines sharply to the north of the forest boundary. Here we present the results of a study of this group in the north of Chaunskiy District (Western Chukotka, the typical tundra subzone). Collections were carried out in 2011 in three landscape areas. Altogether, 32 species of bugs from 8 families were collected, such species richness being quite high for the north of the tundra zone. Widespread multizonal and boreal species made up more than a half of the fauna. Among the most common species there were many xerophilous bugs, including those dominant in the cryophytic steppes of Northeast Asia. Cryophilous bugs, including the Arctic species Chiloxanthus arcticus , Ch. stellatus stellatus , Calacanthia trybomi , and Orthotylus artemisiae , showed high abundance only in certain biotopes, with the exception of the cryoxerophilous species Nysius ericae groenlandicus . The composition of dominants was the most constant in habitats with high percentage of wormwoods, such as zoogenic meadows, ruts, and roadsides, where Europiella artemisiae and N. e. groenlandicus were always present while O. artemisiae occurred locally. A stable composition of bug assemblages was also found on the southern hill slopes where Chlamydatus pullus , N. e. groenlandicus , Coriomerus scabricornis , and Antheminia eurynota remota were the most common. The species composition of bugs in other types of habitats was variable. The Heteroptera complexes differed in their taxonomic, latitudinal, and ecological composition in areas with different landscape and climatic conditions. The Arctic bug species formed the core of the fauna only in humid and coastal habitats in the lowland part of the study region. Absolute dominance of xerophilous species (including tundra and steppe ones) and an almost complete absence of hygrophilous species (resulting in extreme poverty of the bug assemblages in humid habitats) determined the similarity between the bug complex of the northern (driest) part of the mountain area and those in the highlands of the southern Verkhoyansk Area. In the southern, more humid part of the area with more numerous water bodies, the bug fauna was similar to those of the forest-tundra due to lower participation of Arctic species and a higher percentage of southern ones. The high species richness and uniqueness of the Heteroptera assemblages in the study region may have been the result of their continuous development under the condition