The beetles of the families Helophoridae, Georissidae, Hydrophilidae, Hydraenidae, and Elmidae (Insecta: Coleoptera) of Kunashir Island and the Lesser Kurils

The fauna of Kunashir Island and the islands of the Lesser Kuril Chain contains 47 species from 18 genera of Georissidae, Helophoridae, Hydrophilidae, Hydraenidae, and Elmidae. Two species (Enochrus vilis (Sharp, 1884) and Ochthebius inermis Sharp, 1884) are recorded for Russia for the first time. Fifteen species are new to the fauna of Kunashir Island and the Lesser Kurils. The article contains an annotated list of species, including the studied material and published records. The article is illustrated by photographs of habitats and species, maps of their distribution in Kunashir. The relationships between the species richness on an island area and the features of the fauna of Kunashir in comparison with Hokkaido are discussed. The species richness of the studied Polyphaga families in Kunashir is almost 2/3 of the fauna of Hokkaido, while the island’s area is 55 times smaller. The reason for the absence of large species of the genera Hydrochara and Hydrophilus in Kunashir is hypothesized to be a restriction of the northern range species boundaries by the July isotherm of +16°С.