Mesostigmatic mites (Parasitiformes, Mesostigmata) of polar deserts in the Severnaya Zemlya Archipelago

摘要

Eighteen species of mesostigmatic mites were described in the course of two expeditions to Bol'shevik Island (the Severnaya Zemlya Archipelago) in 1997-1998. Among them, seven species are circumpolar, the majority of the rest are known from various arctic regions of Eurasia, and only two species are polyzonal, the palaearctic Arctoseius semiscissus (Berl.) and the holarctic ectoparasite of mammals Haemogamasus ambulans (Thorell). The distribution of two new species of Arctoseius Thor, obviously, is limited by the polar desert zone. For the archipelago fauna the predominance of the species belonging to the genus Arctoseius (11) is characteristic, that forms a great part of the mesostigmatid population in most communities. The representatives of six other genera inhabit only intrazonal sites. Among Arctoseius species, some groupings were distinguished: soil species, inhabitants of small zoogenic meadows, lemming burrows, and various accumulations of decomposing materials. The possible ecological reasons of the Arctoseius prosperity in the Arctic are discussed, among which are probable as follows: a high abundance of potential preys (Collembola, Nematocera), weak press of predators and possible competitors, inclination to "insular" enriched habitats related to phoretic association with trichocerid flies.