Abstract: | Fauna of parasitic and free-living arthropods associated the water vole Arvicola terestris and its nests in various landscape zones and subzones of the south of Western Siberia has been studied. Total abundance of gamasid mites and ticks (Gamasoidea, Ixodidae), fleas and nidicolous arthropods in nests is high, and the set of nidicolous and parasite species is quite diverse, but everywhere the parasite fauna is characterized by a small amount of species reaching a high abundance: Laelaps muris on the voles, Haemogamasus ambulans in nests, Ixodes apronophorus and Megpbotris walkeri both on the voles and nests. Parasitic arthropods living on the voles or in their nests are characterized by higher and stables indices of infection, while these parameters for free-living arthropods were variable. The list of mesostigmatic mites parasitizing the water vole and its nests in the south of Western Siberia (Adamovich, Krylov, 2001) has been considerably supplemented. In total, the fauna of parsitiform mites (Acari: Mesostigmata and Ixodiddes) and fleas (Siphonaptera) associated with the water vole in the south of Western Siberia is represented by 97 arthropod species of 19 families, including 74 species of mesostigmatic mites (Gamasoidea), 6 species of ticks (Ixodidae) and 17 species of fleas. |