NEW DATA ON CHROMOSOMAL VARIABILITY, DISTRIBUTION OF SIBLING-SPECIES AND HYBRIDIZATION OF 46-CHROMOSOMAL FORMS OF MICROTUS ARVALIS SENSU LATO (RODENTIA, ARVICOLINAE) IN THE UPPER VOLGA RIVER BASIN

摘要

New data on the species composition, intraspecific structure, geographical distribution of sibling-species of common voles in the Upper Volga River basin, and the data on the frequency of occurrence and temporary dynamics of the complex chromosomal rearrangement of the fifth pair of autosomes in the Microtus arvalis form obscurus in populations from Nizhny Novgorod region are submitted. A total of 100 specimens of M. arvalis s. 1. collected in 18 localities of the area studied were identified using the methods of chromosomal analysis (routine staining of chromosomes, AgNOR-, C-, G-banding). The following forms of M. arvalis s. 1. were distinguished in the sampling studied: M. rossiaemeridionalis (n = 4), M. arvalis form obscurus (n = 82), M. arvalis form arvalis (n = 11), and 3 specimens of F-1 between the last two. The obtained results confirm ideas of a taxonomical variety of M arvalis s. 1. in the Upper Volga River basin and make a contribution to cadastres of M rossiaemeridionalis, M. arvalis form arvalis and M arvalis form obscurus. In addition, they promote to specify the borders of the distribution of 46-chromosomal forms of M. arvalis s. 1. in the Upper Volga basin and point to the hybridization between them in Nizhny Novgorod region (Sokolsky district), at the territory of which the records of M. arvalis form arvalis and of F-1 hybrids were registered for the first time.