Biology of reproduction and postnatal development of a little-studied Schelkovnikov’s pine vole Microtus schelkovnikovi Satunin, 1907 (Rodentia, Arvicolinae)

Schelkovnikov’s pine vole Microtus schelkovnikovi is a little-studied endemic species of the Talysh-Western Alborz Mountains, covered with relict Hyrcanian broad-leaved forests. Laboratory studies have shown the seasonality of reproduction in the species. M. schelkovnikovi voles have low breeding intensity and small litters, however maintain long-term reproductive activity. Social monogamy is a characteristic of the species under laboratory conditions. Most of the predictions of monogamy are found in M. schelkovnikovi: females mating only within formed pairs, prolonged courtship, small litters, small testes and a low number of ejaculations in males. The copulatory stereotype in M. schelkovnikovi is characterized by a low number of ejaculations, triggered by numerous intromissions and an average level of genital stimulation. The pattern of copulatory stereotype unites the Schelkovnikov’s pine vole with species of such taxa as Microtus s. str., Sumeriomys, and Terricola, which corresponds to distinguishing the West Palearctic branch of voles in the tribe Arvicolini and opposes the East Asian branch identified on the basis of molecular studies.