Communal Reproduction of Females of Two Subspecies of Harting’s Vole Microtus (Sumeriomys) hartingi (Rodentia, Arvicolinae) under Experimental Conditions

Successful reproduction of two subspecies of Harting’s vole in monogamous pairs (monogamous groups, 35 pairs for each) was shown. The results obtained in modeling the experimental polygyny revealed a different attitude of females of the two subspecies to the formation of communal groups. In polygynous groups of M. h. lydius , regardless of the relationship of the females (35 groups consisting of sisters and 20 groups of unrelated females), the intensity of reproduction and the proportion of successfully reared pups decreased significantly compared to the monogamous groups. With high energy costs for reproduction, there were significantly fewer reared pups per mother giving birth than in the monogamous groups, thus suggesting the predominance of monogamy in this subspecies. On the contrary, related females of M. h. hartingi bred successfully in communal groups (35 groups of sisters), demonstrating a high tolerance, a tendency to co-rearing and feeding the pups, and low infant mortality. In polygynous groups consisting of unrelated females (20 groups), reproductive success decreased due to increased infant mortality. Possible benefits of communal reproduction in this subspecies are discussed, as well as the likely relationship with habitat fragmentation under such conditions and with a lack of vacancies for the dispersal of young animals, which may be an important adaptation for this subspecies of voles.