Density?dependent changes of mating system and family structure in Brandt's voles ( <i>Lasiopodomys brandtii</i> )

A mating system is an important life history for animals dealing with changing environments. Population density affects the plasticity of a and subsequently family structure animals, but its impacts on systems social structures are rarely investigated by using molecular markers in field conditions. In this study, microsatellite genetic markers, we examined changes Brandt's voles grassland Inner Mongolia, China, under low-, medium-, high-density enclosures (each enclosure 0.48-ha 4 replicates.) We found, increase population founder introduced into early spring, both sexes increased their number partners, while males resulting more promiscuous system. The fathers mothers per family, offspring male or female, proportion extra-group density, indicating that response to change, which consistent change observed our study. Both female had multiple mates, larger offspring, families. Our study highlights significance density-dependent affecting small mammals.