Socio‐genetic structure of mound‐building mice, Mus spicilegus , in autumn and early spring

Mus spicilegus has become a popular biological model species in the last decade because of the evolutionary interest of its behavioural particularities (the building of mounds, bi‐parental care and monogamous mating system). The genetic structure of M. spicilegus populations should reflect those life‐history traits. Although many studies have reported on mound‐building mouse populations in the field or in a semi‐natural enclosure, only one used hyper variable genetic markers to assess parentage and social structure. In the present study conducted in Hungary, we analysed individuals from seven highly populous mounds in autumn with the set of loci used in a previous study. Our results confirmed that mounds are inhabited by juveniles from several parental units, but revealed population differences. In a capture–recapture field session in spring, we assessed genetic relationships between individuals after dispersal from the mounds, the other key moment of the life cycle of this species. The results indicate that the social structure at this moment reflects a transition phase between the large over‐wintering groups and the monogamous pairs described later in the year. Social bounds forged during the long winter cohabitation may have lasting effects on social and genetic structure of this species. This scenario is discussed in respect of the available literature on this species as well as other species. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 689–699.