Is the socio-spatial distribution of mound-building mice, Mus spicilegus, compatible with a monogamous mating system?

Abstract

International audienceWe tested whether the socio-spatial distribution of mound-building mice, Mus spicilegus, could be compatible with a monogamous mating system as suggested by several behavioural laboratory studies. A five day trapping session took place in an agricultural field in the Gyöngyös region (Hungary) at the end of April 2000. The species was identified through genetic techniques based on the microsatellite locus Musmcka. In total 43 animals were captured, and recapture rate was high (6/10 for males, 17/33 for females). Out of the 33 captured females, 17 were pregnant. Animals were generally recaptured in the same trap. Spatial associations (animals captured in the same trap) were observed between a male and a female (six cases) but also between females (six pairs and two trios) with or without a male. Based on these results we questioned the occurrence of monogamy and we proposed that polygyny could occur at least during the beginning of the reproductive season and in this studied population. Female biased sex-ratio and high population density may have favoured polygyny. However, associations between females could have resulted from the development of strong social bounds during the six months spent together during winter inside the mound. A possible consequence is that polygyny might be restricted to the over-wintering generation