SOCIAL INTERACTIONS IN APODEMUS MYSTACINUS: AN AUTUMNAL INCREASE OF AGGRESSION AT THE ONSET OF BREEDING

Abstract

We have studied social interactions in Apodemus mystacinus coming from two populations in Syria. Ninety-four dyadic interactions in a neutral cage were performed to assess the effects of sex and season. In the autumn and spring, when the studied animals were in reproductive conditions, both sexes were similarly agonistic, as previously reported in most aggressive species of this genus. Nevertheless, as in other Apodemus species, male-male interactions were more agonistic than female-female interactions. In sharp contrast, during the summer period of sexual inactivity, agonistic behavior was nearly absent. Strong association of the reproductive season with aggression supports the hypothesis that the ultimate cause of male aggression in wood mice is the competition for mates.