Male-male interference in a reproductive context: Effect of social status in mice

Direct competition between males in a sexual context was tested in stable male pairs. Albino male mice were exposed to their male antagonist interacting with a female on the other side of a transparent plexiglas partition provided with small holes.The behavioural response of males varied according to their social status, dominant males being more activated by the experimental procedure than subordinate males. In addition, the stimuli that elicited the dominant male’s attention seemed unrelated to the female, but to the simultaneous presence of the female and the male antagonist. In a second experiment, the behavioural performance of males of different rank was evaluated when only one female was introduced into their home-cage, or when an additional female was introduced into the home-cage of the male antagonists, with the males separated by a partition. This experiment indicated that the dominant male’s interest in the female was markedly reduced and exploration of the partition was enhanced when two females were involved in the experimental procedure. In contrast, the subordinate males’ behaviour was unmodified. These data support the initial hypothesis suggesting that dominant males continue to exert a control over the subordinate male’s behaviour in mating contexts.