THE EFFECT OF RELATEDNESS ON REPRODUCTIVE SUCCESS AND MATE CHOICE IN THE WHITE-FOOTED MOUSE, PEROMYSCUS-LEUCOPUS

Genetic similarity between mates has a significant effect on the reproductive success of whitefooted mice. Pairs of mice bred over a range of degrees of relatedness demonstrated a significant inbreeding depression in litter size at weaning and offspring weight at weaning. If juveniles that are lighter at weaning are less likely to be recruited into the breeding population, these experiments also demonstrated a mild outbreeding depression. However, this cost does not appear to be due to the traditional mechanisms of outbreeding depression. Kin recognition appears to affect mate choice in white-footed mice and to act as a mechanism for reducing the costs of inbreeding and outbreeding. In an arena, oestrous females presented with either male odours or actual males showed a preference for males on an intermediate degree of relatedness. Non-oestrous females showed no such preferences. © 1990.