Genetic reconstruction of breeding patterns in gundis (Rodentia: Ctenodactylidae)

Current mating system theory predicts that the number of females breeding in a group will depend on the number of females in the group and the accessibility of unrelated males, whereas the number of males breeding in a group will depend on the ability of males to control access to reproductive females. By combining information on group composition with genetic data, I determined whether breeding patterns in a rock-dwelling rodent, Ctenodactylus gundi, were concordant with these expectations. C. gundi breeding patterns varied from facultative monogamy to uni-male polygyny to multi-male polygyny. The number of reproductive individuals of each sex in a group increased with group size. Whereas communal breeding among related females tended to increase female reproductive success, males breeding in the same group were unrelated to other group members and seemed to compete over access to matings. While some males were assigned offspring from neighboring social groups, most group-living males successfully monopolized the reproduction of females within their group. There was no evidence that females had multiply sired litters, although some bred with alternative males in separate breeding attempts. Although numerous individuals were not assigned as parents or offspring, genetic information enabled me to determine that most unassigned individuals were philopatric group members, whereas only a few were unrelated immigrants into their current social group. Together, these results provide evidence that C. gundi social groups represent fairly distinct reproductive units whose breeding patterns are dependent on group size and composition in accordance with theoretical predictions. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.