The effects of sibling reproduction in the African striped mouse

Sibling reproduction was studied in a captive population of the African striped mouse Rhabdomys pumilio (Sparrman, 1784) to establish the occurrence of inbreeding and whether early association prevents later matings. Sibling and nonsibling pairs were established by pairing animals at weaning (16 days), 30, and 60 days old. The reproductive success of weaning pairs (regardless of genetic relationship) and 30- and 60-day sibling pairs was poorer than that of nonsibling pairs. Inbreeding depression was indicated by high pre-weaning mortality and smaller mass of inbred compared to outbred litters. When pairings were made between sexually mature siblings of consecutive litters that had made brief contact previously, sibling pairs had similar reproductive performance compared to control pairs, but had significantly smaller litter sizes. It appears that incestuous matings in R. pumilio result in inbreeding depression, and that mating between kin or non-kin is prevented by prior association.