Mate choice in male mandrills (Mandrillus sphinx).

Abstract

Male primates that attempt to monopolize access to receptive females by mate-guarding expend time and energy and risk injury, making reproduction costly. Males should therefore show mate choice and preferentially allocate mating effort to females that are likely to be fertile and those that will produce high-quality offspring. Specifically, males should preferentially mate-guard high-ranking females rather than low-ranking females, as such females are more likely to be fertile and are able to invest more in offspring. Males should also prefer parous females to nullipares, for similar reasons. Finally, males should avoid mating with close relatives, to avoid the deleterious effects of inbreeding. We investigated 13 group-years of mate-guarding observations for two semi-free-ranging groups of mandrills to examine the influence of these factors on male investment in mate-guarding. We found that males mate-guarded higher-ranking females more than lower-ranking females, and parous females more than nullipares. Female age, true relatedness and maternal kinship did not influence male mate-guarding. Our results suggest that male mandrills do exercise mate choice for higher-quality females, in the form of higher-ranking and parous females. As alpha males are responsible for the great majority of mate-guarding, this can lead to assortative mating, where high-ranking males reproduce with high-ranking females, and has important implications for social relationships and kin selection.