Mating patterns in relation to the timing of ovulation in Argentine black capuchins

Tufted capuchin ( Sapajus spp.) females have been shown to strongly prefer the alpha male and direct most of their solicitations to this individual. The strength of this preference, however, varies across populations of tufted capuchins and copulations with other males occur in all stud-ied populations. Females thus mate promiscuously, and a focus on the timing of mating with alpha versus other males is crucial to understand female mating strategies better and, in turn, their potential influence on male reproductive skew. However, these questions have been largely unaddressed due to the lack of data matching the timing of ovulation with timing of copulations in wild populations. Here, we examined female mating preference with a specific focus on the distribution pattern of copulations with different males in relation to the timing of ovulation. During four mating seasons, we observed 150 copulations with 17 females belonging to three groups of black capuchins (Sapajus nigritus) in Iguazú National Park, Argentina. Although fe-males showed high preference for the alpha male, 12 out of 17 females also mated with other group males (n = 55 copulations). When considering the timing of ovulation as assessed by faecal progestogen measurements, copulations were highly synchronized with the female fertile phase and copulations with alpha males tended to occur significantly closer to ovulation compared to other males. In addition, Hinde index values showed that females were actively responsible for maintaining proximity to the target male during their proceptive periods. However, Hinde index values did not increase with the approach of ovulation, suggesting that females’ contribution to proximity maintenance was not strictly linked to the timing of ovulation. Overall, females in our study groups seem to show a combination of strategies that aim at both biasing paternity to the alpha male and confusing paternity among group males. Our research complied with the Euro-pean Directive 2010/63/EU.