Should I stay or should I go now: dispersal decisions and reproductive success in male white-faced capuchins (Cebus imitator)

Abstract

Although males often disperse to increase their immediate access to mates, it is unclear whether they also consider potential future reproductive opportunities. We investigated whether immediate or delayed reproductive opportunities predicted dispersal decisions and reproductive success of subordinate immigrant male white-faced capuchins in the Sector Santa Rosa, the Área de Conservación Guanacaste, Costa Rica. We collected genetic, behavioral, and demographic data from four social groups across 20 years. We genotyped individuals at up to 20 short tandem repeat loci to determine paternity. Having previously sired offspring in a group did not predict the subordinate immigrant male’s likelihood of staying or dispersing. Instead, a male was more likely to remain in the group if he was younger and likely to benefit from queuing for future reproductive opportunities. Subordinate immigrant males were more likely to sire offspring if they resided with a long-term alpha male and his mature daughters, who avoid inbreeding. Reproductive output was similar among three categories of males: those that became alpha immediately after immigration, those that became alpha after queuing, and subordinate males that resided with a long-term alpha male and his mature daughters. These three categories of males had higher reproductive success than subordinates who did not reside with mature daughters of the alpha male. Waiting for reproductive opportunities can lead to high reproductive success and could be important in maintaining tolerant or cooperative male-male relationships in species with high reproductive skew, long alpha male tenures, and intense between-group mating competition requiring cooperative male group defense.

Significance statement

We used 20 years of data from white-faced capuchins to assess whether male dispersal decisions were predicted by actual reproduction, perceived reproductive opportunities, or future reproductive opportunities and whether male reproduction was predicted by demographic factors and the male’s social position. Immigrant subordinate males were less likely to disperse from the group if they were younger and likely to benefit from queuing for future reproductive opportunities. Subordinate males residing in groups with a long-term alpha male and his mature daughters produced a similar number of offspring as did alpha males. Queuing for reproductive opportunities may maintain cooperative male-male relationships in populations with high reproductive skew and long alpha male tenures. Because these patterns only become apparent over time, our study highlights the importance of taking longitudinal paternity patterns into account to understand the evolution of dispersal and cooperation in long-lived species.