Male philopatry in spider monkeys revisited

Abstract

Dispersal patterns are critical for understanding social systems as they influence social interactions and relationships. Spider monkeys (Ateles spp.) are typically described as being characterized by male philopatry and female dispersal, with these patterns reflected in stronger affiliative and cooperative relationships among males than among females. Recent findings, however, indicate that male-male relationships may not be as uniformly strong as previously thought, which suggests that male philopatry in spider monkeys may not be universal. Here, we report the first confirmed cases of male immigration and group takeover in spider monkeys. Data were collected on one community of Ateles geoffroyi in northwestern Costa Rica. Behavioral and demographic data were recorded during subgroup follows across 6.5 years, and fecal samples of community members were collected for genetic analysis of relatedness. We documented two separate cases of immigration involving multiple males, which resulted in take-over of the study community by extra-community males and the concomitant disappearance of the resident males. In the study community, males were no more closely related to one another, on average, than females were, contrary to what would be expected if males were the more philopatric sex. Comparison of corrected assignment indices for males and females also revealed no evidence of sex-biased dispersal. Our findings suggest that in spider monkeys male immigration may occur under certain demographic circumstances, contributing to a view of greater flexibility in their social system than previously appreciated. This discovery has implications for other species that are typically characterized by male philopatry.

Male-directed infanticide in spider monkeys (Ateles spp.)

“…Dispersal tends to be strongly female-biased (Shimooka et al 2008;Di Fiore et al 2009, 2011, while males generally remain philopatric (but see Aureli et al 2013), reaching sexual maturity and reproducing in their natal groups. As a result, adult males within a group tend to be related and to form strong bonds, whereas females are unrelated and are often found foraging alone.…”

Demography and life history of a group of white‐bellied spider monkeys (Ateles belzebuth) in western Amazonia

“…As noted above, five adult males disappeared from the original group during the study period, and we presume that these individuals died (rather than emigrated) as we have observed no cases of male immigration into the group (but see Aureli, Di Fiore, Murillo‐Chacon, Kawamura, & Schaffner, ). Three of these males disappeared during a period of time characterized by a high rate of intergroup encounters (Link, ) and might have been killed or injured during episodes of escalated aggression between neighboring groups.…”

“…As noted above, five of the six adult males that were originally present in the group in 2005 have disappeared, and we presume that these individuals died as there is no evidence of male dispersal at TBS (but see Aureli et al, for one case of collective male immigration in Ateles geoffroyi in Costa Rica). Although the causes of their disappearances are not clear, several of these males vanished during a period of frequent and intense intergroup conflict and aggression (Link, ).…”

Social Interactions and Proximal Spacing in Woolly Monkeys: Lonely Females Looking for Male Friends

“…Atelines are the largest Neotropical monkeys, currently including spider monkeys (genus Ateles), woolly monkeys (Lagothrix, including yellow tailed woolly monkeys, formerly Oreonax), and woolly spider monkeys or muriquis (Brachyteles). In Ateles spp., dispersal is mainly performed by females (Symington 1987;Shimooka et al 2008;Di Fiore et al 2009, but see Aureli et al 2013). Moreover, the high degree of fission-fusion dynamics characteristic of spider monkeys can lead to a certain degree of segregation by sex.…”