Mixed‐species associations in cuxiús (genusChiropotes)

Abstract

Polyspecific or mixed-species associations, where two or more species come together to forage and travel as a unit, have been reported in many primate species. These associations appear to offer a number of benefits to the species involved including increased foraging efficiency and decreased risk of predation. While several researchers have suggested that cuxiús (genus Chiropotes) form mixed-species associations, previous studies have not identified the circumstances under which cuxiús form associations or whether they form associations more often than would be expected by chance. Here we present data on the formation of mixed-species associations by four species of cuxiús at eight different sites in Brazil, Suriname, and Guyana. We analyzed data from two of the study sites, (Biological Dynamics of Forest Fragments Project (BDFFP), Brazil and the Upper Essequibo Conservation Concession (UECC), Guyana, to assess whether associations occurred more than would be expected by chance encounters and identify the factors influencing their formation. Cuxiús showed a high degree of inter-site variation in the frequency of time spent in association (ranging from 2 to 26% of observation time) and duration of associations (mean duration from 22 min to 2.5 hr). Sapajus apella was the most common association partner at most sites. At BDFFP, cuxiús formed associations more frequently but not for longer duration than expected by chance. For much of the year at UECC, associations were not more frequent or longer than chance. However, during the dry season, cuxiús formed associations with S. apella significantly more often and for longer duration than predicted by chance. Cuxiús at UECC formed associations significantly more often when in smaller subgroups and when foraging for insects, and alarm called significantly less frequently during associations. We suggest cuxiús form mixed-species associations at some sites as an adaptive strategy to decrease predation risk and/or increase foraging efficiency.

When partitioning is not an option: Resource availability predicts intraguild interactions in two isolated Amazonian primate assemblages

“…For example, although squirrel and capuchin monkeys were among the most common species interacting with gray woolly monkeys in feeding contexts, these interactions did not result in a higher likelihood of aggression, relative to interactions with other atelids. It is possible that the interactions with these species are facilitative, with smaller species benefiting from enhancing their foraging success while interacting with larger species, as reported for Saimiri , Sapajus , and Chiropotes elsewhere (Klein & Klein, 1973; Levi et al, 2013; Shaffer et al, 2016). Another non‐mutually exclusive explanation for this low incidence of aggression is that woolly monkeys benefit from the predator vigilance of smaller species.…”

Mammals of the Saracá-Taquera National Forest, northwestern Pará, Brazil

“…The bearded saki (Chiropotes sagulatus), bearded capuchin (Sapajus apella), Guianan red howler monkey (Alouatta macconnelli (Elliot, 1910)) and the Guianan spider monkey (Ateles paniscus (Linnaeus, 1758)) were the species encountered most frequently. The ecology of the bearded saki and Martin's bare-face tamarin (Saguinus martinsi (Thomas, 1912)) has been monitored in STNF since 2009, and a number of important findings in the area have already been published (Barnett et al 2012;Melo et al 2013;Boyle et al 2015;Shaffer et al 2015).…”

Pitheciid research comes of age: Past puzzles, current progress, and future priorities

“…In this issue, Shaffer et al [] demonstrate repeated, albeit variable, participation in mixed‐species groups by Chiropotes across multiple sites and species. Importantly, these associations occur more frequently than expected by chance, vary seasonally (more common in the dry season than wet season), and are associated with differing foraging strategies.…”

“…The contributions in this issue illustrate the current movement toward hypothesis‐driven research in pitheciid studies. In addition to increasing knowledge of pitheciid behavioral ecology, several articles in this issue provide positive examples of the utility of large‐scale data sharing and collaboration in science [Boyle et al, ; Shaffer et al, ]. Yet, despite these advancements, many gaps in our knowledge of pitheciid biology remain.…”

“…Similarly, the diversity and flexibility of pitheciid social systems [Bowler et al, ; Gregory & Bowler, ; Norconk, ; Shaffer et al, ; Thompson, ] raises questions concerning how these disparate social phenotypes evolved. Although increased male–male tolerance and cooperation seem to be a key characteristic [Garber & Kowalewski, ], we have little empirical knowledge of the selective pressures generating these social phenotypes.…”