Eat the fruit earlier: Sakis (Pithecia chrysocephala) show enhanced temporal fruit resource access compared with squirrel monkeys (Saimiri sciureus) in an urban forest fragment in Brazil

Fruit availability experienced by different primate species is likely to vary due to species‐specific fruit use, even within the same habitat and timeframe. Pitheciines, primates of the subfamily Pitheciinae, particularly favor the seeds of unripe fruits. Researchers consider this dietary characteristic an adaptation to increase access to fruit resources. However, the relative advantages of pitheciines over sympatric non‐pitheciine non‐seed‐eating primates regarding species‐specific fruit availability is not well studied. In a 26‐ha forest within the city of Manaus, Amazonian Brazil, we assessed the wild‐food feeding behavior of free‐ranging groups of golden‐faced sakis (Pithecia chrysocephala) and sympatric common squirrel monkeys (Saimiri sciureus). We hypothesized that sakis would have greater and more consistent access to wild fruit due to (1) a wider variety of fruit species in their diet, and (2) longer consumption periods per fruit species. We recorded the plant species, part (pulp or seed), and developmental stage (ripe or unripe) of wild fruit consumed by both species. We also conducted monthly fruit censuses of 1000 trees and vines to estimate overall wild fruit abundance. As an indicator of fruit availability, we calculated the proportion of available fruiting trees and vines for each primate species separately based on their observed diet. Throughout the year, the proportion of available trees and vines was significantly higher and more temporally stable for sakis than for squirrel monkeys. This was because sakis used shared fruit species longer than squirrel monkeys by consuming both ripe and unripe fruit. Although sakis had a broader fruit repertoire than squirrel monkeys, it did not contribute to the higher fruit availability. Thus, the fruit feeding system of sakis identifies aspects of a niche that is less restricted in the timing of fruit consumption, which led to a relative advantage in fruit availability.

This is the peer reviewed version of the following article: Take, M., Yumoto, T., Barnett, A. A., Onizawa, K., & Spironello, W. R. (2024). Eat the fruit earlier: Sakis (Pithecia chrysocephala) show enhanced temporal fruit resource access compared with squirrel monkeys (Saimiri sciureus) in an urban forest fragment in Brazil. American Journal of Primatology, 86, e23575., which has been published in final form at https://doi.org/10.1002/ajp.23575 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited