Reproductive status affects the feeding ecology and social association patterns of female squirrel monkeys (Saimiri collinsi) in an Amazonian rainforest

Abstract

When making foraging decisions, female primates may follow specific behavioral strategies that reflect their reproductive state. Lactation is considered the most energetically costly phase for females, but we argue that gestation is also energetically expensive for squirrel monkeys. In this study, we examined whether female squirrel monkeys (a seasonally breeding primate) in different reproductive phases showed significant differences in their foraging ecology. We sampled two wild groups of squirrel monkeys (Saimiri collinsi) using the focal animal method, during 12 months (June 2014 to May 2015). During this time, we quantified the effect of reproductive state (mating, gestation, and lactation) and sex (females vs. males) on activity budgets, foraging efficiency, dietary composition, and nearest neighbors. We found significant effects of both sex and reproductive phase on the mean proportion of time spent foraging, resting, traveling, and being social. Females consumed more insects than did males at all times; among females, time spent eating prey and fruit varied according to reproductive state. These data suggest that, due to their life history and seasonal breeding, reproduction is a costly activity for female Saimiri, and not only during lactation. Therefore, adopting the appropriate behavioral strategies is essential to reduce energetic deficits in females.

The geometry of resource constraint: An empirical study of the golden snub‐nosed monkey

“…It has seldom been demonstrated that diet selection in the wild specifically tracks changes in requirements for particular macronutrients. Many studies have shown that mammals increase energy intake during lactation (Cui et al., 2018; Douhard et al., 2016; Droscher et al., 2016; Speakman, 2008), and that they change their diet compositions with a shift to higher protein foods (Dias et al., 2011; Ruivo et al., 2017; Rydell, 1989; Tirado Herrera & Heymann, 2004); few, however, have demonstrated that they specifically select a diet with different macronutrient ratios than when not lactating. Guo et al.…”

“…It has seldom been demonstrated that diet selection in the wild specifically tracks changes in requirements for particular macronutrients. Many studies have shown that mammals increase energy intake during lactation (Cui et al, 2018;Douhard et al, 2016;Droscher et al, 2016;Speakman, 2008), and that they change their diet compositions with a shift to higher protein foods (Dias et al, 2011;Ruivo et al, 2017;Rydell, 1989;Tirado Herrera & Heymann, 2004); few, however, have demonstrated that they specifically select a diet with different macronutrient ratios than when not lactating. Guo et al (2018) found for a different wild population of R. roxellana than this study that intake of fat and carbohydrate, which in primates are the principle macronutrients used in energy metabolism, increased during the cold winter compared with spring, by an amount that closely matched the seasonal difference in energetic requirements for thermoregulation, whereas protein intake remained unchanged.…”

Synchronization of weaning time with peak fruit availability in squirrel monkeys (Saimiri collinsi) living in Amazonian Brazil

“…In order to support such reproductive demands, female S. collinsi in our population consume more animal protein than do males, year-round, but particularly during gestation. In addition, during lactation, females cope with the extra energetic requirements by altering their foraging behaviors and activity budgets (Ruivo et al, 2017). Therefore, females are able to show behavioral flexibility that likely maximizes maternal survival.…”

PREGNANT AND LACTATING Macaca nigra: BEHAVIOR AND FOOD SELECTION

“…In general, the social activity among levels of pregnancy were not significantly different. Ruivo et al (2017) and Gould et al (2011) stated that due to the high energy and nutritional needs during pregnancy, females in the early gestation period will spend a lot of time eating. This behavior aims to compensate for the nutrition shared with the fetus.…”