1Biology, Truman State University, 2Anthropology, Queens College, City University of New York, 3New York Consortium in Evolutionary Primatology, 4Doctoral Program in Anthropology, The Graduate Center, City University of New York, 5Archaeology, University of Cape Town, 6Evolutionary Anthropology, Duke University
April 14, 2016 3:45, A 602
Baboons, among the most adaptable nonhuman primates, have demonstrated the ability to maintain year-round reproduction by altering activity budgets and feeding behavior during the energetically demanding states of pregnancy and lactation. Little is currently known about how females cope with the energetic constraints of estrus, particularly in the context of male mate guarding. Sexual swellings, high rates of received aggression, and decreased foraging efficiency can result in energetic stress during sexually receptive periods. Given the sensitivity of conception to energy availability, individual variation in how females cope with these stressors may translate into differences in reproductive success. We test this hypothesis using observational and hormonal data from 161 reproductive cycles of 32 wild female chacma baboons (Papio hamadryas ursinus) inhabiting the Tokai section of the Table Mountain National Park near Cape Town, South Africa. Urinary c-peptides (UCP) quantified from 659 samples indicated that mean energy balances did not differ significantly between phases of the estrus cycle, but individual means among estrous females varied widely (2.7 - 41.6 ng/mg creatinine). We use generalized linear mixed effect models to a) assess behavioral correlates of this variation, including activity budgets and the extent of mate guarding; b) quantify individual differences in glucocorticoid (GC) levels as general indicators of stress responses; and c) test whether UCP or GC variation predicts the likelihood of conception. We discuss the implications of our results for understanding adaptive female reproductive strategies.
Funding provided by the National Science Foundation (BCS 1318176), Wenner-Gren Foundation, and Nacey Maggioncalda Foundation.