Abstract
The reproductive process of female primates is energetically constrained. However, while there is extensive evidence about factors that influence the maintenance of gestation and lactation, less is known about energetic correlates of cycling and the occurrence of conception in wild primates. We examined how female physical condition affected the occurrence of conception and interbirth intervals (IBI) in female mantled howler monkeys, a species in which females experience long non-conceptive periods. For 6 years we followed 7 females at La Flor de Catemaco (Los Tuxtlas, Mexico). In addition to noting the presence of dependent immatures, we collected fecal samples that were analyzed for thyroid hormone and glucocorticoid metabolite concentrations (N = 1,460). Conception was more likely following months when females were not lactating and had higher thyroid hormone and lower glucocorticoid levels. IBIs were shorter when females had higher thyroid hormone and lower glucocorticoid levels, and when the infant at the beginning of the interval died. Due to their obvious impact on female fecundity and fertility, gestation and lactation are the stages of the reproductive process that have traditionally received more attention in studies of female reproductive performance. Still, the cycling stage accounts for a large proportion of IBIs in many primate species. Here we demonstrate that the reproductive rates of female mantled howler monkeys are energetically constrained: both the occurrence of conception and IBI are positively affected by female energetic condition.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.