A key goal in behavioral ecology is to investigate the factors influencing the access to food resources and energetic condition of females, which are strong predictors of their reproductive success. We aimed to investigate how ecological factors, social factors, and reproductive state are associated with energetic condition in a wild neotropical primate using non-invasive measures. We first assessed and compared urinary C-peptide levels (uCP), the presence of urinary ketones (uKet), and behaviorally assessed energy balance (bEB) in female white-faced capuchin monkeys (Cebus imitator) living in Santa Rosa, Costa Rica. Then, we assessed how these measures were associated with feeding competition, dominance rank, and reproductive state. As predicted, uCP and bEB were positively associated with each other, and bEB was negatively associated with uKet. However, we did not find a relationship between uCP and uKet. Females showed lower uCP and bEB values during periods of intense feeding competition, but this relationship was not dependent on dominance rank. Furthermore, rank was not directly associated with uCP and bEB. Urinary ketones, on the other hand, were only produced in the most adverse conditions: by low-ranking, lactating females during periods of intense feeding competition. Behavioral strategies are assumed to maximize reproductive success and not energetic condition per se, which might explain why rank was not generally associated with energetic condition in our study population. This highlights the importance of considering potential differences between reproductive success and proxies of reproductive success, such as energetic condition or food intake, when investigating predictions of socioecological models.

中文翻译：

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非侵入性估计新热带灵长类动物的进食竞争成本。

行为生态学的一个关键目标是研究影响女性获得食物资源和精力充沛的因素，这些因素是其生殖成功的有力指标。我们旨在通过非侵入性措施研究野生新热带灵长类动物的生态因素，社会因素和生殖状态与能量状况的关系。我们首先评估和比较了生活在哥斯达黎加圣罗莎的雌性白脸卷尾猴（Cebus模仿者）的尿C肽水平（uCP），尿酮的存在（uKet）和行为评估的能量平衡（bEB）。然后，我们评估了这些措施与进食竞争，优势地位和生殖状态之间的关系。如预测的那样，uCP和bEB彼此正相关，而bEB与uKet负相关。但是，我们没有找到uCP和uKet之间的关系。在激烈的喂养竞争中，雌性的uCP和bEB值较低，但这种关系并不取决于主导地位。此外，等级与uCP和bEB不直接相关。另一方面，尿酮仅在最不利的条件下产生：在激烈的喂养竞争期间，低等级的哺乳雌性。假定采取行为策略以最大化生殖成功而不是精力充沛的条件本身，这可能可以解释为什么在我们的研究人群中等级通常与精力充沛的条件不相关。这凸显了考虑生殖成功与生殖成功代理之间潜在差异的重要性，例如精力充沛的状况或食物摄入量，