Prox Lea, Heistermann Michael, Rakotomala Zafimahery, Fichtel Claudia, Kappeler Peter M
Department of Sociobiology/Anthropology, University of Göttingen, Göttingen, Germany; Behavioral Ecology & Sociobiology Unit, German Primate Center, Göttingen, Germany.
Endocrinology Laboratory, German Primate Center, Göttingen, Germany.
Horm Behav. 2025 Jan;167:105669. doi: 10.1016/j.yhbeh.2024.105669. Epub 2024 Dec 4.
Intraspecific competition with fellow group members represents an unavoidable cost of group living. However, the causes of competition can vary among group members, and ecological and reproductive challenges faced by individuals throughout the year can trigger physical conflicts and or physiological responses. To date, few studies in mammals have described both physiological and behavioral responses to competition simultaneously across the year in both males and females. However, such an approach may shed light on ultimate drivers of sex-specific competitive strategies. In this six-year study on multiple groups of wild redfronted lemurs (Eulemur rufifrons), a primate species from Madagascar, we intended to identify the relative importance of feeding vs. reproductive competition for both sexes. We combined data on fecal glucocorticoid metabolite (FGCM) levels, a proxy for the physiological stress response, with behavioral observations on agonistic interactions during ecologically and socially challenging phases across the year. We found that while FGCM levels increased in both sexes with decreasing fruit consumption, this increase was not accompanied by concomitant changes in agonistic behavior. Female aggression and FGCM levels instead peaked during the birth season, while for males, aggression remained fairly constant across the year. Our results suggest that redfronted lemurs have mechanisms to avoid direct competition through aggression at times when individuals may need to conserve energy.
与同群体成员的种内竞争是群体生活不可避免的代价。然而，竞争的原因在群体成员中可能各不相同，个体全年面临的生态和繁殖挑战可能引发身体冲突和/或生理反应。迄今为止，很少有关于哺乳动物的研究同时描述了雄性和雌性在全年对竞争的生理和行为反应。然而，这样的方法可能会揭示性别特异性竞争策略的最终驱动因素。在这项对多组野生红额狐猴（Eulemur rufifrons）进行的为期六年 的研究中，红额狐猴是一种来自马达加斯加的灵长类动物，我们旨在确定觅食竞争与繁殖竞争对两性的相对重要性。我们将粪便糖皮质激素代谢物（FGCM）水平的数据（一种生理应激反应的指标）与全年在生态和社会挑战阶段对攻击性行为的观察数据相结合。我们发现，虽然随着水果消费量的减少，两性的FGCM水平都有所上升，但这种上升并没有伴随着攻击性行为的相应变化。相反，雌性的攻击性和FGCM水平在生育季节达到峰值，而对于雄性来说，攻击性全年保持相当稳定。我们的研究结果表明，红额狐猴具有在个体可能需要保存能量的时候通过攻击来避免直接竞争的机制。
