Doctoral Dissertation Research: The energetics of male reproductive strategies in geladas

在灵长类生殖生态学中，能量对生殖的约束作用往往集中在雌性身上。然而，在包括人类在内的哺乳动物中，雄性生殖努力往往需要大量的代谢成本。这个博士论文项目将研究能量如何限制野生灵长类动物--狮尾狒狒的雄性行为和繁殖。该项目将深入了解动物生理学和生殖努力如何适应自然生态变化，并研究睾丸激素（雄性生殖行为的调节机制）如何直接受到能量的限制。通过研究能量学对非人灵长类动物睾丸激素介导的生殖努力分配的影响，该项目将揭示能量学在塑造非人灵长类动物和人类物种中的选择压力和潜在影响。通过这项研究，Co-PI将为STEM领域代表性不足的本科生提供基于实验室的行为内分泌学技术培训。此外，该项目还将在国内外开展科学教育和保护宣传活动。本项目将以野生狮尾猴为模型，通过雄性间竞争的声音和视觉信号，研究雄性的精力状态、生理和雄性品质之间的关系。为此，该项目将结合联合收割机经典的行为观察与创新的方法（1）数字摄影测量，以评估男性胸部斑块着色，（2）内分泌学，以确定非侵入性收集的尿液和粪便样本的精力充沛的条件。狒狒的一夫多妻制交配系统提供了一个理想的模型，以调查男性生殖能量的对比：后宫举行狒狒领导男性的后代，而单身汉男性在所有男性群体缺乏生殖机会的绝大多数。因此，繁殖成功严重倾向于狮尾狒狒的领导者雄性，单身汉必须在充满挑战的“接管”事件中推翻领导者，以获得与雌性的生殖机会。这项研究将评估男性精力充沛状况的潜在季节性变化，这种变化如何与男性社会地位相关，以及精力充沛状况最终是否会限制睾酮依赖性信号传导和男性生殖策略。虽然有充分的证据表明，较低的食物供应和能源可能会限制男性生殖生理，睾丸激素，能源和生殖之间的相互关系，在雄性灵长类动物的全面图片是必要的。这项研究将是首批评估能量如何成为野生灵长类动物雄性生殖成功的限制因素的研究之一。

In primate reproductive ecology, the role of energy as a constraint on reproduction has often focused on females. Yet across mammals, including humans, male reproductive effort can often entail substantial metabolic costs. This doctoral dissertation project will examine how energy constrains male behavior and reproduction in a wild primate, the gelada monkey. The project will provide insight into how animal physiology and reproductive efforts adjust to natural ecological change, and examine how testosterone, a regulatory mechanism for male reproductive behavior, may be directly limited by energy. By examining the effects of energetics on the allocation of testosterone-mediated reproductive effort in a nonhuman primate, this project will shed light on the selective pressures and potential influence of energetics in shaping non-human primate and hominin species. Through the course of this research, the Co-PI will provide training in lab-based behavioral endocrinology techniques for undergraduate students from groups underrepresented in STEM fields. In addition, the Co-PI will conduct science education and conservation outreach at various domestic and international venues.This project will study wild gelada monkeys as a model to examine the relationship between male energetic condition, physiology, and male quality as assessed from vocal and visual signals used in male-male competition. Towards this end, this project will combine classic behavioral observations with innovative methods in (1) digital photogrammetry to assess male chest patch coloration, and (2) endocrinology to determine energetic condition from non-invasively collected urine and fecal samples. The polygynous mating system of gelada monkeys provides an ideal model to investigate contrasts in male reproductive energetics: harem-holding gelada leader males sire the vast majority of offspring while bachelor males in all-male groups lack reproductive opportunities. Reproductive success is therefore heavily skewed towards gelada leader males, and bachelors must overthrow a leader during energetically challenging "takeover" events to gain reproductive access to females. This research will evaluate the underlying seasonal variation in male energetic condition, how this variation relates to male social status, and whether energetic condition ultimately constrains testosterone-dependent signaling and male reproductive strategies. Although ample evidence suggests that lower food availability and energy may constrain male reproductive physiology, a comprehensive picture of the interrelationship between testosterone, energy, and reproduction in male primates is needed. This research will be one of the first to assess how energy may be a limiting factor for male reproductive success in wild primates.