Doctoral Dissertation Improvement: The Reproductive Trajectories of Geladas (Theropithecus gelada)

在灵长类动物中，强烈的雄性纽带是罕见的，特别是对于雌性纽带的物种。因此，在雌性结合的物种中，雄性结合和生殖策略之间的关系在很大程度上仍然没有得到研究。在雌性粘合物种中，雄性粘连对雄性生殖轨迹的影响提供了一个理想的模型。在获得与雌性的生殖途径之前，“单身汉”美洲狮生活在有凝聚力的全雄性群体中。最终，雄性从这些群体中毕业，获得与一群雌性(一只雄性单位)的唯一生殖途径。单身汉使用以下几种策略中的一种：(1)直接推翻领导男性，(2)顺从地进入一个单位，并试图随着时间的推移将女性从单位中剥离，或(3)利用最近接管的混乱与女性机会主义地交配。此外，有人观察到，单身汉们会合作，试图推翻男性领袖，并与他们的全男性群体的前成员进入一男一女的单位--但最终只有一名男性获得了生殖利益。这个项目研究的是行为和荷尔蒙因素，这些因素决定了雄性狐猴从一个全雄性群体到一个雄性个体的繁殖轨迹。研究人员将(I)描述他们全是男性群体中单身汉之间的社会互动；(Ii)确定影响单身汉参与领导男性接管尝试的行为和荷尔蒙因素；以及(Iii)确定单身汉素质是否预示着生育策略。行为数据和非侵入性粪便激素采样将记录雄性狐狸的繁殖轨迹。此外，还将拍摄男性胸部补丁颜色的数码照片--这一特征可能表明男性的素质--以记录男性从单身群体转向单一男性单位时颜色的变化。这项研究的结果将为这些稀有灵长类动物的保护决策提供参考，调查员在西缅山国家公园的存在有助于阻止这一濒危世界遗产的非法活动。该项目为埃塞俄比亚当地的外勤助理提供收入和培训，联合PI已安排向美国几个州的高中生解释格拉达的行为。

Strong male bonds are rare among primates, especially for female-bonded species. Thus, the relationship between male bonding and reproductive strategies remains largely unexamined in female-bonded species. Geladas (Theropithecus gelada) provide an ideal model for understanding how male bonds influence male reproductive trajectories in a female-bonded species. Prior to acquiring reproductive access to females, "bachelor" geladas live in cohesive all-male groups. Eventually, males graduate from these groups to gain sole reproductive access to a group of females (one-male unit). Bachelors acquire one-male units using one of several strategies: (1) directly overthrowing the leader male, (2) submissively entering a unit and attempting to pare females away from the unit over time, or (3) capitalizing on the chaos of a recent takeover to opportunistically mate with females. Additionally, bachelors have been observed to cooperate in attempts to overthrow leader males and enter one-male units with former members of their all-male group - yet only one male eventually reaps the reproductive benefits. This project investigates the behavioral and hormonal factors that shape the reproductive trajectory of gelada males as they move from an all-male group to a one-male unit. The researchers will(i) describe the social interactions among bachelors within their all-male group; (ii) determine the behavioral and hormonal factors that influence bachelor participation in takeover attempts of leader males, and (iii) determine whether bachelor quality predicts a reproductive strategy. Behavioral data and noninvasive fecal hormone sampling will document the reproductive trajectories of male geladas. Additionally, digital photographs will be taken of male chest patch color - a feature that may indicate male quality - to document changes in color as males move from their bachelor groups to one-male units. Results from this research will inform conservation decisions regarding these rare primates, and the investigator's presence in the Simien Mountains National Park help deter illegal activities in this World Heritage Site that is in danger. This project provides income and training to local Ethiopian field assistants and the co-PI has arranged to explain gelada behavior to high school students in several U.S. states.