Doctoral Dissertation Improvement: The ontogeny of male-male bonds in wild Ethiopian geladas (Theropithecus gelada)

虽然雄性-雄性键在雄性亲水性灵长类动物中相对常见，但在雄性扩散的物种中，这种键的证据很少。尽管有文献表明，在这种情况下，男性-男性之间的联系会产生生殖后果，但人们对这些联系是如何发展的知之甚少。博士生凯特琳·巴拉莱(普林斯顿大学)在丹尼尔·鲁宾斯坦博士的指导下，研究了狐猴(Theropithecus Glada)中雄性-雄性关系的个体发育，这是一个以雄性扩散和雄性-雄性键为特征的物种。这项研究的主要目的是检查雄性-雄性纽带的性质，并识别行为和激素因素，这些因素使幼年狐猴从出生的一雄单位过渡到临时的同龄人组，然后进入完全由雄性组成的单身组，从而走上个体生殖轨迹。该项目有四个具体目标：(1)描述青少年同龄人群体，(2)描述青少年时期的男性-男性纽带，(3)评估这些纽带的短期好处，以及(4)调查男性关系在青春期是如何变化的。研究人员采用横断面和纵向行为分析、社会网络分析和非侵入性粪便激素采样相结合的方法，对埃塞俄比亚西米恩山国家公园的一群雄性幼崽(N=51)进行了研究。这项研究是第一次专门针对幼崽的长期研究。它通过收集行为、生理和基于网络的数据，提供了一个关于狐猴社会发育的有价值的新视角，并启动了第一个关于已知狐猴雄性的纵向数据集。拥有从青春期到成年期的已知个体的详细数据，使研究人员能够将早年生活的影响与终生生殖成功联系起来。这项研究的结果将为灵长类动物的雄性-雄性纽带的发展提供新的数据，推动社会网络理论在动物系统中的应用，并有助于建立早期人、现代人和其他非人类灵长类动物的社会发展模型。

Although male-male bonds are relatively common in male-philopatric primates, evidence for these bonds in species with male dispersal is rare. Despite documentation that male-male bonds have reproductive consequences in this context, little is known about how these bonds develop. Doctoral student Caitlin Barale (Princeton University), under the supervision of Dr. Daniel Rubenstein, investigates the ontogeny of male-male relationships in the gelada (Theropithecus gelada), a species characterized by both male dispersal and male-male bonds. The primary objective of this research is to examine the nature of male-male bonds, and identify the behavioral and hormonal factors that set juvenile gelada males on individual reproductive trajectories as they transition from their natal one-male unit, to a temporary peer group, and onwards into an all-male bachelor group. The project has four specific goals: (1) to describe juvenile peer groups, (2) to characterize male-male bonds in the juvenile period, (3) to evaluate a short-term benefit of these bonds, and (4) to investigate how male relationships change at adrenarche. The investigators employ a combination of cross-sectional and longitudinal behavioral analyses, social network analysis and non-invasive fecal hormone sampling on all juvenile males (N=51) in a band of geladas in the Simien Mountains National Park, Ethiopia.This research represents the first long-term study focused exclusively on juvenile geladas. It provides a valuable new perspective on gelada social development through the collection of behavioral, physiological and network-based data, and initiates the first longitudinal dataset on known gelada males. Having detailed data on known individuals from juvenility to adulthood allows researchers to connect the effects of early life to lifetime reproductive success. The results of this research will contribute novel data on the development of male-male bonds in primates, advance the application of social network theory to animal systems, and help build a model for social development in early hominins, modern-day humans, and other non-human primates.