Doctoral Dissertation Research: Socioendocrinology of Male Reproductive Strategies in the Siamang (Symphalangus Syndactylus)

本研究旨在阐明塑造雄性灵长类动物行为和激素特征的进化力量。特别是，它将探讨在一夫一妻制和多夫制交配系统的背景下，男性内分泌与雄性竞争、亲代努力和雌性生殖状态之间的关系。数据将来自苏门答腊岛（印度尼西亚）的四个一夫一妻制和三个多夫制暹罗猴群体的行为观察和非侵入性激素取样。无生物危害的激素提取物将储存在野外，并在美国进行分析。这些数据将阐明灵长类动物许多引人注目的、鲜为人知的方面的共同进化，包括人类、社会和生殖生物学，如性内和性间攻击、配对结合和父系照顾。这项工作的智力贡献可分为四个方面：首先，这项研究将首次提供野生一夫一妻制和多夫制（非人类）类人猿的激素数据。这些交配系统在哺乳动物中极为罕见（约3%），因此，这些数据对于改进当前哺乳动物社会进化模型至关重要。其次，本研究评估了配对雄性对不同生殖挑战（社会群体内外的性竞争对手）的激素和行为反应。因此，这些数据将测试在人类男性竞争中保护配偶的假设重要作用，并将扩展迄今为止仅在人类中测试过的理论的广度，例如“配偶偷猎”。第三，父系关爱是人类行为生物学的一个显著特征，但在灵长类动物中却很少见。通过提供另一种双亲猿的数据，这项研究将使我们第一次能够评估这些人类模式的普遍性，并阐明与男性养育子女相关的条件和限制。最后，最近的实验数据表明，人类男性的行为受到女性生殖状态的影响（通过视觉或嗅觉线索）。对暹罗猴的类似影响的评估将有助于理解人类和非人类灵长类动物排卵信号与隐藏的起源和功能。它还将有助于确定女性生殖地位影响男性社会和生殖行为的社会和生态条件。这项研究的一个更广泛的影响是它对保护工作的贡献：这项研究将提高对暹罗的人口统计和人口动态的理解，并将提供对栖息地恶化和破碎化影响的准确评估。该项目将雇用和培训至少五名当地外勤助理。此外，印度尼西亚大学的两名硕士生的实地工作将得到支持和监督。目前正在讨论在Way Canguk建立一所灵长类动物野外学校的计划，以进一步促进当地的教育/保护工作。结果将通过同行审查的出版物和参加专业会议来传播。这将有助于指导未来对这群社会一夫一妻制猿类的近因机制（例如关注其他激素）、心理相关因素、分散模式和雌性生殖策略的研究。最后，该项目将为获奖者提供广泛的现场内分泌学和实验室程序实践，并将拓宽他可以教授的学科范围，以及他将为未来的工作场所带来的专业知识。

This research seeks to clarify the evolutionary forces shaping the behavioral and hormonal profiles of male primates. In particular, it will explore the correlations between male endocrinology and male-male competition, parental effort and female reproductive state, in the context of monogamous and polyandrous mating systems. Data will come from behavioral observation and non-invasive hormonal sampling of four monogamous and three polyandrous groups of siamangs (Hylobatidae: Symphalangus syndactylus) in Sumatra (Indonesia). Non-biohazardous hormonal extracts will be stored in the field and analyzed in the U.S.These data will shed light on the co-evolution of many striking and poorly understood aspects of primate, including human, social and reproductive biology, such as intra- and intersexual aggression, pair bonding and paternal care. The intellectual contributions of this work fall into four broad areas:First, this study will provide the first hormonal data on a wild monogamous and polyandrous (nonhuman) hominoid. These mating systems are extremely rare among mammals (about 3%), thus, these data are essential for the improvement of current models of mammalian social evolution.Second, this investigation evaluates the hormonal and behavioral responses of pair-bonded males to different reproductive challenges (sexual competitors within or outside the social group). These data will therefore test the hypothetically important role of mate guarding in human male competition, and will expand the breadth of theories so far tested only in humans, such as "mate poaching".Third, paternal care is a conspicuous feature of human behavioral biology, but rather exceptional among primates. By providing data on an additional biparental ape, this study will allow us, for the first time, to assess the generality of these human patterns, and clarify the conditions and constraints associated with male parenting.Finally, recent experimental data shows that human male behavior is affected by female reproductive state (through visual or olfactory cues). An evaluation of similar effects on siamangs will contribute to the understanding of the origin and function of signaling versus concealment of ovulation in human and non-human primates. It will also help determining the social and ecological conditions under which female reproductive status affect male social and reproductive behavior.One broader impact of this research is its contribution to conservation efforts: the study will improve the understanding of siamang demography and population dynamics, and will provide an accurate assessment of the impact of habitat deterioration and fragmentation.The project will employ and train at least five local field assistants. In addition, the fieldwork of two Masters students at the University of Indonesia will be supported and supervised. Plans are being discussed to establish a primatology field school at Way Canguk, to further local education/conservation efforts.Results will be disseminated through peer-reviewed publications and participation in professional meetings. This will help to guide future studies of proximate mechanisms (e.g. focusing on other hormones), psychological correlates, dispersal patterns, and female reproductive strategies in this group of socially monogamous apes.Finally, this project will provide the awardee's with extensive practice with field endocrinology and laboratory procedures, and it will broaden the range of subjects he can offer to teach, as well as the expertise that he will bring to future working places.