Doctoral Dissertation Improvement: Assessing the Interaction of Risk Aversion and Social Organization in Juvenile Primates

灵长类动物在哺乳动物中是独一无二的，它们有较长的幼年依赖期。对于这种延长的幼年期，人们提出了几种进化上的解释，但这些解释中很少得到实地检验，部分原因是幼年期很少成为行为研究的重点。为数不多的实地研究明确考察了灵长类动物的幼年发育，这些研究主要集中在生活在雌性亲爱和雌性结合的社会群体中的分类群上，而忽略了在该目其他动物中发现的社会组织的广泛多样性。相比之下，本研究将为生活在厄瓜多尔Yasuni生物圈保护区以高水平雌性分散为特征的社会中的野生分类群的幼崽发育和生活史提供新的数据，无论是在凝聚力（低地毛猴，Lagothrix poeppigii）还是裂变融合（白腹蜘蛛猴，Ateles belzebuth）社会群体中。在收集一系列行为和发育数据的过程中，本研究将主要通过研究在裂变融合和凝聚力群体提供的不同社会环境中，预期会发生变化的捕食避免、食物竞争和效率以及社会发展等方面，来研究幼年动物的发育和行为如何与社会组织明确联系在一起。这项研究还将为灵长类动物延长幼年期的进化提供第一个被广泛接受的解释，即生态风险规避假说，该假说认为灵长类动物延长幼年期是发育过程中代谢减慢的结果，这是由于需要保持在社会群体的中心，以躲避捕食者，因为激烈的食物竞争阻止了足够的食物摄入。最终，这项研究将填补我们对灵长类动物幼年期理解的重要空白，既增加了灵长类动物幼年期数据的多样性，又明确地将社会组织与幼年期行为发展联系起来，这可能反过来揭示包括人类在内的灵长类动物明显延长的幼年期的进化。此外，该项目在蒂普蒂尼生物多样性站培养的科学人员将能够培训来自灵长类动物栖息地国家的几名实地助理，并对生物站作出贡献。它的使命是厄瓜多尔教育、生态发现和亚马逊保护。

Primates are unique among mammals in having extended periods of juvenile dependency. Several evolutionary explanations for this prolonged juvenile phase have been proposed, but few of these have been tested in the field, in part because juveniles have rarely been the focus of behavioral research. The few field studies that have explicitly examined juvenile development in primates have focused on taxa that live in female philopatric and female-bonded social groups, neglecting the broad diversity in social organization found in the rest of the Order. By contrast, this study will provide new data on juvenile development and life histories for wild taxa living in societies characterized by a high level of female dispersal, either in cohesive (lowland woolly monkeys, Lagothrix poeppigii) or fission-fusion (white-bellied spider monkeys, Ateles belzebuth) social groups in the Yasuni Biosphere Reserve, Ecuador. In collecting an array of behavioral and developmental data, this study will examine how aspects of juvenile development and behavior may be explicitly tied to social organization, primarily through examining aspects of predation avoidance, food competition and efficiency, and social development that are expected to vary in the different social environments offered by fission-fusion and cohesive groups. This research will also provide the first comparative field test of the most widely accepted explanation for the evolution of extended juvenility in primates, the Ecological Risk Aversion Hypothesis, which argues that the extended juvenile phase in primates is the result of a metabolic slowdown during development arising from the need to remain in the center of social groups to elude predators where high food competition prevents adequate food intake.Ultimately, this study will fill important gaps in our understanding of the juvenile phase in primates, both through increasing the diversity of juvenile primate data available and by explicitly linking social organization to juvenile behavioral development, which may in turn shed light on the evolution of the markedly extended juvenile phase seen in primates, including humans. Additionally, the scientific presence at the Tiputini Biodiversity Station fostered by the project will enable the training of several field assistants from primate habitat countries, and contribute to the biological station?s mission of Ecuadorian education, ecological discovery, and Amazonian conservation.