Ecology, feeding competition, and social relationships of Phayre's leaf monkeys

非人灵长类动物是所有生物中最具社会性的，在社会组织中表现出最广泛的变化。因此，对非人类灵长类动物的行为和生态学的研究在解决诸如为什么包括人类在内的生物体首先生活在群体中，为什么他们生活在特定大小的群体中，以及什么因素影响群体成员之间的社会关系等问题方面最有影响力。食叶猴特别有趣，因为它们的生态和社会组织之间的关系与目前的理论不一致。它们以大量丰富的资源为食，应该生活在大群体中，并表现出弱的统治关系。然而，它们通常生活在具有强大统治等级的小群体中。为了解决这一争议，该研究正在追踪新的解释思路，研究(i)间接喂养竞争或杀婴行为或两者是否限制了Phayre叶猴（Trachypithecus phayrei）的群体规模，以及（ii）资源分配、喂养竞争和雌性繁殖成功是否符合预测的雌性社会关系和分散模式。研究在泰国东北部的Phu Khieo野生动物保护区进行，该保护区有8种同栖灵长类动物，包括2种叶猴（T. cristatus， T. phayrei）和4种猕猴（Macaca arctoides， M. assamensis， M. mulatta， M. nemestrina）。研究区（156,000公顷）未受干扰，包括两种主要栖息地类型（山地常绿和干常绿森林）。从长远来看，这种设置将允许在不同栖息地中比较体型相似的灵长类属和物种，以及在同一栖息地中比较体型相似的物种和属。这项研究是基于与两所泰国大学（曼谷Kasetsart大学和Mahidol大学）的研究人员以及政府机构（曼谷皇家森林部）的官员的合作。每年至少有两名当地工作人员，两名应届毕业生和一名博士后研究员，并提供论文研究机会。这项研究将促进泰国国内以及与美国的合作，支持保护区的保护工作，并为学生提供培训和就业机会。

Nonhuman primates are the most social among all organisms and exhibit the broadest range of variation in social organization. Consequently, research on the behavior and ecology of nonhuman primates has been most influential in addressing questions as to why organisms including humans live in groups in the first place, why they live in groups of particular sizes, and what factors influence the social relationships among group members. Leaf-eating monkeys are particularly interesting, because the relationship between their ecology and social organization is not consistent with current theory. Feeding on supposedly large abundant resources, they should live in large groups and exhibit weak dominance relationships. Quite often, however, they live in small groups with strong dominance hierarchies. The study is following up new explanatory ideas to resolve this controversy examining (i) whether indirect feeding competition or infanticide or both constrain group size of Phayre's leaf monkeys (Trachypithecus phayrei) and (ii) whether resource distribution, feeding competition, and female reproductive success conform to the predicted female social relationships and dispersal patterns.Research is conducted at Phu Khieo Wildlife Sanctuary, Northeastern Thailand harboring eight sympatric primates including two leaf monkeys (T. cristatus, T. phayrei) and four macaques (Macaca arctoides, M. assamensis, M. mulatta, M. nemestrina). The study area (156,000 ha) is undisturbed including two major habitat types (hill evergreen and dry evergreen forest). In the long range this setting will allow comparisons within primate genera and species of similar body size across habitats as well as across species and genera of similar body size within the same habitat. The study is based on a collaboration with researchers from two Thai Universities (Kasetsart and Mahidol University, Bangkok) and officials from governmental agencies (Royal Forest Department, Bangkok). Per year it will involve a minimum of two local staff, two recent graduates and one post-doctoral researcher and provide the opportunity for thesis research. The study will foster cooperation within Thailand and with the United States, support conservation efforts in the sanctuary, and provide training and career opportunities for students.