Doctoral Dissertation Improvement: Contest competition and its relation to behavior and stress physiology in wild Cercopithecus mitis

众所周知，环境条件会影响动物社会系统的几个关键方面，包括群体规模和组成，以及攻击、隶属和合作的频率。在非人类灵长类动物中，有证据表明，食物的丰富度和分布是特别重要的变量，通过它们在群体内部和群体之间带来的竞争来发挥作用。社会生态学理论认为，当稀缺资源可以被个人和群体垄断时，竞争各方之间将出现高水平的激进（直接）竞争；然而，其他人无法有效排除的资源应该导致争夺（间接）竞争，竞争各方竞相首先消耗食物，很少或没有侵略。只有激烈的竞争才会导致社会冲突的增加，（根据理论）形成强大的社会等级制度。在这种情况下，地位高的个体在终身繁殖成功或健康方面应该受益。然而，迄今为止，人类和非人类灵长类动物的低繁殖率和长寿命使得测量繁殖成功变得困难，从而难以研究食物资源和健康之间的联系。例如，在研究物种中，先前的研究揭示了雌性之间的线性优势等级，表明群体内的激烈竞争；然而，令人惊讶的是，生殖率与社会地位无关。这一发现的一个可能的原因是，繁殖率本身可能不能准确地评估这些繁殖缓慢的动物的社会和生态条件的适应性后果。在哺乳动物社会中，生理应激可能提供了一种新的健康测量方法。与正常应激反应模式的偏差，特别是长期升高的水平，已知会产生许多病理后果，包括对免疫和寿命的长期影响。这项研究将调查食物竞争的变化如何影响应激生理和行为调整，使用肯尼亚两个种群的蓝猴作为模型系统。cord和Foerster将描述三个野生社会群体的激烈竞争，这些群体从人类那里获得的食物补充水平不同。在18个月的时间里，他们将以前所未有的采样频率，使用个别已知雌性的粪便提取物，非侵入性地监测糖皮质激素（应激）代谢产物。它们将同时体验社交和觅食行为。与以前的研究不同，这种密集的抽样制度允许研究人员评估是什么决定了受试者内部和受试者之间的糖皮质激素水平变化，以应对短期和长期的社会和环境压力。cord和Foerster将控制其他已知影响压力水平的因素，如生殖状况、食物供应、能量消耗和应对行为的发生。从更广泛的影响来看，本研究完成了福斯特博士的培养。此外，肯尼亚当地和国际实地助理将接受灵长类动物行为生态学实地方法的培训。一名肯尼亚研究生将与内罗毕灵长类动物研究所合作，对粪便样本进行寄生虫学研究。这项研究的结果将有助于评估食物补充对这种动物和其他野生非人灵长类动物健康的长期影响，从而对野生动物种群的保护和管理产生影响。

Environmental conditions are known to affect several key aspects of animal social systems including group size and composition, and the frequency of aggression, affiliation and cooperation. In non-human primates, there is evidence that the abundance and distribution of food are especially important variables, exerting their effect through the competition they bring about, both within and between groups. Socioecological theory suggests that when scarce resources can be monopolized by individuals and groups, there will be high levels of aggressive (direct) competition between the competing parties; however, resources from which others cannot be effectively excluded should result in scramble (indirect) competition, with competing parties racing to consume the food first, with little or no aggression. Only aggressive competition leads to increased social conflict and (according to theory) to the formation of strong social hierarchies. Under such circumstances, individuals with high status should benefit in terms of lifetime reproductive success, or fitness. However, the low reproductive rate and long lifespan of human and non-human primates has so far made it difficult to measure reproductive success, and thus to examine the link between food resources and fitness. In the study species, for example, previous research revealed linear dominance hierarchies among females, indicating within-group aggressive competition; surprisingly, however, reproductive rates were not related to social status. A possible reason for this finding is that reproductive rates alone may not accurately assess fitness consequences of social and ecological conditions in these slowly reproducing animals. Physiological stress may provide a new alternative measure of fitness in mammalian societies. Deviations from the normal stress response pattern, particularly chronically elevated levels, are known to have many pathological consequences, including long-term effects on immunity and lifespan. This research will investigate how variation in competition for food influences stress physiology and behavioral adjustments, using blue monkeys in two populations in Kenya as a model system. Cords and Foerster will characterize aggressive competition in three wild social groups that differ in the level of food supplementation they receive from humans. Over an 18-month period, they will monitor glucocorticoid (stress) hormone metabolites non-invasively, using fecal extracts from individually known females at an unprecedented sampling frequency. They will simultaneously sample social and foraging behavior. Unlike previous studies, this intensive sampling regime allows the investigators to assess what determines both within- and between-subject variation in glucocorticoid levels in response to both short- and long-term social and environmental stressors. Cords and Foerster will control for other factors known to influence stress levels, such as reproductive status, food availability, energy expenditure, and the occurrence of coping behavior. In terms of broader impacts, this research completes the doctoral training of Foerster. In addition, both local Kenyan and international field assistants will receive training in field methods of primate behavioral ecology. A Kenyan graduate student will conduct a parasitological study on fecal samples in collaboration with the Institute of Primate Research, Nairobi. Results from this research will help to assess long-term effects of food supplementation on the health of this and other species of wild non-human primates, and thus has implications for the conservation and management of wild animal populations.