Doctoral Dissertation Improvement: Nutritional ecology of Mexican black howler monkeys: The role of nutrient mixing, plant secondary metabolites, and behavioral flexibility

许多灵长类动物全年都在利用低质量和难以加工的资源，或者在一年中食物有限的时候作为备用食物。除了解剖上的特化外，灵长类动物还发展出行为和认知上的解决方案，以提高觅食效率或在寻找低质量食物时减少能量需求。最优觅食理论被用来解释灵长类动物的觅食行为，并预测个体的食物选择最好用能量摄入最大化来描述。然而，根据最近的营养生态学模型，营养混合框架可能为灵长类动物的觅食策略提供更有力的解释。本研究考察了阿鲁阿塔pigra的营养生态学，阿鲁阿塔pigra是一种濒危灵长类动物，以低质量资源为食，但与近缘物种相比，其特点是生长速度快，生殖产量高。具体而言，本研究通过综合营养、能量、生态和行为数据，研究了食物和斑块选择、食物摄取率、植物资源的营养成分、食物供应的季节性变化、生殖营养需求和群体内喂养竞争等因素如何影响生活在墨西哥南部两个相邻群体的雄性和雌性黑吼猴的觅食策略。三个模型的解释力将使用营养的几何框架进行检验。这将通过对被标记个体的详细行为观察来完成；植被评估和确定种群活动范围内的食物供应；以及从树木中采集的食物的植物化学分析。虽然有关于吼猴喂养生态学的数据，但影响雄性和雌性食物选择的确切营养因素却知之甚少。通过构建每个焦点动物的完整饮食档案，并使用营养显式模型分析个体觅食决策，本研究为营养平衡在评估灵长类动物食物选择和决策中的重要性提供了重要的见解。该项目还将为圈养灵长类动物的管理提供有价值的营养信息，加强墨西哥和美国大学之间的伙伴关系，并为墨西哥本科生（包括理科女生）提供培训机会。

Many primate species exploit low quality and difficult to process resources year-round or as fallback foods during food-limited times of the year. In addition to anatomical specializations, primates have developed behavioral and cognitive solutions that serve to increase foraging efficiency or reduce energetic requirements when exploiting low quality foods. Optimal Foraging Theory has been used to explain foraging behavior in primates, and predicts that individual food choice is best described in terms of maximization of energy intake. However, according to recent nutritional ecology models, a nutrient mixing framework may provide a stronger explanation of primate foraging strategies. This study examines the nutritional ecology of Alouatta pigra, an endangered primate that feeds on low quality resources and yet is characterized by rapid growth rates and a high reproductive output compared to closely related species. Specifically, by integrating nutritional, energetic, ecological, and behavioral data, this research investigates how factors such as food and patch choice, food intake rates, the nutritional composition of plant resources, seasonal changes in food availability, the nutritional requirements of reproduction, and within-group feeding competition affect male and female foraging strategies in two neighboring groups of black howler monkeys living in Southern Mexico. The explanatory power of three models will be tested using a Geometric Framework for nutrition. This will be accomplished by detailed behavioral observations of marked individuals; vegetation assessments and determination of food availability in the groups' home ranges; and phytochemical analyses of foods collected from feeding trees.While there are data on howler monkey feeding ecology, the precise nutritional factors affecting male and female food choices are poorly understood. By constructing complete dietary profiles for each focal animal, and analyzing individual foraging decisions using a nutritionally explicit model, this research provides critical insight into the importance of nutrient balancing in assessing primate food choice and decision-making. The project also will provide valuable nutritional information for the management of captive primates, strengthen partnerships between Mexican and US universities, and offer training opportunities for Mexican undergraduates, including female students in science.