Collaborative Research: Ecological and Functional Morphology of Feeding in Free-Ranging Mantled Howling Monkeys

生物人类学家长期以来一直对饮食和摄食对灵长类生物学各个方面的影响感兴趣，包括灵长类动物的进化、行为和形态。灵长类动物头骨和牙齿结构的比较研究、饮食选择和觅食行为的实地研究以及圈养灵长类动物摄食动态的实验室研究都为这一努力做出了重要贡献。然而，这些研究项目从未被完全整合，每个项目的固有假设限制了将饮食和喂养与灵长类动物生物学和适应性联系起来的假设的强度。例如，实验室研究的一个假设是，实验室记录的进食行为和颚肌活动准确地反映了野生灵长类动物在其自然栖息地的进食行为。同样，当将野外工作应用于灵长类动物摄食进化的问题时，必须假设野外观察与实验室观察到的咀嚼功能有关。本研究的目的是将多种实验室和现场方法整合到哥斯达黎加La Pacifica庄园自由放养的披毛嚎叫猴的觅食研究中。首先，使用专门为该项目设计的新技术，当这些动物在自然栖息地进食时，将记录下颌肌肉的肌电图数据。其次，在记录期间所消耗的食品的机械性能将被量化。第三，牙齿磨损将在记录周期之前和之后立即量化。最后，在记录期间收集个体的摄食和测距行为。这项研究的数据将用于证明灵长类动物在进食天然食物时如何使用颚肌，并产生有关颚肌功能与颚结构的生态学相关假设。下颌肌肉活动数据也将与食物的力学特性、摄食行为和牙齿磨损的进展相关联。更广泛地说，这项拟议的研究将是同类研究中首次将基于实验室的颚肌功能记录技术与灵长类动物摄食生态学、行为和牙齿形态的实地研究相结合。此外，该项目的综合性质将确定灵长类动物摄食器官、摄食行为和饮食的适应和功能之间的额外联系，这可能不会从任何一个独立的研究项目中得到证实。这项研究的广泛影响包括促进四所大学不同专业领域的科学家之间的合作，以及通过学生积极参与这项研究来培训学生。综合方法将为这些学生提供实地技术、肌电图、机械性能和行为数据收集和分析方面的实践训练。此外，有关披毛嚎叫猴摄食行为的信息将有助于这些灵长类动物及其在中美洲和南美洲栖息地的长期可持续性的保护管理决策。最后，该项目由一名少数族裔女性研究员领导，从而促进了少数族裔在科学领域的代表性。

Biological anthropologists have a long-standing interest in the influence of diet and feeding on all aspects of primate biology, including primate evolution, behavior and morphology. Comparative studies of the structure of primate skulls and teeth, field studies on dietary selection and foraging behaviors, and laboratory studies on the dynamics of feeding in captive primates have all contributed significantly to this endeavor. However, these research programs have never been fully integrated, and assumptions inherent to each limit the strength of hypotheses linking diet and feeding to primate biology and adaptations. For example, an assumption of lab research is that feeding behaviors and jaw-muscle activity recorded in the lab accurately reflect those of wild primates feeding in their natural habitats. Likewise, when applying field work to questions about the evolution of primate feeding, it must be assumed that field observations are related to masticatory function as observed in the lab.The goal of this study is to integrate multiple lab and field methods into a study of foraging in free-ranging mantled howling monkeys at Hacienda La Pacifica, Costa Rica. First, using new technology designed specifically for this project, electromyographic data will be recorded from their jaw muscles while these animals feed in their natural habitat. Second, the mechanical properties of the foods consumed during the recording period will be quantified. Third, tooth wear will be quantified immediately prior to and following the recording period. Finally, feeding and ranging behaviors of individuals will be collected during the recording period. Data from this study will be used to demonstrate how primates use their jaw-muscles during feeding on their natural foods and to generate ecologically relevant hypotheses relating jaw-muscle function to jaw structure. The jaw-muscle activity data will also be correlated with food mechanical properties, feeding behaviors and the progression of tooth wear. More generally, the proposed research will be the first of its kind to combine lab-based techniques for recording jaw-muscle function with field research on primate feeding ecology, behavior and dental morphology. Moreover, the integrative nature of this project will identify additional links between adaptations and function in the primate feeding apparatus, feeding behavior and diet that may not be evident from any one independent research program. Broader impacts of this study include the promotion of collaboration between scientists at four universities with different areas of expertise and the training of students through their active participation in research for this project. The integrative approach will provide these students with hands-on training in field techniques, electromyography, and mechanical properties and behavioral data collection and analysis. It is also expected that information on mantled howling monkey feeding behaviors will benefit conservation management decisions regarding the long-term sustainability of these primates and their habitats in Central and South America. Finally, this project is led by a minority female researcher, thereby contributing to minority representation in the sciences.