Dietary Properties and Chewing Patterns in Primates: An Analysis of Cyclical Loading

本计画探讨灵长类动物的饮食与咀嚼行为之间的关系，以增进我们对灵长类动物与人类摄食行为演化与变异的了解。研究人员将测量23种灵长类动物的咀嚼模式，这些灵长类动物的食物具有一系列材料特性，以了解每个物种的个体如何处理不同的食物，以及这种处理如何与它们的下巴和头骨形状相关。这些比较数据不仅对构建现存灵长类物种的生态学研究非常重要，而且对基于颌骨和头骨化石重建灭绝灵长类和人类物种的饮食和进食行为也很重要。该项目将促进跨学科的培训和教育方法，涉及代表性不足的群体的成员，并将支持博士后研究员，研究生和本科生以及当地STEM教师和学生的培训和指导，所有这些人都将参加实验室学徒，科学演示和向当地机构和普通公众的公共宣传。 因此，对社会的另一个好处包括为下一代学术研究人员和教育工作者开发一种新的培训环境。灵长类头骨的表型变异受咀嚼应力的影响，类群依赖于坚硬或坚韧的食物，有专门的颌骨，牙齿和颌骨肌肉。 然而，在现存和化石灵长类动物中，饮食和颌骨形状之间的联系却知之甚少。 难以理解的适应多样性的喂养装置是由于两个缺点的证据有关饮食相关的咀嚼和加载行为。第一个是这样一个事实，即罕见的，高幅度的力量引起相同的生理和进化的反应，在骨低幅度，周期性负荷。 在头骨中，第二个和相关的问题是一个令人惊讶的不完整的知识的作用，食物特性的变化，咀嚼行为的基础上负载相关的变化，在灵长类动物的颌骨形状。 考虑到周期性负载被用来解释化石人类的颌骨健壮性的普遍性，这种咀嚼模式的关键行为数据的显著缺乏不能被夸大。 使用在国内机构保存的23种代表性灵长类动物的体内数据，该项目测试的假设，即食物材料的性能影响咀嚼参数的变化的灵长类动物颌骨的周期性负载：咀嚼频率，咀嚼投资，咀嚼持续时间。 高速视频将记录孤立和不受约束的成年灵长类动物的动态饮食相关咀嚼模式，这些灵长类动物提供了一种已知的五种食物，这些食物跨越了一系列材料特性，这些特性与野生灵长类动物摄入的物品的价值多样性相似。 种内和种间分析将比较咀嚼参数与食物硬度，韧性和各自的口腔破碎指数。 由于其实验和比较的重点，这种体内研究很可能为生物人类学和其他有机体和生物医学领域的理论和方法进步提供信息。

This project investigates relationships between diet and chewing behaviors in primates, to improve our understanding of the evolution and variation in primate and hominin feeding behaviors. The investigators will measure chewing patterns in 23 primate species that are given foods spanning a range of material properties, to see how individuals in each species process the different foods and how this processing relates to the shape of their jaw and skull. These comparative data will be important not only for framing ecological research in living primate species, but for reconstructing diet and feeding behaviors in extinct primate and hominin species based on fossil jaws and skulls. The project will foster interdisciplinary approaches to training and education involving members of under-represented groups, and will support training and mentorship of a postdoctoral fellow, graduate students and undergraduates as well as local STEM teachers and students, all of whom will participate in lab apprenticeship, scientific presentations and public outreach to local institutions and the lay public. Therefore, another benefit to society includes development of a novel training environment for the next generation of academic researchers and educators.Phenotypic variation in the primate skull is influenced by masticatory stress, with taxa relying on stiff or tough foods having specialized jaws, teeth and jaw muscles. However, the link between diet and jaw form in living and fossil primates is poorly understood. Difficulty understanding adaptive diversity in the feeding apparatus is due to two shortcomings of the evidence about diet-related chewing and loading behaviors. The first is the fact that infrequent, high-magnitude forces elicit the same physiological and evolutionary responses in bone as do low-magnitude, cyclical loads. In the skull, a second and related issue is a surprisingly incomplete knowledge of the role of food properties on variation in chewing behaviors that underlie load-related variation in primate jaw form. Given the ubiquity with which cyclical loading is invoked to explain jaw robusticity in fossil hominins, the remarkable lack of key behavioral data on this chewing pattern cannot be overstated. Using in vivo data on 23 representative primate species kept in domestic institutions, this project tests the hypothesis that food material properties affect masticatory parameters underlying variation in cyclical loading of primate jaws: chewing frequency, chewing investment, and chewing duration. High-speed video will record dynamic diet-related chewing patterns in isolated and unrestrained adult primates presented a known mass of five foods that span a range of material properties paralleling the diversity of values for items ingested by wild primates. Intra- and interspecific analyses will compare chewing parameters with food stiffness, toughness, and respective oral fragmentation indices. Due to its experimental and comparative focus, this in vivo research is likely to inform theoretical and methodological advances in biological anthropology and other organismal and biomedical fields.