The mechanics of anterior tooth use in primates

灵长类动物使用前牙的机制

• 批准号: 0412153
• 负责人: Christopher Vinyard
• 金额: $ 2.32万
• 依托单位: Northeast Ohio Medical University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0412153&HistoricalAwards=false
• 关键词: mechanics; anterior; tooth; use; primates

The prevalence of tree exudate feeding (e.g., tree gums and saps) or gummivory among primates suggests that this feeding behavior has significantly influenced primate evolution. Some gummivorous primate species actively elicit tree exudate flow by mechanically damaging trees with their anterior teeth. This type of biting behavior is defined as gouging. This project will record jaw forces and jaw gapes (or the magnitude of jaw opening) during gouging in the South American common marmoset (Callithrix jacchus). Anthropologists previously have hypothesized that tree gouging involves large jaw forces or large jaw gapes relative to those experienced during chewing and incision. These hypotheses have been put forth without any attempt to measure the jaw forces or jaw gapes during gouging. The proposed research will generate novel information about the possible mechanical effects that gummivory might have on primate skull form and function. Based on preliminary data, gouging appears to require relatively large jaw gapes, but not necessarily relatively large jaw forces. This finding contradicts earlier ideas about this behavior and emphasizes the under-appreciated significance of jaw gapes in primate biting. With few exceptions, in vivo studies of primate jaw and tooth function (i.e., studies of living animals performing a behavior) have not focused on anterior tooth use or biting. This shortcoming persists despite several researchers noting the likely significance of biting for primate morphology and ecology. This proposal is important because it will be one of the first in vivo studies of jaw mechanics during a biting behavior in primates and therefore will contribute new insights into how biting might affect the form and function of primate skulls. The in vivo data collected in this project will play a key role in studying adaptations for gouging in the marmoset head. Using recently collected field data, the substrates that marmosets gouge in the lab will be made to mimic the trees that marmosets gouge in the wild. By matching the lab substrates to wild ones, this project can more realistically study jaw performance during gouging. This in turn provides improved tests of adaptive hypotheses for this behavior. Furthermore, the in vivo data are a core reference for comparisons of skull functional morphology, quantitative genetics of skull form, jaw-muscle fiber architecture and jaw trabecular structure between marmosets and non-gouging tamarins. These analyses will provide an extensive characterization of tree gouging adaptations in marmosets and serve as a model approach for other anthropologists for combining lab, field and skull morphometric methods in studying primate adaptations. Another important goal of this project involves training students through integrating education and research. The promotion of student learning and training through active participation will be emphasized in this project. Because in vivo research skills can only be mastered through interactive apprenticeship and these opportunities are relatively rare, this project will provide a significant educational resource for biological anthropology. Finally, the inclusive project studying skull function and ecology of tree gouging in marmosets links researchers from U.S. and Brasilian universities fostering interaction and intellectual exchange between them.

在灵长类动物中，树分泌物摄食（如树胶和树液）或树胶的普遍存在表明，这种摄食行为对灵长类动物的进化有显著影响。一些食胶灵长类动物通过用它们的前牙机械地破坏树木，从而主动引起树木渗出液流。这种类型的咬人行为被定义为凿食。该项目将记录南美普通狨猴（Callithrix jacchus）在开凿过程中的颚力和颚间隙（或颚开口的大小）。人类学家此前曾假设，与咀嚼和切割过程中所经历的情况相比，凿树涉及到更大的颌力或更大的颌口。这些假设的提出没有任何尝试测量颚力或颚间隙在凿。拟议的研究将产生新的信息，可能的机械效应，胶质可能对灵长类动物的头骨形式和功能。根据初步数据，刨削似乎需要相对较大的颚间隙，但不一定需要相对较大的颚力。这一发现与早期关于这种行为的观点相矛盾，并强调了灵长类动物咬人时下颌张开的重要性。除了少数例外，灵长类动物下颌和牙齿功能的体内研究（即对活体动物执行某种行为的研究）并没有集中在前牙的使用或咬人上。尽管一些研究人员注意到咬对灵长类动物形态学和生态学的可能意义，但这一缺点仍然存在。这一建议很重要，因为它将是灵长类动物咬人行为中首次在体内研究颌骨力学的研究之一，因此将为咬伤如何影响灵长类动物头骨的形式和功能提供新的见解。本项目收集的体内数据将在研究狨猴头部对刨削的适应性方面发挥关键作用。利用最近收集到的野外数据，我们将制作出狨猴在实验室里凿出的基质，以模仿狨猴在野外凿出的树木。通过将实验室衬底与野外衬底相匹配，本项目可以更真实地研究刨削过程中的颚部性能。这反过来又为这种行为的适应性假设提供了改进的测试。此外，体内数据是比较绒猴和非凿毛猴颅骨功能形态学、颅骨形态定量遗传学、下颌肌纤维结构和下颌小梁结构的核心参考。这些分析将为狨猴的采树适应性提供广泛的特征，并为其他人类学家结合实验室、野外和头骨形态测量学方法研究灵长类动物的适应性提供模型方法。该项目的另一个重要目标是通过整合教育和研究来培养学生。通过学生的积极参与促进学生的学习和训练将在这个项目中得到强调。由于体内研究技能只能通过互动学徒的方式掌握，而这些机会相对较少，因此该项目将为生物人类学提供重要的教育资源。最后，研究狨猴颅骨功能和凿树生态学的包容性项目将美国和巴西大学的研究人员联系起来，促进他们之间的互动和知识交流。