Using stable isotopes to discern the advantages of tool-mediated shellfish exploitation in a monkey model system

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。对高质量蛋白质的偏好可能促成了我们早期人类祖先的关键变化。研究人员假设，早期现代人对海洋蛋白质（如贝类）的食用有助于古人类从非洲迅速扩散，而早期的石器工具使人类更容易获得动物蛋白质和脂肪，从而促进了大脑发育和认知的能量需求。由于缺乏合适的灵长类模型系统，测试关于海洋蛋白质对早期人类种群迁移和生物适应的重要性的假设一直很困难。然而，这个项目已经确定了一个这样的模型系统，一个独特的猕猴种群，它们使用石头提取和食用贝类，个体猴子使用工具的能力不同。研究人员将测量贝类消费、单个猴子体内蛋白质水平和工具使用之间的关系，以确定石器技术能力的差异如何影响蛋白质摄入量。该项目在地方、国家和国际层面具有更广泛的影响，包括为代表性不足的学生提供培训和专业发展，与朱拉隆功大学开展国际研究合作，在K-12环境中开展教育推广，以及通过各种媒体传播学术界以外的研究成果。该项目将开始探索石器使用和贝类开发中个体差异的适应性后果。在泰国Koram岛使用石器工具的长尾猕猴种群中，研究人员将使用碳和氮稳定同位素分析来测量贝类食用对单个猴子毛发蛋白的贡献，并量化工具使用对蛋白质同化的好处。这些目标将通过1)测量猕猴毛发和所有食物来源的碳和氮稳定同位素组成，2)在贝叶斯稳定同位素混合模型中结合同位素数据和觅食行为数据（作为信息先验）来估计蛋白质来源对毛发的比例贡献，作为石器工具使用和技术熟练程度的直接函数。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).A preference for high quality protein may have contributed to key changes in our early human ancestors. Researchers have hypothesized that early modern human consumption of marine protein (e.g., shellfish) aided the rapid dispersal of hominins from Africa, and that early stone tools enabled greater access to animal protein and fat that fueled the energetic demands of brain growth and cognition. Testing hypotheses about the importance of marine protein for early human population movements and biological adaptations has been difficult given the dearth of suitable model primate systems. However, this project has identified one such model system, a unique population of macaques that use stones to extract and eat shellfish, with individual monkeys differing in tool-use abilities. The investigators will measure relationships among shellfish consumption, protein levels in individual monkeys, and tool use, to determine how variation in technical competence with stone tools may influence protein intake. The project has broader impacts at the local, national, and international levels, including training and professional development for underrepresented students, international research collaborations with Chulalongkorn University, educational outreach in K-12 settings, and the dissemination of research findings beyond academia through various media. This project will begin to explore the fitness consequences of individual variation in stone tool use and shellfish exploitation. The investigators will use carbon and nitrogen stable isotope analysis to measure the contribution of protein from shellfish consumption to the hair protein of individual monkeys within a stone-tool using population of long-tailed macaques in Koram Island, Thailand, and quantify the benefit of tool use to protein assimilation. These objectives will be achieved by 1) measuring the carbon and nitrogen stable isotope composition of macaque hair and all food sources, and 2) combining isotopic data with behavioral data on foraging (as informative priors) in a Bayesian stable isotope mixing model to estimate the proportional contributions of protein sources to hair as a direct function of stone tool use and technical proficiency.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.