Food Resource Partitioning Among Sympatric Hapalemur Species: Behavioral, Mechanical, and Morphological Correlates

同域 Hapalemur 物种之间的食物资源分配：行为、机械和形态相关性

• 批准号: 0420133
• 负责人: Nayuta Yamashita
• 金额: $ 7.8万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0420133&HistoricalAwards=false
• 关键词: Food; Resource; Partitioning; Among; Sympatric

Three species of Hapalemur (Primates) coexist in a rainforest in Madagascar, where they subsist on different parts of an unusual food resource, bamboo. These circumstances create an intriguing natural experiment for examining behavioral and morphological variables that contribute to the coexistence of these species on a similar diet. This project will specifically examine relationships between physical parameters of diets and the form and performance of jaws and teeth where food is first encountered. Positive relationships between these factors will support the hypothesis that differences represent feeding adaptations that allow the lemurs to exploit similar resources without being in direct competition. These results can serve as a model for interpreting morphology and dietary reconstruction of extinct primates in the fossil record, while also addressing the extent to which dietary properties influence morphological evolution and adaptation.Toward these goals, this project will investigate whether the observed dietary differences among Hapalemur species are solely related to behavioral aspects of food choice or whether they are also linked to variation in the form and performance of the masticatory apparatus. Specifically, the project will determine: 1) whether the segregation or overlap of Hapalemur diets can be linked to variation in plant properties, 2) whether these plant properties are correlated with variation in dental and jaw morphology, and 3) whether morphological differences translate into performance differences in biting and chewing behaviors among species. Even though divergence in form is typically used as evidence of adaptive specialization, these morphological differences must result in differential performance if current morphological variation is the result of directional selection. If physical dietary properties, jaw and tooth form, and performance of the masticatory apparatus during chewing and biting are correlated across the lemur species, then this would suggest that differences in the ability to procure specific foods could have contributed to reduction of feeding competition. Fieldwork will involve: 1) observing feeding behaviors to identify exact plant parts eaten and establish individual and species differences in food ingestion and processing; 2) quantifying food properties by testing plant parts eaten and rejected by the lemurs for toughness, hardness, and elastic modulus using a portable mechanical tester; and 3) comparing the morphology and performance of the jaws and teeth of Hapalemur individuals by taking tooth impressions, measuring jaws, quantifying maximum jaw gapes, and estimating maximum bite force capabilities on anesthetized animals. This project has a strong educational component that involves supporting and training students in the host country. Malagasy students will work with the researchers in all aspects of this project. In addition to providing assistance in the field, each student will be supervised in separate, parallel research projects toward completion of their Master's equivalent degrees. The future conservation of these primates and other rare endemic species will be led by local researchers who must be well-trained. It is the hope of the project investigators to contribute to this effort by exposing students to broad evolutionary questions and fieldwork opportunities that they can then apply to their own research programs.

三种Hapalemur（灵长类动物）共存于马达加斯加的雨林中，在那里它们以一种不寻常的食物资源竹子的不同部分为生。 这些情况创造了一个有趣的自然实验，用于检查行为和形态变量，这些变量有助于这些物种在类似的饮食中共存。 这个项目将专门研究饮食的物理参数与第一次遇到食物的颌骨和牙齿的形式和性能之间的关系。这些因素之间的正相关关系将支持这一假设，即差异代表摄食适应，使狐猴利用类似的资源，而不直接竞争。这些结果可以作为解释化石记录中灭绝灵长类动物形态和饮食重建的模型，同时也解决了饮食特性影响形态进化和适应的程度。该项目将调查观察到的哈帕勒穆尔物种之间的饮食差异是否仅与食物选择的行为方面有关，或者它们是否也与形式的变化有关。和咀嚼器的性能。具体而言，该项目将确定：1）Hapalemur饮食的隔离或重叠是否与植物特性的变化有关，2）这些植物特性是否与牙齿和颌骨形态的变化相关，以及3）形态差异是否转化为物种之间咬合和咀嚼行为的表现差异。尽管形式上的差异通常被用作适应性专业化的证据，但如果当前形态变化是定向选择的结果，这些形态差异必然导致差异表现。如果身体的饮食特性，下巴和牙齿的形状，咀嚼和咬合过程中的咀嚼器的性能在狐猴物种之间是相关的，那么这将表明，在获得特定食物的能力的差异可能有助于减少摄食竞争。实地工作将包括：1）观察进食行为以识别被吃掉的确切植物部分并建立食物摄取和加工中的个体和物种差异; 2）通过使用便携式机械测试仪测试被狐猴吃掉和拒绝的植物部分的韧性、硬度和弹性模量来量化食物性质;和3）通过获取牙齿印模、测量颌骨、量化最大颌骨间隙，以及估计麻醉动物的最大咬合力能力。该项目有一个强有力的教育部分，涉及支持和培训东道国的学生。马达加斯加学生将与研究人员在这个项目的各个方面。除了在该领域提供帮助，每个学生将在独立的，平行的研究项目，对他们的硕士同等学位完成监督。 这些灵长类动物和其他稀有地方物种的未来保护将由当地研究人员领导，他们必须受过良好的训练。项目研究人员希望通过让学生接触到广泛的进化问题和实地考察机会，从而为这一努力做出贡献，然后他们可以将这些问题和机会应用到自己的研究项目中。