Collaborative Research: RUI: The challenges of living small: functional tradeoffs in the vertebral bone structure of diminutive mammals

合作研究：RUI：小型生活的挑战：小型哺乳动物椎骨结构的功能权衡

• 批准号: 2223965
• 负责人: Charles Stayton
• 金额: $ 19.83万
• 依托单位: Bucknell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2223965&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; challenges; living

This research explores how body size affects the structure and function of bones in very small (miniaturized) mammals. Miniaturization is common across animal groups and is significant because it is often associated with the evolution of new features despite the unique challenges faced by small animals. The effects of miniaturization on the vertebrate skeleton are particularly fundamental because the skeletal system supports all other organ systems, and must withstand internal and external applied forces while still facilitating efficient body motion. It remains poorly understood how the skeletons of the smallest vertebrate animals withstand and transmit everyday forces. 3D imaging techniques, computer modeling, and physical testing on mammalian backbones (vertebrae) will be used to assess how the skeletons of several related groups of small mammals (shrews, moles, hedgehogs, and solenodons) have evolved to function at small size. The project is testing whether smaller bones are stronger (more resistant to breaking) or stiffer (more resistant to bending), and how internal and external bone structure work together to allow very small mammals to move safely and efficiently. Planned activities will promote scientific and public understanding of how natural selection leads to changes in the shapes of bones, and how body size influences the way animals interact with their environment. This project involves training of six students from a primarily undergraduate institution (Bucknell University) in independent research. Outreach activities through the Field Museum will promote public awareness of the incredible diversity and importance of small mammals, which are often overlooked but are critical to ecosystem function.This research leverages the taxonomic richness and ecological and body size diversity of the mammalian clade Eulipotyphla to: 1) measure the contributions of trabecular and cortical bone tissues to whole-bone performance in the eulipotyphlan lumbar spine; 2) quantify the selective pressures to maximize bone strength, stiffness, or both in very small mammals; and 3) determine when tradeoffs between strength and stiffness occur as very small mammals adopt novel ecologies. By focusing on the morphology and performance of trabecular and cortical bone in the axial skeleton, specifically the lumbar spine, this research takes advantage of a system that is developmentally constrained via Hox patterning but also morphologically plastic and heavily involved in quadrupedal locomotion. The integrative approach of this study synthesizes Finite Element Analysis (FEA) results with body size, phylogenetic, ecological, and morphometric data to assess morpho-functional tradeoffs and quantify selective pressures on vertebral bone. The use of Eulipotyphla for this clade-wide functional study is novel but appropriate, as the group is taxonomically and ecologically diverse and includes the smallest mammal by mass (weighing less than two grams). These investigations will yield novel quantitative evidence about the relative importance of, and interaction between, trabecular and cortical bone under stress, and test long-standing hypotheses about how selection acts on bone morphology to produce appropriately strong, stiff bony structures at small sizes. In addition, educational and outreach outcomes include undergraduate research training, a treasure hunt activity to find small mammals at the Field Museum, and a learning kit for the Field Museum to support middle school learning standards.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.

这项研究探讨了体型大小如何影响非常小的（小型化）哺乳动物的骨骼结构和功能。小型化在动物群体中很常见，而且意义重大，因为尽管小动物面临着独特的挑战，但它通常与新特征的进化相关。小型化对脊椎动物骨骼的影响尤其重要，因为骨骼系统支撑所有其他器官系统，并且必须承受内部和外部施加的力，同时仍然促进有效的身体运动。人们对最小脊椎动物的骨骼如何承受和传递日常力量仍知之甚少。 3D 成像技术、计算机建模和哺乳动物脊柱（椎骨）的物理测试将用于评估几个相关小型哺乳动物（鼩鼱、鼹鼠、刺猬和螺齿龙）的骨骼如何进化到在小体型下发挥功能。该项目正在测试较小的骨骼是否更坚固（更耐折）或更硬（更耐弯曲），以及内部和外部骨骼结构如何协同工作以使非常小的哺乳动物安全有效地移动。计划的活动将促进科学和公众对自然选择如何导致骨骼形状变化以及体型如何影响动物与环境互动方式的理解。该项目涉及对来自本科院校（巴克内尔大学）的六名学生进行独立研究培训。通过菲尔德博物馆开展的外展活动将提高公众对小型哺乳动物令人难以置信的多样性和重要性的认识，这些哺乳动物经常被忽视，但对生态系统功能至关重要。这项研究利用哺乳动物分支Eulipotyphla的分类丰富性以及生态和体型多样性来： 1) 测量小梁骨和皮质骨组织对 eulipotyphlan 腰椎全骨性能的贡献； 2）量化选择压力，以最大限度地提高非常小型哺乳动物的骨骼强度、硬度或两者； 3）确定当非常小的哺乳动物采用新的生态系统时，何时会出现强度和刚度之间的权衡。通过关注中轴骨骼（特别是腰椎）中小梁骨和皮质骨的形态和性能，本研究利用了一个通过 Hox 图案发育受限但形态可塑且大量参与四足运动的系统。本研究的综合方法将有限元分析 (FEA) 结果与体型、系统发育、生态和形态测量数据相结合，以评估形态功能权衡并量化对椎骨的选择压力。使用 Eulipotyphla 进行这项全进化枝功能研究是新颖但适当的，因为该类群在分类学和生态学上具有多样性，并且包括质量最小的哺乳动物（重量不到两克）。这些研究将产生关于应力下小梁骨和皮质骨的相对重要性和相互作用的新的定量证据，并测试关于选择如何作用于骨形态以产生适当坚固、坚硬的小尺寸骨结构的长期假设。此外，教育和推广成果包括本科生研究培训、在菲尔德博物馆寻找小型哺乳动物的寻宝活动，以及为菲尔德博物馆提供支持中学学习标准的学习工具包。该奖项反映了 NSF 的法定使命，并被视为值得通过使用基金会的智力优点和更广泛的影响审查标准进行评估来支持。