DISSERTATION RESEARCH: The functional basis of whole-organism trade-offs between locomotor economy and physical competitive ability

本研究将研究雄性小鼠的四肢、肌肉和生理特征，以确定导致运动与身体竞争之间可能的权衡的潜在因素。对大多数物种来说，运动和身体竞争是至关重要的活动。然而，在这些行为中提高表现的解剖和生理特征可能会损害另一种行为的表现。在处于社会支配地位的雄性家鼠中，那些更有能力获得和控制有雌性的领地的雄性家鼠是以效率较低的运动为代价的。这种权衡可能与特定的解剖和生理特征有关。这项研究的结果将增加对动物功能和相互冲突的进化压力的理解。此外，本研究还将参与几个公众参与项目，包括犹他州惩教机构的科学系列讲座，犹他州自然历史博物馆的非正式科学交流活动，以及其他将当地相关科学带给犹他州居民的项目。该项目还将为本科生提供研究、演讲和拓展机会。本研究将通过比较显性和非显性雄性小鼠的以下特征，探讨影响运动经济性和体育竞技表现的潜在因素：1)骨骼比例和解剖力学优势；2)躯干和四肢肌肉的肌肉质量分布；3)前肢和后肢近端和远端肌肉纤维类型。这些数据将与之前收集的半自然环境下的竞争能力数据和在全封闭跑步机上使用开放流呼吸测量法的运动经济性数据相结合。总之，这些数据将允许识别哪些特征在生物组织的哪些水平上是运动竞争权衡的基础。此外，因为在雄性竞争中赋予最大优势的特征通常也是那些最具两性二态性的特征，所以关于优势雄性和非优势雄性之间差异的相同假设也适用于雄性和雌性之间的差异。这项研究将有助于回答自然选择和性选择之间长期存在的未解之谜。

This study will examine the characteristics of limbs, muscles and physiology of male mice in order to identify the underlying factors leading to a possible trade-off in locomotion versus physical competition. Locomotion and physical competition are critically important activities for most species. However, anatomical and physiological traits that improve performance in either of these behaviors may impair performance in the other. In socially dominant male house mice, those with greater ability to gain and control territories containing females do so at the cost of less efficient locomotion. This trade-off is likely associated with specific anatomical and physiological traits. The results of this study will increase understanding of animal function and conflicting evolutionary pressures. Additionally, this study will be involved in several public engagement projects, including a science lecture series at correctional institutions in Utah, informal science communications events at the Natural History Museum of Utah, and other programs that bring locally-relevant science to Utah residents. This project will also provide research, presentation, and outreach opportunities for undergraduate students.This research will investigate underlying factors that influence locomotor economy and physical competitive performance by comparing the following traits in dominant versus non-dominant male mice: 1) skeletal proportions and anatomical mechanical advantages, 2) muscle mass distribution of the trunk and limb muscles, and 3) muscle fiber types of the proximal and distal forelimb and hindlimb using antibody-based histochemistry. These data will be combined with previously collected data on competitive ability in semi-natural enclosures and locomotor economy using open-flow respirometry in a fully enclosed treadmill. Together, these data will allow the identification of which traits at what levels of biological organization underlie the locomotion-competition trade-off. Additionally, because traits that confer the greatest advantage during male-male contests are also typically those that are the most sexually dimorphic, the same hypotheses for differences between dominant and non-dominant males will be applied to male-female differences. This research will help to answer long-standing, unanswered questions at the intersection of natural and sexual selection.