Data from: A disparity between locomotor economy and territory holding ability in male house mice

Both economical locomotion and physical fighting are important performance traits to many species because of their direct influence on components of Darwinian fitness. Locomotion represents a substantial portion of the total daily energy budget of many animals. Fighting performance often determines individual reproductive fitness through the means of resource control, social dominance, and access to mates. However, phenotypic traits that improve either locomotor economy or fighting ability may diminish performance in the other. Here we test for a predicted disparity between locomotor economy and competitive ability in wild-derived house mice (<I>Mus musculus</I>). We used 8-week social competition trials in semi-natural enclosures to directly measure male competitive ability through territorial control and female occupancy within territories. We also measured oxygen consumption during locomotion for each mouse using running trials in an enclosed treadmill and open-flow respirometry. Our results show that territory-holding males have higher absolute and mass-specific oxygen consumption when running (i.e., reduced locomotor economy) as compared to males that do not control territories. This relationship was present both before and after 8-week competition trials in semi-natural enclosures. This disparity between physical competitive ability and economical locomotion may impose viability costs on males in species for which competition over mates is common and may constrain the evolution of behavioral and phenotypic diversity, particularly in natural settings with environmental and resource variability.

对于诸多物种而言，节能运动与身体对抗均为关键性能性状，因其直接影响达尔文适合度（Darwinian fitness）的组成要素。运动行为占据诸多动物每日总能量预算的显著份额。格斗性能往往通过资源掌控、社会支配以及配偶获取途径，决定个体的繁殖适合度。然而，能够提升运动经济性或格斗能力的表型性状（phenotypic traits），可能会削弱另一项性能的表现。本研究针对野生来源家鼠（Mus musculus）开展试验，验证运动经济性与竞争能力之间的预测性差异。我们在半自然围栏（semi-natural enclosures）中开展为期8周的社会竞争试验，通过领地掌控情况以及领地内的雌性占据数量，直接测定雄性的竞争能力。我们还利用封闭跑步机跑步试验与开放式呼吸测热法（open-flow respirometry），测定每只小鼠运动过程中的耗氧量。研究结果显示，相较于未掌控领地的雄性，拥有领地的雄性在跑步时的绝对耗氧量与单位体重耗氧量（mass-specific oxygen consumption）均更高，即运动经济性更差。这一关联在半自然围栏中的8周竞争试验前后均存在。身体竞争能力与节能运动能力之间的这种权衡差异，可能会在配偶竞争普遍存在的物种中对雄性造成生存成本（viability costs），并且可能约束行为与表型多样性的演化，在存在环境与资源波动的自然环境中尤为如此。