Data from: Repeatability of locomotor performance and of morphology - locomotor performance relationships

There is good evidence that natural selection drives the evolution of locomotor performance, but the processes that generate among individual variation in locomotion, the substrate upon which selection acts, are relatively poorly understood. We measured prolonged swimming performance, Ucrit, and morphology in a large cohort (n=461) of wildtype zebrafish, Danio rerio, at ∼6 months and again at ∼9 months. Using mixed model analyses to estimate repeatability as the intraclass correlation coefficient, we determined that Ucrit was significantly repeatable (r = 0.55; 95% CI: 0.45 -0.64). Performance differences between the sexes (males 12% faster than females) and changes with age (decreasing 0.07% per day) both contributed to variation in Ucrit and, therefore, the repeatability estimate. Accounting for mean differences between sexes within the model decreased the estimate of Ucrit repeatability to 21% below the naïve estimate, while fitting age in the models increased the estimate to 14% above the naïve estimate. Greater consideration of factors such as age and sex is therefore necessary for the interpretation of performance repeatability in wild populations. Body shape significantly predicted Ucrit in both sexes in both assays, with the morphology – performance relationship significantly repeatable at the population level. However, morphology was more strongly predicative of performance in older fish, suggesting a change in the contribution of morphology relative to other factors such as physiology and behaviour. The morphology – performance relationship changed with age to a greater extent in males than females.

现有充分证据表明，自然选择可驱动运动性能的演化，但产生运动性状个体间变异的过程——即选择所作用的表型基础——目前仍相对缺乏深入研究。本研究于受试斑马鱼约6月龄和约9月龄时，对大样本队列（n=461）的野生型斑马鱼（Danio rerio）的持久游泳性能、临界游泳速度（Ucrit）以及躯体形态进行了两次测量。我们采用混合模型分析（mixed model analyses），以组内相关系数（intraclass correlation coefficient）估计重复性，结果显示临界游泳速度具有显著重复性（r=0.55；95%置信区间：0.45~0.64）。雌雄个体间的性能差异（雄性较雌性快12%）以及随年龄产生的性能变化（每日下降0.07%）均会影响临界游泳速度的变异，进而影响重复性估计结果。在模型中纳入雌雄均值差异后，临界游泳速度的重复性估计值较朴素估计降低了21%；而在模型中加入年龄因素后，估计值则较朴素估计提升了14%。因此，在解释野生种群的性能重复性时，有必要更多地考量年龄与性别等混杂因素。两次检测中，雌雄个体的躯体形态均可显著预测临界游泳速度，且种群水平上的形态-性能关联具有显著重复性。不过，在月龄更大的个体中，躯体形态对游泳性能的预测性更强，这表明相较于生理学、行为学等其他因素，躯体形态的贡献发生了变化。且雄性的形态-性能关联随年龄的变化程度显著大于雌性。