Competition for resources shapes ecological and evolutionary relationships. Physiological capacities such as in locomotor performance can influence the fitness of individuals by increasing competitive success. Social hierarchy too can affect outcomes of competition by altering locomotor behaviour or because higher ranking individuals monopolize resources. Here, we tested the hypotheses that competitive success is determined by sprint performance or by social status. We show that sprint performance of individuals measured during escape responses (fast start) or in an accelerated sprint test did not correlate with realized sprint speed while competing for food within a social group of five fish; fast start and accelerated sprint speed were higher than realized speed. Social status within the group was the best predictor of competitive success, followed by realized speed. Social hierarchies in zebrafish are established within 7 days of their first encounter, and interestingly, there was a positive correlation between social status and realized speed 1 and 4 days after fish were placed in a group, but not after 7 days. These data indicate that physiological performance decreases in importance as social relationships are established. Also, maximal physiological capacities were not important for competitive success, but swimming speed changed with social context.

对资源的竞争塑造了生态和进化关系。运动表现等生理能力可以通过增加竞争成功来影响个体的健康。社会等级制度也可以通过改变运动行为或因为较高等级的个人垄断资源来影响竞争结果。在这里，我们测试了竞争成功取决于冲刺表现或社会地位的假设。我们表明，在逃避反应（快速启动）或加速冲刺测试中测量的个体的冲刺表现与在五条鱼的社会群体中竞争食物时实现的冲刺速度并不相关；快速启动和加速冲刺速度高于实际速度。群体内的社会地位是竞争成功的最佳预测因素，其次是实现的速度。斑马鱼的社会等级在第一次相遇后 7 天内建立，有趣的是，在鱼被放入群体后 1 天和 4 天，社会地位和实现速度之间存在正相关，但 7 天后则不再存在。这些数据表明，随着社会关系的建立，生理表现的重要性下降。此外，最大生理能力对于竞争成功并不重要，但游泳速度会随着社会背景而变化。