Miln Clare, Ward Ashley J W, Seebacher Frank
School of Life and Environmental Sciences A08, University of Sydney, NSW 2006, Australia.
R Soc Open Sci. 2021 Apr 7;8(4):210146. doi: 10.1098/rsos.210146.
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。诸如运动表现等生理能力可通过提高竞争成功率来影响个体的适应性。社会等级制度也可通过改变运动行为或因地位较高的个体垄断资源而影响竞争结果。在此，我们检验了以下假设：竞争成功是由冲刺表现或社会地位决定的。我们发现，在五条鱼组成的社会群体中争夺食物时，在逃避反应（快速启动）期间或加速冲刺测试中测得的个体冲刺表现与实际冲刺速度并无关联；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指标，其次是实际速度。斑马鱼的社会等级制度在首次相遇后的7天内建立，有趣的是，在将鱼放入群体后的第1天和第4天，社会地位与实际速度之间存在正相关，但7天后则不存在。这些数据表明，随着社会关系的建立，生理表现的重要性降低。此外，最大生理能力对竞争成功并不重要，但游泳速度会随社会环境而变化。
