Data for: Social rank and not physiological capacity determines competitive success in zebrafish (Danio rerio)

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
monopolise resources. Here we tested the alternative 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 realised sprint speed while competing for food within a
social group of five fish; fast start and accelerated sprint speed were
higher than realised speed. Social status within the group was the best
predictor of competitive success, followed by realised speed. Social
hierarchies in zebrafish are established within seven days and,
interestingly, there was a positive correlation between social status and
realised speed one and four days after fish were placed in a group, but
not after seven 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.