The fraction of all test fish that followed replica leaders away from the food patch according to the group size at the food patch, rather than the group size that initially started the trial.

The numerator is the number of test fish leaving the food patch across all trials, the denominator is the number of test fish that went to the food patch. Tests to compare the number of fish that went to the food patch against the number of fish that left the food patch in the presence of 1 leader and in the presence of 2 leaders were carried out using a χ2 test of independence. Two-tailed P values are presented for comparisons at each group size.