Behav Ecol Sociobiol (2003) 55:22–31

Owing to an unfortunate oversight, the published version of the Results and Discussion sections of this paper did not take into consideration the journal’s requirements with regard to the reporting of the outcome of statistical tests. After copy-editing, these sections should read as follows (Pages 26, 27, 28):

Page 26
figure 1

 

Page 27
figure 2

 

Page 28
figure 3