Figure 1

Mean (± standard error of the mean (SEM)) urine release by dominant (grey bars) and subordinate (white bars) animals in male fights (Male F), female fights (Fem F), mixed-sex fights (Ma-Fe F) and reproductive interactions (Repr Int). Male crayfish were labelled as dominant animals (grey bars) in reproductive interactions. Asterisks indicate differences between interactants (*P < 0.05, **P < 0.01, paired t test).