Figure 3.

Bar graphs illustrating the influence of amine depletion on (a) level of aggression and (b) fight duration after residency (circle/bold line, median; bar, i.q.r.). The crickets were treated prior to the initial fight with either vehicle (white bar), reserpine (cross-hatched bar), AMT (upwards-hatched bar) or AMTP (downwards-hatched bar). The aggressiveness of treated animals was evaluated in an initial fight (naive versus naive) and in a second contact 15 min later before which the losers remained in the arena either without a shelter (control-loser versus intruder) or with a shelter that they always occupied (resident-loser versus intruder, grey background). n is given in parentheses beneath each column, excepting initial fight, which is pooled. Asterisks denote statistically significant differences (for unpaired datasets: Mann–Whitney U-test).