Meeting Abstract

P1.161  Tuesday, Jan. 4  Losing reduces the maximum performance of traits that underlie winning. CONDON, C*; EDWARDS, J; LAILVAUX, S; School of Biological Sciences, The University of Queensland, Australia; Department of Biological Sciences, University of New Orleans; Department of Biological Sciences, University of New Orleans c.condon@uq.edu.au

In animal conflicts, an individual’s past win and loss experiences modify their fighting behaviour in future contests. Prior conflicts are thought to provide information for an individual to assess its own fighting ability and then adjust future behaviour to avoid or engage in combat. Current theory predicts that losers are more likely to lose again due to a decrease in aggression after a defeat, not due to a change in underlying performance capacity. We tested this hypothesis by examining the effect of fight experience on maximum bite performance in the house cricket (Acheta domesticus). Firstly, the maximum bite force of 165 male crickets was measured and individuals were then fought against size-matched opponents. The outcome of the first round of fighting determined their opponent in the second round; winners fought against other winners while losers fought other losers. To test the effect of win/loss experience on performance, maximum bite force was re-measured on all crickets and on a control treatment (no contests). We found winning or losing in the first fight had a significant effect on bite force. Losing the initial fight led to a 20% decrease in relative bite force, compared to crickets that won both rounds. However, winning did not increase performance as there was no difference between those that won twice and the control treatment. The influence of loser effects is not only restricted to behavioural strategies of avoiding future conflicts. Past defeats can alter the maximal performance of traits that contribute to contest outcomes.