Losing reduces maximum bite performance in house cricket contests

Whole-organism performance capacities influence male combat outcomes in many animal species. However, several species also exhibit winner and loser effects, and current theory predicts that losers are more likely to lose again due to a decrease in aggression following defeat, not because of any change in underlying maximum performance capacity.
To test the effect of fight experience on performance, we measured the maximum bite force of male Acheta domesticus crickets that were pitted against size-matched opponents in staged fights. Winners then fought a second contest against other winners while losers fought other losers, after which we measured the change in bite force in all contest crickets and in a control group that did not take part in any contests.
Bite force predicted fight outcomes in the first round, and losing the first fight had a significant effect on bite force, leading to a 20% decrease in relative bite force compared to crickets that won both rounds. However, winning ...