Data for: The effect of brief or prolonged bouts of winning or losing male-male contests on plasticity in sexually selected traits

Fight outcomes often affect male fitness by determining their access to mates. Thus ‘winner-loser’ effects, where winners often win their next contest, while losers tend to lose, can influence how males allocate resources towards pre- and post-copulatory traits. We experimentally manipulated the winning/losing experiences of pairs of size-matched male Gambusia holbrooki for either a day, a week or three weeks to test whether prior winning/losing experiences differentially affect the plasticity of male investment into either mating effort (pre-copulatory) or ejaculates (post-copulatory). When winner/loser pairs directly competed for a female, winners had better pre-copulatory outcomes than losers for three of the four traits we measured: mating attempts, successful attempts, and time spent with the female (but not aggression). However, winners and losers did not differ in either their total sperm counts nor sperm velocity. Interestingly, absolute male size, an important predictor of figh...