The Effect of Brief or Prolonged Bouts of Winning or Losing Male-Male Contests on Plasticity in Sexually Selected Traits

Autor: Lauren Maree Harrison, Regina Vega-Trejo, Michael D Jennions
Rok vydání: 2023
Předmět:
Zdroj: The American Naturalist. 201:442-459
ISSN: 1537-5323
0003-0147
Popis: 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 fighting success, mediated winner-loser effects on how long males then spent near a female. Compared to losers, smaller winners spent more time with the female than did larger winners, suggesting that how males respond to prior social experiences is size-dependent. We discuss the general importance of controlling for inherent male condition when comparing male investment into condition-dependent traits.
Databáze: OpenAIRE