Meeting Abstract
Males often gain access to females by winning agonistic interactions, but females have the ultimate choice of who to mate with. We used Bolitotherus cornutus (forked fungus beetles) as a system to determine which behavioral traits are favored for male competition and if females prefer to associate with the chemical cues of winning males. In two separate experiments, we first observed male behaviors in dyadic competition trials. We found that relative body size and absolute aggression predicted whether a male emerged as a winner or loser. Our results support the large body of research showing that body and weapon size determine success in agonistic interactions. We also report here that initiation of aggression is important for winning agonistic interactions. In our second experiment, we placed females in arenas with filter papers containing chemical cues of two males and measured the time each female spent associated with the cue of either male. Next, we allowed the two males to interact and determined winners and losers. We then placed females in new preference trials following male-male interactions and measured the amount of time they spent on winning and losing male chemical cues. Females did not prefer to associate with either future winning or future losing males before male-male interaction but changed their preference to avoid losing males after male-male interaction. Taken together, our results indicate that male reproductive success in B. cornutus is driven by the outcomes of male competition. Larger, more aggressive males likely gain more opportunities to mate via winning competitions and female avoidance of losing males.
