Data from: Does losing reduce the tendency to engage with rivals to reach mates? An experimental test

Male-male contests for access to females or breeding resources is critical
in determining male reproductive success. Larger males and those with more
effective weaponry are more likely to win fights. However, even after
controlling for such predictors of fighting ability, studies have reported
a winner-loser effect: previous winners are more likely to win subsequent
contests, while losers often suffer repeated defeats. While the effect of
winning-losing is well-documented for the outcome of future fights, its
effect on other behaviors (e.g., mating) remains poorly investigated.
Here, we test whether a winning versus losing experience influenced
subsequent behaviors of male mosquitofish (Gambusia holbrooki) towards
rivals and potential mates. We housed focal males with either a smaller or
larger opponent for 24 hours to manipulate their fighting experience to
become winners or losers, respectively. The focal males then underwent
tests that required them to enter and swim through a narrow corridor to
reach females, bypassing a cylinder that contained either a larger rival
male (competitive scenario), a juvenile or was empty (non-competitive
scenarios). The tests were repeated after one week. Winners were more
likely to leave the start area and to reach the females, but only when a
larger rival was presented, indicating higher levels of risk-taking
behavior in aggressive interactions. This winner-loser effect persisted
for at least one week. We suggest that male mosquitofish adjust their
assessment of their own and/or their rival’s fighting ability following
contests in ways whose detection by researchers depends on the social
context.