Meeting Abstract
For many animals, winning agonistic interactions with conspecifics is critical for obtaining necessary resources. Although competitive success may be dependent on differences in resource holding potential, previous social experience can also alter an individual’s investment in future fights, giving rise to winner-loser effects. Male green anole lizards often engage in aggressive interactions mediated by visual displays, including dewlap extensions, push-ups, and changes in body color between green and brown. Here, we investigated whether dorsal coloration is altered due to competitive losses. We conducted a series of loser effect trials in which we tested if previous experience in losing makes a lizard more likely to exhibit a brown coloration and to lose subsequent encounters. Sixteen male lizards were “trained” to lose agonistic interactions by pairing them with a series of trainer males (assigned to maximize the differences in each pair in mass, snout-vent length, and head size) for one hour on each of three consecutive days. Following these trials, focal males competed with a size-matched, novel male to test for a loser effect. Eight of these trials yielded a clear loser in which 7 focal males lost and 1 focal male won, suggesting the presence of a loser effect. Individuals that were more often brown prior to the trials were more likely to lose in the training trials, supporting our previous findings that predominant body color is predictive of the outcome of agonistic interactions. Also, the predominant body color of lizards that lost their fourth trial was more likely to become brown after this final interaction. These results indicate that competitive experiences affect both behavior and appearance of green anoles.
