Competition for females on leks when male competitive abilities differ: empirical test of a model

Leks are mating arenas visited by females seeking copulations and can be thought of as patches differing in female encounter rate. Recently, the ideal free distribution model of unequal competitors with interference has been applied to explain male distributions between leks. This model predicts that the males of highest competitive ability should be present on the leks with the highest female encounter rates and should be most successful. I tested the predictions from the model with empirical data from the ruff, Philomachus pugnax. Contrary to the predictions from the model, low-ranking males preferentially visited the leks with highest female encounter rates, where the degree of male aggression was greatest. Furthermore, there was no general relationship between female encounter rate and male success, and the empirical data again refute the predictions from the model. The results illustrate the problem of using male per-capita success when predicting individual behavior Several more general problems with applying the ideal free distribution of unequal competitors model to competition for mates are also discussed.