Imperfect female choice and male mating skew on leks of different sizes

We present a model of error-prone female choice on leks, and investigate th e effects of different degrees of error on the distribution of mating succe ss among males present at leks of different sizes. At higher levels of erro r, the best male is predicted to gain a smaller share of matings, while low -ranking males gain a larger share. Males who are of high rank but not the most desirable on the lek do best at intermediate levels of error, since th e top-ranked male does not then claim all the matings, but assessment is st ill sufficiently accurate for females to discriminate between high-ranking and low-ranking competitors. The effects of error are shown to be more pron ounced on larger leks, due to smaller expected differences in mating value between males of adjacent ranks. This interaction between lek size and erro r suggests that observed negative relationships between lek size and mating skew need not be attributed solely to intrasexual competition, as previous ly suggested, but could also be a result of imperfect choice.