Predators, reproductive parasites, and the persistence of poor males on leks

Lekking males are thought to face strong directional selectionon secondary sexual traits. How variation in male traits canpersist under these conditions remains problematic (the lekparadox). Here, we present several game-theoretic models thatshow that avoidance of costly and mobile predators, sneakers,or brood parasites (enemies) leads to variation in female choice.This can result in maintenance of variation in male quality."Enemies" will congregate around higher quality males. Femalesmust then trade-off the benefits of mating with high-qualitymales against the increased risk of enemies. At equilibrium,the models predict a positive correlation between the qualityof a male and the proportions of both enemies and females visitinghim. In the first model, we use this framework to predict thelowest quality male on the lek that will receive any matings.In the second model, we examine the influence of this female-enemygame on the maintenance of variation in male quality. Low-qualitymales are likely to persist when enemies are costly to femalesor occur at high density, and when there is some spatial structureon the lek, so that neighboring males are typically of similarquality. If enemies are more costly to males than to females,high-quality males may benefit from receiving fewer female visits.In the third model, we consider the special case when enemiesare male reproductive parasites. These models illustrate theimportance of considering the simultaneous decisions of multipleplayers in mate choice games.