Lek paradox

Greater sage-grouse at lek, with multiple males displaying for the less conspicuous females

The lek paradox is a conundrum in evolutionary biology that addresses the persistence of genetic variation in male traits within lek mating systems, despite strong sexual selection through female choice. This paradox arises from the expectation that consistent female preference for particular male traits should erode genetic diversity, theoretically leading to a loss of the benefits of choice. The lek paradox challenges our understanding of how genetic variation is maintained in populations subject to intense sexual selection, particularly in species where males provide only genes to their offspring. Several hypotheses have been proposed to resolve this paradox, including the handicap principle, condition-dependent trait expression, and parasite resistance models.