Kin selection does not explain male aggregation at leks of 4 manakin species

In lek-mating systems, males aggregate at display arenas and females visit solely for the purpose of mating. This breeding system is characterized by high variance in male mating success with one male often receiving most copulations. High reproductive skew among males has led to question why males join leks when their chances of reproductive success are so low. Kin selection has been invoked as a mechanism to explain the evolution of lekking behavior, whereby nonreproducing but genetically related males gain indirect inclusive-fitness benefits. Evidence for kin selection among lek-mating birds is, however, mixed. Here, we show that kin selection is unlikely to be an important explanation for evolution of lekking behavior in manakins (Aves: Pipridae). We found that for 4 species chosen from several major clades within Pipridae, males within leks were not significantly more related than expected from random assortment of males in the population. This means that nonreproducing males do not gain indirect inclusive-fitness benefits by joining leks. This result suggests alternative mechanisms must be invoked to explain the evolution of lek-mating systems in manakins. Copyright 2007, Oxford University Press.