Relatedness within and between leks of golden-collared manakin differ between sexes and age classes

Several hypotheses have been advanced to explain the evolution of leks, a mating system in which males aggregate at display sites where females choose their mates. Only a small proportion of males obtain copulations, and why other males join the lek remains unexplained. One hypothesis has called kin selection into play: if juvenile males join leks where their relatives display and contribute to attract females to the lek, they can gain indirect fitness benefits. We investigated the genetic structure of eight leks of golden-collared manakin, a tropical Passerine. Adult court-holder males, females, and immature males were caught within lek boundaries and the geographical location of the courts was recorded. For court-holding males, within-lek relatedness among four leks was significantly higher than average across-lek relatedness. Courts of more closely related males were not spatially associated within leks. Relatedness among immature males was relatively lower, yet higher within than be...