Beyond plumage: acrobatic courtship displays show intermediate patterns in manakin hybrids

A major goal of evolutionary biology is to understand how sexual traits arise and diversify among populations. One way to address this objective is by studying sexual traits in closely related species and their hybrids. Here, we used this approach to study the evolution of elaborate behavioural display characteristics used during courtship. We focus on bearded manakins (genus: Manacus), where males of this avian clade perform an acrobatic jump-snap display to court females. Hybridization is common among Manacus taxa, and thus, we studied courtship dance behaviour in a hybrid population between golden-collared manakins, Manacus vitellinus, and white-collared manakins, Manacus candei. We found that, despite being genetically more similar to white-collared manakins, hybrid males performed key dance manoeuvres like golden-collared manakins. Hybrids performed other dance manoeuvres intermediate to the two species, or more like their white-collared parents. Select components of the birds' dance routines may have therefore introgressed from the golden-collared population into the whitecollared populations. We hypothesize that such modular evolution occurs in response to sexual selection, whereby specific components of the bird's dance routine shift to yield a broader change in its functional appearance.