Courtship dance similarity, but not complexity, may explain patterns of hybridization in manakins (Aves: Pipridae)

Summary

Differences in behaviour can play an important role in the emergence of species and the maintenance of species boundaries. In birds, behavioural isolation mechanisms range from simple vocalizations to elaborate courtship displays. The breakdown of these isolation mechanisms could result in the production of viable hybrid offspring. In general, we might expect a negative relationship between the complexity of a behavioural isolation mechanism and the incidence of hybridization. I tested this prediction in manakins, a Neotropical bird family that shows a large variety of courtship displays. I compiled a database of reliable hybrid records and quantified the complexity of species-specific courtship displays. Binary logistic regressions indicated that courtship similarity was a better predictor of hybridization probability than courtship complexity. However, this pattern was strongly influenced by phylogenetic relatedness, in that closely related species exhibited similar courtship displays that were already being performed by their common ancestor. The main limitation of this study concerns the incomplete dataset. I could assess the courtship complexity for only 22 manakin species; consequently, not all hybrid combinations could be included in the analyses. Nonetheless, these findings provide important insights into the role of courtship displays in explaining patterns of hybridization.