Song Divergence in Passerines
presentationposted on 14.06.2017, 00:00 by Dianna Brutsman
Song is important for mate choice among passerines because males use song to attract mates and females determine mate quality based on song. Therefore, song is likely a reproductive isolating mechanism between populations or species. We can examine the differences in song between hybridizing and non-hybridizing species to better understand speciation. We compared song parameters for 23 pairs of closely related hybridizing and non-hybridizing sympatric passerine species. We predicted that hybridizing species pairs would have more similar songs than non-hybridizing species pairs. Hypervolumes were constructed, from song parameters, for each species and we quantified the differences between pairs as the distance between centroids of the hypervolumes. We found a non-significant trend where hybridizing species had greater differences in songs than non-hybridizing species, which is not what we predicted. Most pairs of hybridizing and non-hybridizing species had the same range of song differences. Hybridizing species pairs with the greatest song differences were Eastern and Western meadowlarks, Golden-winged and Blue-winged warbles, and Grace's and Black-throated Gray warblers. Non-hybridizing species pairs with the smallest song differences were Bay-breasted and Blackburnian warblers, Northern and Louisiana waterthrushes, and Pyrrhuloxias and Northern Cardinals. Song has an influence on reproductive isolation for certain species, but across passerines it might not be a good predictor for reproductive isolation. Environmental niche divergence might be a better predictor for reproductive isolation across passerines than song.