Song divergence by sensory drive in Amazonian birdsSong divergence by sensory drive in Amazonian birds
Faculty of Sciences. Biology
Evolutionary ecology group (EVECO)
2010Lancaster, Pa, 2010
Evolution. - Lancaster, Pa
64(2010):10, p. 2820-2839
University of Antwerp
Visual signals are shaped by variation in the signaling environment through a process termed sensory drive, sometimes leading to speciation. However, the evidence for sensory drive in acoustic signals is restricted to comparisons between highly dissimilar habitats, or single-species studies in which it is difficult to rule out the influence of undetected ecological variables, pleiotropic effects, or chance. Here we assess whether this form of sensory driveoften termed acoustic adaptationcan generate signal divergence across ecological gradients. By studying avian communities in two Amazonian forest types, we show that songs of 17 bamboo-specialist bird species differ in predictable ways from their nearest relatives in adjacent terra firme forest. We also demonstrate that the direction of song divergence is correlated with the sound transmission properties of habitats, rather than with genetic divergence, ambient noise, or pleiotropic effects of mass and bill size. Our findings indicate that acoustic adaptation adds significantly to stochastic processes underlying song divergence, even when comparing between habitats with relatively similar structure. Furthermore, given that song differences potentially contribute to reproductive isolation, these findings are consistent with a wider role for sensory drive in the diversification of lineages with acoustic mating signals.