Does vocal learning accelerate acoustic diversification? Evolution of contact calls in Neotropical parrots

• Published in: The Journal of the Acoustical Society of America 2015-09, Vol.138 (3_Supplement), p.1902-1903
• Main Authors: Araya-Salas, Marcelo, Medina-Garcia, Angela, Wright, Timotthy
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4933981

Learning has been traditionally though to accelerate the evolutionary change of behavioral traits. We evaluated the evolutionary rate of learned vocalizations and the interplay of morphology and ecology in the evolution of these signals. We examined contact calls of 51 species of Neotropical parrots of the tribe Arini from recordings obtained in Central and South America. Parrots are ideal subjects due to their wide range of body size and habitats and their open-ended vocal learning that allows them to modify their calls throughout life. We estimated the evolutionary rate of acoustic parameters of parrot contact calls and directly compared them to those of morphological traits and habitat. We also evaluated the effect of body mass, bill length and vegetation density on acoustic parameters of contact calls while controlling for phylogeny. Evolutionary rates of acoustic parameters did not differ from those of our predictor variables except for spectral entropy, which had a significantly slower rate of evolution. We found support for correlated evolution of call duration, and fundamental and peak frequencies with body mass; and of fundamental frequency with bill length. We demonstrate that parrot contact calls, which are learned acoustic signals, show similar evolutionary rates to morphological traits. This is the first study to our knowledge to provide evidence that change through cultural evolution does not necessarily accelerate the evolutionary rate of traits acquired through life-long learning.