Efecto del hábitat y el tamaño corporal en la variación del canto de las especies del género Scytalopus (Rhinocryptidae)

Abstract

In songbird species, the habitat can interfere with the effective transmission of acoustic signals due to its physical characteristics, in response to this interference, species can modify their song so that the acoustic signal is transmitted effectively, in such a way that in habitats with higher plant density, songs with lower frequencies, narrower bandwidth and slower rhythm (among others) are produced. This is derived from the predictions framed in the Acoustic Adaptation Hypothesis, in contrast, the Morphological Adaptation Hypothesis proposes the modification of the song as a result of morphological modifications such as body size and peak; a larger body size influences the production of lower frequencies, given its effect on the size of the syrinx. The above hypotheses have been verified in several families of Passeriformes, being in the case of suboscines support for both in three families, therefore, given the variability of the song in the species of the genus Scytalopus and its importance in the separation of the species of this group, the objective of this study corresponds to analyze the song variations of the species of the genus Scytalopus to verify if they meet the two mentioned hypotheses. For this work, 360 measured songs of the 44 species described for the genus were included, to establish the relationships derived from the hypotheses, a phylogenetic principal component analysis (PPCA) was applied to find the relationships between the song variables and later a Phylogenetic least squares test (PGLS) in the genus and in its three clades. Support was found for the morphological adaptation hypothesis for the genus, while the acoustic adaptation hypothesis holds for the clade of the southern Andes and the morphological adaptation hypothesis for the clade of the tropical Andes. In general, body weight was found to be the most influential factor in song variation in Scytalopus species.