Hábito alimentar e história evolutiva moldam a forma do bico dos passeriformes da Mata Atlântica

Abstract

In the present study, we aimed to analyze the effect of the feeding habit, phylogenetic history, size and habitat in the beak shape of the Atlantic Forest passerine birds, as a whole group and also comparing the two suborders Passeri and Tyranni. We used geometric morphometrics to quantify beak shape of 1070 specimens from 386 species of the order Passeriform. We classified each species diet accordingly to the main feeding categories observed for the group, the habitat as open or closed and how they occupy the vegetation vertical stratum. Using a phylogeny in the literature, we recovered the evolutionary history of the group. The effect of size, habitat and vertical stratum in the beak shape were non-existence accordingly to our analyses. Our results indicate that feeding habits have strong influence on shaping the beak of passerines, although most of this influence is associated with a strong phylogenetic effect in the whole group. Suborder Passeri presented a stronger relationship with feeding habit and greater variability in beak shape, when compared with Tyranii. This high morphological disparity can be associated with the adaptive speciation events which occurred in the group after their arrival in South America. In contrast, the beak shape of Tyranni had stronger correlation with phylogeny and less morphological disparity. This indicates the last has a more conservative morphology and feeding habits in respect to its phylogenetic history, since most families of this suborder are mostly insectivores.