Genetic and developmental effects, and morphological influences on the acoustic structure of individual distance calls in female Bengalese finchesLonchura striatavar.domestica

Abstract

Recent studies of the vocal mechanisms of songbirds have shown that there are physical effects on sound production. Interspecific and phylogenetic comparisons have shown that body mass and bill morphology are two major factors affecting vocalizations such as songs. We analyzed the distance calls of female Bengalese finches Lonchura striata var. domestica, the non-vocal learning sex, to assess the potential physical effects on the acoustic structure of vocalizations. By experimentally controlling rearing condition using cross-fostering we could examine the effects of the developmental environment and genetic background. None of the tested factors affected the peak frequency of the distance calls, but we found that larger-billed birds tended to produce shorter bout calls with higher trill rates. These results suggest that the divergence of bill morphology can affect acoustic features at the within-population level. We also found that the birds reared in the same foster brood and siblings from the same genetic parents tended to produce calls with similar trill rates. This implies that the trill rate is under the influence of developmental and genetic factors.

Machine learning and statistical classification of birdsong link vocal acoustic features with phylogeny

“…Our estimates of phylogenetic inertia provide further evidence that power distribution and spectrotemporal features are minimally constrained in their evolution (i.e., low phylogenetic inertia), suggesting that these features may reflect the plasticity needed to alter song features for inter- and intra-specific competition. Analyses using ppMantel tests showed that body size is correlated with frequency features in our species, a common finding in animals including birds 53 , 84 , 85 . Previous studies suggest that changes in frequency features may be constrained to changes in morphological features associated with body size such as size of the organs that produce (e.g., syrinx) or modulate (e.g., beaks) vocalizations 84 .…”

“…Analyses using ppMantel tests showed that body size is correlated with frequency features in our species, a common finding in animals including birds 53 , 84 , 85 . Previous studies suggest that changes in frequency features may be constrained to changes in morphological features associated with body size such as size of the organs that produce (e.g., syrinx) or modulate (e.g., beaks) vocalizations 84 . Relatively small effect sizes for the frequency-to-morphology correlations, however, may suggest that differences in frequency characteristics may be further explained by factors other than the evolutionary changes in body or organ size.…”

“…The ppMantel performs comparative analyses of traits that are expressed as pairwise distances comparable to the independent contrasts for correlational analyses using raw trait data of individual species 123 – 125 . Tarsus length and body mass were used as morphometric measures of body size following previous conventions for correlating bird acoustics to body size 16 , 84 , 85 . Morphometric measures for the six wild type species were collected from the AVONET dataset 126 .…”