Biology subjects

Bravo, G. A.

Publications and source records attributed to Bravo, G. A..

4 recordsLinked to original sources

bioRxiv2025

Song complexity in suboscine birds: evolutionary drivers and ecological constraints

Acoustic signal complexity varies widely in the animal kingdom for reasons that remain unclear. In birds, it is widely proposed that vocal complexity evolves as an honest signal of individual quality driven by sexual selection. Other hypotheses related to social interactions include competition for ecological resources (social selection) and intra-group communication in group- living animals, both of which may favour signal complexity. However, these hypotheses are rarely explored at macroevolutionary scales, particularly in the context of constraints on sound production, transmission and detection, leading to ongoing uncertainty about the evolutionary origins of complex vocal signals. Using Bayesian phylogenetic models, we test whether different forms of social communication and ecological constraints predict the temporal and spectral complexity of songs in 1,288 species of suboscine passerine birds. We found that song complexity was reduced by sexual selection, along with other limiting factors including large body size and dense vegetation. Conversely, territoriality boosted the temporal complexity of songs. These findings challenge the common assumption that sexual selection is the main driver of increased signal complexity, and instead highlight the role of social selection as a key component of multiple inter-related drivers and constraints.

evolutionary biology↗

bioRxiv2025

Efficient Inference of Macrophylogenies: Insights from the Avian Tree of Life

The exponential growth of molecular sequence data over the past decade has enabled the construction of numerous clade-specific phylogenies encompassing hundreds or thousands of taxa. These independent studies often include overlapping data, presenting a unique opportunity to build macrophylogenies (phylogenies sampling > 1,000 taxa) for entire classes across the Tree of Life. However, the inference of large trees remains constrained by logistical, computational, and methodological challenges. The Avian Tree of Life provides an ideal model for evaluating strategies to robustly infer macrophylogenies from intersecting datasets derived from smaller studies. In this study, we leveraged a comprehensive resource of sequence capture datasets to evaluate the phylogenetic accuracy and computational costs of four methodological approaches: (1) supermatrix approaches using concatenation, including the "fast" maximum likelihood (ML) methods, (2) filtering datasets to reduce heterogeneity, (3) supertree estimation based on published phylogenomic trees, and (4) a "divide-and-conquer" strategy, wherein smaller ML trees were estimated and subsequently combined using a supertree approach. Additionally, we examined the impact of these methods on divergence time estimation using a dataset that includes newly vetted fossil calibrations for the Avian Tree of Life. Our findings highlight that recently developed fast tree search approaches offer a reasonable compromise between computational efficiency and phylogenetic accuracy, facilitating inference of macrophylogenies.

evolutionary biology↗

bioRxiv2019

Systematics, biogeography and diversification of Scytalopus tapaculos (Rhinocryptidae), an enigmatic radiation of Neotropical montane birds

We studied the phylogeny, biogeography and diversification of suboscine birds in the genus Scytalopus (Rhinocryptidae), a widespread, speciose, and taxonomically challenging group of Neotropical birds. We analyzed nuclear (exons, regions flanking ultraconserved elements) and mitochondrial (ND2) DNA sequence data for a taxonomically and geographically comprehensive sample of specimens collected from Costa Rica to Patagonia and eastern Brazil. We found that Scytalopus is a monophyletic group sister to Eugralla, and consists of three main clades roughly distributed in (1) the Southern Andes, (2) eastern Brazil, and (3) the Tropical Andes and Central America. The clades from the Southern Andes and Eastern Brazil are sister to each other. Despite their confusing overall uniformity in plumage coloration, body shape and overall appearance, rates of species accumulation through time in Scytalopus since the origin of the clade in the Late Miocene are unusually high compared to those of other birds, suggesting rapid non-adaptive diversification in the group which we attribute to their limited dispersal abilities making them speciation-prone and their occurrence in a complex landscape with numerous barriers promoting allopatric differentiation. Divergence times among species and downturns in species accumulation rates in recent times suggest that most speciation events in Scytalopus predate climatic oscillations of the Pleistocene. Our analyses identified various cases of strong genetic structure within species and lack of monophyly of taxa, flagging populations which likely merit additional study to establish their taxonomic status. In particular, detailed analyses of species limits are due in S. parvirostris, S. latrans, S. speluncae, the S. atratus complex, and the Southern Andes clade.

evolutionary biology↗

bioRxiv2019

Integrating natural history-derived phenomics with comparative genomics to study the genetic architecture of convergent evolution

Evolutionary convergence has been long considered primary evidence of adaptation driven by natural selection and provides opportunities to explore evolutionary repeatability and predictability. In recent years, there has been increased interest in exploring the genetic mechanisms underlying convergent evolution, in part due to the advent of genomic techniques. However, the current genomics gold rush in studies of convergence has overshadowed the reality that most trait classifications are quite broadly defined, resulting in incomplete or potentially biased interpretations of results. Genomic studies of convergence would be greatly improved by integrating deep vertical, natural history knowledge with horizontal knowledge focusing on the breadth of taxonomic diversity. Natural history collections have and continue to be best positioned for increasing our comprehensive understanding of phenotypic diversity, with modern practices of digitization and databasing of morphological traits providing exciting improvements in our ability to evaluate the degree of morphological convergence. Combining more detailed phenotypic data with the well-established field of genomics will enable scientists to make progress on an important goal in biology: to understand the degree to which genetic or molecular convergence is associated with phenotypic convergence. Although the fields of comparative biology or comparative genomics alone can separately reveal important insights into convergent evolution, here we suggest that the synergistic and complementary roles of natural history collection-derived phenomic data and comparative genomics methods can be particularly powerful in together elucidating the genomic basis of convergent evolution among higher taxa.

evolutionary biology↗