Biology subjects

Tubaro, P. L.

Publications and source records attributed to Tubaro, P. L..

4 recordsLinked to original sources

bioRxiv2025

Evaluating the association between vocalizations and colouration in finches (Fringillidae), a passerine group with elaborate signals

The interaction between multiple secondary sexual characters simultaneously expressed by an organism remains poorly understood. In fact, different interpretations of the role of concurrently expressed signals predict that the correlation of their elaboration across species should be positive, negative or absent --all three possibilities have been supported by studies of different avian groups. In this context, we analysed the interaction between plumage and song elaboration in the passerine family Fringillidae (finches). We used a two-scale approach and studied this association both at the family level and in more detail within the genera Crithagra and Spinus. At both scales, we determined colour elaboration (defined by the number of plumage colour patches in each species and their contrast) and established its association with three aspects of vocal elaboration: energy investment (song length and rate of syllable production), song complexity (repertoire index) and vocal performance (vocal deviation). We found an absence of association between colour elaboration and the three evaluated aspects of song elaboration at both scales, which has been the most frequent result in other avian groups. At first glance, this result appears to be partially discordant with previous findings in finches, but considering these studies together this might not necessarily be the case. We also confirmed that finches have complex songs and a remarkable vocal performance compared to other families of passerines. Considered together, our results suggest an independent evolution of colour and the notable vocal elaboration present in finches.

evolutionary biology↗

bioRxiv2025

Continental diversification and insular speciation in a widespread passerine (Troglodytes musculus) in southern South America

Understanding how the evolutionary dynamics of geographically widespread species play out in space and time is critical for uncovering the processes shaping biodiversity. We integrated mitochondrial DNA and genome-wide SNPs to investigate the history of diversification of the Southern House Wren (Troglodytes musculus) in southern South America and its insular relative, Cobbs Wren (T. cobbi), from the Malvinas/Falkland Islands (MFI). T. musculus is an abundant and widespread species, and by studying its population structure and demographic history we aim to uncover the processes that may have shaped the evolutionary history of this and other co-distributed taxa in southern South America. All analyses indicate a latitudinal divergence, with an initial split between northern populations (Bolivia, Northern and Central Argentina, Uruguay) and southern populations from Patagonia and the MFI. Shortly after this initial divergence, further diversifications occurred, including the colonization of the MFI from Patagonia, where this newly formed insular population became isolated from the continent, and the split between an Andean lineage and a widespread, lowland lineage occurring in lowland Bolivia, Northern and Central Argentina and Uruguay. Both the timing of these splits and the mitochondrial and genomic patterns of variation uncovered in T. musculus are consistent with a major role of glaciations -and particularly the Great Patagonian Glaciation-in the diversification of this species in the southern Neotropics. The negligible gene flow between the MFI and the continent, which derived in the formation of a new species, Cobbs Wren, contrasts with the notorious gene flow in the secondary, post-glacial contact zones between the northern and southern lineages, although with reduced gene flow between the Andean and lowland populations. We also observed cases of mito-nuclear discordance, highlighting the value of multi-locus approaches in revealing complex evolutionary histories. These results underscore how historical divergence, ecological barriers and corridors, and secondary contact after varying degrees of differentiation in allopatry jointly shape population structure and genetic diversity, with implications for understanding the diversification of widely distributed taxa.

evolutionary biology↗

bioRxiv2020

Mechanisms involved in the production of differently colored feathers in the structurally-colored Swallow Tanager (Tersina viridis; Aves: Thraupidae)

Non-iridescent, structurally-based coloration in birds originates from the feathers internal nanostructure (the keratin spongy matrix), but the presence of melanin and the characteristics of the barbs cortex can affect the resulting color. Here we investigate how this nanostructure is regulated and combined with other elements in differently-colored plumage patches. To do so, we investigated the association between light reflectance and the morphology of feathers from the back and belly plumage patches of male Swallow Tanagers (Tersina viridis), which look greenish-blue and white, respectively. Both plumage patches have a reflectance peak around 550 nm, but the reflectance spectrum is much less saturated in the belly. The barbs of both types of feathers have similar spongy matrices at their tips which produce similar reflectance spectra. However, the color of the belly feather barbs changes from light green at the tip to white closer to the rachis. These barbs lack pigments and their morphology changes considerably: the spongy matrix is reduced, being almost hollow, and has a different shape towards the rachis. Instead, we observed deposition of melanin underneath the spongy matrix in the back feathers which had a much saturated coloration that was consistent along the barbs length. Overall, our results suggest that the color differences between the white and greenish-blue plumage are mostly due to the differential deposition of melanin and a reduction of the spongy matrix in some parts of the belly feather barbs, and not a result of changes in the periodicity of the spongy matrix.

evolutionary biology↗

bioRxiv2019

Phylogeography of two Andean frogs: Test of vicariance versus elevational gradient models of diversification

The tropical and subtropical Andes have among the highest levels of biodiversity in the world. Understanding the forces that underlie speciation and diversification in the Andes is a major focus of research. Here we tested two hypotheses of species origins in the Andes: 1. Vicariance mediated by orogenesis or shifting habitat distribution. 2. Parapatric diversification along elevational environmental gradients. We also sought insights on the factors that impacted the phylogeography of co-distributed taxa, and the influences of divergent species ecology on population genetic structure. We used phylogeographic and coalescent analyses of nuclear and mitochondrial DNA sequence data to compare genetic diversity and evolutionary history of two frog species: Pleurodema borellii (Family: Leiuperidae, 130 individuals; 20 sites), and Hypsiboas riojanus (Family: Hyllidae, 258 individuals; 23 sites) across their shared range in northwestern Argentina. The two showed concordant phylogeographic structuring, and our analyses support the vicariance model over the elevational gradient model. However, Pleurodema borellii exhibited markedly deeper temporal divergence ([≥]4 Ma) than H. riojanus (1-2 Ma). The three main mtDNA lineages of P. borellii were nearly allopatric and diverged between 4-10 Ma. At similar spatial scales, differentiation was less in the putatively more habitat-specialized H. riojanus than in the more generalist P. borellii. Similar allopatric distributions of major lineages for both species implies common causes of historical range fragmentation and vicariance. However, different divergence times among clades presumably reflect different demographic histories, permeability of different historical barriers at different times, and/or difference in life history attributes and sensitivities to historical environmental change. Our research enriches our understanding of the phylogeography of the Andes in northwestern Argentina.

evolutionary biology↗