Biology subjects

Freitas, A. V. L.

Publications and source records attributed to Freitas, A. V. L..

8 recordsLinked to original sources

bioRxiv2026

Contrasting signatures of interspecific gene flow in the Atlantic Forest endemic butterfly Heliconius besckei

Gene flow between diverging species can reshuffle genomic variation and greatly influence the speciation process, sometimes reinforcing, sometimes eroding species boundaries. However, the effect of ecological and historical processes on the patterns of introgression remains poorly understood. Here, we focus on the evolutionary history of Heliconius besckei, a geographically restricted butterfly endemic to the Brazilian Atlantic Forest, together with the mimetic H. melpomene nanna, the sympatric non-mimetic H. ethilla narcaea, and its closely related H. numata robigus. Using whole-genome sequencing, genome-wide tests of introgression, demographic modelling and palaeoclimatic species distribution models, we tested the extent and timing of interspecific gene flow in relation to mimicry, ecological context, and changes in geographic overlap. Despite strong genomic differentiation among the four focal Heliconius species, we detected widespread signatures of interspecific gene flow, greatly influenced by geographical overlap. Demographic models including post-divergence gene flow were better supported than strict-isolation models. In addition, genome-wide introgression analyses showed more numerous and larger candidate introgressed regions between H. besckei and H. ethilla narcaea, consistent with recurrent opportunities for exchange between these currently sympatric species. Species distribution models further recovered repeated expansions of suitable habitat for H. besckei during cold periods, providing a potential geographic context for secondary contact within the Atlantic Forest. Together, our results reveal recurrent gene flow occurring under different temporal, geographic, and potentially selective contexts, and show that the evolutionary history of a geographically restricted lineage can be shaped by repeated genetic exchange while substantial species differentiation is maintained.

evolutionary biology↗

bioRxiv2026

Decoupled wing evolution reveals trait-specific links between morphology, geography, and diversification in Ithomiini butterflies.

Understanding when species diversification and phenotypic evolution are coupled remains a central challenge in macroevolution. Such coupling may depend on the traits considered, phenotypic integration, or the geographic context in which diversification occurs. Here, we investigate these relationships in Ithomiini, a diverse Neotropical butterfly tribe whose diversification is strongly associated with the Andes-Amazonia system. We quantified forewing and hindwing size and shape for 1,618 individuals representing 291 species using geometric morphometrics, and combined these data with phylogenetic comparative methods, diversification-rate estimates, and spatial analyses of species distributions. Evolutionary rate shifts were largely trait- and wing-specific, indicating limited coupling between forewing and hindwing evolution. Across the phylogeny, wing size evolution and extant wing size were not associated with species diversification, nor was hindwing shape evolution. By contrast, forewing shape evolutionary rates showed a positive association with diversification. Spatial analyses revealed that this coupling was geographically concentrated in the Andes, where high diversification rates coincided with elevated forewing size and shape diversity and increased forewing evolutionary rates. Hindwing diversity, by contrast, more closely tracked phylogenetic diversity and showed weaker or opposing relationships with diversification. Our results show that diversification and phenotypic evolution in Ithomiini are neither generally coupled nor fully independent, but linked in trait-specific and geographically structured ways. More broadly, they highlight the need to decompose complex phenotypes and integrate spatial context when testing macroevolutionary coupling.

ecology↗

bioRxiv2025

Aposematic color patterns are the dominant axis of phenotypic diversification in Nymphalid butterflies

Butterfly wing patterns serve diverse roles in visual communication, from aposematic signaling and mimicry to mate attraction and camouflage. In brush-footed butterflies (Nymphalidae), this diversity can be traced to the wing pattern "ground plan" that generates phenotypes deterministic in origin yet highly multidimensional in form. Quantifying such complexity at scale has long been a challenge, limiting our understanding of how visual signals interact, constrain one another, and evolve. Here, we used computer vision to extract high-dimensional traits from standardized museum specimens and assembled the largest comparative dataset of wing color patterns to date, spanning over one third of all known Nymphalid species. We first tested whether chemically defended species occupy a distinct region in morphospace and then derived a quantitative score for aposematism from the principal color patterns associated with defense. Using this score, we examined whether aposematic signals are expressed consistently across wing surfaces and sexes, and whether their origins are linked to shifts in evolutionary rate. We found that the dominant axis of morphospace is defined by chromatic and achromatic contrast, along which defended and undefended species cluster. Validation with an expert-labeled moth dataset confirmed that this axis separates aposematic from non-aposematic phenotypes across Lepidoptera. Consistent with theory, strongly aposematic species showed greater visual similarity between dorsal and ventral surfaces, between sexes, and among individuals. Rate analyses further indicated that aposematic patterns evolved repeatedly and were associated with non-linear shifts in evolutionary tempo. Together, these results identify aposematism as the dominant organizing axis of wing color pattern evolution in Nymphalidae. Significance statementButterflies are renowned for their striking diversity of wing patterns, including the warning colors that signal chemical defense to predators. Yet whether such warning patterns share common features across lineages has remained unclear. Here, we applied a metric computer vision model to more than 16,000 museum specimens spanning one third of all Nymphalid species, encoding their wing patterns into a common morphospace. Within this space, high-contrast aposematic patterns emerged as the dominant axis of diversification, explaining up to 20% of phenotypic variance. These signals were expressed consistently across wing surfaces, sexes, and individuals, and evolved repeatedly across the family. Our approach demonstrates how computer vision enables meaningful comparative analyses of complex patterns, revealing general principles of butterfly diversification.

evolutionary biology↗

bioRxiv2025

Phylogeny, systematics and evolution of mimicry patterns in Neotropical limenitidine butterflies

The Neotropical butterfly genus Adelpha Hubner exhibits remarkable species diversity and striking convergence in wing colour patterns potentially explained by mimicry, making it an exceptional model for exploring trait evolution and its relationship with speciation. To date, unresolved phylogenetic relationships hinder a comprehensive understanding of the evolutionary biology of the genus. Using a novel multi-marker dataset combining one mitochondrial and 15 nuclear gene fragments, we generate the most comprehensive phylogeny of the genus Adelpha to revisit its systematics and investigate the evolution of mimicry colour patterns. Our data set encompasses 83 of the 87 known extant species and six Limenitis species that were recently excluded from Adelpha (134 of c. 160 subspecies in total), collectively displaying 14 distinct mimicry patterns. We provide conclusive evidence that corroborates previous work on the polyphyly of Adelpha as historically conceived, and describe the genus Adelphina Paez & Willmott n. gen. to stabilize the nomenclature, both genera representing Neotropical limenitidines. The comprehensive phylogeny provided in this study lays a solid foundation for future research into the processes driving diversification within these species interacting through mimicry. Ancestral character state reconstruction reveals gradual evolution of mimicry pattern. The more common mimicry pattern IPHICLUS (forewing with orange subapical spot and white band) is inferred as ancestral, but repeated convergent evolution is also recovered. Evolutionary convergence is also observed for the second most abundant mimicry pattern, COCALA (orange-white banded). Increased rates of mimicry pattern evolution are also found toward the equator. These results underscore the complexity of mimicry evolution in the Neotropical limenitidines i.e., Adelpha and Adelphina, emphasizing the need to explore its interplay with other biotic and abiotic factors.

evolutionary biology↗

bioRxiv2021

Supergene formation is associated with a major shift in genome-wide patterns of diversity in a butterfly

Selection shapes genetic diversity around target mutations, yet little is known about how selection on specific loci affects the genetic trajectories of populations, including their genome-wide patterns of diversity and demographic responses. Here we study the patterns of genetic variation and geographic structure in a neotropical butterfly, Heliconius numata, and its closely related allies in the so-called melpomene-silvaniform clade. H. numata is known to have evolved an inversion supergene which controls variation in wing patterns involved in mimicry associations with distinct groups of co-mimics whereas it is associated to disassortative mate preferences and heterozygote advantage at this locus. We contrasted patterns of genetic diversity and structure 1) among extant polymorphic and monomorphic populations of H. numata, 2) between H. numata and its close relatives, and 3) between ancestral lineages. We show that H. numata populations which carry the inversions as a balanced polymorphism show markedly distinct patterns of diversity compared to all other taxa. They show the highest genetic diversity and effective population size estimates in the entire clade, as well as a low level of geographic structure and isolation by distance across the entire Amazon basin. By contrast, monomorphic populations of H. numata as well as its sister species and their ancestral lineages all show lower effective population sizes and genetic diversity, and higher levels of geographical structure across the continent. One hypothesis is that the large effective population size of polymorphic populations could be caused by the shift to a regime of balancing selection due to the genetic load and disassortative preferences associated with inversions. Testing this hypothesis with forward simulations supported the observation of increased diversity in populations with the supergene. Our results are consistent with the hypothesis that the formation of the supergene triggered a change in gene flow, causing a general increase in genetic diversity and the homogenisation of genomes at the continental scale.

evolutionary biology↗

bioRxiv2019

Mesoamerica is a cradle and the Brazilian Atlantic Forest is a museum of Neotropical butterfly diversity (Lepidoptera: Nymphalidae: Brassolini)

Regional species diversity is ultimately explained by speciation, extinction, and dispersal. Here we estimate dispersal and speciation rates of Neotropical butterflies to propose an explanation for their distribution and diversity of extant species. We focus on the tribe Brassolini (owl butterflies and allies): a Neotropical group that comprises 17 genera and 108 species, most of them endemic to rainforest biomes. We infer a robust species tree using the multispecies coalescent framework and a dataset including molecular and morphological characters. This formed the basis for three changes in Brassolini classification: 1) Naropina, SYN. NOV. is subsumed within Brassolina; 2) Aponarope, SYN. NOV. is subsumed within Narope; 3) Selenophanes orgetorix, COMB. NOV. is reassigned from Catoblepia to Selenophanes. By applying biogeographical stochastic mapping, we found contrasting species diversification and dispersal dynamics across rainforest biomes, which might be partly explained by the geological and environmental history of each bioregion. Our results reveal a mosaic of biome-specific evolutionary histories within the Neotropics, where butterfly species have diversified rapidly (cradles: Mesoamerica), have accumulated gradually (museums: Atlantic Forest), or have alternately diversified and accumulated (Amazonia). Our study contributes evidence from a major butterfly lineage that the Neotropics are a museum and cradle of species diversity.

evolutionary biology↗

bioRxiv2017

Renewed diversification following Miocene landscape turnover in a Neotropical butterfly radiation

\"This preprint has been reviewed and recommended by Peer Community In Evolutionary Biology (http://dx.doi.org/10.24072/pci.evolbiol.100032)\"\n\nThe Neotropical region has experienced a dynamic landscape evolution throughout the Miocene, with the large wetland Pebas occupying western Amazonia until 11-8 my ago and continuous uplift of the Andes mountains along the western edge of South America. Although the complex dynamics between the Andes and Amazonia may have strongly affected the trajectory of Neotropical biodiversity, there is little evidence for such an influence from time-calibrated phylogenies of groups that diversified during this period. Here, we generate one of the most comprehensive time-calibrated molecular phylogenies of a group of Neotropical insects: the butterfly tribe Ithomiini. Our tree includes 340 species (87% of extant species), spanning 26 million years of diversification in the Neotropics. We investigate temporal and spatial patterns of diversification, focusing on the influence of Miocene landscape tranformations on the dynamics of speciation, extinction and biotic interchanges at the Amazonia/Andes interface. We find that Ithomiini likely began diversifying at the interface between the Andes and the Amazonia around 26.4 my ago. Five subtribes with a very low extant diversity started diversifying early in western Amazonia, but a rapid decrease in diversification rate due to increased extinction rate between 20 and 10 my ago suggests a negative impact of the Pebas wetland system on these early lineages. By contrast, the clade containing the five most species-rich subtribes (85% of extant species) was characterized by a high, positive net diversification rate. This clade diversified exclusively in the Central Andes from 20 to 10 my ago. After the demise of the Pebas system (11-8 my ago), we found a sudden increase of interchanges with the Northern Andes and Amazonia, followed by local diversification, which led to a substantial renewal of diversification. In general, ecological turnovers throughout the Miocene strongly determined the dynamics of speciation, and extinction and interchanges, and appear as a key driving force shaping the regions current extraordinary biodiversity.

evolutionary biology↗

bioRxiv2017

North Andean origin and diversification of the largest ithomiine butterfly genus

The Neotropics harbour the most diverse flora and fauna on Earth. The Andes are a major centre of diversification and source of diversity for adjacent areas in plants and vertebrates, but studies on insects remain scarce, even though they constitute the largest fraction of terrestrial biodiversity. Here, we combine molecular and morphological characters to generate a dated phylogeny of the butterfly genus Pteronymia (Nymphalidae: Danainae), which we use to infer spatial, elevational and temporal diversification patterns. We first propose six taxonomic changes that raise the generic species total to 53, making Pteronymia the most diverse genus of the tribe Ithomiini. Our biogeographic reconstruction shows that Pteronymia originated in the Northern Andes, where it diversified extensively. Some lineages colonized lowlands and adjacent montane areas, but diversification here remained scarce. The recent colonization of lowland areas was reflected by an increase in the rate of evolution of species elevational ranges towards present. By contrast, speciation rate decelerated with time, with no extinction. The geological history of the Andes and adjacent regions have likely contributed to Pteronymia diversification by providing compartmentalized habitats and an array of biotic and abiotic conditions, and by limiting dispersal between some areas while promoting interchange across others.

evolutionary biology↗