@article{23093, abstract = {Land-use change, such as the transformation of woody ecosystems into open pastures, acts as a strong ecological filter, favouring some species while excluding others according to differences in ecological niche breadth. Understanding how differences in niche breadth influence species responses under anthropogenic filters is crucial to anticipate their persistence or displacement. In this study, we quantified realized niche breadth in two sympatric ecosystem engineers, the Neotropical leaf-cutter ants Atta cephalotes and Atta laevigata, to test whether breadth differences are consistent with specialist and generalist ecological strategies. We characterized realized niche breadth across fine-scale environmental gradients by integrating hemispherical photography, microclimatic data, mound architecture, and edaphic profiles from 114 colonies across a regional transect in the Colombian Andes, alongside macroclimatic data from Copernicus. Principal Component Analysis (PCA) and PERMANOVA identified canopy openness and bushes- and tree-type vegetation density as the principal axes of interspecific niche partitioning. The observed differences in realized niche breadth were consistent with specialist and generalist ecological strategies. A. laevigata was predominantly associated with open-canopy areas, warmer micro- and macroclimatic conditions, and narrower edaphic dispersion. In contrast, A. cephalotes occupied a wider range of microhabitat conditions. This broader realized niche breadth is compatible with previous reports of A. cephalotes occurring in urban areas. Together, these findings suggest that niche breadth may influence how Neotropical leaf-cutter ants respond to habitat transformation, helping to understand the ecological consequences of land-use change.}, author = {Garcia Castillo, Diego Fernando}, issn = {1932-6203}, journal = {Plos One}, number = {10}, pages = {e0351518}, publisher = {Public Library of Science}, title = {{Generalism vs. specialization: Does niche breadth influence species responses to anthropogenic land-use change in Neotropical leaf-cutter ants?}}, doi = {10.1371/journal.pone.0351518}, volume = {21}, year = {2026}, } @phdthesis{20991, abstract = {Rapid local adaptation to new environments is critical for species persistence, especially in introduced populations. The evolutionary success of these populations is fundamentally dictated by the organization of genetic variation—the genomic architecture—in the face of severe demographic constraints, such as the founder effects and genetic bottlenecks that frequently accompany colonization. A central question in evolutionary biology is whether rapid adaptation relies on major-effect loci, such as chromosomal inversions, or on many small-effect loci dispersed across the genome. Furthermore, the genomic architecture strongly influences the extent to which evolutionary outcomes are predictable. Using introduced populations of the marine snail, Littorina saxatilis, as a model, this thesis investigates how genetic variation and genomic structure drive adaptation following introduction. We employed a population genomics approach on experimentally and accidentally introduced populations to dissect the specific genomic features that underpin divergence in newly colonized environments. In Chapter 2, we tested the predictability of local adaptation through an uncommon 30-year transplant experiment in nature. By distinguishing allele and chromosomal inversion frequency changes from neutral expectations, we found that evolutionary change was highly predictable at the macro-scale (phenotypes and chromosomal inversions), but less robust at the level of individual collinear loci. This result demonstrates that evolution can be predictable when a population possesses sufficient standing genetic variation (SGV), with chromosomal inversions acting as key integrated units that facilitate a rapid response to selection. Building on this, Chapter 3 applied whole-genome sequencing to three accidentally introduced populations (Venice, San Francisco, and Redwood City) to investigate their likely source and genomic patterns of divergence. We identified genomic regions of remarkable divergence potentially associated with local adaptation, and likely fuelled by SGV, while explicitly acknowledging the difficulty in disentangling selection signals from the genome-wide effects of demographic processes. Furthermore, we found that the divergence patterns relied extensively on the collinear genome in these introduced populations, and less clearly on the chromosomal inversions. This observation contrasts with local adaptation observed in the experimental system that relied on both collinear loci and highly selected chromosomal inversions, highlighting how demographic history and genomic architecture influence the detectable signature of local adaptation. A major limitation to conducting large-scale comparative evolutionary studies is the lack of data standardization, which prevents the integration of community knowledge and high-resolution environmental and genetic data. Chapter 4 addresses this by developing a community database for the Littorina system. This platform implements standardized protocols for the integration of diverse phenotypic and environmental data from multiple Littorina species. Likewise, the platform also centralizes the availability of associated genomic data through links to external repositories. This database represents a crucial tool to test complex, large-scale evolutionary hypotheses. Collectively, this thesis strongly reinforces the fundamental importance of SGV as the raw material for successful local adaptation, a conclusion supported by evidence in both experimental and accidental introductions. Furthermore, this work highlights the critical role of the genomic architecture—specifically chromosomal inversions—in driving the predictability and effectiveness of adaptive responses. Our findings underscore how the interplay between SGV and genomic architecture dictates the trajectory and detectability of evolution in colonizing populations, while simultaneously providing a necessary tool to advance comparative evolutionary genomics in emerging model organisms.}, author = {Garcia Castillo, Diego Fernando}, isbn = {978-3-99078-077-0}, issn = {2663-337X}, pages = {199}, publisher = {Institute of Science and Technology Austria}, title = {{The genomic architecture of local adaptation in introduced populations}}, doi = {10.15479/AT-ISTA-20991}, year = {2026}, } @article{18491, abstract = {Predicting the outcomes of adaptation is a major goal of evolutionary biology. When temporal changes in the environment mirror spatial gradients, it opens up the potential for predicting the course of adaptive evolution over time based on patterns of spatial genetic and phenotypic variation. We assessed this approach in a 30-year transplant experiment in the intertidal snail Littorina saxatilis. In 1992, snails were transplanted from a predation-dominated environment to one dominated by wave action. On the basis of spatial patterns, we predicted transitions in shell size and morphology, allele frequencies at positions throughout the genome, and chromosomal rearrangement frequencies. Observed changes closely agreed with predictions and transformation was both dramatic and rapid. Hence, adaptation can be predicted from knowledge of the phenotypic and genetic variation among populations.}, author = {Garcia Castillo, Diego Fernando and Barton, Nicholas H and Faria, Rui and Larsson, Jenny and Stankowski, Sean and Butlin, Roger and Johannesson, Kerstin and Westram, Anja M}, issn = {2375-2548}, journal = {Science Advances}, number = {41}, publisher = {AAAS}, title = {{Predicting rapid adaptation in time from adaptation in space: A 30-year field experiment in marine snails}}, doi = {10.1126/sciadv.adp2102}, volume = {10}, year = {2024}, } @misc{18498, abstract = {Scripts and data used in the research study Predicting rapid adaptation in time from adaptation in space: a 30-year field experiment in marine snails. https://doi.org/10.1101/2023.09.27.559715}, author = {Garcia Castillo, Diego Fernando and Barton, Nicholas H and Faria, Rui and Larsson, Jenny and Stankowski, Sean and Butlin, Roger and Johannesson, Kerstin and Westram, Anja M}, publisher = {Zenodo}, title = {{Data and code for: Predicting rapid adaptation in time from adaptation in space: a 30-year field experiment in marine snails}}, doi = {10.5281/ZENODO.12159343}, year = {2024}, } @article{14796, abstract = {Key innovations are fundamental to biological diversification, but their genetic basis is poorly understood. A recent transition from egg-laying to live-bearing in marine snails (Littorina spp.) provides the opportunity to study the genetic architecture of an innovation that has evolved repeatedly across animals. Individuals do not cluster by reproductive mode in a genome-wide phylogeny, but local genealogical analysis revealed numerous small genomic regions where all live-bearers carry the same core haplotype. Candidate regions show evidence for live-bearer–specific positive selection and are enriched for genes that are differentially expressed between egg-laying and live-bearing reproductive systems. Ages of selective sweeps suggest that live-bearer–specific alleles accumulated over more than 200,000 generations. Our results suggest that new functions evolve through the recruitment of many alleles rather than in a single evolutionary step.}, author = {Stankowski, Sean and Zagrodzka, Zuzanna B. and Garlovsky, Martin D. and Pal, Arka and Shipilina, Daria and Garcia Castillo, Diego Fernando and Lifchitz, Hila and Le Moan, Alan and Leder, Erica and Reeve, James and Johannesson, Kerstin and Westram, Anja M and Butlin, Roger K.}, issn = {1095-9203}, journal = {Science}, number = {6678}, pages = {114--119}, publisher = {American Association for the Advancement of Science}, title = {{The genetic basis of a recent transition to live-bearing in marine snails}}, doi = {10.1126/science.adi2982}, volume = {383}, year = {2024}, }