Fernanda Baena-Díaz

Sexual and natural selection jointly contribute to the rapid evolution of mating-related traits, making hybridizing systems particularly informative for exploring how different classes of traits diverge during early speciation. The damselflies Ischnura elegans and Ischnura graellsii form two hybrid zones in Spain that differ in demographic structure and spatial genetic patterns, providing a natural framework to compare patterns of divergence in reproductive (male caudal appendages and the female prothorax) and non-reproductive (wings) traits. Using geometric morphometrics within a phylogenetic comparative framework, together with population genetic information, we compared evolutionary integration, rates of divergence, and evolutionary dynamics across traits and species. In I. elegans, both the shape and size of male caudal appendages and the female prothorax evolved in strong evolutionary correlation, whereas in I. graellsii this association was restricted to shape. Reproductive structures evolved at significantly higher rates than wings, indicating greater evolutionary lability in traits directly involved in mating. Evolutionary model comparisons revealed contrasting dynamics between shape and size, suggesting that multiple processes contribute to trait divergence rather than a single dominant mechanism. Estimates of isolation by distance and gene flow revealed contrasting demographic contexts between species, with I. elegans showing more restricted gene flow than I. graellsii. Overall, our findings suggest that reproductive and non-reproductive traits differ in their evolutionary integration, rates, and dynamics, highlighting how trait-specific evolutionary patterns and demographic context contribute to morphological divergence in recently diverged taxa.

Ivermectin is the most common antiparasitic medication used in cattle in some regions of the world, despite residues excreted in dung being highly toxic for non-target coprophagous insects that provide highly valuable ecosystem services, such as dung beetles. Whereas closely related species and distant populations can considerably differ in ivermectin tolerance, this is unknown for dung beetles, which are highly sensitive. Here, we evaluated ivermectin tolerance in six populations of the dung beetle Euoniticellus intermedius and measured fitness-related traits in beetles exposed to different ivermectin concentrations under laboratory conditions. These populations were sampled along an altitudinal gradient to capture natural variation in life history traits associated with contrasting environmental conditions across the gradient. As expected, large inter-population variation was observed in LC50 (i. e. tolerance), being more than 200 times higher in the most tolerant compared to the least tolerant population, where nearly zero laid eggs emerged at high concentrations. We also confirmed our prediction that populations from intermediate altitudes would have the highest tolerance, which is potentially explained by gene flow from low and highlands. Ivermectin accelerated development in higher populations and consistently reduced body size. However, contrary to expectations, the most tolerant population was the only one where tradeoffs between offspring number and size were clearly exaggerated by ivermectin. These findings indicate that geographically close populations of dung beetles show high variability in susceptibility to ivermectin and suggest that adaptation to ivermectin can be facilitated by adaptation to certain altitudes.

Plant–pollinator interactions are essential to ecosystem functioning, yet the mechanisms that determine why some plant species become highly connected within interaction networks remain insufficiently understood, particularly in tropical coastal systems. Here, we examine how multiple plant traits predict the interactive role of species within a bee–plant network in a coastal ecosystem in the Gulf of Mexico. Using an existing dataset comprising 35 plant species and 47 bee species, we quantified each plant’s interactive role through species degree, betweenness, and closeness centrality. We then evaluated how six traits (i.e., flower number, flower size, flower color, number of stamens, plant height, and life form) influence these network positions. Our results show that four traits significantly predicted plant interactive roles. Plants surrounded by more open flowers and those with larger flowers interacted with a greater diversity of bee species, indicating that resource detectability and accessibility strongly shape visitation patterns. Herbaceous species also exhibited higher interactive roles than woody plants, likely due to their rapid growth, abundant and synchronous flowering, and predictable resource availability in dynamic coastal environments. Additionally, yellow-flowered species received disproportionately more visits and achieved higher interactive roles, consistent with known sensory biases of bees toward yellow wavelengths. In contrast, plant height and stamen number showed no detectable influence on network position. Overall, our findings demonstrate that a combination of vegetative and floral traits (particularly those signaling abundant, accessible, and visually detectable resources) drives the emergence of key plant species within bee–plant networks. Integrating plant traits with network metrics provides a powerful framework for identifying species that sustain pollinator diversity and for predicting community responses to environmental change.

The honeybee Apis mellifera L. (Apidae) is a eusocial species of significant ecological and economic importance, known for its ability to adapt to diverse climates. Native to Europe, Africa and Asia, it has now spread globally beyond its native range. While individual bees may exhibit flower constancy, colonies function as generalist pollinators, interacting with a broad spectrum of plant species. However, some plant species are more frequently visited than others, emphasizing the need to understand traits that increase A. mellifera visitation. Such insights would clarify its foraging preferences, interactions with plant species and broader ecological impacts across its native and introduced ranges. We analysed the plant species and floral traits associated with A. mellifera visits across both its native and introduced ranges, using data from 147 plant‐floral visitor networks (107 native, 40 introduced). We found that A. mellifera visited 404 plant species, showing a marked preference for families such as Asteraceae, Rosaceae and Fabaceae. Our results revealed that A. mellifera monopolized plant resources similarly in both native and introduced areas, though the proportion of visits varied according to plant traits, particularly in native areas, suggesting more specialization in resource use. Complementary, A. mellifera visits in the native areas were distributed in fewer plants, being more consistent than in the introduced areas, where more plants where visited. These findings shed light on A. mellifera 's role in shaping plant‐bee relationships in both its native and introduced environments, offering important insights into its ecological impact and potential competition with native pollinators.

Genetic diversity is an important attribute of populations, essential for understanding the ecological and evolutionary processes affecting them and assessing their health status. In Hymenoptera, such as eusocial bees, colony management can influence genetic diversity in both natural and managed populations. Management can impact admixture, increasing the number of alleles due to colony displacement and decreasing the number of alleles in natural populations due to colony extraction. In this study, we analyzed genetic diversity in natural and managed colonies as well as in drone congregations of Scaptotrigona mexicana (Guérin), to assess genetic diversity, patterns of genetic structure and gene flow, and the presence of diploid males. We identified three distinct genetic groups: Northern, Central, and Southern. Although genetic differentiation and limited gene flow among genetic groups were evident, we detected significant gene flow from wild to managed populations, suggesting that natural populations can be an important reservoir of genetic diversity. The highest genetic diversity was found in the Northern group, composed of managed localities. This is likely due to the introduction of new alleles through to colony translocation. Notably, some loci exhibited more than three alleles in localities where all analyzed individuals were from the same colony, indicating possible polyandry in the species. We also detected diploid males, which suggests inbreeding and/or inefficient mechanisms for their elimination from the colony. Our results provide an initial assessment of genetic diversity in both natural and managed populations, as well as in drone congregations of S. mexicana.

Premise: Evolution of cross‐pollination efficiency depends on the genetic variation of flower traits, the pollen vector, and flower trait matching between pollen donors and recipients. Trait matching has been almost unexplored among nonheterostylous species, and we examined whether the match of anther length in pollen donors and stigma length in pollen recipients influences the efficiency of cross‐pollination. To explore potential constraints for evolutionary response, we also quantified genetic variation and covariation among sepal length, petal length and width, stamen length, style length, and herkogamy.Methods: We created 58 experimental arrays of Turnera velutina that varied in the extent of mismatch in the position of anthers and stigmas between single‐flowered plants. Genetic variation and correlations among flower traits were estimated under greenhouse conditions.Results: Style length, but not herkogamy, influenced the efficiency of cross‐pollination. Plants with stamen length that matched the style length of other plants were more efficient pollen donors, whereas those with the style protruding above the stamens of other plants were more efficient pollen recipients. Significant broad‐sense heritability (0.22 > h_B² < 0.42) and moderate genetic correlations (0.33 > r < 0.85) among floral traits were detected.Conclusions: Our results demonstrated that anther‐stigma mismatch between flowers contributed to variation in the efficiency of cross‐pollination. The genetic correlations between stamen length and other floral traits suggests that any change in cross‐pollination efficiency would be driven by changes in style rather than in stamen length.

Urbanisation is occurring globally, leading to dramatic environmental changes that are altering the ecology and evolution of species. In particular, the expansion of human infrastructure and the loss and fragmentation of natural habitats in cities is predicted to increase genetic drift and reduce gene flow by reducing the size and connectivity of populations. Alternatively, the ‘urban facilitation model’ suggests that some species will have greater gene flow into and within cities leading to higher diversity and lower differentiation in urban populations. These alternative hypotheses have not been contrasted across multiple cities. Here, we used the genomic data from the GLobal Urban Evolution project (GLUE), to study the effects of urbanisation on non‐adaptive evolutionary processes of white clover (Trifolium repens) at a global scale. We found that white clover populations presented high genetic diversity and no evidence of reduced N_e linked to urbanisation. On the contrary, we found that urban populations were less likely to experience a recent decrease in effective population size than rural ones. In addition, we found little genetic structure among populations both globally and between urban and rural populations, which showed extensive gene flow between habitats. Interestingly, white clover displayed overall higher gene flow within urban areas than within rural habitats. Our study provides the largest comprehensive test of the demographic effects of urbanisation. Our results contrast with the common perception that heavily altered and fragmented urban environments will reduce the effective population size and genetic diversity of populations and contribute to their isolation.

Urbanization is occurring globally, leading to dramatic environmental changes that are altering the ecology and evolution of species. In particular, the expansion of human infrastructure and the loss and fragmentation of natural habitats in cities is predicted to increase genetic drift and reduce gene flow by reducing the size and connectivity of populations. Alternatively, the “urban facilitation model” suggests that some species will have greater gene flow into and within cities leading to higher diversity and lower differentiation in urban populations. These alternative hypotheses have not been contrasted across multiple cities. Here, we used the genomic data from the Global Urban Evolution project (GLUE), to study the effects of urbanization on non-adaptive evolutionary processes of white clover ( Trifolium repens ) at a global scale. We found that white clover populations presented high genetic diversity and no evidence of a reduction in N _e linked to urbanization. On the contrary, we found that urban populations were less likely to experience a recent decrease in effective population size than rural ones. In addition, we found little genetic structure among populations both globally and between urban and rural populations, which showed extensive gene flow between habitats. Interestingly, white clover displayed overall higher gene flow within urban areas than within rural habitats. Our study provides one of the largest comprehensive tests of demographic effects of urbanization and our results contrast the common perception that heavily altered and fragmented urban environments will reduce the effective population size and genetic diversity of populations and contribute to their isolation.