Biology subjects

Luna, L. W.

Publications and source records attributed to Luna, L. W..

4 recordsLinked to original sources

bioRxiv2026

Habitat specialization structures population divergence and demographic variation in Amazonian floodplain birds

Understanding how species respond to environmental change requires linking ecological traits to gene flow and demographic history across dynamic landscapes. Using population genomic data from twelve co-distributed Amazonian riverine island birds, we show that habitat specialization predicts genetic structure, divergence, and effective population size. Species specialized on dynamic sandbar scrub habitats exhibit higher gene flow, and higher genetic diversity despite smaller effective population sizes. These patterns are consistent with dispersal tracking shifting resources, which decouples genetic diversity from population size. In contrast, river-edge forest specialists show stronger spatial genetic structure and lower genetic diversity despite larger populations, consistent with long-term isolation in more stable habitats. We also detect regional variation in effective population sizes and genetic diversity across Amazonian river sub-basins, potentially reflecting historical differences in floodplain habitat availability. Overall, our results highlight how non-equilibrium dynamics shape genomic variation and emphasize habitat-driven dispersal in diversification and persistence in seasonal systems.

evolutionary biology↗

bioRxiv2026

Sex and breeding stage differences in neurogenomic profiles reflect hormone signaling in a socially polyandrous shorebird

In sex-role reversed species, females are socially polyandrous and compete for multiple mates, whereas males conduct the majority of parental care. To understand the extent to which physiological differences between females and males are shaped by sex roles, we examined sex differences in gene expression in sex-role reversed northern jacanas (Jacana spinosa). Given that females compete for mating opportunities, and males cycle between courtship and parental care, we predicted that transcriptomic profiles would be more similar between females and courting males, in contrast to female and parenting males. Leveraging a high quality de novo genome assembly, we conducted RNA-seq on two brain regions associated with the regulation of social behavior: the preoptic area of the hypothalamus and the nucleus taeniae. The majority of genes differentially expressed between the sexes were male-biased. Of these male-biased genes, the majority were located on the Z-chromosome. Contrary to our prediction, the greatest difference in autosomal gene expression was between females and courting males, in the preoptic area of the hypothalamus. Several differentially expressed genes related to elements of hormone signaling that are likely to be behaviorally salient, including higher expression of androgen receptor in females relative to parenting males, and higher expression of prolactin receptor in males, regardless of breeding stage. Some sex-associated gene networks were also associated with competitive traits, whereas others were associated with aggressive behaviors, regardless of sex. Few genes were differentially expressed between courting and parenting males, yet some nonetheless had connections to behavioral endocrinology, including prolactin, thyroid and insulin-like growth factor pathways. Our investigation of sex differences in gene expression can help to reveal the molecular mechanisms underlying female competition and male parental care in socially polyandrous species. We conclude that social polyandry is not a simple reversal in the direction of sex-biased gene expression in the brain, but rather a result of complex genetic and hormonal interactions that warrants further study.

genomics↗

bioRxiv2025

Sexually selected traits predict female-biased philopatry in a sex-role reversed shorebird

Sex-biased dispersal plays a key role in shaping population dynamics and genetic structure. Two main hypotheses have been proposed for how territoriality and mating competition impact sex-biased dispersal. Female-biased dispersal is expected in monogamous systems with male resource defense, whereas male-biased dispersal is expected in polygynous systems with male competition over mates. However, patterns of sex-biased dispersal in polyandrous species, where females compete for both territories and mates, remain poorly understood. We investigated sex-biased dispersal in two polyandrous Jacana species, the Northern Jacana (Jacana spinosa) and Wattled Jacana (J. jacana), which exhibit intense female-female competition for territories and mates and differ in the strength of sexual selection. We analyzed sex-biased dispersal by assessing genetic differentiation and individual assignment indices in these jacana species across Central America. Our findings reveal strong male-biased dispersal in Northern Jacanas, indicated by higher genetic structuring and philopatry in females. In contrast, Wattled Jacanas showed no significant dispersal bias between sexes. Furthermore, sexually selected traits in Northern Jacana females, such as larger body mass, tarsus, and wing spur length, were associated with philopatry, suggesting that larger females retain territories, whereas smaller females disperse. To our knowledge, this is the first genetic evidence of male-biased dispersal in a polyandrous species. Our findings reveal that sexually selected traits, in addition to territorial and mate competition, are important for understanding species and sex differences in dispersal evolution.

evolutionary biology↗

bioRxiv2023

The impact of Quaternary Amazonian river dynamics on patterns and process of diversification in uakari monkeys (genus Cacajao)

AimWestern Amazonia is a region that underwent several landscape changes during the Quaternary. While Riverine Barrier Hypothesis is traditionally used to explain the influence of rivers on speciation, processes such as river rearrangements have been overlooked to explain the geographic distribution and evolutionary history of the Amazonia biota. Here we test how river rearrangements in western Amazonia influenced the evolutionary history of uakari monkeys, a primate group most associated with seasonally flooded forests in western Amazonia. LocationWestern Amazonia TaxonThe uakari monkey (genus Cacajao) MethodsWe performed a continuous phylogeographic analysis using 77 cytochrome b sequences and used digital elevation models to identify the role of landscape and riverscape characteristics in the geographic distribution of Cacajao. Finally, we used genome-wide SNPs variation (ddRADseq) to investigate population structure, gene flow and demographic history in three Cacajao species that were impacted by river rearrangements. ResultsOur continuous phylogeographical reconstruction points that the ancestral Cacajao lineage occupied the flooded forests of the Solimoes River at [~]1.7 Mya, and descendant lineages dispersed throughout western Amazonia more recently. We identified gene flow among both black and bald-headed uakari populations, even across rivers considered barriers (e.g., the Negro River). Landscape analysis showed that river rearrangements influenced the geographic distribution and population structure in Cacajao. The demographic analysis indicates that C. calvus, C. amuna, and C. rubicundus went through a population decline in the last 70 Kya and have a low effective population size. Main conclusionOur results support that the river rearrangements have shaped the geographic distribution and divergence of recently diverged Cacajao lineages. Landscape and riverscape changes, along with retractions of the flooded forests, isolated some Cacajao populations in floodplain areas. Our study also suggests that these events led to the recent population decline in species with a restricted geographic distribution.

evolutionary biology↗