Biology subjects

Dudaniec, R. Y.

Publications and source records attributed to Dudaniec, R. Y..

5 recordsLinked to original sources

bioRxiv2026

Asymmetric migration shapes genetic structure of the invasive avian vampire fly (Philornis downsi) across the Galapagos Islands.

Biological invasions on islands provide a natural framework to study how dispersal and connectivity influence evolutionary and ecological processes. The avian nest parasitic fly, Philornis downsi - first recorded in Darwins finch nests in 1997 - causes high mortality in endemic land birds, yet its inter-island and sex-specific patterns of dispersal and genetic structure remain poorly understood. We use low-coverage whole genome sequencing to investigate genome-wide patterns of genetic diversity, directional migration and effective population size in P. downsi across five major Galapagos Islands and its native range in mainland Ecuador. We find evidence for a genetic bottleneck in the Galapagos, isolation by distance, and evidence that the island closest to the Ecuadorian mainland, San Cristobal, is genetically divergent from the other four islands sampled, despite retaining the highest genetic diversity. No evidence was found for sex-biased dispersal; however, sex-biased genetic structure was detected using only markers from inferred autosomal scaffolds. We found asymmetric gene flow with higher migration rates from San Cristobal westward to the other islands, matching the direction of both southeast trade winds and major cargo shipping routes. Our results suggest both natural and human-mediated colonisation of P. downsi from the mainland through San Cristobal to the other islands, followed by high inter-island dispersal among closely situated sink islands. Our findings are critical for prioritising islands for control strategies that will reduce P. downsi impacts on vulnerable endemic birds and underscore the value of understanding directional migration patterns for managing invasive species in metapopulations.

evolutionary biology↗

bioRxiv2026

Landscape viromics of introduced honeybees and bumblebees reveal distinct environmental and host-specific effects

Understanding how viral communities vary across co-occurring hosts and environments is essential for assessing species-specific viral risks under changing land use and climate. This is particularly relevant for managing introduced bees, which face persistent viral threats themselves, as well as transmitting plant viruses. Here, we compare RNA viromes of the long-established honeybee (Apis mellifera, introduced to Tasmania in 1831) and the more recent invader, the bumblebee (Bombus terrestris, invasive since 1992), across 14 Tasmanian sites - an island still free of the viral vector, Varroa destructor. Using a metatranscriptomic approach on total RNA from whole bees, we identified insect- and plant-associated viruses and inferred phylogenetic patterns of insect viral sharing, divergence, and potential cross-species transmission. We also assessed spatial and environmental drivers of viral composition, diversity, and richness. Geographic longitude, precipitation, temperature, and pasture percentage influenced the total, insect-, and plant-associated viromes of B. terrestris. In contrast, for A. mellifera, only precipitation and temperature were associated with insect and plant viral alpha diversity and community composition. Phylogenetic analyses revealed that Black Queen Cell virus in A. mellifera from Tasmania has diverged from mainland Australian sequences, and two distinct sub-strains of Lake Sinai virus 1 were shared by both bee species. Lake Sinai virus 3 showed evidence of interspecies transmission between A. mellifera and B. terrestris. Notably, this study provides the first detection of Moku virus in Australian bees and globally in bumblebees, suggesting potential interspecies transmission among social Hymenoptera. Overall, our findings demonstrate local viral diversification and reveal that B. terrestris viromes are more strongly shaped by environmental factors than those of A. mellifera, underscoring the importance of monitoring invasive pollinators as reservoirs and vectors of viral emergence.

evolutionary biology↗

bioRxiv2025

Signatures of genomic adaptation to Cuckoo brood parasitism in Reed Warbler hosts across Europe

Behaviour is a fundamental defence mechanism for animals facing enemies, yet its plasticity makes finding associated genomic evidence for coevolution challenging. As a solution, we apply landscape genomics methods more typically deployed with abiotic variables to a coevolutionary model system: Reed Warblers (Acrocephalus scirpaceus) and their Cuckoo (Cuculus canorus) brood parasites. Using continental sampling of genome-wide data from hosts breeding under varying brood parasitism rates, we reveal that gene flow varies among populations, and, controlling for variation due to environmental differences, identify genomic regions and putative genes that differ with exposure to brood parasitism. Therefore, our results suggest that variable host responses to selection are possible, even by highly mobile and connected populations, supporting long-held assumptions that behavioural defences may reflect genomic adaptation despite their plasticity. Further studies, including those linking genetic variation to individual-level behaviours involved in parental responses to brood parasitism, are required to confirm a genetic basis to specific coevolutionary adaptations, and to test for other biotic or abiotic variables potentially confounding with local parasitism rate.

evolutionary biology↗

bioRxiv2024

Landscape-wide metabarcoding of the invasive bumblebee (Bombus terrestris) shows interactions among the gut microbiome and pollenbiome

Many species of social insects introduced to regions beyond their native ranges have become highly invasive. The introduction of the eusocial European buff-tailed bumblebee, Bombus terrestris, to the island of Tasmania (Australia) [~]30 years ago is of concern due to its ecological impacts and its potential to spill over pathogens to native bees or commercially important honeybees. The health of B. terrestris is intricately connected with its gut microbiome and diet; however, environmental variables may also interact, particularly during invasion into novel environments. Using landscape-wide sampling and a metabarcoding approach to characterize the gut bacteria (16S rRNA) and diet composition from foraged pollen (ITS2: floristic diversity of pollen baskets), this study investigates how the gut microbiota of B. terrestris workers is affected by nutritional diversity ( pollenbiome) and environmental variation across diverse landscapes of its invasive range in Tasmania. Gut bacterial community composition and diversity were significantly predicted by site annual precipitation and percentage of pasture. Further, a positive interaction between site annual precipitation and site annual temperature significantly predicted gut bacterial diversity. The interaction effect of pollen diversity and average summer wind velocity was also significantly and positively related to gut bacterial diversity. Following comparison of Akaike information criterion (AIC) and sum of weights, the percentage of pasture was identified as the most strongly weighted variable, which, along with pollen diversity, had a negative impact on gut bacterial diversity. These insights help to uncover how environmental interactions affect the gut microbiome of B. terrestris in an invaded landscape with novel nutritional resources. This knowledge contributes to understanding the factors that predict the spread and persistence of invasive bumblebees.

ecology↗

bioRxiv2024

Genomic introgression between critically endangered and stable species of Darwin's tree finches on the Galapagos Islands

Natural hybridisation among rare or endangered species and stable congenerics is increasingly topical for the conservation of species-level diversity under anthropogenic impacts. Evidence for beneficial genes being introgressed into or selected for in hybrids raises concurrent questions about its evolutionary significance. In Darwins tree finches on the island of Floreana (Galapagos Islands, Ecuador), the Critically Endangered medium tree finch (Camarhynchus pauper) undergoes introgression with the stable small tree finch (Camarhynchus parvulus), and hybrids regularly backcross with C. parvulus. Earlier studies in 2005-2013 documented an increase in the frequency of Camarhynchus hybridisation on Floreana using field-based and microsatellite data. With single nucleotide polymorphism (SNP) data from the same Floreana tree finches sampled in 2005 and 2013 (n = 95), we examine genome-wide divergence across parental and hybrid birds and evidence for selection in hybrids. In assessing previous estimates of introgression we found that just 18% of previously assigned hybrid birds based on microsatellites were assigned to hybrids using SNPs. Over half of the previously assigned hybrids (63%) were reassigned to C. parvulus, though parental species showed concordance with prior assignments. Of 4869 private alleles found in hybrid birds, 348 were at a high frequency ([≥]0.30) that exceeded their parental species of origin 89-96% of the time. Across the two years, 3436 (70.6%) private alleles underwent a substantial ([≥]0.30) allele frequency increase or decrease. Of these, 28 private alleles were identified as candidate loci under selection via local PCA genome scans and outlier tests. Alleles were annotated to genes associated with inflammation, immunity, brain function and development. We provide evidence that introgression among a critically endangered and stable species of Darwins tree finch is being retained by selection across years and may aid in the retention of genetic diversity in birds threatened with extinction.

evolutionary biology↗