Biology subjects

Huemer, P.

Publications and source records attributed to Huemer, P..

3 recordsLinked to original sources

bioRxiv2025

Contrasting genetic differentiation of urban and rural populations of two grassland lepidopterans across Europe

Urbanisation is transforming environments globally. The altered abiotic conditions and biotic interactions in urban habitats impose divergent selection pressures on urban versus rural populations, while genetic drift may also be significant in typically small urban populations. A key question in urban evolution concerns the origin and spread of urban genotypes. Examples exist of both single and multiple origins of urban genotypes, but these have proven difficult to generalize. Here, we address genetic differentiation among urban populations, among rural populations, and between urban and rural populations. We conducted an extensive population genomic double digest restriction-site associated DNA sequencing analysis of two non-model grassland lepidopterans, Coenonympha pamphilus and Chiasmia clathrata, across Europe. The genetic population structures of the study species were strikingly different: Co. pamphilus showed strong population differentiation, while this was almost absent in Ch. clathrata, which instead showed signs of high current and past gene flow among populations. Results of Co. pamphilus are consistent with multiple origins of urban populations, and multiple origins seem plausible also in Ch. clathrata. These results suggest that past and large-scale population dynamics need to be integrated into urban evolution research, because population history affects urban evolutionary dynamics.

evolutionary biology↗

bioRxiv2023

Patterns of speciation in a parapatric pair of Saturnia moths as revealed by Target Capture

The focus of this study is to understand the evolutionary relationships and taxonomy of widely distributed parapatric species pair of wild silk moths, Saturnia pavonia and Saturnia pavoniella (Lepidoptera: Saturniidae) in Europe. To address species delimitation challenges associated with many parapatric taxa, target enrichment and mtDNA sequencing was employed alongside phylogenetic, species delimitation, admixture and introgression analyses. The dataset included individuals from both species, two hybrids generated in the lab, as well as individuals from outside the contact zone. Nuclear markers strongly supported both S. pavonia and S. pavoniella as two distinct species, with the hybrids grouping together as intermediate and separate from both species. However, the maximum likelihood (ML) tree generated from mtDNA sequencing data presented a different picture, showing both taxa to be phylogenetically intermixed. This inconsistency may be attributed to mitonuclear discordance, which can arise from biological factors (e.g., introgressive hybridization or incomplete lineage sorting) or alternatively operational factors (e.g., incorrect species delimitation). We further provide the evidence of past introgression to have taken place, but no evidence of current admixture between the two species. Finally, we discuss our results from evolutionary point of view taking into consideration the past climatic oscillations that has likely shaped the present dynamics between the species. Overall, this study demonstrated the effectiveness of the target enrichment approach in resolving the phylogenetic relationships between closely related parapatric species and providing insights into their taxonomic delimitation.

evolutionary biology↗

bioRxiv2023

Species Delimitation Under Allopatry: Genomic Divergences Within and Across Continents in Lepidoptera

Delimitation of allopatric populations into species remains subjective and largely arbitrary. Many cold-adapted species from the subarctic and Central and Southern European Mountain systems display frequent allopatry with disjunct distributions of their populations. The same concerns Holarctic species which are many and which almost regularly show various degrees of differentiation between the continents. In this study, we analyze high- throughput target enrichment data for ten groups of arctic-alpine and Holarctic lepidopteran species sampled from four main regions across the Holarctic realm - Fennoscandia, North America, Alps and Altai. We first aimed to assess whether the genetic differences in the nuclear genome reflect observed DNA barcode divergences and second, whether the gap between population and species-level differences can be dissected using genomic data. We compared the phylogenetic trees and uncorrected pairwise genetic distances obtained from target enrichment and the mitochondrial cytochrome oxidase I (COI) barcodes for each of the study species. Additionally, we also performed a suite of population genetic and species delimitation analyses to further shed light on patterns of intraspecific variation using a large number of nuclear markers. We observed that in about one half of the cases, DNA barcodes tended to show phylogenetic relationships similar to the target enrichment markers. We report varying levels of nuclear genetic differentiation among the populations analyzed, starting from low differentiation of geographically separated populations to the deeper separation of some Nearctic population and further arctic-alpine disjunction. Given that no single consistent pattern emerged across different case studies, we demonstrate that the delimitation of allopatric populations into species could be done much more efficiently and in a consistent manner if based on a large set of universal genetic loci, which would help in reaching standards for taxonomic delimitation of allopatric populations.

evolutionary biology↗