Siblings in Flight: Unravelling Reproductive Barriers Between Two Butterfly Sister Species
5 affiliations
- 1Departamento de Bioloxía Universidade da Coruña A Coruña Spain
- 2Institut de Biologia Evolutiva (CSIC‐Univ. Pompeu Fabra) Barcelona Spain
- 3Department of Karyosystematics, Zoological Institute of Russian Academy of Sciences Universitetskaya nab. 1 St. Petersburg Russia
- 4Biodiversity Genomics Laboratory, Institute of Biology University of Neuchâtel Neuchâtel Switzerland
- 5Grupo de Investigación en Bioloxía Evolutiva, Centro Interdisciplinar de Química e Bioloxía (CICA) Universidade da Coruña A Coruña Spain
Abstract
Understanding how reproductive isolation is maintained between closely related taxa is a central question in evolutionary biology. Here, we investigate the mechanisms underlying divergence and isolation between two sister butterflies, Erebia palarica and Erebia meolans , which occur in sympatry in the Cantabrian Mountains (N Spain) and in allopatry elsewhere. Using an integrative approach, we combine genetic, genome synteny and cytogenetic analyses, Wolbachia screening, and geometric morphometrics to assess their evolutionary history and elucidate potential reproductive barriers between these species. The phylogeographic pattern suggests that both species diverged in allopatry, coming into secondary contact along the Cantabrian Mountains after the last glacial maximum. Both mitochondrial and nuclear markers recover reciprocal monophyly, indicating the absence of recent hybridisation. The identical chromosome numbers in both species (2 n = 28), the absence of major chromosomal rearrangements or straightforward genitalia differentiation, and the presence of the same Wolbachia strain in all infected individuals suggest that neither chromosomal rearrangements nor Wolbachia ‐induced incompatibilities contribute to their reproductive isolation in sympatry. In contrast, morphometric analyses show a significant divergence in wing size consistent with asymmetric character displacement: sympatric populations of E. palarica exhibit larger wings relative to both allopatric conspecifics and sympatric E. meolans , whereas E. meolans shows little size variation across northern Spain. Our findings point to wing size divergence in E. palarica as a response to sympatry with E. meolans . Overall, this study provides novel empirical evidence for morphometric character displacement in the family Nymphalidae, highlights the importance of multidisciplinary approaches for understanding species differentiation, and sets a framework for future genomic studies of speciation and reproductive isolation between closely related taxa.
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BibTeX
@article{torradoblanco2026siblings,
title = {{Siblings in Flight: Unravelling Reproductive Barriers Between Two Butterfly Sister Species}},
author = {Laura Torrado‐Blanco and Roger Vila and Vladimir A. Lukhtanov and Carmen Seoane‐Rodríguez and Camille Cornet and Kay Lucek and Marta Vila},
journal = {Ecology and Evolution},
year = {2026},
month = nov,
doi = {10.1002/ece3.74533},
url = {https://onlinelibrary.wiley.com/doi/10.1002/ece3.74533},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Siblings in Flight: Unravelling Reproductive Barriers Between Two Butterfly Sister Species
AU - Laura Torrado‐Blanco
AU - Roger Vila
AU - Vladimir A. Lukhtanov
AU - Carmen Seoane‐Rodríguez
AU - Camille Cornet
AU - Kay Lucek
AU - Marta Vila
PY - 2026
DA - 2026/11/08
JO - Ecology and Evolution
DO - 10.1002/ece3.74533
UR - https://onlinelibrary.wiley.com/doi/10.1002/ece3.74533
AB - Understanding how reproductive isolation is maintained between closely related taxa is a central question in evolutionary biology. Here, we investigate the mechanisms underlying divergence and isolation between two sister butterflies, Erebia palarica and Erebia meolans , which occur in sympatry in the Cantabrian Mountains (N Spain) and in allopatry elsewhere. Using an integrative approach, we combine genetic, genome synteny and cytogenetic analyses, Wolbachia screening, and geometric morphometrics to assess their evolutionary history and elucidate potential reproductive barriers between these species. The phylogeographic pattern suggests that both species diverged in allopatry, coming into secondary contact along the Cantabrian Mountains after the last glacial maximum. Both mitochondrial and nuclear markers recover reciprocal monophyly, indicating the absence of recent hybridisation. The identical chromosome numbers in both species (2 n = 28), the absence of major chromosomal rearrangements or straightforward genitalia differentiation, and the presence of the same Wolbachia strain in all infected individuals suggest that neither chromosomal rearrangements nor Wolbachia ‐induced incompatibilities contribute to their reproductive isolation in sympatry. In contrast, morphometric analyses show a significant divergence in wing size consistent with asymmetric character displacement: sympatric populations of E. palarica exhibit larger wings relative to both allopatric conspecifics and sympatric E. meolans , whereas E. meolans shows little size variation across northern Spain. Our findings point to wing size divergence in E. palarica as a response to sympatry with E. meolans . Overall, this study provides novel empirical evidence for morphometric character displacement in the family Nymphalidae, highlights the importance of multidisciplinary approaches for understanding species differentiation, and sets a framework for future genomic studies of speciation and reproductive isolation between closely related taxa.
SN - 2045-7758
SN - 2045-7758
ER -