Differentiation in putative male sex pheromone components across and within populations of the African butterfly Bicyclus anynana as a potential driver of reproductive isolation |
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| Authors: | Paul M B Bacquet Maaike A de Jong Oskar Brattström Hong‐Lei Wang Freerk Molleman Stéphanie Heuskin George Lognay Christer Löfstedt Paul M Brakefield Caroline M Nieberding |
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| Institution: | 1. Evolutionary Ecology and Genetics Group, Biodiversity Research Centre, Earth and Life Institute, Université catholique de Louvain, Louvain‐la‐Neuve, Belgium;2. Biological Sciences, University of Bristol, Bristol, UK;3. Department of Zoology, University Museum of Zoology, University of Cambridge, Cambridge, UK;4. Department of Biology, Pheromone Group, Lund University, Lund, Sweden;5. Indian Institute of Science Education and Research Thiruvananthapuram, Vanasiri Evolutionary Ecology Lab, College of Engineering Trivandrum Campus, Trivandrum, Kerala, India;6. Laboratory of Analytical Chemistry, Department of AgroBioChem, Gembloux Agro‐Bio Tech, University of Liege, Gembloux, Belgium;7. Evolutionary Ecology and Genetics Group, Biodiversity Research Centre, Earth and Life Institute, Université catholique de Louvain, Louvain‐la‐Neuve, BelgiumCo‐last authors. |
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| Abstract: | Sexual traits are often the most divergent characters among closely related species, suggesting an important role of sexual traits in speciation. However, to prove this, we need to show that sexual trait differences accumulate before or during the speciation process, rather than being a consequence of it. Here, we contrast patterns of divergence among putative male sex pheromone (pMSP) composition and the genetic structure inferred from variation in the mitochondrial cytochrome oxidase 1 and nuclear CAD loci in the African butterfly Bicyclus anynana (Butler, 1879) to determine whether the evolution of “pheromonal dialects” occurs before or after the differentiation process. We observed differences in abundance of some shared pMSP components as well as differences in the composition of the pMSP among B. anynana populations. In addition, B. anynana individuals from Kenya displayed differences in the pMSP composition within a single population that appeared not associated with genetic differences. These differences in pMSP composition both between and within B. anynana populations were as large as those found between different Bicyclus species. Our results suggest that “pheromonal dialects” evolved within and among populations of B. anynana and may therefore act as precursors of an ongoing speciation process. |
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| Keywords: | Lepidoptera male sex pheromone mitochondrial introgression population divergence reproductive isolation speciation |
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