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Hybrid speciation in Heliconius butterflies
Presented by: Neil Rosser, Museum of Comparative Zoology, Harvard University, Cambridge, and Princeton University, Princeton, USA
Abstract: Hybridisation allows adaptations to be shared among lineages and may trigger the evolution of new species. However, convincing examples of homoploid hybrid speciation remain rare, because it is challenging to demonstrate that hybridisation was critical in generating reproductive isolation. Here, we combine population genomic analysis with quantitative trait locus mapping of species-specific traits to dissect a new case of hybrid speciation in Heliconius butterflies. We show that H. elevatus is a hybrid species which is sympatric with both parents and has persisted as an independently evolving lineage for at least 180,000 years. This is despite pervasive and on-going gene flow with one parent, H. pardalinus, which homogenises 99% of their genomes. The remaining 1% introgressed from the other parent, H. melpomene, and is spread widely across the genome in islands of divergence from H. pardalinus. These islands harbour multiple traits under disruptive selection, including colour pattern, wing shape, host plant preference, sex pheromones and mate choice. Collectively, these traits place H. elevatus on its own adaptive peak and permit coexistence with both parents. Our results show that speciation was driven by introgression of ecological traits and that speciation with gene flow is possible with a multilocus genetic architecture.
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Thomas C. Emmel Seminar Series presents: Expanding Horizons in Lepidoptera Research
Continuing from Fall 2020, the McGuire Center is hosting this webinar series as an opportunity for both early career researchers as well as established leaders in the field to present their work. We hope that you will join us to hear about current advances in many diverse fields of Lepidoptera research.