Description
Evolutionary convergence of colour pattern in mimetic species is tightly linked with the evolution of chemical defences. Yet, the evolutionary forces involved in natural variations of chemical defences in aposematic species are still understudied. Herein, we focus on the evolution chemical defences in the butterfly tribe Heliconiini. These neo-tropical butterflies contain large concentrations of cyanogenic glucosides, cyanide-releasing compounds acting as predator deterrent. These compounds are either de novo synthesized or sequestered from their Passiflora host-plant, so that their concentrations may depend on host-plant specialization and host-plant availability. We sampled 375 wild Heliconiini butterflies across Central and South America, covering 43% species of this clade, and quantify individual variations in the different cyanogenic glucosides using liquid chromatography coupled with tandem mass spectrometry. We detected new compounds and important variations in chemical defences both within and among species. Based on the most recent and well-studied phylogeny of Heliconiini, we show that ecological factors such as mimetic interactions and host-plant specialization have a significant association with chemical profiles, but these effects are largely explained by phylogenetic relationships. Our results therefore suggest that shared ancestries largely contribute to chemical defence variation, pointing out at the interaction between historical and ecological factors in the evolution of Müllerian mimicry.
| Date made available | 2019 |
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| Publisher | Dryad |