Mémoire
| Résumé : | Context: Centuries of observations by naturalists around the world have made butterflies (Papilionoidea) model organisms in evolutionary biology, ecology, conservation, and mimicry. The tribe Amathusiini (Nymphalidae) is diverse in tropical and subtropical Asia. It includes several genera of camouflaged butterflies and the genus Taenaris, which is apparently aposematically coloured.Objectives and methods: We undertook an integrative approach to studying this group by analysing a suite of life history traits in the context of a robust molecular phylogeny. We inferred the evolutionary history of Amathusiini and closely related tribes by sequencing up to 391 genetic markers from 85% of all described species including all genera and estimated phylogenies using parsimony, likelihood, and Bayesian approaches, including inference of a time-calibrated tree. We then inferred the biogeographic history of the group and mapped life history characters onto the tree to investigate the evolution of aposematism from a camouflaged ancestor.Results and discussion: We found that the tribe Amathusiini is polyphyletic with numerous taxa requiring taxonomic revision due to non-monophyly of genera. The ancestor of Taenaris split from its MRCA with Faunis ca. 10 mya, and this divergence is associated with: 1) dispersal to New Guinea from Southeast Asia; 2) a radical shift to light wing coloration with large eyespots on the dorsal hindwings; and 3) a shift from crepuscular to diurnal activity. Surprisingly, most Taenaris larvae feed on palms and other monocots lacking obvious defensive compounds. Observations of adults imbibing cycad exudates suggests that chemical defence is acquired in this way, and a few derived species evolved cycad-feeding larvae. |
