Evolutionary feedback between traits and species diversification: convergence and divergence in sympatric butterflies of the Amazonian rainforest – OUTOFTHEBLUE

This project will bridge gaps between micro and macro evolution by ascertaining the evolutionary feedbacks between trait and species diversification, focusing on closely-related species living in sympatry. Sympatric species often differ in suites of traits involved in niche partitioning: how do ecological interactions induce the sequential evolution of series of traits? In turn, how does phenotypic divergence open up new niches and fuel sympatric speciation? The project focuses on the neo-tropical butterfly genus Morpho where multiple behavioural and morphological traits strikingly differ between sympatric species living in the canopy vs. understorey. Studying trait variations within and among these closely-related species living in sympatry allows reconstructing the evolutionary steps leading to the divergence in suites of traits linked to niche specialization. Within the understorey clade, striking parallel geographic variations are observed among sympatric species, resulting in repeated local convergences in iridescent blue wing patterns, that may be driven by mimicry among these fast-flying, conspicuous butterflies. Such evasive mimicry may induce costly reproductive interferences, favouring segregation of circadian activities between species and thus contributing to the speciation process. The project relies on the original combination of both up-to-date and field-based approaches: (1) cutting-edge phenotypic characterisation of complex traits (eg. iridescence, flight) (2) empirical estimations of selective forces with wild butterflies (3) machine learning-based population genomics applied to demographic inferences (4) and mathematical modelling of density-dependent processes with stochasticity. These innovative approaches will shed light on unrevealed ecological interactions between species, impacting diversification of traits and species, therefore bringing major scientific breakthrough and attracting society attention on biodiversity loss in Amazonia.