The research projects developed in the team focus on the identification of feedbacks between trait and species diversification by investigating the links between colour patterns evolution and species diversification in butterflies. In butterflies, wing colour pattern variations are submitted to selective pressures generated by both (2) conspecifics behaviour, through mate choice, as well as by (2) ecological interactions with other species living in sympatry. Wing colour pattern of butterflies have also been shown to be involved in species recognition, and are thus assumed to play a role in initiating speciation and reinforcing species barriers. Furthermore, conspicuous colour patterns are frequently displayed in distasteful butterfly species. These colorations can indeed be learnt by predators that will then avoid prey displaying them. This learning by predators generates positive density-dependent selection favouring the display of a similar colour pattern in prey species targeted by the same predator community. This predation pressure thus promotes mutualistic interactions in prey species and evolutionary convergence of wing colour pattern in butterfly communities living in sympatry. Because a switch in colour pattern can lead to both (1) local adaptation through mimicry towards the local community of defended prey and (2) reproductive isolation because of colour pattern-based mate choice, they are considered as so-called magic-trait favouring speciation. Our research projects aim at linking the processes acting a micro-evolutionary scale, such as mate choice and mutualistic interactions, on the patterns of diversification of traits and species at larger evolutionary scale, focusing on two main case-studies, the neo-tropical genus Morpho and the butterfly family Papilionidae.
ERC project OUTOFTHEBLUE (2023-2028)
The research project named OUTOFTHEBLUE funded by an ERC consolidator grant focuses on the diversification of Morpho butterflies in sympatry. Though not chemically-defended, blue Morpho species are scarcely caught by bird predators due to their fast and erratic flight (Le Roy et al., 2021a). Their iridescent blue dorsal pattern strongly contrasts with their cryptic brownish ventral pattern resulting in a series of flashes during flapping flight, that increases the difficulty in capturing them. This colour pattern may in turn act as a signal of their strong escape ability and hence deter potential attacks. Evasive mimicry may therefore be promoted among sympatric species in a manner similar to Müllerian mimicry (Páez et al., 2021), hence favouring local convergence in wing colour patterns. Consistent with this hypothesis, we demonstrated a striking parallelism in the phenotypic diversification of three blue Morpho species throughout their sympatric distribution, resulting in multiple local convergence in the width of their dorsal blue band (Llaurens et al., 2021). Using a behavioral experiment in the field in Amazonian Peru, we documented substantial reproductive interference generated by colour pattern resemblance, with aggressive interactions between males and courtship with females from all three mimetic species (Le Roy et al., 2021b).
The OUTOFTHEBLUE project aims at (1) determining the genetic and developmental basis of colour pattern convergence in the 3 sister-species of the genus Morpho, to test for molecular convergence; (2) characterizing the ecological interactions either increasing (escape mimicry) or decreasing (reproductive interferences) colour pattern convergence, through behavioural experiments in the field; (3) reconstructing the history of speciation and of colour pattern evolution using population genomics (4) identifying the eco-evolutionary feedbacks between the evolution of traits (colour patterns, temporal niche) within and among sympatric species, using mathematical modelling.
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Le Roy C., Amadori D., Charberet S., Windt J., Muijres F. T., Llaurens V. et Debat, V., « Adaptive evolution of flight in Morpho butterflies », Science, vol. 374, n° 6571, 2021, p. 1158-1162.
Le Roy C., Roux C., Authier E., Parrinello H., Bastide H., Debat V. et Llaurens V., « Convergent morphology and divergent phenology promote the coexistence of Morpho butterfly species », Nature communications, vol. 12, n° 1, 2021, p. 1-9.
Llaurens V., Le Poul Y., Puissant A., Blandin P. et Debat V., « Convergence in sympatry: Evolution of blue‐banded wing pattern in Morpho butterflies », Journal of Evolutionary Biology, vol. 34, n° 2, 2021, p. 284-295.
Páez E., Valkonen J. K., Willmott K. R., Matos-Maraví P., Elias M., et Mappes J., « Hard to catch: experimental evidence supports evasive mimicry », Proceedings of the Royal Society B, vol. 288, n° 1946, 2021.
