Convergent morphology and divergent phenology promote the coexistence of Morpho butterfly species

The fascinating iridescent-blue Morpho butterflies from the Amazon shed a new light on the diversification of traits and species within the same ecological niche. Their shared blue signal reduces individual predation by advertising their high escape ability, favoring resemblance between species. However, such co-existence of similar-looking species may trigger erroneous mate choice or irrelevant male-male competition. Using solar-powered dummy butterflies placed in the wild, we quantified the costly interspecific behavior of males. By investigating the genomic variations in these species, we then revealed strong genetic isolation between species despite these inter-specific interactions, probably facilitated by the strong difference in flying hours between species. Our study highlights how joint convergent and divergent evolution of different traits fuels biodiversity.