International audience Eyespots are wing color pattern elements repeatedly observed in many butterflies,whose developmental genetics has been extensively documented. Nevertheless, theevolutionary forces shaping their diversification across species still remain largelyunknown. Here we investigate the evolution of eyespots in the 30 species of theneotropical genus Morpho. Morpho butterflies display a series of eyespots locatedon the ventral side of their wings, highly variable among species, ranging from large,conspicuous structures to vestigial spots. Applying geometric morphometrics to a largesample (N = 910) spanning all Morpho species and both sexes, we assess eyespotnumber, position, size, and shape. We detect a divergence in eyespot position betweenunderstory and canopy species, with an L-shaped configuration in canopy species anda line pattern in understory species, where the eyespots tend to fuse and form a stripein white and pale species. This effect is stronger than expected based on a Brownianmotion model of phylogenetic divergence, suggesting an adaptation to the microhabitatand an influence of the wing color on the evolution of pattern elements. Remarkably,this shift in color pattern is strongly correlated with a shift in wing shape. However,using a thin-plate spline interpolation, we show that the shape change is insufficientto explain the evolution of eyespot position as a developmental side effect of wingshape evolution, also pointing at an adaptive effect. Finally, we find a significant negativecorrelation between eyespot relative size and the within-species variation in eyespotnumber, position, size, and shape, suggesting a relaxed or apostatic selection on smalleyespots (rare phenotypes being favored as they are less likely to be remembered andthus detected by predators). We hypothesize that contrasted ecology may explain theobserved differences between species: large and phenotypically stable eyespots mightact as attack deflectors, small, variable faded eyespots might rather enhance crypsis,and pale species stripe pattern might disrupt the outline of the wing.