More Than Colours: An Eco-Evolutionary Framework for Wing Shape Diversity in Butterflies

Wings are key innovations that have revolutionized the life of winged organisms and have moulded terrestrial ecosystems through new interactions (e.g. pollination). Among flying organisms, butterflies draw attention for their astonishing diversity of colour patterns, but their wings are much more than colours. The wing morphology may vary for different reasons, including communication. Thus, the different factors, acting together or under conflicting ways, moulded the wing shape. Mimicry rings are promising model systems for evaluating the evolution of wing shapes since trait convergence for mimicry is an identifiable force among others selective pressures. An eco-evolutionary framework can help us disentangle the relative role of each step in the evolution of wing shapes. Biotic and abiotic filters can affect wing morphology through pathway changes during the ontogeny, including sexual dimorphism, developmental trade-offs, nutritional food quality and environmental conditions. During the adult stage, both sexual and natural selection determine the combination of genes that are selected and will persist for future generations. All these selective pressures acting repeatedly over the time must result in different macroevolutionary scenarios of traits, like as genetic drift, vicariance, adaptive radiation and speciation. Finally, we propose that comparative studies on mimicry rings, with closely related species presenting changes in wing morphology according to both environmental and sexual behaviour, including sex-limited dimorphism, can be useful systems to understand the role of selective pressures driving the evolution of wing shapes.