The genetics and evo-devo of butterfly wing patterns

Key Points Butterfly wings show a spectacular diversity of patterns of colours and shapes both within and among species. Butterfly wing patterns are ideal systems for an integrated study of the reciprocal interactions between the evolutionary and developmental processes that shape morphology. The evolutionary flexibility of butterfly wing patterns might be facilitated by the compartmentalization of pattern elements (such as eyespots and chevrons) in individual wing regions. The 'nymphalid groundplan', a theoretical model that describes homologies among butterfly wing patterns on the basis of morphology, has been very useful to compare different patterns, but might not always reflect developmental homologies. The mechanistic dissection of wing-pattern diversity has focused on the cellular components and genetic pathways that underlie eyespot formation. Future work will need to integrate different aspects of these mechanisms in species from different taxa that have different wing patterns, and combine such studies with a more detailed ecological analysis in nature. Understanding how the spectacular diversity of colour patterns on butterfly wings is shaped by natural selection, and how particular pattern elements are generated, has been the focus of both evolutionary and developmental biologists. The growing field of evolutionary developmental biology has now begun to provide a link between genetic variation and the phenotypes that are produced by developmental processes and that are sorted by natural selection. Butterfly wing patterns are set to become one of the few examples of morphological diversity to be studied successfully at many levels of biological organization, and thus to yield a more complete picture of adaptive morphological evolution.