Butterflies are known for their striking and colorful wing patterns but how are those patterns built? Through an evolutionary recycling process, the same tools that build beetle wings and fly legs are repurposed to create totally new pattern elements in butterfly wings. The eyespot pattern, which functions in predator evasion and mate selection, is a stunning example of a new structure created using recycled tools. Here, we test the necessity of Dpp (decapentaplegic) signaling, known for its role in fly leg development, in the formation of the butterfly eyespot. Two butterfly species were injected with an inhibitor of Dpp signaling. Eyespot size and color ratios were analyzed on the adult wing. Patterns of protein expression were also examined in the developing wing tissue of one species. These functional tests may allow us to demonstrate that Dpp has been recycled and acquired a new role in butterfly wing pattern development.
