We have developed germ line transformations for the nymphalid butterfly Bicyclus anynana in order to be able to test the function of genes implicated in the development of the wing color patterns. We have first transformed B. anynana with piggyBac and Hermes constructs carrying the marker gene EGFP driven by an eye specific promoter. On going efforts involve the production of lines with specific candidate genes under the control of a heat-shock promoter from Drosophila. In these lines we are attempting to activate candidate genes in specific areas of the wing at specific times of development by means of a targeted laser heat-shock. In addition, we are developing “fast” ways of testing gene function. This involves introducing the candidate gene into the wing epidermis using plasmid injections followed by in vivo electroporation. These same tools will enable us to explore the ways in which these developmental genes acquired their novel color patterning function during evolution of the Lepidoptera.