Synopsis: How novel traits originate over the course evolution is still poorly understood. My lab has been investigating this question focusing on the developmental origin of eyespot color patterns on the wings of nymphalid butterflies, as well as on their ecological function. I will describe how eyespots function both in predator avoidance and in sexual signaling, how they originated close to the base of the nymphalid clade, presumably from simpler spot patterns, and how eyespots likely originated via the co-option of the antennal gene regulatory network to the wing margin.