Butterflies are colourful and recognition of specific wing colour pattern is likely use as a (1) species recognition and (2) mating cue. The evolution of wing colour pattern likely trigger the evolution of colour vision.
Chazot, N., Panara, S., Zilbermann, N., Blandin, P., Le Poul, Y., Cornette, R., et al. (2016) Morpho morphometrics: Shared ancestry and selection drive the evolution of wing size and shape in Morpho butterflies: MORPHO MORPHOMETRICS. Evolution, 70, 181–194.