In addition to warning predators, the color patterns of Heliconius butterflies are used as conspecific recognition cues during mating. Previously, we have shown that the white vs. yellow wing color difference between H. cydno and H. pachinus (the K locus) is a critical recognition cue and a major QTL for male color preference is tightly linked to color itself. We are currently applying genetic and association mapping approaches to identify the genetic basis of assortative color preference in Heliconius and characterize the association between color and preference.