Several different swallowtail butterfly variations showing mimicry and polymorphism, or different forms of the same species. Row 1: A female and male Papilio protenor, the species that is closely related to Papilo polytes, the focal of the new study. InP. protenor, males and female look the same and they do not mimic. Row 2: Papilio ambrax, a species where males and females look different and the female is a mimic. In this species, there is no female polymorphism. The new study shows that its evolutionary ancestor was polymorphic, but females lost that train and only display the mimetic form. Row 3: Polymorphic Papilio polytes, (L-R) A mimetic female form (one of 3 mimetic forms in this species), a non-mimetic female, and the male. Row 4: A distantly related swallowtail, Pachliopta aristolochiae. This is the toxic species that the species in the new study mimic.