Swallowtail butterfly tiger swallowtail), Y-linkage determines whether the females are either wild-type (yellow and black) or melanic (dark melanin replaces the yellow background). This genetic difference stems from the fact that melanism is controlled by a single gene, which controls the level of dopamine in the organism. The enzyme BAS, which assists dopamine in producing the yellow pigmentation, normally found on the wings' background, is suppressed. Without the pigmentation, the butterfly appears mostly black (the melanic form) and is a Batesian mimic of "Battus philenor", the pipevine swallowtail. There are also "Papilio glaucus" that are not wholly black; several possess an intermediate
Scarce swallowtail the purpose of camouflage. The green pupae develop on host plants and develop directly while brown pupae enter into diapause in the leaf litter. Pupating larvae tend to form green pupae before August while after August they tend to form brown pupae. Duration of the or light period appears to be the mechanism which dictates the path of development of the pupa. The results suggest that the green pupa develop on food plants to avoid predation by small mammals and visual avian predators while the brown pupa develop on leaf litter to avoid avian predators. Scarce swallowtail The scarce swallowtail