Anise Swallowtail Butterfly Pictures
The Anise Swallowtail butterfly is found in western North America. Often mistaken for the Western Tiger Swallowtail, this species has a shorter body and lacks the thin black stripes that converge on the tail of the Western Tiger. Anise Swallowtail caterpillars feed on plants of the carrot family that contain essential oils known as anisic aldehyde. The caterpillar converts this to a foul-smelling chemical that it releases when threatened. Adult females have chemical receptors that allow them to determine if a host plant contains this essential oil before laying her eggs on the plant.