Orange Sulphur

Notes:

Orange sulphurs historically were a western species in the Nearctic region, but moved eastward across North America during the late 1800’s due to logging and the planting of alfalfa fields. They now are found throughout North America to southern Mexico. Males spend their days patrolling their territories daily seeking females. They recognize the females visually, focusing on the coloration of the underside of the hindwing. The males are repelled by ultraviolet reflection on other males’ wings. Females appear not to care about the coloration of the males but ultraviolet reflection must be present, which helps reduce hybridization with yellow sulphurs Colias philodice that lack the reflection.