The Pink-edged Sulphur is a medium- size butterfly in the Pieridae family (1). They range from western Canada and eastern Oregon, through the Great Lakes region to northern New England, southward through Pennsylvania, eastern West Virginia, and northwest Virginia (2). In Maryland, the species is only known from high elevations of the Allegheny Plateau in Garrett Co. and it has a state rank of S1, highly state rare (3, 4).
The Pink-edged Sulphur has a wingspan of 1 ½ to 2 ⅝ inches (2) and is named for the pink fringe on the edge of their wings (5). Males have black borders on the upperside of their outer wing, while females have a faded black border on the forewing apex (5). Their underside is mostly pale greenish-yellow with a hollow dot on each wing (5).
This butterfly can be easily confused by the Orange Sulphur (Colias eurytheme) which has an orange tint on the uppersides, and the Clouded Sulphur (Colias philodice), which has faint black dots along the submarginal area of their ventral wings. Both of the latter species are common in Maryland (3).
Females lay eggs midsummer on the larval host plants, Lowbush Blueberry and Velvetleaf Blueberry (Vaccinium myrtilloides) (2, 3, 4, 6). In Maryland, Velvetleaf Blueberry is a vulnerable species, with a rank of S1 (3).
Adults have one flight period from July to early August and hibernate during their third instar (6, 7). They tend to visit non-native Red Clover (Trifolium pratense) and Heal-all (Prunella vulgaris) also known as Common Selfheal (3, 4). Males can be found awaiting females with a slow flight (2).
The Pink-edged Sulphur can be found in bogs with blueberry or shrubland habitat (4). They prefer Lowbush Blueberry and Velvetleaf Blueberry where they will spend their days feeding as caterpillars (4, 6).
Data from Maryland Biodiversity Project. Includes historical data and may overrepresent the current range of the species.
Understanding and becoming aware of the Pink-edged Sulphurs' habitat is necessary for their survival (5). This species is currently under review and the state rank will likely be changed to extirpated (personal comm. Jennifer Selfridge).
© 2020 Price Lab for Entomology, Courtney Rogall