Pieris virginiensis, the West Virginia white, is a butterfly found in North America in the Great Lakes states, along the Appalachians from New England to Alabama, and in southern Ontario. They are often found in moist deciduous forests. Forestry, development, and a highly-invasive species that it confuses with its host plant (Cardamine) are causing this species to decline. Two members of the Cardamine genus Cardamine diphyla and Cardamine concatenata are reported to be its host plants in Alabama.
This small, white semi-transparent butterfly may have no yellowish tinge, but it can have tawny or gray color and hazy brown or pale gray color in the hindwing vein underside. There is only one generation that is produced each year, and they are active adults for a short period of about one month, typically early spring (April or May), when they emerge despite potential dry springs. Similar to the other members of the Brassicaceae family, Cardamine diphylla is a plant that uses chemical elements to attract Pieris virginiensis for pollination. Allaria petiolata is an invasive plant that was introduced into the native habitat of Pieris virginiensis, which causes a rapid decline in Allaria petiolata population. This rapid decline is due to a “mismatch event,” where P. Virginiensis lays its eggs on the invasive plant instead of its host plant, Cardamine diphylla.
Ecological Role
Ecologically, Pieris virginiensis is an important pollinator in forested areas, but it faces competition from the introduced Cabbage White, known as Pieris rapae, which competes for nectar and larval food plants.