Northern Marble (Euchloe creusa [Doubleday])
Wing span: 1 3/8 - 1 5/8 inches (3.5 - 4.2 cm).
Identification: Pale markings at tip of upperside of front wing; cell bar narrow. Fore- and hindwing bases dark on the uppersides.
Underside of hindwing with considerable "fractured" dark marbling.
Life history: Females lay single eggs on host plant flower buds; caterpillars eat flowers and fruits. Chrysalids hibernate.
Flight: One flight from May-July.
Caterpillar hosts: Plants of the mustard (Brassicaceae) family.
Adult food: Flower nectar. Specific plants not reported.
Habitat: Mountains, rocky outcrops, trails, roadsides.
Range: Alaska south and east to British Columbia, Alberta, and Saskatchewan. Northern Montana in Glacier National Park.
Conservation: Widespread in Alaska, but very restricted in lower 48 states.
Management needs: Study habitat requirements and manage accordingly.
The Nature Conservancy Global Rank: G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.
References:
Opler, P. A. 1968. Studies on nearctic Euchloe. Part 5. Distribution. Journal of Research on the Lepidoptera 7(2): 65-86. Opler, P. A. 1969 (1970). Studies on nearctic Euchloe. Part 6. Systematic of adults. Journal of Research on the Lepidoptera 8(4): 153-168. Opler, P. A. 1974. Studies on nearctic Euchloe. Part 7. Comparative life histories, hosts, and the morphology of immature stages. Journal of Research on the Lepidoptera 13(1): 1-20. Scott, J. A. 1986. The butterflies of North America. Stanford University Press, Stanford, Calif. 583 pages, 64 color plates. Tilden, J. W. 1986. A field guide to western butterflies. Houghton-Mifflin Co., Boston, Mass. 370 pages, 23 color plates.
Author: Jane M. Struttmann