Great Basin Fritillary (Speyeria egleis [Behr])
Wing span: 1 3/4 - 2 3/8 inches (4.5 - 6 cm).
Identification: Upperside bright to dull orange-brown with dark markings evenly spaced. Underside of hindwing has triangular, silver submarginal spots; other spots small with brown edging; spots may or may not be silvered.
Life history: Males patrol during the day for females, who lay eggs on leaf litter near violets. First-stage caterpillars hibernate unfed until spring, when they feed on violet leaves.
Flight: One brood from late June-August.
Caterpillar hosts: Violets including Viola adunca, V. nuttallii, V. purpurea, and V. walteri.
Adult food: Flower nectar.
Habitat: Mountain meadows, forest openings, exposed rocky ridges.
Range: North Dakota southwest through Oregon to California, south to Colorado.
Conservation: Not usually of concern but subspecies tehachapina has a very small range and could be devastated by a single event.
Speyeria egleis tehachapina has The Nature Conservancy rank of T3 -Very rare or local throughout its range or found locally in a restricted range (21 to 100 occurrences). (Threatened throughout its range).
Speyeria egleis as a whole has the The Nature Conservancy Global Rank of G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.
Management needs: Monitor subspecies tehachapina and evaluate for conservation action.
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
State and Regional References:
Brown, F.M., Eff, J.D., and B. Rotger. 1957. Colorado Butterflies. Denver Museum of Natural History, Denver. Ferris, C.D. and F.M. Brown. 1980. Butterflies of the Rocky Mountain States. University of Oklahoma Press. Norman. Layberry, R.A., Hall, P.W. & Lafontaine, D.J., 1998. The Butterflies of Canada. University of Toronto Press, Toronto, ON. 280 pp. Opler, Paul A. 1999. Peterson Field Guide to Western Butterflies, revised edition. Houghton Mifflin Co., Boston, Mass. Stanford, R.E. and P.A. Opler. 1993. Atlas of Western USA Butterflies. Privately published, Denver, Colo. Tilden, J.W. and A.C. Smith. 1986. A Field Guide to Western Butterflies. Houghton Mifflin Co., Boston, Mass.