Spring White (Pontia sisymbrii [Boisduval])
Wing span: 1 1/4 - 1 3/4 inches (3 - 4.5 cm).
Identification: Upperside of both wings with dark veins on white to creamy yellow background; front wing cell bar is narrow. Veins of underside of hindwing may be edged widely with olive.
Life history: Males patrol hilltops, ridges, or bottoms of canyons in search of females. Eggs are laid singly on any part of the host plants. Young caterpillars feed on leaves, older ones on flowers. Chrysalids hibernate.
Flight: One flight from February-July.
Caterpillar hosts: Plants in the mustard family (Brassicaceae) including hedge mustard (Sisymbrium), rock cresses (Arabis), and tansy-mustard (Descurainia) species.
Adult food: Not reported.
Habitat: Desert hills and other dry slopes, rocky canyons and outcrops, roadsides, open coniferous forests.
Range: British Columbia south to Baja California, east to western Nebraska and western South Dakota.
Conservation: Not usually required.
Management needs: None noted.
The Nature Conservancy Global Rank: G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.
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:
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.