North American Butterflies and Moths List

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Butterflies of North America

Butterflies of Montana

Becker's White (Pontia beckerii)
JPG -- species photo

Becker's White (Pontia beckerii [W. H. Edwards])

Wing span: 1 5/8 - 2 inches (4 - 5 cm).

Identification: Upperside of both male and female is white, with black spots near tip of forewing. Inside the forewing cell is a square black bar with a curved white center. The underside of the hindwing of both sexes has wide green edging along the veins, confined by a white median band.

Life history: Males patrol ravines in search of females. Females lay eggs singly on host stems, buds, leaves, flowers, and fruits.

Flight: Several flights from March-October.

Caterpillar hosts: Plants of mustard (Brassicaceae) family including mustards (Brassica), and hedge mustard (Sisymbrium) species; and bladder-pod (Isomeris arborea) in the caper family (Capparidaceae).

Adult food: Flower nectar including hedge mustard and alfalfa.

Habitat: Arid brushlands, desert foothills and canyons, fields.

Range: British Columbia and Alberta south to Baja California; east of the Cascades and Sierra Nevada, east and south to western Montana and New Mexico.

Conservation: Not required.

Management needs: None required.

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:

Elrod, M.J. 1906. The Butterflies of Montana. Bulletin of the University of
     Montana 30: 1-174.

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.
Becker's White (Pontia beckerii)
distribution map
map legend

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