Speyeria edwardsii
Edwards’ Fritillary

Family Description:
Alternate Common Name:
Green Fritillary.
Caterpillar: The caterpillar is yellow on top and gray mottled with orange on the sides. It is covered with both greenish and yellow spines, with a white-ringed black patch at the base of each. The head is dark brown and the region behind the head is yellow.
Adult: The Fritillaries as a group are very similar in appearance, and the differences between individual species are often minor and difficult to see. Positive identification to the species level is difficult and requires detailed examination. This is a large Fritillary, with a wingspan of 2 3/8 to 3 3/8 inches. The upperside ranges from golden orange to orange, and is edged with a thick black line spotted with yellow. The bases of the wings may appear clouded with brown. The forewing is marked with four to five short, wavy black lines on the leading edge, most of which are nearly parallel. A thick, wavy black line runs vertically across the center of the wing, followed by a row of black spots. The wing veins are outlined thinly in black. The hindwing is marked similarly. Underneath, the forewing is rosy orange near the base, light yellow towards the tip, and bordered with olive green. It is marked with brown as above, and additionally with silver spots or triangles in the border and at the tip. The underside of the hindwing is yellowish olive green and is marked with brown wing veins and many large silver spots. A curved row of flattened silver spots lines the edge.

This species of Fritillary has a fairly small range, from southern Alberta and Manitoba south to northern New Mexico. It has been documented to occur in Idaho only in Franklin County.

It occurs in prairies and grasslands, forest openings, and chaparral.


Caterpillar: Caterpillars feed on the leaves of violets (Viola spp.), especially V. adunca and V. nuttallii.
Adult: Butterflies drink flower nectar, often from thistles (Cirsium spp.) and dogbane (Apocynum spp.), and may obtain additional moisture and nutrients from dung.

There is one new generation of caterpillars each year. Eggs hatch in the fall; the newly emerged caterpillars, having not yet fed, enter a physiological state called diapause to overwinter. In the spring the young caterpillars feed on the new leaves of host plants. Adults generally fly from mid-May through late October. Fritillaries are long-lived for a butterfly, surviving several weeks to months.

Males patrol in search of receptive females in open areas. pheromones, chemicals used to locate and attract the opposite sex, are produced by both male and female Fritillaries. These chemicals are believed to play an important role in assisting these butterflies to find and recognize other members of their own species. Eggs are laid singly near host plants. In cases where the violet plant has already withered and blown away, females are still able to lay their eggs near to where the host plant will reappear the next spring. This is possible, it is believed, because females are able to locate violet roots by smell!

Idaho Status: Unprotected nongame species.
Global Rank:

G5; populations are widespread, abundant, and secure.

Ferris, C.D. and F.M. Brown (eds.) 1981. Butterflies of the Rocky Mountain States. Univ. of Oklahoma Press, Norman, Oklahoma, USA, 442 pp.

Opler, P. A., H. Pavulaan, and R. E. Stanford. 1995. Butterflies of North America. Jamestown, North Dakota, USA: Northern Prairie Wildlife Research Center Home Page. http://www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/bflyusa.htm (Version 05Nov98).

Opler, P. A. and A. B.Wright. 1999. A Field Guide to the Western Butterflies. Second Edition.  Peterson Field Guide Series. Houghton Mifflin Company, New York, New York, USA, 540 pp.

Pyle, R. M. 1981. National Audubon Society Field Guide to North American Butterflies. Alfred A. Knopf, Inc., New York, New York, USA, 924 pp.

Scott, J. A. 1986. The Butterflies of North America. Stanford University Press, Stanford, California, USA, 583 pp.

Stanford, R. E. and P. A. Opler. 1993. Atlas of Western U.S.A. Butterflies (Including Adjacent Parts of Canada and Mexico). Published by authors, Denver, Colorado, USA, 275 pp.