Regal Fritillary (Speyeria idalia) Identification: Large. Upperside of forewing bright red-orange with black markings. Upperside of hindwing black with postmedian row of white spots; submarginal row of spots is orange in male and white in female.
Regal Fritillary (Speyeria idalia) Wing Span: 2 5/8 - 4 1/8 inches (6.7 - 10.5 cm).
Regal Fritillary (Speyeria idalia) Life History: The regal fritillary population size seems to fluctuate. In some years individuals will be abundant and will scatter more widely while in other years, they are scarce. There is a single annual generation in this species. In South Dakota the first males appear in mid-June and fly until August, while the females flight period is early July to mid-September. The light brown eggs are laid near violets. After hatching, the unfed caterpillars over-winter beneath leaves on the ground. In spring, as temperatures rise, the larvae begin feeding on the leaves of violets. They are nocturnal feeders, staying hidden during the day. Mature larvae are velvety black with dull yellow to reddish orange stripes and six rows of tapering, fleshy spines. When full grown, the caterpillars shed their skin and form a light brown chrysalis with black spots. About two weeks later, the chrysalis splits open and the adult emerges.
Regal Fritillary (Speyeria idalia) Flight: One brood from mid-June to mid-August.
Regal Fritillary (Speyeria idalia) Caterpillar Hosts: Larvae feed on violets, including prairie violet.
Adult Food: Nectar from flowers of milkweeds, thistles, red clover, and mountain mint.
Habitat: Tall-grass prairie and other open sites including damp meadows, marshes, wet fields, and mountain pastures.
Range: The historical range of Speyeria idalia extended from the Maritime Provinces of Canada south through the New England states to North Carolina and west across the northern half of the U. S. to eastern Colorado and Montana. The species no longer occurs in the Maritimes or much of New England and is rapidly declining in most of its remaining range except the
Conservation: Rapidly vanishing or declining in much of its range. A species of concern for the United States Fish and Wildlife Service. All populations should be conserved.
NCGR: G3 - Very rare or local throughout its range or found locally in a restricted range (21 to 100 occurrences). (Threatened throughout its range).
Management Needs: Monitor populations and manage populations on public lands and preserves.
Source: Gary Marrone, HCR-33, Box 4C, Ft. Pierre, SD 57532. 1992.