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Montana Field Guide

Montana Field Guides

Regal Fritillary - Speyeria idalia

Native Species

Global Rank: G3?
State Rank: SNA

Agency Status

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General Description
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001] Forewing 4.2-4.7 cm. Large. Body brownish-black. Uppersurface of forewing reddish-orange with ornate black markings, hindwing velvety black with a postmendian row of white spots and a submarginal row of whitish spots in female, orangish in male; undersurface of forewing similar to uppersurface, hindwing dark and slightly greenish-brown, many elongate whitish spots, lacking pale subterminal band.

One flight; June to early September (Scott 1986). Mainly mid-June to mid-September (Glassberg 2001). Early June to mid-September in northeastern Kansas (Kopper at al. 2011a).

Diagnostic Characteristics
Best determined by the large size, body brownish-black, uppersurface of forewing reddish-orange with ornate black markings, hindwing velvety black with a postmendian row of white spots and a submarginal row of whitish spots in female, orangish in male, undersurface of hindwing dark brown with many elongate whitish spots.

Range Comments
Formerly Manitoba south through plains to central Colorado, Kansas, northeastern Oklahoma, Missouri, and in east from New Brunswick south the northwestern North Carolina. Now rare or absent from areas east of Mississippi River; primarily restricted to midgrass and tall-grass prairie and preserves of the central Great Plains (Scott 1986; Opler and Wright 1999; Kopper et al. 2000; Glassberg 2001). In Montana, documented in the late 19th century from Custer County (Kohler 1980; Stanford and Opler 1993). Rare to uncommon in the west (Glassberg 2001).

Observations in Montana Natural Heritage Program Database
Number of Observations: 1

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Non-migratory; some irregular dispersal westward (Scott 1986) perhaps tied to annual precipitation fluctuations.

Wet meadows, undisturbed prairie near marshes, dry to mesic tallgrass prairie, shortgrass prairie, restored prairie (Ferris and Brown 1981; Scott 1986; Debinski and Babbit 1997; Swengel 1997; Opler and Wright 1999; Glassberg 2001). Habitat in Montana not described, but likely similar.

Food Habits
Larval food plants include several species of Viola (Scott 1986; Swengel 1997). Adults feed on flower nectar, including Apocynum, Asclepias, Calyophus, Carduus, Centaurea, Chrysanthemum, Cirsium, Cornus, Coronilla, Dianthus, Echinacea, Eryngium, Helianthus, Liatris, Lobelia, Medicago, Monarda, Pycnanthemum, Rhus, Rubus, Rudbeckia, Salvia, Shrankia, Trifolium, Vernonia, and Veronica (Kopper et al. 2001a; Tooker et al. 2002; Scott 2014).

Reproductive Characteristics
Females lay eggs singly in shaded sites of grass and forbs near the ground, usually on the undersides of dead vegetation, often near larval food plant but never on it. Larvae build no nests; overwinter (hibernate) as L1 instars (Scott 1986; Kopper et al. 2000, 2001a). Males patrol low (10-50 cm) above the ground for distances of 5-30 m throughout the day in search of females, circling back 1-2 m above ground and repeating the low upwind flight; both sexes take the role of flight while copulating; females mate once, experience a post-mating reproductive diapause before initiating egg-laying (Scott 1986; Kopper et al. 2001a, 2001b).

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Citation for data on this website:
Regal Fritillary — Speyeria idalia.  Montana Field Guide.  .  Retrieved on , from