Great Basin Fritillary - Speyeria egleis
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 2.3-3.4 cm. Variable; a small to middle-sized greater fritillary. Uppersurface orange with black spots and bars, dark forewing margins, basal half of wings darkened; undersurface with brown disk (pale to dark brown to greenish) usually mottled in appearance, postmedian silvery spots smaller than in most Speyeria and relatively elongate, marginal spots slightly triangular or rounded with brown or greenish caps.
One flight; late June to mid-August (Scott 1986); June to September (Glassberg 2001); mid-June to early September (Pyle 2002).
Determined by a combination of smoky or hazy dorsal appearance on the upper surface, heavy dark scaling on the basal half of upperwings, under hindwing disk with greenish overtones and red-brown color, smaller size and elongated appearance of postmedian under hindwing spots, underwing marginal spots slightly triangular with brown or greenish caps.
Eastern Washington, Idaho, and western Montana south to southwestern Oregon and northern California in the Cascades, southern California in the Sierra Nevada, central Nevada in the Great Basin, and central Utah and northern Colorado in the Rocky Mountains (Scott 1986, Glassberg 2001; James and Nunallee 2011); 610-3050 m elevation. Throughout the mountainous western third of Montana (Kohler 1980; Stanford and Opler 1993), to at least 2135 m elevation (Ferris and Brown 1981; Debinski 1993). Uncommon to common, sometimes abundant in Sierra Nevada, California (Glassberg 2001); uncommon in Greater Yellowstone Ecosystem (Debinski and Pritchard 2002).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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Varies with subspecies. To high elevation in montane forest openings and meadows, stream banks, exposed rocky ridges, pumice flats (Ferris and Brown 1981; Scott 1986; Pyle 2002; James and Nunnallee 2011). Forest openings and exposed rocky ridges in the Greater Yellowstone Ecosystem (Debinski and Pritchard 2002); montane wet meadows and above treeline in alpine terrain in Glacier National Park (Debinski 1993).
Larval food plants include several species of Viola (Scott 1986; Pyle 2002; James and Nunnallee 2011). Adults feed on flower nectar (including Achillea, Agastache, Apocynum, Calyptridium, Chrysothamnus, Cirsium, Prunus, Senecio) and mud (Ferris and Brown 1981; Pyle 2002; James and Nunnallee 2011; Scott 2014).
Females lay eggs singly on or near host plants. Eggs hatch in about 15 days (depending on temperature), larvae diapause (overwinter) as L1 instars. L1 emerge from diapause in spring and reach L2 in 8 days, another 34 days to pupate, an additional 12 days to eclose (emerge from pupae). Most larval feeding is nocturnal. Larvae are solitary, do not build nests but seek refuge as L1 in curled leaves and dried seedpods; mature larvae silk together leaves as pupation tents close to the ground, many pupae fall to the ground (Scott 1986; James and Nunnallee 2011). Males patrol throughout the day low to the ground in shaded open spaces (including roads) or hilltops as they seek females (Scott 1975b, 1986).
- Literature Cited AboveLegend: View Online Publication
- Debinski, D. 1993. Butterflies of Glacier National Park, Montana. Occasional Papers of the Museum of Natural History, the University of Kansas, Lawrence, Kansas. No. 159: 1-13.
- Debinski, D.M. and J.A. Pritchard. 2002. A field guide to the butterflies of the Greater Yellowstone Ecosystem. Lanham, MD: Roberts Rinehart Publishers. 107 p.
- Ferris, C.D. and F.M. Brown (eds). 1981. Butterflies of the Rocky Mountains. Univ. of Oklahoma Press. Norman. 442 pp.
- Glassberg, J. 2001. Butterflies through Binoculars: A Field Guide to the Butterflies of Western North America. Oxford University Press.
- James, D.G. and D. Nunnallee. 2011. Life histories of Cascadia butterflies. Corvallis, OR: Oregon State University Press. 447 p.
- Kohler, S. 1980. Checklist of Montana Butterflies (Rhopalocera). Journal of the Lepidopterists' Society 34(1): 1-19.
- Opler, P.A. and A.B. Wright. 1999. A field guide to western butterflies. Second edition. Peterson Field Guides. Houghton Mifflin Company, Boston, Massachusetts. 540 pp.
- Pyle, R.M. 2002. The butterflies of Cascadia: a field guide to all the species of Washington, Oregon, and surrounding territories. Seattle Audubon Society, Seattle, Washington. 420 pp.
- Scott, J.A. 1975b. Mate-locating behavior of western North American butterflies. Journal of Research on the Lepidoptera 14:1-40.
- Scott, J.A. 1986. The butterflies of North America: a natural history and field guide. Stanford University Press, Stanford, California.
- Scott, J.A. 2014. Lepidoptera of North America 13. Flower visitation by Colorado butterflies (40,615 records) with a review of the literature on pollination of Colorado plants and butterfly attraction (Lepidoptera: Hersperioidea and Papilionoidea). Contributions of the C.P. Gillette Museum of Arthopod Diversity. Fort Collins, CO: Colorado State University. 190 p.
- Stanford, R.E. and P.A. Opler. 1993. Atlas of western USA butterflies: including adjacent parts of Canada and Mexico. Unpubl. Report. Denver and Fort Collins, Colorado 275 pp.
- Additional ReferencesLegend: View Online Publication
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- Allen, T.J., J.P. Brock, and J. Glassberg. 2005. Caterpillars in the field and garden: a field guide to the butterfly caterpillars of North America. Oxford University Press.
- Brock, J.P. and K. Kaufman. 2003. Kaufman Field Guide to Butterflies of North America. Houghton Mifflin Company, New York, NY 284 pp.
- Caruthers, J.C., and D. Debinski. 2006. Montane meadow butterfly species distributions in the Greater Yellowstone Ecosystem. University of Wyoming National Park Service Research Center Annual Report, 2006. Vol. 30, Art. 14. 85-96.
- Debinski, D. M. 1991. Inventory and monitoring of biodiversity: an assessment of methods and a case study of Glacier National Park, MT. Ph.D. Dissertation. Montana State University, Bozeman. 205 p.
- Fultz, J.E. 2005. Effects of shelterwood management on flower-visiting insects and their floral resources. M.Sc. Thesis. Bozeman, MT: Montana State University. 163 p.
- Layberry, R.A., P.W. Hall, and J.D. LaFontaine. 1998. The Butterflies of Canada. University of Toronto Press. 280 pp. + color plates.
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