Northwestern Fritillary - Speyeria hesperis
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 2.2-3.2 cm. Forewing pointed in some populations. Eyes blue-gray. Uppersurface of forewing borders usually black, males with swollen black areas along forewing veins; undersurface of hindwing fairly evenly colored red-brown to orange-brown basal disk, spots either silvered or unsilvered.
One flight; late June to August (Scott 1986), mid-June to mid-September (Glassberg 2001). Mid-June to early September in Oregon and Washington (Pyle 2002; Warren 2005); late June to early August in British Columbia (Guppy and Shepard 2001).
Best determined by the uppersurface forewing border usually black; undersurface of hindwing basal disk fairly evenly colored red-brown to orange-brown, spots either silvered or unsilvered; eyes blue-gray.
Alaska, central Yukon, southwestern Northwest Territories (MacKenzie River drainage) south in the Cascades and Sierra Nevada to central California, in the Rocky Mountains to central Arizona and southern New Mexico, east to southwestern Manitoba; also the Black Hills, South Dakota (Opler and Wright 1999): to 2440 m elevation in Oregon (Warren 2005), to 3260 m elevation in Colorado (Brown 1957; Scott and Scott 1978). In Montana, probably reported from the western 2/3 of the state (Kohler 1980; Stanford and Opler 1993), but needs review due to contentious taxonomy with S. atlantis, with which it was formerly included (Warren 2005). Mainly common to abundant (Glassberg 2001).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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Moist and mesic montane meadows, forests, gulches, along creeks, valley bottoms (Scott and Scott 1978; Scott 1986; Opler and Wright 1999; Glassberg 2001; Guppy and Shepard 2001; Pyle 2002; Warren 2005). In Glacier National Park, Montana reported from xeric and mesic montane meadows (Debinski 1993).
Larval food plants include several species of Viola (Scott 1986, 1992, 2006; Warren 2005; James and Nunnallee 2011). Adults feed on flower nectar (including Achillea, Agastache, Agoseris, Anaphalis, Anemone, Apocynum, Arctium, Arnica, Asclepias, Buddleia, Carduus, Ceanothus, Centaurea, Chrysothamnus, Cirsium, Clematis, Conium, Dipsacus, Erigeron, Erioganum, Euphorbia, Gaillardia, Geranium, Grindelia, Haplopappus, Heracleum, Heterotheca, Holodiscus, Jamesia, Liatris, Monarda, Nepeta, Physocarpus, Prunus, Rhus, Rudbeckia, Sedum, Senecio, Solidago, Symphoricarpos, Symphyotrichum, Taraxacum, Trifolium, Viguiera), tree sap, dung, and mud (Scott 1986, 2014).
Females lay eggs eggs singly and haphazardly in shaded litter on the undersides of dried leaves, pine needles, stems, other debris near host plant (Scott 1986, 1992, 2006). Eggs hatch in 5-18 days (depending on temperature), L1 instars overwinter (diapause) without feeding. Development after diapause to L6 instar and pupation takes about 22 days, another 17 days to adult emergence from pupae (eclosion). Larvae nocturnal, build no nest (Scott 1986; James and Nunnallee 2011). Males patrol throughout the day in open areas, especially moist valley bottoms and along streams, in search of females (Scott 1975b, 1986).
- Literature Cited AboveLegend: View Online Publication
- Brown, F.M. 1957. Colorado Butterflies. Proceedings; Numbers Three through Seven. Denver Museum of Natural History, Denver, Co.
- 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.
- 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.
- Guppy, C.S. and J.H. Shepard. 2001. Butterflies of British Columbia: including western Alberta, southern Yukon, the Alaska Panhandle, Washington, northern Oregon, northern Idaho, northwestern Montana. UBC Press (Vancouver, BC) and Royal British Columbia Museum (Victoria, BC). 414 pp.
- 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. 1992. Hostplant records for butterflies and skippers (mostly from Colorado) 1959-1992, with new life histories and notes on oviposition, immatures, and ecology. Papilio new series #6. 185 p.
- Scott, J.A. 2006. Butterfly hostplant records, 1992-2005, with a treatise on the evolution of Erynnis, and a note on new terminology for mate-locating behavior. Papilio new series #14. 74 p.
- 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.
- Scott, J.A. and G.R. Scott. 1978. Ecology and distribution of the butterflies of southern central Colorado. Journal of Research on the Lepidoptera 17(2): 73-128.
- 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.
- Warren, A.D. 2005. Lepidoptera of North America 6: Butterflies of Oregon, their taxonomy, distribution, and biology. Contributions of the C. P. Gillette Museum of Arthropod Diversity, Colorado State University. Fort Collins, Colorado. 406 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.
- 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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