Great Basin Wood Nymph - Cercyonis sthenele
[From Ferris and Brown 1981; Scott 1986; Glassberg 2001; Guppy and Shepard 2001; Pyle 2002] Forewing 2.2-2.6 cm. Light to dark brown above, with two dark eyesponts on forewing (upper one larger) with or without yellow rings and pupils (eyespots larger on females); silvery brown underneath, ventral hindwing strongly two-toned and striated (dark inner part, pale outer third often frosted), two ventral forewing eyespots, usually fewer than six small ventral hindwing eyespots.
One flight; mostly late June to early August (mid-June to mid-July in the Coast Ranges)(Scott 1986); mainly July to August, but mid-May to mid-September across range (Glassberg 2001); late June to late September (Pyle 2002); mid-June to mid-September (James and Nunnallee 2011).
Best distinguished by the two large eyespots on the forewing, the rear eyespot smaller than the front one, easiest to see size difference on under forewing; outer portion of under hindwing lighter than inner half, with strong line separating the two areas.
Southern British Columbia south to extreme southern California, extreme northern Arizona and northwestern New Mexico, east to central Montana, western Wyoming, and western Colorado (Scott 1986; Glassberg 2001); to at least 1525 m in the Pacific Northwest (James and Nunnallee 2011). In Montana, found at lower elevations in the montane western third of the state (Kohler 1980; Stanford and Opler 1993). Uncommon to common (Glassberg 2001).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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Lower-elevation arid-zone chaparral, moist canyons, juniper and oak woodlands, ponderosa pine and Douglas-fir woodlands, sagebrush-steppe, rangelands (Scott 1986; Guppy and Shepard 2001; Pyle 2002; James and Nunnallee 2011). Habitat in Montana not described.
Larval food plants are undetermined grasses. Festuca and Poa reported; raised in captivity on Setaria glauca (Ferris and Brown 1981; Guppy and Shepard 2001; Pyle 2002; James and Nunnallee 2011). Adults feed on flower nectar, including Achillea, Asclepias, Chrysothamnus, Cirsium, Eriodictyon, Melilotus, and Solidago (Pyle 2002; James and Nunnallee 2011; Scott 2014).
Limited information. Females lay 100-150 eggs singly on host plant. Eggs hatch in about 5-7 days, L1 instars rest on host plant and enter diapause (overwinter) without feeding. In captivity, development from L1 to adult eclosion lasts 110 days; L1-L5 occupy 26, 10, 8, 12, and 22 days, respectively; pupal stage lasts 32 days before adults emerge (eclose). Larvae feed on grass at night, returned to base of host plant during day; no nests built. Pupate on host plant; adults live 5-10 days in wild (Emmel 1969; Scott 1986; Guppy and Shepard 2001; James and Nunnallee 2011).
- Literature Cited AboveLegend: View Online Publication
- Emmel, T.C. 1969. Taxonomy, distribution and biology of the genus Cercyonis (Satyridae). I. Characteristics of the genus. Journal of the Lepidopterists' Society 23:165-175.
- 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.
- 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. 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.
- 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.
- Maxell, B.A. 2016. Northern Goshawk surveys on the Beartooth, Ashland, and Sioux Districts of the Custer-Gallatin National Forest: 2012-2014. Montana Natural Heritage Program. Helena, MT. 114pp.
- Scott, J.A. 1975b. Mate-locating behavior of western North American butterflies. Journal of Research on the Lepidoptera 14:1-40.
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