Arrowhead Blue - Glaucopsyche piasus
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 1.4-1.7 cm. Uppersurface of both sexes dull blue with irregular black margins, lack dark cell-end bars, female with variable amounts of orangish scaling toward wing margins. Undersurface wing fringes white, checkered black at tips of veins, a pattern of black spots on gray background, distinctive white patches of submarginal and postmedian arrowhead-shaped marks directed inward toward one outstanding white arrowhead on the disk.
One flight; late May to early July in most of range, late March to May in southern California (Scott 1986). Late March to May in southern and lowland California, May to June and July farther north and at higher elevations (Glassberg 2001). Early April to late August in Oregon and Washington (Pyle 2002, Warren 2005), mid-May to early July in British Columbia (Guppy and Shepard 2001).
Best determined by the hindwing undersurface with distinctive white patches of submarginal and postmedian arrowhead-shaped marks directed inward toward one outstanding white arrowhead on the disk.
Southern British Columbia and Alberta south through the western US mountains to southern California, Nevada, northern Arizona, northwestern New Mexico, east to the Black Hills of South Dakota (Scott 1986; Opler and Wright 1999; Glassberg 2001); mostly 1829 m to 3048 m elevation in Colorado (Brown 1957; Scott and Scott 1978; Ferris and Brown 1981), 60 m to 2438 m elevation in Oregon (Warren 2005), to 1250 m elevation in British Columbia (Guppy and Shepard 2001). Locally rare to uncommon (Glassberg 2001).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
Montane openings, ponderosa pine woodland, sagebrush flats, foothill canyons (Scott 1986; Opler and Wright 1999; Glassberg 2001). In Glacier National Park, Montana reported from subalpine transition areas and above treeline in alpine terrain (Debinski 1993); the report from alpine terrain seems unlikely and may be in error.
Larval food plants include Astragalus and several species of Lupinus (Scott 1986, 1992, 2006; Warren 2005; James and Nunnallee 2011). Adults feed on flower nectar (including Astragalus, Barbarea, Ceanothus, Chrysothamnus, Cirsium, Conium, Cryptantha, Erigeron, Eriogonum, Geranium, Glycrrhiza, Jamesia, Phacelia, Sedum, Senecio), damp ash, and mud (Scott 1986, 2014; Pyle 2002; Warren 2005).
Females lay eggs singly on host plant flower buds, sometimes on leaves and stems (Scott 1986, 1992; James and Nunnalee 2011); larvae feed mostly on host plant flowers and fruits, less often on leaves. Eggs hatch in 2-3 days (depending on temperature), L1 instar burrows into flowers or buds, L2-L4 instars associated with fruits encased in pods. Larvae build no nest, are attended by ants, overwinter as pupae (Scott 1979, 1986; Warren 2005, James and Nunnallee 2011). Males patrol throughout the day near host plants to seek 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.
- 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. 1979. Hibernal diapause of North American Papilionoidea and Hesperioidea. Journal of Research on the Lepidoptera 18(3): 171-200.
- 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.
- 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.
- Kohler, S. 1980. Checklist of Montana Butterflies (Rhopalocera). Journal of the Lepidopterists' Society 34(1): 1-19.
- Layberry, R.A., P.W. Hall, and J.D. LaFontaine. 1998. The Butterflies of Canada. University of Toronto Press. 280 pp. + color plates.
- 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 Sources of Information Related to "Insects"