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Montana Field Guides

Boisduval's Blue - Icaricia icarioides
Other Names:  Icarioides Blue

Native Species

Global Rank: G5
State Rank: S5

Agency Status

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General Description
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 1.4-1.8 cm. Variable. Uppersurface of male dull lilac-blue with broad black submarginal area on both wings, female brown to blue with diffuse blackish wing borders. Undersurface dark brown to off-white, two bands of roundish to irregular black spots encircled with white on forewing, the postmedian band larger and more prominent than submarginal band, hindwing spots bands often replaced by white areas.

One flight mid-June to mid-August in most of range, June and July in Oregon, April to June in southern California; two flights late May to June and August to early September in Black Forest on Colorado plains (Scott 1986). Mainly May to July but beginning mid-March in lowland California to early September in the north and at high elevation (Glassberg 2001). Early April to early September in Oregon and Washington (Pyle 2002; Warren 2005), mid-May to mid-August in British Columbia (Guppy and Shepard 2001).

Diagnostic Characteristics
Best determined by the undersurface with two bands of roundish to irregular black spots encircled with white on forewing, the postmedian band larger and more prominent than submarginal band, hindwing spots bands often replaced by white areas.

Species Range
Montana Range Range Descriptions


Range Comments
Southern British Columbia east to the western edge of the Great Plains in Alberta and Saskatchewan, south to New Mexico, Arizona, southern California, and Baja California (Scott 1986; Opler and Wright 1999; Glassberg 2001); mostly 1829 m to 3048 m elevation in Rocky Mountain region (Ferris and Brown 1981), 2133 m to 3200 m elevation in Colorado but rare above 3048 m (Brown 1957; Scott and Scott 1978), 26 m to more than 2743 m elevation in Oregon (Warren 2005). In Montana, reported throughout the state except the northeastern 1/6 (Kohler 1980; Stanford and Opler 1993); to at least 2027 m elevation (Downey and Dunn 1964).

Observations in Montana Natural Heritage Program Database
Number of Observations: 12

(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)


Montane meadows, grassy hillsides, prairie, sagebrush flats, chaparral, coastal dunes, fields, roadsides (Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002). In Glacier National Park, Montana reported from xeric and mesic montane meadows (Debinski 1993); in the Greater Yellowstone Ecosystem seen most frequently in drier sagebrush meadows (Debinski and Pritchard 2002; Debinski et al. 2013).

Food Habits
Larval food plants include numerous species of Lupinus, usually the hairiest at any site (Scott 1986, 1992, 2006; Pyle 2002; Warren 2005; James and Nunnallee 2011); specific food plants in Montana include L. arbustus, L. argenteus, L. caudatus, L. leucophyllus, and L. sericeus (Downey and Fuller 1961; Downey and Dunn 1964). Adults feed on flower nectar (including Achillea, Aesculus, Allium, Apocynum, Astragalus, Ceanothus, Erigeron, Eriogonum, Harbouria, Helianthus, Heterotheca, Lupinus, Melilotus, Mentha, Mertensia, Oxytropis, Phacelia, Plantago, Potentilla, Prunus, Salix, Sedum, Senecio, Solidago, Trifolium), sweat, leafhopper honeydew, and mud (Scott 1986, 2014; Pyle 2002; Warren 2005).

Reproductive Characteristics
Females lay eggs singly on host plant leaves (more often on underside than upperside), stems, flowers, seed pods, especially on new growth, sometimes on grass blade near host plant (Scott 1986, 1992, 2006). Number of eggs per ovariole (1/8 of total) 120 (Ehrlich and Ehrlich 1978). Eggs hatch in about 5 days, young larvae eat host plant leaves and reach L2 instar in about 14 days post-hatch, diapause as L2 instar, develop from L2 to L4 instar and pupate in 40 days, adults eclose (emerge from pupae) about 10-14 days later; may rarely overwinter as pupa. Larvae do not build nests, are tended by several species of ants (especially Formica pilicornis), spend the day underground in holes dug by ants, emerge at night to feed, may sometimes be cannibalistic when overcrowded (Scott 1979, 1986; Pyle 2002; James and Nunnallee 2011). Males patrol throughout the day near host plants 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.
    • 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.
    • Debinski, D.M., J.C. Caruthers, D. Cook, J. Crowley, and H. Wickham. 2013. Gradient-based habitat affinities predict species vulnerability to drought. Ecology 94(5): 1036-1045.
    • Downey, J.C. and D.B. Dunn. 1964. Variation in the lycaenid butterfly Plebejus icarioides III. Additional data on food-plant specificity. Ecology 45(1): 172-178.
    • Downey, J.C. and W.C. Fuller. 1961. Variation in Plebejus icarioides (Lycaenidae) I. Foodplant specificity. Journal of the Lepidopterists' Society 15(1): 34-42.
    • Ehrlich, A.H. and P.R. Ehrlich. 1978. Reproductive strategies in the butterflies: I. Mating frequency, plugging, and egg number. Journal of the Kansas Entomological Society 51(4): 666-697.
    • 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. 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.
    • 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
    Do you know of a citation we're missing?
    • 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., R.E. VanNimwegen, and M.E. Jakubauskas. 2006. Quantifying relationships between bird and butterfly community shifts and environmental change. Ecological Applications 16(1): 380-393.
    • 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.
    • Hendricks, P. and M. Roedel. 2001. A faunal survey of the Centennial Valley Sandhills, Beaverhead County, Montana. Report to the U.S. Bureau of Land Management and U.S. Fish and Wildlife Service. Montana Natural Heritage Program, Helena, MT. 44 pp.
    • Opler, P.A., K. Lotts, and T. Naberhaus, coordinators. 2010. Butterflies and moths of North America. Big Sky Institute, Bozeman, MT. Available at: (Accessed 15 June 2015).
    • Simanonok, M.P., and L.A. Burkle. 2014. Partitioning interaction turnover among alpine pollination networks: Spatial temporal, and environmental patterns. Ecosphere 5(11):149.
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Boisduval's Blue — Icaricia icarioides.  Montana Field Guide.  .  Retrieved on , from