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Montana Field Guide

Montana Field Guides

Nelson's Hairstreak - Callophrys nelsoni

Native Species

Global Rank: G5T5
State Rank: SNR

Agency Status


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General Description
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 1.2-1.3 cm. Single-tailed. Uppersurface brown to orange-brown; undersurface orange-brown sometimes with a purplish sheen, with or without partial white submedian band, faint submarginal spots on hindwings dark to bluish-gray, only weakly two-toned and darker basally.

One flight; mostly mid-May to June but as early as April or as late as July (Scott 1986). Mid-April to early August but mainly mid-May to mid-July (Glassberg 2001). Late March to early August in Oregon and Washington (Pyle 2002), late April to early August in Oregon (Warren 2005), late April to late June in British Columbia (Threatful 1988; Guppy and Shepard 2001).

Diagnostic Characteristics
Best determined by undersurface orange-brown sometimes with a purplish sheen, with or without partial white submedian band, only weakly two-toned and darker basally.

Species Range
Montana Range


Range Comments
Southern British Columbia south through Cascades, Coast Ranges, Sierra Nevada to southern California, east through northern Idaho to extreme western Montana (Opler and Wright 1999; Glassberg 2001); 60 m to at least 1036 m elevation in Oregon (Warren 2005), to at least 457 m elevation in southeastern British Columbia (Threatful 1988). In Montana, reported from Lincoln, Mineral, Ravalli, and Sanders counties bordering Idaho (Kohler 1980; Stanford and Opler 1993). Abundant (Glassberg 2001). Taxonomy remains unstable and confusing, compounded by unintended introductions on host plants used in ornamental plantings; some authorities treat nelsoni as a subspecies of Callophrus gryneus (Johnson 1976, 1978; Pyle 2002; Warren 2005).

Non-migratory. Dispersal movements of a few kilometers possible (Scott 1986).

Mixed conifer forests with incense-cedar (Calocedrus decurrens) or western redcedar (Thuja plicata), damp roadsides, and old fields (Threatful 1988; Opler and Wright 1999; Glassberg 2001; Pyle 2002). Habitat in Montana not described, but range overlaps that of western redcedar and indicates it is likely similar.

Food Habits
Larval food plants include Calocedrus, Juniperus, Thuja (the primary host plant in Montana and Idaho), and Tsuga (Johnson 1976; Scott 1986, 1992; Pyle 2002; Warren 2005). Adults feed on flower nectar (including Achillea, Cryptantha, Mimulus, Myosotis, Potentilla, Rubus, Senecio, Taraxacum, Trifolium), honeydew, and mud (Pyle 2002; Warren 2005; James and Nunnallee 2011; Scott 2014).

Reproductive Characteristics
Females lay eggs singly on host plant foliage tips, either the top or underneath, especially new growth (Scott 1986; James and Nunnalee 2011). Eggs hatch in about 5-6 days, larvae develop from L1 instar to L4 instar and pupate in about 39 days. Larvae build no nest, feed on new spring-growth terminal needles, may go through 5 larval instars in some populations, are solitary, possibly cannibalistic if crowded, probably pupate high in trees, pupae overwinter (diapause)(Scott 1979, 1986; James and Nunnallee 2011). Males perch throughout the day on tops and sides of host trees, more often on ridges than in valleys, to await passing females (Scott 1975b; 1986).

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Citation for data on this website:
Nelson's Hairstreak — Callophrys nelsoni.  Montana Field Guide.  .  Retrieved on , from