Montana Field Guide

Treated as a subspecies of Polygonia gracilis (Hoary Comma) with a broad region of intergradation (Scott 1984, 1986); earlier authors considered it a separate species. See the Hoary Comma entry for the full account. The following is slightly modified from that species account to reflect this subspecies.

[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002) Forewing 2.3-2.7 cm. Uppersurface hindwing lacking black spot in middle of wing, but with yellow submarginal spots in dark band, the spots running together posteriorly to form a band; undersurface gray-brown, outer half distinctly pale, often hoary-white or silver-gray, comma mark on under hindwing abruptly curved in shape of an unbarbed fishhook.

One flight in the north; in August and overwintering until June. Two flights farther south (Colorado, Nevada); late June to early August and late August overwintering until May. Possibly three flights in California (Scott 1986). Mid-March to early October with peaks in May and August in the Oregon and Washington (Pyle 2002; James and Nunnallee 2011); July and August overwintering to May and June in British Columbia (Guppy and Shepard 2001).

Best determined by a combination of uppersurface hindwing lacking black spot in middle of wing, upper hindwing with yellow submarginal spots in dark band and the spots running together posteriorly; undersurface two-toned with outer half paler. P. g. zephyrus with less two-toned undersurface than P. g. gracilis, yellow submarginal spots enlarged and blended more into median color on hindwing uppersurface than P. g. gracilis (Scott 1984, 1986).

Elevational migrant; appears to fly to higher elevations in summer, returning to lower elevations in autumn where it hibernates (Scott 1986; Pyle 2002; James and Nunnallee 2011).

Montane dry and wet meadows, along streams, roads, trails, subalpine conifer forest, riparian woodland, towns, prairie, to above treeline in alpine tundra and on summits (Emmel 1964; Scott 1986; Opler and Wright 1999; Guppy and Shepard 2001; Pyle 2002; James and Nunnallee 2011). In Glacier National Park, Montana reported from mesic meadows and high elevation subalpine-alpine ecotones (Debinski 1993).

Larval food plants include Menziesia, Rhododendron, Ribes (several species), and Ulmus (Scott 1986; Pyle 2002; James and Nunnallee 2011); Alnus and Salix reported in British Columbia for P. g. gracilis (Guppy and Shepard 2001). Adults feed on flower nectar (including Anaphalis, Antennaria, Apocynum, Arctostaphylos, Arnica, Aster, Barbarea, Berberis, Calyptridium, Ceanothus, Centaurea, Chrusothamnus, Cirsium, Erigeron, Erioganum, Erysimum, Geranium, Jamesia, Physocarpus, Potentilla, Prunus, Ribes, Rubus, Rudbeckia, Salix, Sedum, Senecio, Solidago, Taraxacum, Thermopsis, Thlaspi, Wyethia), rotten fruit, sap, aphid honeydew, mud, and dung (Emmel 1964; Scott 2014).

Females lay eggs singly or in groups of 3-4 usually on undersides of host plant leaves. Eggs hatch in 4-5 days (depending on temperature) and develop to pupation in another 25 days, each instar averaging 5 days. Larvae rest on host plant stems or leaves when not feeding, usually on the undersides; do not construct shelters or nests but feed openly. Adults emerge from pupae after about 9 days; overwinter (hibernate) as adults (Scott 1992; James and Nunnallee 2011). Males perch mostly in afternoon on bushes or shrubs, stones, logs in gullies and valley bottoms waiting for females to pass nearby (Scott 1975b, 1986).

Subspecies status still debated; currently treated as a subspecies of Polygonia gracilis (Hoary Comma) with a broad region of intergradation (Scott 1984, 1986). Steve Kohler recommended treating this subspecies as a full species. P. g. zephyrus and P. g. gracilis are distinguishable morphologically at the extremes of their ranges (zephyrus west; gracilis east), but intermediates exist in between. Genetics, thus far, has not made a clear division between them and they may be merging or diverging (see A09WAH01MTUS).