Montana Field Guide

[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 2.0-2.8 cm. Tip of forewing squared-off; upperside dark with a wide orange submarginal band grading inward to yellow, forewing cells with two orange to red-orange bars; a narrow black marginal border on both wings upper surface, the hindwing border may contain blue spots; undersurface dark striated brown with paler submarginal band.

One flight in the far north and higher elevations, mostly late July overwintering to June; two flights at lower elevation and in the east, late June to early August and late August overwintering to May (Scott 1986). Mid January to early October in Oregon and Washington with peaks in April to June and July to August (Pyle 2002);

Best determined by a combination of the outer margins irregular with a short tail-like hindwing projection, uppersurface outer third orange grading inward to yellow-orange, a narrow black marginal border on hindwing sometimes including blue spots; undersurface of wings with a pale submarginal band.

Semi-migratory; appears to make seasonal elevational movements in the western US mountains, flying upslope in summer, downslope in autumn (Shapiro 1974, 1979; Scott 1986, 1992; James and Nunnallee 2011). In areas of alpine karst, this species may overwinter in caves (Taylor et al. 2009).

Montane wet meadows, moist streamsides, riparian areas, open woodlands, parks, gardens, above treeline in alpine habitats (Ferris and Brown 1981; Opler and Wright 1999; Glassberg 2001; Pyle 2002). In Glacier National Park, Montana reported from mesic montane meadows and above treeline in alpine habitat (Debinski 1993).

Larval food plants include Urtica in particular (several species), rarely Helianthus, Laportea, Ribes, Salix (Ferris and Brown 1981; Scott 1986, 1992, 2006; Pyle 2002). Adults feed on flower nectar (including Achillea, Allium, Anaphalis, Apocynum, Arctostaphylos, Arnica, Barbarea, Ceanothus, Chrysothamnus, Cirsium, Crypthantha, Erigeron, Erioganum, Erysimum, Helianthella, Heterotheca, Jamesia, Medicago, Monarda, Monardella, Phlox, Prunus, Salix, Sedum, Senecio, Solidago, Taraxacum), sap, fermetted fruit, and mud (Ferris and Brown 1981; Scott 1986, 2014; Pyle 2002; James and Nunnallee 2011).

Females lay eggs in clusters (as many as 713) on the undersides of host plant leaves. Eggs hatch in about 5-7 days (depending on temperature), with pupation occurring 21 days after egg-hatch; 4, 3, 4, 3, and 7 days spent in L1-L5 instars, respectively (depending on temperature). L5 instars pupate away from host plant, adults eclose (emerge) from pupae in 7 days. Larvae gregarious when young, live in a silk nest atop host plant. Older larvae (L4-L5) usually solitary, may live in rolled-up leaves tied with silk; L5 may leave nests and feed openly. Overwinter (hibernate) as pupae or adults (Ferris and Brown 1981; Scott 1986, 1992, 2006; Guppy and Shepard 2001; James and Nunnallee 2011). Spring males perch behind shrubs and on logs mostly in the afternoon and usually on rocky places below hilltops, sometimes on banks where no hilltops are present, to await passing females; hill-topping behavior not noted in autumn (overwintering) males (Scott 1975b, 1982, 1986).