Montana Field Guide

[From Ferris and Brown 1981; Scott 1986; Layberry et al. 1998; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 1.1-1.2 cm. Small, fringe yellowish. Uppersurface of male yellow-orange and extending along veins, with dark toothed borders and a sinuous forewing stigma; uppersurface of female with heavier dark markings, almost-transparent light spots. Undersurface of hindwing yellow-tan (in some areas chocolate-brown to gray) with yellow veins, pale-yellow to almost white postmedian chevron extending outward along veins and inwardly connected to basal spots, brownish spots between veins at the outer margin with dark spots at the vein ends.

One flight, mostly mid-July to September in California, June to early September in Colorado; several flights, June to early September elsewhere; many flights mid-April to October in lowland California and Nevada (Scott 1986). June to September in one-brood areas, May to September in two-brood areas, April to September in three-brood areas (Glassberg 2001). Late June to mid-July for montane populations, May to September for lower elevation populations in the Rocky Mountain states (Ferris and Brown 1981). Mid-June to early August in Colorado (Scott and Scott 1978), mid-June to mid-August in northern California (Emmel and Emmel 1962; Shapiro 1977), early May to late October on Oregon and Washington (Pyle 2002), mid-May to early October in Oregon (Warren 2005), May to early September in British Columbia (Layberry et al. 1998).

Best determined by a combination of small size, yellowish fringe, undersurface of hindwing yellow-tan (in some areas chocolate-brown to gray) with yellow veins, pale-yellow to almost white postmedian chevron extending outward along veins and inwardly connected to basal spots, brownish spots between veins at the outer margin with dark spots at the vein ends.

Non-migratory.

Alkali grasslands, dry and moist meadows, lawns, parks, salt marshes, sand dunes, sagebrush flats, roadsides, ditch banks, riparian areas, above treeline in alpine terrain (Emmel and Emmel 1962; Shapiro 1977; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002; Warren 2005). Habitat in Montana not described but probably similar.

Larval food plants are native and exotic grasses, including Agrostis, Cynodon, Distichlis, Festuca (multiple species), Hordeum, Poa, Puccinellia, and Sporobolus (Shapiro 1977; Ferris and Brown 1981; Scott 1986, 1992, 2006; Graves and Shapiro 2003), also Setaria in captivity (James and Nunnallee 2011). Adults feed on flower nectar (including Astragalus, Carduus, Centaurea, Chrysothamnus, Cirsium, Cleome, Erigeron, Grindelia, Haplopappus, Helenium, Heterotheca, Machaeranthera, Medicago, Phlox, Polygonum, Solidago, Symphyotrichium, Taraxacum, Trifolium, Verbesina) and mud (Garland 1977; Pyle 2002; Warren 2005; Scott 2014)

Females lay eggs singly on underside of host plant leaf, also on sedges, horsetail, soil near host plant (Scott 1986, 1992, 2006); one captive fall-brood female laid 40 eggs in 7 days (James and Nunnallee 2011). Fall eggs hatch in about 9 days (depending on temperature), develop to L5 instar and pupae in about 43 days (depending on temperature, adults eclose (emerge from pupae) in about 24 days; some larvae enter diapause before pupation. Spring brood eggs hatch in about 6 days, develop to L4 instar and pupae in 63 days, adults eclose (emerge from pupae) in about 35 days (James and Nunnallee 2011). Larvae feed on host plant leaves, live in silk-tied leaf-tube nests, pupate on inert surfaces either vertically or horizontally, enter diapause as pupae (Scott 1979, 1986; James and Nunnallee 2011) but possibly as larvae (Scott 1992; James and Nunnallee 2011). Males perch throughout the day in low grassy areas, on flowers in meadows, on low spots in alkali flats (do not hill top), awaiting passing females (Scott 1975b,1986).