Montana Field Guide

[From Ferris and Brown 1981; Scott 1986; Layberry et al. 1998; Opler and Wright 1999; Glassberg 2001] Forewing 1.5-1.6 cm. Uppersurface yellow-orange with broad dark-gray borders, male forewing stigma black with yellow interior felt; undersurface of hindwing orange-brown with white bar at base of discal cell, white postmedian spots (6) usually in a complete chevron, posterior arm of 4 spots straight and more or less parallel to wing margin.

One flight, mostly mid-June to early July in the north (late June through July at high elevation); several flights in the south, mid-April to mid-October (Scott 1986). May through July in one brood areas, Aril to October in two brood areas (Glassberg 2001), June to early July in Canada (Layberry et al. 1998), late May through July in the Rocky Mountain states (Ferris and Brown 1981), early June to mid-August in Colorado (Scott and Scott 1978), April to November in Arizona (Bailowitz 1988), late June to late August in western Nebraska (Johnson and Nixon 1967), early June to late July in North Dakota (McCabe and Post 1976).

Best determined by a combination of uppersurface with dark gray rather than blackish border, male forewing stigma black with yellow interior felt, undersurface of hindwing with white bar at base of discal cell, white postmedian spots (6) usually in a complete chevron, posterior arm of 4 spots straight and more or less parallel to wing margin.

Non-migratory. Typically move about 200 m as adult, perhaps as much as 1000 m (Scott 1973, 1975c, 1986; Bock et al. 2007).

Foothill prairie, desert grassland, oak grassland, open pine woodland (Ferris and Brown 1981; Scott 1986; Bailowitz 1988; Layberry et al. 1998; Opler and Wright 1999; Glassberg 2001); a Pleistocene relict in formerly-extensive montane coniferous forest on the Northern Great Plains (Johnson 1975). Habitat in Montana not described but probably similar.

Larval food plants are grasses, including Bouteloua gracilus and Erioneuron pulchellum (Scott 1973, 1986, 1992; Ferris and Brown 1981; Layberry et al. 1998). Adults feed on flower nectar (including Asclepias, Astragalus, Baccharis, Carduus, Cirsium, Cleome, Cryptantha, Descurainia, Erigeron, Eriogonum, Erysimum, Hedysarum, Heterotheca, Hymenopappus, Jamesia, Leucelene, Linaria, Machaeranthera, Melilotus, Mirabilis, Monarda, Opuntia, Oxytropis, Penstemon, Polygonum, Sedum, Senecio, Symphoricarpos, Symphyotrichum, Thamnosma, Thermopsis, Trifolium, Zinnia) and mud (Scott 1973, 2014).

Limited information. Adult lifespan typically less than 7 days, but up to 10 days. Females lay eggs singly on undersurface of host plant leaf or near host plant. Larvae build silk-tied leaf-tube nests, feed on host plant leaves, hibernate as half-grown (L3 or L4 instar?) larvae (Scott 1973, 1979, 1986, 1992). Males perch on rocks and low plants throughout the day on hilltops and ridge crests awaiting passing females (Scott 1973, 1975b, 1986).