Montana Field Guide

Some authorities elevate the subspecies Hesperopsis alpheus gracielae (MacNeill's Sootywing) to full species status (MacNeill 1970; Ferris and Brown 1981; Opler and Wright 1999), other authorities do not (Scott 1986; Glassberg 2001). The following account includes gracielae as a subspecies of H. alpheus.

[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001] Forewing 1.1-1,4 cm. Small, fringes checkered at least on forewing. Uppersurface of forewing dark grayish-brown (frosted) with series of tiny white spots at base of darker discal dashes; undersurface of hindwing dark brown, usually with white bar in middle.

One flight, mostly April to mid-June (June at higher elevation) across much of range; multiple flights, April to November in the south (Scott 1986). May to July in one flight areas, May to mid-September in two flight areas (March to June in California and southern Nevada)(Glassberg 2001). May to September (June and July at higher elevation) in the Rocky Mountain states (Ferris and Brown 1981), mid-May to early August in Colorado (Scott and Scott 1978).

Best determined by a combination of habitat and flight behavior (moth-like and through shrub canopy), small size, dark color, checkered wing fringes, uppersurface of forewing with series of tiny white spots at base of darker discal dashes; undersurface of hindwing dark brown, usually with white bar in middle.

Non-migratory. Hesperopsis alpheus gracielae apparently fail to cross habitat gaps of 30-160 km (Pratt and Wiesenborn 2011).

Saltbush alkali flats, arid canyons, dry washes and ditches, riparian corridors (Scott 1986; Opler and Wright 1999; Glassberg 2001), often in native or mixed native-exotic riparian vegetation where exotic trees or shrubs (Tamarix in particular) not dominant (Nelson 2007; Nelson and Wydoski 2008; Pratt and Wiesenborn 2011). Habitat in Montana not described but probably similar.

Limited information. Larval food plants are shrubs in the Chenopodiaceae, including Atriplex (multiple species) and Chenopodium (Ferris and Brown 1981; Scott 1986, 1992; Pratt and Wiesenborn 2011). Adults feed on flower nectar (including Erigeron, Heliotropium, Malvella, Medicago, Pluchea, Portulaca, Prosopis, Psorelea, Sesuvium, Tamarix), possibly honeydew (Scott and Scott 1978; Scott 2014; Pratt and Wiesenborn 2009, 2011).

Limited information. Females lay eggs singly or in small loose cluster on host plant leaf. Larvae feed on host plant leaves, live in silk-tied rolled-leaf nests, feed primarily nocturnally, pupate on host plant leaf possibly in leaf litter beneath host plant (Scott 1986; Pratt and Wiesenborn 2009, 2011). Males patrol throughout the day in gullies, around host plant, in search of females (Scott 1975b, 1986; Pratt and Wiesenborn 2009).