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Montana Field Guides

Afranius Duskywing - Erynnis afranius


Global Rank: G5
State Rank: S5

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General Description
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 1.3-1.8 cm. Hindwing fringes pale-tipped. Upperside brownish-black, the forewing with scattering of flat white scales and several clear spots, not hairy. Male with brownish patch just distal to forewing cell, a costal fold containing yellow scent scales; female with a patch of scent scales on 7th abdominal segment.

Phenology
Two flights, mostly May to early August; several flights March to August in southern California (Scott 1986). March to May and late June to September (Glassberg 2001). April to May and July to September in the Rocky Mountain states (Ferris and Brown 1981), late April to late May and early July to early September in Colorado (Scott and Scott 1978), April to early June and early July to September in the Pacific Northwest (Pyle 2002).

Diagnostic Characteristics
The duskywing skippers (genus Erynnis) can be a challenge to identify, particularly in prairie habitat where all three species may occur together. The white spots in the forewing tip are useful characters for separating these species.

The Afranius Duskwing and the Persius Duskywing (Erynnis persius) both have at least two (usually three or four) spots, while the Dreamy Duskywing (Erynnis icelus) has only one spot or none at all. The Afranius Duskywing is more difficult to separate from the Persius Duskywing. The Afranius Duskywing is more brown in colour, not grey, and the fore- and hindwing do not contrast grey (forewing) and grey-brown (hindwing) to the same extent that the Persius Duskywing does. Individuals from a short-grass prairie habitat in August are almost certainly the Afranius Duskywing, since the Persius Duskywing does not have a second brood (Schmidt no date). Uncertain specimens must be dissected for diagnostic characteristics of the male genitalia; see Scott (1986) and Guppy and Shepard (2001) for illustrations.


Species Range
Montana Range

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Range Comments
Southern Alberta south in Rocky Mountain states to central Mexico, west in the north to northern Idaho, in the south through northern New Mexico and northern Arizona to southern California, east to southern Saskatchewan and Manitoba, western Dakotas, western Nebraska, the high prairies of Colorado and New Mexico; isolated population in central Alaska and adjacent Yukon Territory (Scott 1986; Opler and Wright 1999; Glassberg 2001); usually below 2438 m elevation in the Rocky Mountain states (Ferris and Brown 1981), 1676 m to 2134 m elevation Colorado, but reported to 3658 m (Brown 1957; Scott and Scott 1978). In Montana, reported from across the state in at least 40 counties (Kohler 1980; Stanford and Opler 1993; FLMNH Lepidopterists' Society database), to at least 1311 m elevation, but Kohler (personal communication, 5 March 2017) states "It has not been recorded from west of the Divide. Many E. persius have been misidentified as E. afranius." Considered a relict of extensive montane coniferous forest climax in the western Great Plains following recession of the Pleistocene glaciers (Johnson 1975). Uncomon to common (Glassberg 2001).

Summary of Observations Submitted for Montana
Number of Observations: 1

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Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Migration
Non-migratory.

Habitat
Prairie hills, canyons, badlands, chaparral, open conifer woodlands, meadows, edges, stream corridors, tundra (Johnson 1975; Scott 1986; Opler and Wright 1999; Glassberg 2001). Habitat in Montana not described but probably similar.

Food Habits
Larval food plants are various legumes including Astragalus (multiple species), Lotus, Lupinus (multiple species), and Thermopsis (Ferris and Brown 1981; Scott 1986, 1992, 2006; Pyle 2002). Adults feed on flower nectar (including Allium, Apocynum, Campanula, Cirsium, Convolvylus, Grindelia, Heterotheca, Hymenoxys, Lathyrus, Lesquerella, Lupinus, Marrubium, Medicago, Melilotus, Monarda, Oxytropis, Penstemon, Psoralea, Senecio, Solidago, Symphoricarpos, Taraxacum, Thermopsis, Thlaspi, Verbena) and mud (Scott 1986, 2014).

Reproductive Characteristics
Limited information. Females lay eggs singly on the undersides of host plant leaves, mostly near base of young leaves. Larvae eat host plant leaves, live in nests of rolled or silk-tied leaves, develop to mature larvae (L4 or L5 instar), hibernate (overwinter) as mature larvae (in a leaf nest), pupate between leaves tied with silk (Scott 1986, 1992, 2006). Males perch all day in gullies and swales awating passing females (Scott 1975b, 1986).

References
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Citation for data on this website:
Afranius Duskywing — Erynnis afranius.  Montana Field Guide.  .  Retrieved on , from