The Persius Duskywing is difficult to distinguish from the species, E. afranius. Refer to the species discussion for E. afranius for details.
Scudder (1889b) gives the only description. The egg has 10-14 ribs, with usually 11 or 12, and is pale yellowish green. The mature larval head is variable in colour but is usually reddish brown with pale, inconspicuous vertical streaks. The body is pale green with numerous white spots.
Specimens from the northern half of BC are probably subspecies borealis Cary, 1907 (TL: "mouth North Nahanni River, Mckenzie"). Placement of the southern populations awaits a thorough knowledge of the foodplants in BC and of the relationship of southeastern BC populations to the Thermopsis-feeding subspecies, fredericki Freeman, 1943, described from SD. In southern BC specimens, the wing pattern contrasts more with the ground colour than in northern populations. We did not attempt to map the putative subspecies ranges.
The name Erynnis is derived from the Erinnyes or Furies who harried wrongdoers (Emmet 1991). Schrank used the generic name for all skippers, and used it to describe the erratic flight characteristic of skippers, as though they were avoiding the Furies. The Erinnyes sprang from the dark, thus the common name "duskywings" in reference to the dark wings. Scudder (1889b) was the first to use the name "duskywings" for the genus.
This and the remaining genera of the Pyrginae have rounded forewing tips, short discal cells, inconspicuous antennal tips, and porrect palpi. The genus Erynnis is distinguished by the mottled black background of the wings, hence the common name "duskywings". This Holarctic genus contains 17 Nearctic and 5 Palearctic species. Five species are found in BC. Closely related genera are all Neotropical. The larvae of this genus have been recorded as feeding on Quercus, Salix, Populus, Ceanothus, and Fabaceae. The various BC species cover this wide range of foodplant preferences, but individual species are restricted to one or a few closely related foodplants. Burns (1964) wrote the definitive work on the genus. Reference to Lindsey et al. (1931) is necessary for drawings of male genitalia, the only reliable structures for distinguishing most species. The shape of the left valve is the critical characteristic.
Adults fly from early May to late June, with peak flight depending on elevation and latitude. Eggs are laid singly on the upper surface of foodplant leaves, hatch within the week, and develop into mature larvae by late July. Mature larvae overwinter and pupate the following spring (Scudder 1889b). Scudder reported a partial second brood in some areas of New England. Burns (1964) reports that the species is univoltine everywhere in its range except California and Oregon. In BC there is only one brood per year. Scudder (1889b) recorded various Salix and Populus species as foodplants. In Arizona, Burns (1964) recorded several ovipositions and partial rearings of "persius" on Thermopsis rhombifolia var. montana. In Saskatchewan, Hooper (1973) found adults associated with Thermopsis rhombifolia and Oxytropis sp., and seldom near Salix. Observations of oviposition by J. Pelham (pers. comm.) indicate that Lupinus arcticus is the foodplant in most of Washington. If southern Rocky Mountain persius are monophagous on Thermopsis sp., as maintained by Ferris and Brown (1981), then there must be a sharp change to another foodplant in BC, as Thermopsis is found only in southeastern BC. Lupinus species appear to be the most likely foodplants in BC.
As presently understood, the Persius Duskywing is the most widely distributed species of Erynnis in BC, having been recorded in every area but the Queen Charlotte Islands. In the southern part of the province, it is usually found in mid- and high-elevation meadows, but is also taken in lower meadows and along low-elevation streams in association with E. icelus. It is usually associated with Lupinus species.
The Persius Duskywing is found across North America from AK to New England. In CAN the species is not found east of MB. South in the Sierras/Cascades and the Rockies it is found in mountainous regions.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2019. E-Fauna BC:
Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab
for Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
2020-06-03 10:25:35 AM]
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