The Silver-spotted Skipper is easily distinguishable from all other BC skippers by the presence of a large white area in the centre of the ventral hindwing. Another key characteristic is the median row of yellow spots on the dorsal forewing. The ground colour of the wings is brown. This is the largest skipper in the province, with a forewing length of 2.2-2.7 cm for BC and WA specimens.
Immature Stages
This species has not been reared in BC but the common and conspicuous larvae have often been described elsewhere. Scudder (1889b) gives the best account. The egg has 16-18 ribs and is green with a red spot at the top in eastern North American populations. Eggs from the East Kootenay are white with pink around the micropyle and a band of pink around the middle of the egg (CSG). The mature larval head is dark brownish red, with a bright orange spot between labrum and ocellus on each side of the head. The body is yellow green, with darker green transverse lines.
Subspecies
Specimens from southeastern BC belong to the nominate subspecies, E.c. clarus (TL: Dayton, VA), which is widely distributed in temperate North America. Hinchliff (1996) also recognized E.c. californicus MacNeill, 1975 (TL: China Flat, El Dorado Co., CA). This name applies to the rare individuals that were historically seen on Vancouver Island and the Lower Mainland. They utilize a different larval foodplant, as noted above, and have a slightly different pattern on the ventral hindwing.
Genus Description
The name Epargyreus is derived from the Greek argyros (silvered). referring to the white spot on the ventral hindwing. There is no common name for the genus. Evans (1952) recognized 15 species in this Neotropical genus. The larvae feed on various genera of Fabaceae.
Biology
Adults are on the wing from late May to early August, with peak flight occurring in the first week of July. Eggs are laid singly on the foodplant, hatch within the week, develop into mature larvae by late September, and pupate before winter (Scudder 1889b). There is one brood per year in BC. Further south, the Silver-spotted Skipper is multivoltine. Elsewhere the larvae have been found on a number of woody Fabaceae. J. Pelham (pers.comm.) reared subspecies E.c. californicus on Lotus crassifolius in western Washington. CSG has observed oviposition by subspecies E.c. clarus at the leaf bases of Glycyrrhiza lepidota (wild licorice) at Bummer’s Flats, north of Cranbrook. This plant is one of the two major larval foodplants for this species in the southern Rocky Mountains (Ferris and Brown 1981). In our region, the introduced black locust, Robinia pseudoacacia, is also a likely foodplants for west Kootenay populations.
Habitat
The Silver-spotted Skipper has been recorded from the Gulf Islands, the Lower Mainland, and the southern Kootenays. In the Trail area, it is found in recently established populations in disturbed areas, associated with black locust trees. The Wasa Lake and Bummer's Flats populations are the only known native, permanently breeding populations.
Distribution
Distribution
The Silver-spotted Skipper is found throughout temperate North America. In adjacent PNW states it is recorded from the Puget Sound Trough, the Columbia Basin, and the Rocky Mountains, but not from the Olympic Peninsula, the Cascades, or the Okanogan Highlands, except for one record from near Kettle Falls, WA.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. 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:
2025-03-15 2:00:13 PM]
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