Great Arctics are large, golden brown butterflies with dark wing borders. They have two eyespots on the dorsal forewing and one on the dorsal hindwing. The ventral hindwings are mottled grey and brown, without a distinct band crossing the wing. Males have a large dark stigma, a patch of sex pheromone scales, covering the forewing discal cell. There are white patches along the margin of the hindwings, which gives a scalloped appearance to the wing edge. In females the dorsal forewing is heavily dusted with grey scales out to at least half, and frequently three-quarters, of the discal cell.
Eggs from Mt. Finlayson, near Goldstream on Vancouver Island, are subconical and have 18-19 vertical ribs. First instar larvae are initially pale red grey and then turn white green, and have two short tails. There is a narrow red brown dorsal and subdorsal line, and a broad red brown lateral band. The basal ridge is lighter than the ground colour, and there is a fine brown line under it. The head, underside, legs, and prolegs are green yellow with a brown tint (Edwards 1887-97). Mature larvae of the nominate subspecies in California are buff brown. The dorsal stripe is black, below which is a whitish stripe shading outward to brown and streaked longitudinally with dark brown and black. The subdorsal line is black, and below it the ground colour is buff with black speckles. The lateral band is deep black, the spiracular band green buff, the basal ridge yellow white, and the underside, legs, and prolegs brown buff (Edwards 1887-97).
The subspecies of Great Arctic that occurs in BC is gigas (Butler, 1868), which was described from southern Vancouver Island. The mainland populations are slightly different from gigas, but are closer to that subspecies than to any other named subspecies.
The name Oeneis refers to Oeneus, king of the ancient city of Calydon in western Greece, husband of Althaea and father of Meleagr and Tydeus. The name of the European genus Melanargia is derived from Meleagr, and another species of Satyrinae was derived from Tydeus. The common name "arctics" was first used by Holland (1898) in reference to the arctic and alpine distribution of many species.
Arctics are medium-sized brown or grey butterflies. They usually have eyespots on the wings. They fly rapidly and erratically over short distances, and then drop suddenly to the ground or onto a tree trunk. Arctics all have a two-year life cycle, with the young larvae hibernating the first winter and the almost mature larvae hibernating the second winter. The two-year life cycle results in many species having adults in flight only every second year, with butterflies in alternate years being greatly reduced in abundance or missing entirely in some or all areas.
Eggs are white or off-white in colour, and are conical in shape, with vertical ribs down the side. First instar larvae are thinly covered with hairs, and are tan or greenish. Mature larvae are slender and are tan or greenish with longitudinal stripes of various colours down the back and sides. They are thinly covered with hairs that are frequently reddish in colour. Pupae are roughly cylindrical and rounded, and have brown,yellow brown, and olive markings. Descriptions of the immature stages are all from outside BC, with the exception of the Great Arctic.
Larval foodplants are usually grasses and sedges. One species, the Jutta Arctic, also feeds on rushes. Eggs are laid singly on leaves of the foodplant, or nearby on dead leaves or debris. The foodplants naturally utilized in BC are not known for any species; the little information that is available is from Manitoba, Alberta, or the American Rocky Mountains.
Arctics fall into three basic ecological groups (Masters 1969): forest-dwelling species (macounii, nevadensis, jutta); prairie and steppe species (uhleri, chryxus, alberta); and arctic taiga-tundra/alpine summit species (bore, melissa, polixenes). Oeneis bore and polixenes can sometimes be difficult to identify by wing pattern alone, but the valves of the male genitalia are distinctly different. Oeneis rosovi is also difficult to distinguish from O. polixenes, but there are no genitalic differences between the two species.
Great Arctics fly in June and July at low to middle elevations, and in August in subalpine habitats. Masters (1974) stated that they fly only in even-numbered years throughout their distribution. On Vancouver Island, however, they fly in both odd and even years. At anyone site on Vancouver Island, they tend to be much more abundant in alternate years, but the greater abundance may occur in either odd or even years. Great Arctics were common in the Goldstream area in both 1891 and 1893 (1892 was too rainy), when C. de Blois Green and W.G. Wright collected them (Edwards 1887-97). In Oregon several colonies of subspecies nevadensis fly in both odd and even years (Newcomer 1964d). Natural larval foodplants are unknown, but are probably grasses, on which the larvae feed in captivity.
Great Arctics occur on Vancouver Island and in the southern Coast Range. They inhabit forest openings and edges of meadows, from sea level to above timberline. The males are usually found on ridgetop clearings but also in forest openings lower down (Guppy 1962, 1970).
Great Arctics occur only along the Pacific coast, from Vancouver Island and Lillooet, BC, south to northern CA.
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:
19/11/2019 1:43:59 AM]
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