Mountain Alpines are small butterflies with a row of spots across both the forewings and the hindwings that are red on the upperside and cream or pale yellow on the underside of the wings. This species has traditionally been called Erebia theano (Tauscher, 1806) in North America; however, E. theano is a more strongly marked species restricted to the mountains of eastern Siberia and Mongolia (Korshunov and Gorbunov 1995; Tuzov 1997).
In Colorado, subspecies ethela eggs are weakly ribbed and are cream-coloured with red brown spots (Bird et al. 1995). First instar larvae are cream with faint longitudinal lines (Scott 1992). Mature larvae are tan with a dark brown dorsal longitudinal stripe, and three dark brown stripes on each side. There are two bumps at the hind end, covered in hairs (Bird et al. 1995).
The nominate subspecies was described from the Great Sibagly River basin, central Yakutia, Russia. The subspecies found in BC is E.p. alaskensis Holland, 1900 (TL: Eagle City and American Creek, AK).
The name Erebia is derived from the Greek Erebus, the region of darkness situated between earth and Hades (Reed 1871), in reference to the dark, dusky colour (Emmet 1991). The common name "alpines" was first used by Holland (1898) in reference to the alpine habitat of many species.
Alpines are medium-sized dark brown to black butterflies that have either submarginal eyespots or a red-flushed area on the forewings. In species with eyespots, there are usually orange-flushed areas around the spots. There are about 80 species worldwide, most of which are slow-flying.
The life histories of only some species are known. In these species, eggs are laid singly on leaves of grasses or sedges. They are white, cream, or yellow brown, and conical in shape with vertical ribs down the sides. First instar larvae are thinly covered with hairs, and are greenish with longitudinal stripes. Mature larvae are slender, and yellow green with light and dark longitudinal stripes down the back and sides. They are thinly covered with hairs, and may have two short tails. Alpines hibernate as partly grown larvae, and there are five or six instars. Pupae are roughly cylindrical, rounded, and suspended from a cremaster. They are pale brown. All alpines have only one generation each year, and some may take two years to mature. Erebia youngi and E. lafontainei are occasionally difficult to separate reliably (worn specimens), in which case they can be distinguished by the shape of the valves of the male genitalia.
Mountain Alpines are univoltine. They have a two-year life cycle and are in flight in July. In many Colorado populations, Mountain Alpine adults fly only every second year (Ferris and Brown 1981), mostly during even years but in some locations during odd years. Young larvae probably hibernate the first year, and mature larvae the second year (Scott 1992). Adults are very weak fliers, and are easily observed once found. The larval foodplants are unknown, but eggs are laid on dead grass or sedge leaves, and larvae eat Poa pratensis in the lab (Scott 1992).
In BC Mountain Alpines are known only from Stone Mountain Provincial Park. They inhabit subalpine wet grassy meadows and bogs. Outside the arctic, their colonies are usually very small in area and widely scattered. This, combined with their flight in alternate years and their weak flight pattern, makes detection of populations very difficult.
Mountain Alpines occur from the Sayan Mountains and northern Mongolia in Asia east across Siberia, AK, and YT to Churchill, MB, and in scattered colonies down the Rocky Mountains to CO.
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:
2020-07-02 12:12:17 AM]
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