Arctic Blue (Agriades glandon) (de Prunner, 1798)
Diagnosis: The upperside is dark greyish blue with diffuse grey borders in the male, dark grey or greybrown in the females. Both sexes have heavy bars at the end of the cell in both wings, often ringed with lighter scales, and a row of ringed dark spots on the hindwing margin. The underside is grey. Both wings have black spots heavily ringed with white; on the hindwing the black scaling is reduced, leaving white patches with or without tiny black centres. There may be a trace of orange and blue on the largest spot near the hindwing margin. Wingspan: 17 to 23 mm.
Subspecies: Six subspecies are currently recognized in North America, but we arrange Agriades glandon in North America into four subspecies. Subspecies franklinii is the smallest and darkest subspecies, with little blue shading on males; it occurs throughout the high arctic south to northern mainland of Nunavut and the Northwest Territories, the west coast of Hudson Bay, the arctic coast of Yukon and Alaska, and northeastern Canada. Subspecies megalo (including lacustris (T.N. Freeman)and bryanti (Leussler)) is larger, with extensive steel-blue shading above on males; it occurs throughout British Columbia and the mountains of Alberta, most of Yukon, southern Northwest Territories, and the northern Prairie Provinces. Subspecies rusticus occurs in prairie habitat in the three Prairie Provinces, north into the aspen parkland, and south to New Mexico; rusticus-like forms also occur in xeric habitats in southern Yukon. The fourth subspecies, podarce (C. & R. Felder), occurs in California and Oregon. In Eurasia, the nominate subspecies glandon, associated with Primulaceae, occurs in the mountains of central Europe; subspecies aquilo (Boisduval), associated with Fabaceae (Astragalus), is intermediate in appearance between subspecies franklinii and subspecies megalo and occurs in northern Europe and Russia. Some authors (e.g., Ferris, 1989; Emmel and Emmel, 1995) treat from four to six of these subspecies as full species, based primarily on foodplant associations. Intergradation zones between the three subspecies in Canada, and our scanty knowledge of foodplant preferences, make species recognition of these subspecies premature at this time.
Range: Agriades glandon is found in Newfoundland and Ungava and throughout the western provinces, Yukon, Alaska, the Northwest Territories, Nunavut north to Ellesmere Island, and the northern coast of Greenland. It is absent from the Maritimes, most of Quebec south of 53°N, and Ontario except for a few locations on the coast of Hudson Bay. It is also found in Europe and Asia.
Similar Species: None in Canada.
Early Stages: The eggs are laid singly under leaves or on flowers, and larvae eat buds and flowers.The larvae are pale green with reddish marks on the dorsal surface, covered with long, fine hair. They feed on various plants in the Primulaceae, Fabaceae, and Saxifragaceae, and, at least in Newfoundland and Baffin Island, on Diapensia lapponica (Diapensiaceae). Oviposition has been observed in Newfoundland on Black Crowberry (Empetrum nigrum). Specimens in the Canadian National Collection from Ellesmere Island were reared on Saxifraga oppositifolia.
Abundance: The Arctic Blue is often common to abundant.
Flight Season: There is one flight per year, from mid-May (southern Manitoba) or mid-June to late July in most areas and until mid-August in Labrador; there is rarely a small partial second generation in subspecies rusticus in September in parts of southeastern Alberta (Kondla and Schmidt, 1991).
Habits: The Arctic Blue usually flies in dry open places in tundra and mountainous areas, but on the James Bay Highway, Quebec, and in Saskatchewan they can be found on small rocky outcrops at low altitude often hundreds of miles south of treeline. Subspecies rusticus lives in open grassland on the Prairies, often in dry sandy areas, and, in the Peace River District, in Jack Pine sandhills.
Remarks: Agriades glandon has a fast erratic flight, usually just a few centimetres above the ground, although when disturbed it sometimes lifts up and allows the wind to carry it rapidly to safety. Its grey coloration makes it very hard to see on the ground. Like the Grizzled Skipper (Pyrgus centaureae), Agriades glandon can easily be mistaken for a moth when in flight.
© 2002. This material is reproduced with permission from The Butterflies of Canada by Ross A. Layberry, Peter W. Hall, and J. Donald Lafontaine. University of Toronto Press; 1998. Specimen photos courtesy of John T. Fowler.
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