White-veined Arctic (Oeneis bore) (Schneider, 1792)
Diagnosis: The upperside is dull greyish brown, slightly translucent; females are often tawny. There are no eye-spots, but the hindwing often has a row of diffuse pale buff spots between the veins. Males have a diffuse dark grey sex patch in the centre of the forewing. The hindwing underside has a prominent darker medial band with dark brown lines representing the margins of the band; the basal and outer thirds of the wings are paler, particularly near the medial band because of pale grey shading adjacent to it. The underside of the forewing has one, sometimes two, dark brown lines near the middle of the wing representing the inner and outer elements of the medial band on the hind wing. Usually the veins of the hindwing underside are white, at least where they cross the medial band. Wingspan: 37 to 49 mm.
Subspecies: The nominate subspecies is from northern Fennoscandia and there are six rather weakly differentiated subspecies in North America, three in Canada. Subspecies taygete, from Labrador and northern Quebec, is yellowish brown above, with the white veins on the hindwing underside prominent and contrasting; subspecies gaspeensis, from Mont-Albert in the Gaspé, is slightly darker above, on average, and the veins on the hindwing underside are less contrasting; subspecies hanburyi in the west is highly variable above, but the veins on the underside of the hindwing are less contrasting than in subspecies taygete.
Range: Oeneis bore occurs in Lapland and northern Russia, and in North America across the Arctic from Labrador and northern Quebec to Nunavut and the Northwest Territories, including Victoria Island, northern British Columbia, the Rocky Mountains of British Columbia and Alberta, Yukon, and Alaska. There are isolated colonies near Labrador City, on the Gaspé Peninsula, Quebec, in western Alberta, and in U.S. Rocky Mountain states.
Similar Species: The Melissa Arctic (O. melissa) and Polixenes Arctic (O. polixenes) lack the dark transverse line(s) near the middle of the forewing underside, the veins on the hindwing below are not lined with white, and males lack the dark sex patch present on the upperside of the forewing in most bore males. [compare images]
Early Stages: The pale brown larvae have a brown dorsal stripe and white, reddish-brown, and dark brown lateral lines. They feed on sedges (e.g., Carex misandra) and oviposition has been observed on dead leaves of grasses (Festuca mibra, F. brachyphylla, and F. vivipara) at Churchill, Manitoba (Scott,1986).
Abundance: Oeneis bore is the most common arctic in open-tundra areas of subarctic Canada and Alaska.
Flight Season: The flight period is from mid-June to late July. In most areas it flies every year, but is reported only in even years at Churchill. The colonies near Labrador City were discovered in 1991; it is not known if they fly there each year, but most biennial species in Labrador fly in even-numbered years.
Habits: The White-veined Arctic flies in arctic and alpine tundra, usually in wet hummocky areas, but also occasionally in rocky areas and on sandy and gravelly ridges near wet grassy tundra.
Remarks: There has been a debate about whether subspecies taygete is actually a separate species from bore of Eurasia and northwestern North America. The main differences were considered to be thewhite veins on the hindwing underside of taygete and the less prominent male sex patch on the forewing. Most eastern populations have white veins, but some individuals lack them. Populations have been discovered in the east and the west where white-veined and non-white veined individuals occur together with intermediate forms and a great deal of variation in the sex patch. It seems more likely that the white veins are a characteristic of Oeneis bore taygete with a broad area of intergradation in the west, but more work is needed to fully resolve the issue.
© 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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