Rocky Mountain Parnassian (Parnassius smintheus) (Doubleday, )
Diagnosis: This species and Phoebus Parnassian (P. phoebus) are best distinguished from the other two parnassians by the antennae being alternately ringed in black and white. Like most members of its genus, smintheus is a predominantly white butterfly with black and red markings. The two black spots on the forewing leading edge are much more intensely black than the marginal and submarginal grey bands. The forewing usually has some red spots, but wing markings vary among individuals and populations and sometimes there is little red evident. High-altitude populations are generally darker than lower-altitude ones. Wingspan: 40 to 68 mm.
Subspecies: There are numerous named subspecies and forms throughout its range. Four subspecies are found in Canada. Subspecies smintheus occurs from the Rocky Mountains of Alberta and adjacent British Columbia northward to east-central British Columbia; subspecies magnus occurs through the interior of British Columbia, usually at elevations between 1000 and 2000 metres; subspecies olympiannus flies in northwestern Washington and southwestern British Columbia onVancouver Island; and subspecies yukonensis flies in southern Yukon and northern British Columbia.
Range: Parnassius smintheus occurs from southern Yukon south to northern California and New Mexico. In Canada, it flies in the front range of the Rockies in Alberta, and is widespread in British Columbia and southern Yukon. There is a population in the Milk River Valley north of Del Bonita, Alberta, that is the only substantiated prairie population in Canada (Sperling and Kondla, 1991). It also occurs in the Cypress Hills in southwestern Saskatchewan
Similar Species: The Clodius and Eversmann's Parnassians (P. clodius and P. eversmanni) rarely have any red spots on the forewing and lack the banded antennae. The dark spots on the leading edge of the forewing of these two species are only slightly darker than other blackish-grey areas of the forewing. Parnassius smintheus is very similar to the Phoebus Parnassian, which occurs mainly north of its range. [compare images]
Early Stages: This species overwinters as an egg. The larva is black with short black hairs and numerous yellow spots. It feeds on stonecrop (Sedum spp.), especially Lance-leaved Stonecrop (Sedum lanceolatum), and tends to prefer drier habitats.
Abundance: This striking butterfly can regularly be found in mountain meadows in the west.
Flight Season: There is one flight, from June to mid-August.
Habits: In sunny mountain meadows smintheus flies close to the ground with regular but shallow wingbeats, reflecting the sunlight from its semi-transparent wings. It is also an avid flower visitor.
Remarks: Shepard et al. (1994) have suggested that most populations of parnassians in North America formerly treated as subspecies of the Old World species Phoebus Parnassian (P. phoebus) actually belong to the North American species smintheus. This is based on examination of egg micro sculpture of parnassian species and details of wing markings and body vestiture. Parnassius phoebus occurs in North America only in Alaska and adjacent western Yukon. The specimen of smintheus illustrated in Swallowtail Butterflies of the Americas (Tyler et al., 1994) from the Northwest Territories is actually from Plateau Mountain, Alberta (Jim Ebner, pers. comm.)
© 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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