Gorgone Checkerspot (Chlosyne gorgone) (Hübner, 1810)
Diagnosis: One of the smaller Checkerspots (wingspan: 27 to 38 mm), this species has the typical upperside of an orange ground colour with black spots and markings. The hindwings have a row of submarginal black dots. The hindwing underside is silvery grey with a distinctive band of white arrowhead markings across it.
Subspecies: Only subspecies carlota occurs in Canada.
Range: The Gorgone Checkerspot is a butterfly mainly of the Great Plains, but populations also extend into the eastern U.S. In Canada, it is mainly a prairie species, but there is an isolated population in the Peace River District in Alberta. A specimen was taken at Deschambault Lake, Saskatchewan, among Jack Pines (Hooper, 1973). On 6 June 1891, four specimens were taken at Scarborough, Ontario, east of Toronto. Other historical records exist from the Humber Valley, west of Toronto, and London, Ontario, and recently, specimens taken in 1907 at White River, Algoma District, northern Ontario, were discovered in the USNM collection in Washington. However, there were no recent eastern records and the species was considered to be extirpated in Ontario (Holmes et al., 1991). In 1996, more than 12 colonies were discovered in eastern Ontario in a region bounded by Kemptville and Merrickville to the north and Spencerville and Brockville to the south.
Similar Species: The hindwing underside pattern, with zigzag black lines defining a median band of arrowhead-shaped spots, distinguish it from other checkerspots. It is darker and flies faster than the Northern Crescent (Phyciodes cocyta), with which it has probably been confused in the east. [compare images]
Early Stages: The larvae have three colour forms. Two are black, with fine white spots and palelongitudinal lines; in one these are very faint, almost indistinguishable, and in the other they are quite distinct. A third uncommon form is mainly orange. All have black spines. In the west they feed on the leaves of sunflowers (Helianthus spp.) and occasionally on asters (Aster spp.). In Ontario they feed on Black-eyed Susan (Rudbeckia hirta) with first- and second-instar larvae occasionally occurring on asters (Aster lanceolatus and A. novae-angliae). Most larvae from the spring and summer broods go into diapause in early instars, but some continue to mature to produce another flight of adults about six weeks later. The larvae are strongly gregarious in the early instars.
Abundance: Chlosyne gorgone can be locally common or even abundant in the Prairies, particularly on hilltops; it is local and uncommon in eastern Ontario and is easily overlooked, even when present.
Flight Season: There is a single brood between early May and late July in the west. In Ontario there are three flights, in late May and early June, in July and early August, and in September; how many generations this represents is not clear.
Habits: The Gorgone Checkerspot is usually found in dry prairie and grassy hillside habitats in the west, and abandoned fields and dry roadsides in Ontario, usually on sandy soil overlying limestone. In the extreme northern parts of its range, there are isolated colonies in open pine forests.
Remarks: The discovery of the Gorgone Checkerspot in eastern Ontario by Paul Catling in the spring of 1996 caught most butterfly enthusiasts by surprise, since it had not been reported in eastern Canada in over a century. More than a dozen colonies were found in eastern Ontario in 1996 in abandoned, dry sandy fields, roadsides, and hydro lines. These areas are not relict prairie sites where the species might have survived before the land was cleared for farming; however, most of the sites have enough native vegetation to suggest that relict prairie habitat formerly existed in the area. Its peculiar foodplant in Ontario (Black-eyed Susan) also suggests a long history of the species in the east.
© 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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