Zerene Fritillary
Speyeria zerene (Boisduval, 1852)

Click on image for larger view

Diagnosis: The upperside of the Zerene Fritillary is bright to dull orange with heavy black markings. The base of the forewing underside is usually flushed with reddish orange; the ground colour of the hindwing underside is dark reddish brown (ssp. bremnerii), reddish brown (ssp. picta), or pale reddish brown with a slight olive cast (ssp. garetti). The outer edge of the forewings is very slightly concave. This is a highly variable species and it can be confused with several other species. Wingspan: 50 to 64 mm.

Subspecies: There are many named subspecies, but only three occur in Canada. The British Columbia coastal records are subspecies bremnerii; specimens from the interior of British Columbia are subspecies picta; those from southeastern British Columbia to southern Saskatchewan are subspecies garretti.

Range: The Zerene Fritillary occurs from the west coast east to the Rocky Mountain foothills and across the southern Prairies to the Cypress Hills of Saskatchewan.

Similar Species: The Zerene Fritillary is one of three similar species (Speyeria zerene, S. egleis, and S. coronis) in which the silver spots on the margin of the hindwing underside are low and rounded, usually oval or lens-shaped in outline. In most other fritillaries in the west these spots are higher and more triangular. The Great Basin Fritillary (S. egleis) is slightly smaller, the forewing underside lacks a reddish-orange flush at the wing base, and the hindwing is greenish brown at the base; the spots on the hindwing underside are usually unsilvered in egleis but are silvered in subspecies albrighti in Montana and subspecies linda in Idaho, the two subspecies that might occur in Canada. The Coronis Fritillary (S. coronis snyderi) occurs as far north as central Montana and central Idaho, and S. coronis semiramis occurs in Washington State; either could possibly wander to southern Canada. Speyeria coronis is larger than zerene and has more distinctly greenish-brown shading on the hindwing beneath, and would fly earlier in the season, probably in June. [compare images]

Early Stages: The mature larva is orange brown to grey with black markings and has a black stripe down the side.

Abundance: The Zerene Fritillary is fairly common in most of its range and is often the most common fritillary.

Flight Season: This showy butterfly can be seen flying from late July into early September in its Canadian range.

Habits: The habitat of this species is mainly mountains and foothills, but it also wanders out into nearby prairie regions to nectar on wild flowers.

Remarks: The great variety within this species may be related to the level of humidity. In moist habitats it is darker orange with heavier dark markings than in drier habitats. Seasonal humidity changes can also affect it.

© 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.

The Toronto Entomologists' Association thanks Agriculture and Agri-Food Canada for providing the content and computer code for this web page.