Regal Fritillary
Speyeria idalia (Drury, [1773])

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Diagnosis: This striking species is one of the largest (wingspan: 66 to 92 mm) and most easily identified of the greater fritillaries. On the upperside the forewing is orange with black spots and a dark border, and the hindwing is black with a row of white spots and a row of orange spots. The hindwing underside is dark brown with large striking silver spots.

Range: This is mainly a butterfly of the U.S. Great Plains, extending eastward in the U.S. to Maine. It reaches into Canada only in southern Ontario, east to Kitchener, in southern Manitoba north to Riding Mountain National Park, and one record from Saskatchewan. There are probably no permanent colonies, but fresh specimens were taken in 1986 and 1987 at Culross, Manitoba (Klassen et al., 1989), which may suggest a temporary colony.

Similar Species: No other fritillary has dark hindwings with white spots.

Early Stages: The yellowish-brown larva has yellow lines and black spots. It feeds on a number of species of prairie violets.

Abundance: Even in its U.S. range, idalia is becoming increasingly uncommon and local and has disappeared from many areas. Canadian records are reports scattered over many years.

Flight Season: Canadians records are in July and August.

Habits: This species should be looked for mainly in tall-grass prairies and in wet prairie-like clearings in woodlands where violets grow. Like the other fritillaries, it often visits flowers. In all of its range, it became increasingly scarce as its prairie grasslands disappeared under the plough. As a result, the butterfly is endangered in many areas where it was formerly common

Remarks: The only Saskatchewan record is a very worn specimen caught on July 26, 1998 by RAL, on a salt flat on the south side of Big Muddy Lake, just 3 miles from the US border. It was being blown by a very strong southwesterly wind from Montana, beyond the usually-reported western limit of idalia.

© 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.