Question Mark (Polygonia interrogationis) (Fabricius, 1798)
Diagnosis: Our largest Polygonia (wingspan: 45 to 68 mm), it can be distinguished on the wing from the others by its size, its wing shape, and the long, violet-edged hindwing tails. The silver mark on the underside of the hindwing is broken into two parts, a curved line and a dot, creating a ?-shaped markthat gives the species its common name. The summer generation (form "umbrosa") is darker; the hindwing upperside is almost black, and the underside is more heavily marked than in the overwintering generation.
Range: The Question Mark occurs in eastern North America from Mexico north to St. John's, Newfoundland (one record), St-Félicien, Quebec, and Lukinto Lake, Ontario, and west through southern Manitoba to southeastern Saskatchewan. There is one record from the Blackfoot Hills near Lloydminster, Alberta.
Similar Species: It can be distinguished from all other Polygonia species by the characters given under Diagnosis above.
Early Stages: The spiny larvae are variable in colour; most often they are reddish brown, with irregular lighter areas. They feed singly on the underside of the leaves of the foodplants, usually Stinging Nettle (Urtica dioica), elm (Ulmus spp.), or Hops (Humulus lupulus).
Abundance: This can be a highly variable butterfly in terms of abundance; some years they are very rare, while in years that are good for other migrants they can be common.
Flight Season: There are two generations per year with the adults overwintering, but probably not in Canada. Even in southwestern Ontario, the pale overwintering specimens are never seen until late May (mid-June at Ottawa, late June in Manitoba). They fly until early July. The second generation emerges in late July or early August, and is seen until only mid-September. This contrasts with the behaviour of the other Polygonia species, strongly suggesting a southward migration in the fall, overwintering in the southern U.S., and a return migration, occasionally in fairly large numbers, in the late spring.
Habits: Usually seen in or near woodlands, but in late summer in good migrant years it can be found in almost any type of habitat, even in downtown parks. It rarely feeds on flowers, but is often seen on sap, mud, carrion, or animal droppings.
© 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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