Hodges#4459.1

Pronunciation

How to pronounce Speyeria hesperis: /ˈspaɪəriə ˈhɛspərɪs/

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Summary

Speyeria hesperis, known as the northwestern fritillary, is a butterfly in the family Nymphalidae, characterized by its bright orange upper surfaces and reddish undersides. Found mainly in the northwestern United States and western Canada, it inhabits forested areas, displaying significant variability within populations.

Physical Characteristics

Wingspan of 45–58 millimeters (1.8–2.3 inches), bright orange uppersides (yellow in females), thinner black markings than most fritillaries.

Identification Tips

Males are bright orange with lighter margins, while females are typically yellow. Distinctive reddish underside with silvered spots; more pronounced variations in color depending on location. Can be confused with Speyeria egleis, hydaspe, and atlantis.

Habitat

Moist Aspen and Spruce-Fir forests and woodlands, typically found in sunny openings such as meadows and streamsides, rarely far from forest cover.

Distribution

Northwestern United States and western Canada; reaches as far east as Manitoba and the Dakotas.

Diet

Larvae feed on Violas (Violet species).

Life Cycle

Adults primarily seen in late spring and early summer, mainly in July in most regions. Overwinters as young larvae and matures in spring.

Evolution

Previously considered part of Speyeria atlantis but identified as a separate species due to distinct populations that occur together and hybridization while retaining identifiable traits.

Similar Taxa

• Speyeria aphrodite
• Speyeria atlantis

Misconceptions

Often confused with other Speyeria species due to morphological similarities and hybridization issues.

Tags

• butterfly
• Speyeria
• Nymphalidae
• northwestern fritillary