Euphydryas chalcedona
Chalcedon checkerspot, variable checkerspot
Species Guides
2- Euphydryas chalcedona a paradoxa
- Euphydryas chalcedona(Chalcedon Checkerspot)
Euphydryas chalcedona is a of checkerspot in the Nymphalidae, commonly known as the Chalcedon checkerspot or variable checkerspot. It is native to western North America, with its range extending from British Columbia south to Baja California and east to the Rocky Mountains. The species exhibits considerable variation in wing pattern and coloration across its geographic range. Like other members of the Euphydryas, it is associated with specific larval plants and has been subject to conservation concern due to loss and climate change impacts affecting butterfly across the western United States.
Pronunciation
How to pronounce Euphydryas chalcedona: /juːˈfaɪdrɪəs ˌkælsɪˈdoʊnə/
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Distribution
Western North America, ranging from British Columbia south through Washington, Oregon, and California to Baja California, and eastward to the Rocky Mountains including portions of Idaho, Montana, Wyoming, Colorado, Utah, Nevada, Arizona, and New Mexico.
Host Associations
- Scrophulariaceae family plants - larval Primary larval plant , including such as Penstemon, Castilleja, and Keckiella
- Plantaginaceae family plants - larval Secondary larval , particularly Penstemon
- Orobanchaceae family plants - larval Includes parasitic plant such as Castilleja (Indian paintbrush)
Similar Taxa
- Euphydryas aniciaOverlapping range in western North America; both utilize similar plants in the Scrophulariaceae ; E. chalcedona typically has more extensive black markings on the wing surface
- Euphydryas edithaSimilar checkerspot pattern; E. editha (Edith's checkerspot) has more restricted range and is associated with different plant including Collinsia and Plantago; wing pattern differences in spot arrangement
- Euphydryas phaetonEastern North American with similar wing pattern; E. chalcedona distinguished by western distribution and more variable coloration ranging from orange-red to yellow
- Chlosyne gabbiiSympatric in California; Gabb's checkerspot has more rounded wing margins and reduced black markings on the forewing compared to E. chalcedona
More Details
Conservation context
The Euphydryas has been extensively studied in the context of climate change impacts on . Research published in Science (Forister et al., 2021) documented that Euphydryas editha (Edith's checkerspot) declined in at least two independent datasets across the western United States, with fall warming identified as a significant factor. While E. chalcedona was not specifically highlighted in this study, the pervasive declines documented across western butterfly faunas suggest that similar factors may affect this . The Euphydryas anicia cloudcrofti (Sacramento Mountains checkerspot) from the Lincoln National Forest in New Mexico is currently proposed for listing under the Act, indicating conservation concern for related in the genus.
Taxonomic notes
Euphydryas chalcedona exhibits substantial phenotypic variation across its range, with multiple described including E. c. chalcedona, E. c. colon, E. c. anicia, and others. The taxonomic boundaries between these subspecies and their relationship to E. anicia remain subject to ongoing research, with some authorities treating certain as distinct rather than subspecies.