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Euphydryas chalcedona Scudder, 1872
Chalcedon Checkerspot; Checkerspots
Family: Nymphalidae (Brushfoots)
Species account authors: Crispin Guppy and Jon Shepard.
Extracted from Butterflies of British Columbia.
Introduction to the Lepidoptera of BC
Introduction to the Butterflies of BC
The Families of Lepidoptera of BC

Photograph

© Norbert Kondla     (Photo ID #7349)

Map

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Distribution of Euphydryas chalcedona in British Columbia.
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Source: Butterflies of British Columbia by Crispin Guppy and Jon Shepard © Royal BC Museum

Illustration

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Illustration 2

Illustration Source: : Butterflies of British Columbia by Crispin Guppy and Jon Shepard © Royal BC Museum

Species Information


Adult

The harpe of the male genitalia is the only reliable character for identifying the species. The dorsal arm is short and at a right angle to the longer ventral arm. This character can be seen only in genitalia kept in vials. If the preparation is mounted on a slide, the character is distorted. This may account for the confusion in the literature, with several authors treating the Chalcedon and Anicia checkerspots as one species (Layberry et al. 1998; Scott 1980). For a further description, see the "Adult" discussion under Anicia Checkerspot.

Immature Stages

Emmel and Emmel (1973) illustrate and describe the immatures of the nominate subspecies. The egg is lemon yellow. The mature larva is black with whitish dorsal and lateral bands along the body. The entire body is covered with small tubercles that are white with white hairs.

Subspecies

The Western Checkerspot, E.c. paradoxa McDunnough, 1927 (TL: Seton Lake, BC) is the only BC subspecies. All previous authors have ascribed Vancouver Island populations to E.c. perdiccas (W.H. Edwards, 1881) (TL: Tenino, Thurston Co., WA), which is a synonym of E.c. colon (W.H. Edwards, 1881) (TL: Kalama, Cowlitz Co., WA). The type locality of E.c. perdiccas was erroneously restricted to Tenino, and it is herein re-restricted by Shepard to Kalama, Cowlitz Co., WA. E. chalcedona has never been collected at or near Tenino, despite Brown (1966). The BC subspecies also occurs in the Olympic Mountains of Washington.

Genus Description


The name Euphydryas is derived from the Greek euphys (a goodly shape) and dryas (a dryad or wood nymph) (Emmet 1991), hence these checkerspots are goodly shaped wood nymphs. The common name "checkerspots" is derived from the checkerboard pattern of the upperside of the wings.

The Euphydryas checkerspots differ from Charidryas checkerspots by having brick red, not tawny, spots alternating with the black spots. The male genitalia lack the saccus. This is a Holarctic genus, with five Nearctic species and four Palearctic species. None of the individual species are Holarctic. The larvae feed on a variety of plants. Adults of three western North American species, all of which are in BC, are very hard to distinguish without reference to the male genitalia. These three species are in the subgenus Euphydryas (= Eurodyras Higgins = Occidryas Higgins). The fourth BC species, E. gillettii, is in the subgenus Hypodryas. All species worldwide are in one or the other of the two North American subgenera.

The figure illustrates the one part of the male genitalia, the harpe, that is diagnostic for species. The short arms of the harpe, one rounded and toothed and the other flattened out, are diagnostic for the subgenus Hypodryas. In the subgenus Euphydryas, at least one arm of the harpe is longer than the body of the harpe. This subgeneric classification is supported by recent DNA analysis of worldwide Melitaeinae by Zimmermann et al. (2000), who prefer subgenera to genera. Once this paper has been examined closely, however, others may choose to recognize two genera instead of one for the North American fauna.

Biology


The adults formerly flew in late May and June at lower elevations on Vancouver Island. On the mainland, populations occur from 1,250 to 1,900 m in the south, but at lower elevations in the north. All fly from early July through early August in normal years, and later if snow melt is delayed. Nothing is known of the life cycle in BC, but the adjacent Olympic Mountains populations feed on Penstemon (J. Pelham, pers. comm.), which is a known larval foodplant further south. The species overwinters as larvae in California (Emmel and Emmel 1973), and presumably do the same in BC. As in other checkerspots, the eggs are laid in clusters and the early instar larvae are gregarious.

Habitat


The Chalcedon Checkerspot is found in BC from Atlin south in a narrow band along the Coast Ranges to the WA border at Mt. Cheam, and formerly in the Malahat, Vancouver Island. From what can be discerned from museum specimens, the Vancouver Island populations occurred on bare hillsides from near sea level to 1,250 m. The Cascade and Coast populations occur from 1,250 to 1,900 m in the south and along the eastern shore of Atlin Lake in the north.

Distribution

Distribution

The Chalcedon Checkerspot is found in BC from Atlin south in a narrow band along the Coast Ranges to the WA border at Mt. Cheam, and formerly in the Malahat, Vancouver Island. From what can be discerned from museum specimens, the Vancouver Island populations occurred on bare hillsides from near sea level to 1,250 m. The Cascade and Coast populations occur from 1,250 to 1,900 m in the south and along the eastern shore of Atlin Lake in the north.

Status Information

Scientific NameOrigin StatusProvincial StatusBC List
(Red Blue List)		COSEWIC
Euphydryas aniciaNativeS5YellowNot Listed
Euphydryas chalcedonaNativeS5YellowNot Listed



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