In Washington we have ten species of butterflies which are loosely grouped as checkerspots owing to the cancellate or squarish patterning of intersecting lines on the ventral hindwings. Our checkerspots are placed in three separate genera, Euphydryas, Phyciodes and Chlosyne. The genus Euphydryas includes three species in our area and can be distinguished by their straight leading forewing edges. Phyciodes and Chlosyne include four and three species respectively, and have strongly curved forewings, especially near the body. Phyciodes has a distinct light crescent mark on the ventral hindwing while Chlosyne lacks this mark.

Euphydryas editha flies on both sides of the Cascades and in the Olympics and Blue Mtns. The subspecies E. e. taylori (Taylor’s Checkerspot), a resident of remnant prairies west of the Cascades, is endangered due to habitat loss. Beyond Cascadia E. editha occurs from southern British Columbia and Alberta to Baja, Montana and Colorado. The flight period here is mid-April to mid-August, and it flies from near sea level to over 8,000 ft elevation. The preferred habitat includes mountains, high ridges, coastal prairies and chaparral, open woodland and alpine areas. Many larval host plants are used in Cascadia including Castilleja (paintbrush), Plantago (plantain), Collinsia (blue-eyed mary), Penstemon (beardtongue), Pedicularis (lousewort) and Orthocarpos (owl clover).

Adults eclose April to July, depending on elevation; receptive females are passive, unreceptive ones flutter their wings or fly away. Oviposition occurs soon after mating; eggs are laid in clusters of 20-350 on the undersides of leaves or on the inflorescence of the host plant, and hatch in 8-9 days. Young larvae are highly gregarious, feeding together and living in communal silk nests on the undersides of leaves. Larvae feed on flowers or on host leaves, skeletonizing or consuming them entirely. Larval growth from hatch to L3 takes 20-30 days whereupon the larvae enter diapause. The following spring the larvae may opportunistically use a different host plant, for example Collinsia or Plantago, even though they may have fed on Castilleja the previous summer. Overwintered larvae disperse and live solitary lives with no nests; in captivity they grow to maturity in less than two weeks and pupate a few days later. The pupa ecloses to an adult in about 9 days. Euphydryas editha has five larval instars and is single-brooded throughout its range. The larvae of Edith’s Checkerspot can be distinguished from our other Euphydryas species by their broad black dorsolateral stripes and their more solidly orange dorsal spines.

The adults of our three Euphydryas checkerspots are very similar in appearance; Anicia and Snowberry Checkerspots are reliably separated only by dissecting the male genitalia, while the Edith’s Checkerspot is more easily identified by the presence of a black line (“Editha line”) across the ventral hindwing, this line bordered by orange on both sides. Additionally E. editha is more cleanly and sharply marked dorsally compared to the somewhat more “blurry” markings of E. colon and E. anicia.

All photos this page by Dave Nunnallee.

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