Despite their superficial resemblance to whites, Parnassians are closely related to the swallowtails and are placed in the family Papilionidae. Characters which they share with the swallowtails include large adult size and, in the larvae, chemical-producing eversible organs called osmeteria behind the head for defense. In Washington we have nine species in the Papilionidae, including two species of parnassians (genus Parnassius) and the remainder all swallowtails (genus Papilio).

Parnassius smintheus is a single-brooded butterfly of the mountains, occurring from upper foothills to the alpine zone on both sides of the Cascades of BC, Washington and NE Oregon, also in mountainous areas of western N America from Alaska to New Mexico and California. Larval host plants are stonecrops including Sedum lanceolatum (Lanceleaved Stonecrop), S. rosea (Western Roseroot), S. divergens (Spreading Stonecrop), S. oreganum (Oregon Stonecrop) and S. stenopetalum (Wormleaf Stonecrop). The flight period is late May to early September, depending on elevation. The preferred habitat is usually a rocky open slope with abundant stonecrops, low shrubs and nectar plants but few trees, often at higher altitudes. Males cruise relentlessly in search of mates while females remain hidden in the vegetation or visit nectar plants. Mating lasts several hours during which the male secretes a waxy structure called a sphragis on the female’s abdomen to prevent further mating. At Quartz Mtn, Kittitas Co, one female was observed visiting a small stonecrop plant, probing it several times with her abdomen. She then moved to a nearby blade of dead grass and laid a single egg. Eight more eggs were found nearby within an hour’s search, most on small diameter (~ 1 mm) dead vegetation 1-2 inches above the ground and within 2-3 inches of stonecrop plants. Only one egg was found directly on a stonecrop. Adults nectar on composites, buckwheats and stonecrops. While Males of most species of swallowtails frequent wet spots where they imbibe minerals in “puddle parties,” parnassians appear to shun this behavior.

Parnassian eggs are large compressed spheres with well textured surfaces. The egg with mature embryo is the overwinter stage, hatching very quickly, sometimes within only 2 hours of removal from refrigeration in captivity. Larvae have a foul-smelling bright yellow osmeterium behind the head which can suddenly be everted to deter predators. The dark larvae develop sharply contrasting yellow or gold spots in later instars. In the wild, larvae twitch violently when disturbed and drop to the ground as an escape response. Older larvae may bask openly or remain concealed among Sedum. Larvae feed mostly on leaf tips, and feeding damage is often obvious. Mature larvae weave a loose cocoon and pupate within it, and adults eclose after ~14 days. There are five larval instars and no nests are made. The bright yellow larval spots appear aposematic, so it is likely that the larvae are distasteful and possibly toxic. The Mountain Parnassian is difficult to rear from eggs, however later instars are easily found in the wild where they are most easily spotted by searching for bright yellow spots, rather than the black bodies.

Parnassians can resemble whites in flight, however whites are usually much smaller. No white in Washington has red markings on the dorsal (upper) wing surfaces as do parnassians. The two species of parnassians which occur here can be confused with each other, however there are easily observed differences. Neither species wanders far from its host plant; the Clodius Parnassian uses bleedingheart or steershead while the Mountain Parnassian uses stonecrops, and these plants usually do not overlap significantly, but there are places where both butterflies occur. The Mountain Parnassian has red spots on its dorsal forewings (quite limited in some males), while Clodius does not. And the Mountain Parnassian has black antennae with numerous white rings, while in Clodius they are solid black. In the Mountain Parnassian the female has stronger red markings on the dorsal forewing than the male; also the wingtips of the female’s forewings have large unscaled areas which appear blackish, while such areas are more reduced in males.

G’num2011Vol12No2