Clodius Parnassian

The Clodius parnassian is a relative of the swallowtails that looks nothing like one. Its wings are white with gray bars and smudges, and each hindwing carries two red spots, with none on the forewings. Males spend much of the day on the wing, patrolling back and forth over meadows, open woods and rocky slopes in search of females. There is just one flight each year, in early to midsummer.

Mating comes with an unusual twist. Afterward, the male attaches a large white pouch, called a sphragis, to the tip of the female’s abdomen, which keeps other males from mating with her. Look closely at a resting female and you may see it.

Its caterpillars feed on bleeding hearts, including Pacific bleeding heart, a pink-flowered plant of moist woods from the coast to middle elevations. Females scatter single eggs on and around the host plant, and the eggs wait out the winter. The caterpillars feed by night, low on the host plant, then spin a loose silk cocoon above the ground. NatureServe notes that as a butterfly of high elevations it could be affected by a warming climate, though for now it is widespread and shows no sign of decline.