Western Tiger Swallowtail

Description:

Upperside of hindwing with upper-most marginal spot yellow or lacking. Underside of forewing with separate yellow spots forming marginal band. Hindwing has narrow marginal spots and no orange tint except for 2 spots near end of inner margin. Wing Span: 2 3/4 - 4 inches (7 - 10 cm). Life History: Males patrol canyons or hilltops for receptive females. Females lay eggs singly on surface of host plant leaves. Caterpillars feed on leaves and rest on silken mats in shelters of curled leaves. Chrysalids hibernate.

Habitat:

This beautiful butterfly is often observed gliding lazily among the willows. When disturbed, its rapid flight capability becomes apparent. It is not often seen nectaring at flowers, although in the canyons it occasionally comes down to the wet sand and mud along a stream to sip water and nutrients (a phenomenon known as "puddling"). Range: Western North America from British Columbia south to southern New Mexico and Baja California; east to western South Dakota and southeast Colorado. A rare stray to central Nebraska.

Notes:

The Tiger Swallowtail is one of the largest and most commonly observed butterfly in the West. A person can attract these butterflies to a garden by planting zinnias, milkweeds, thistles, penstemons and other flowers. Certain species of wasps lay their eggs on a caterpillar as the caterpillar is spinning its last silk threads before it pupates. At this point the caterpillar is totally defenseless. The wasp's eggs will develop inside the caterpillar and feed upon it, killing the caterpillar. In summer, it takes about ten to fifteen days (weather depending) for the caterpillar to change into the adult butterfly. The chrysalis will be green in summer and brown in winter.