Family Papilionidae, the Swallowtails and Parnassians
- In Idaho, this family consists of two subgroups, the Swallowtails (Subfamily
Papilioninae) and the Parnassians (Subfamily Parnassiinae). The Swallowtails
are large butterflies bearing one or two long, tail-like extensions off the
rear of the hindwing. They are often black and yellow in color.
Parnassians are medium- to large-sized white butterflies that often have sections
of their wings which appear somewhat transparent.
- About 30 species belong to this Family in North America, with nine occurring
in Idaho. Of those eight, two are species of Parnassians. There
is only one other species of Parnassian that occurs in North America, and
it occurs in Alaska and northwestern Canada.
- In additon to the traits described above, members of this family are generally
characterized by the following: 1) medium to large size; 2) unique pattern
of wing vennation on the fore- and hindwing; and 3) fully developed and functioning
forelegs in both sexes.
- Other interesting traits of Swallowtails include a behavior called hill
topping, in which males and females congregate at the tops of slopes or ridges
in their effort to locate a mate. Swallowtails continue to move their
wings while taking nectar from flowers, unlike other butterflies. This
behavior is believed to help stabilize the large butterflies who otherwise
might unbalance the flower, causing it to tip or bend.
- Eggs of both Swallowtails and Parnassians are round and green. The
young caterpillars of Swallowtails often look like a bird dropping while older
caterpillars are often greenish and marked with large eyespots. They
are equipped with an osmeterium, a
Y-shaped gland located behind the head which can be pushed out to emit a chemical
disagreeable to potential predators. The Parnassian caterpillars vary
in appearance but are often black, and they may be equipped with an osmeterium.
Swallowtail pupae form no cocoon, often have both a cremaster and a silk girdle,
and typically are the overwintering stage. Parnassian pupae generally
are in a loose cocoon located on the ground in leaf litter; the egg and the
caterpillar are the usual overwintering stages.
Family Members in Idaho: