Spicebush Swallowtail

Spicebush Swallowtails are similar to the other dark swallowtails, but can be quickly identified, even in flight, by the series of pale blue half-moons near the trailing edge of the hindwings. This one is a bit worn, missing its tails. The spicebush swallowtail derives its name from its most common host plant, the spicebush, members of the genus Lindera. The family to which spicebush swallowtails belong, Papilionidae, or Swallowtails, include the largest butterflies in the world. The Swallowtails are unique in that even while feeding, they continue to flutter their wings. Unlike other Swallowtail butterflies, Spicebushes fly low to the ground instead of at great heights.

Males patrol in woods, roads and woodland edges to find receptive females. Females lay single eggs on underside of host plant leaves. Caterpillars live in shelters of folded-over leaves and come out to feed at night. Some chrysalids from each generation hibernate. In general, spicebush swallowtails tend to stick to plants that are members of the family Lauraceae. The preference for Lauraceae is so consistent among spicebush swallowtails that under experimental conditions, when placed in an environment with leaves other than Lauraceae, P. troilus died without eating anything.

This fact is especially noteworthy because Lauraceae are distantly related to the host plants of other species that are food for Papilio caterpillars.The fact that spicebush swallowtails live and feed primarily on Lauraceae only is noteworthy also because most other varieties of swallowtail butterflies are nowhere near as specific. Part of the reason for the selective nature of P. troilus and host plants may have to do with the requirement of positive stimuli to confirm that a plant is Lauraceae among P. troilus before they will feed on it, while P. glaucus, for example, will at once try to feed on any plant presented to it.

Posted in: Papilionidae,S,Spicebush Swallowtail