NC State Extension Publications

Description and Biology

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Spicebush swallowtails, Papilio troilus, are butterflies that have a conspicuous tail on each hind wing. The forewings and body are black. The wings have a row of white spots near the outer margin and another small row on the margin. The hind wings are black with two orange spots, two rows of white spots and a conspicuous pale bluegreen area. Females lay eggs singly on the underside of host leaves. The worms generally fold leaves together to form a shelter in which they live on a silk lining. Young caterpillars mimic bird dropping. Older caterpillars are green with lovely blue spots. They also have ferocious eyespots, probably to deter predators. These worms usually feed on sweet bay, spicebush, and sassafras. The prepupae assume an comma shape. The chrysalis has two anterior horns and is suspended from a twig by a narrow silk band. The chrysalides may be brown or green, but overwintering chrysalides are always brown. Several generations occur each year.

Spicebush swallowtail caterpillars resemble tiny green snakes or

Spicebush swallowtail caterpillars resemble tiny green snakes or tree frogs.

Mature spicebush swallotail caterpillars are brownish below.

Mature spicebush swallotail caterpillars are brownish below.

A prepupal spicebush swallowtail caterpillar assumes a comma sha

A prepupal spicebush swallowtail caterpillar assumes a comma shape.

The spicebush swallowtail chrysalis is either green or brown.

The spicebush swallowtail chrysalis is either green or brown.

A chrysalis just hours before eclosion.

A chrysalis just hours before eclosion.

The markings of a spicebush swallowtail are usually greenish blu

The markings of a spicebush swallowtail are usually greenish blue.

Spicebush swallowtails sip nectar from a wide variety of flowers

Spicebush swallowtails sip nectar from a wide variety of flowers.

Host Plants

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Although they have two pairs of ferocious eyespots, spicebush swallowtail caterpillars are harmless. The worms usually feed on sweet bay, spicebush, and sassafras as well as tulip tree. They typically fold leaf margins over to form a silk-lined shelter in which they retreat when they are not feeding. Their leaf-folding and leaf-feeding are usually minor enough to escape notice.

Residential Recommendation

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Although spicebush butterflies are not rare, the caterpillars are seldom noticed. It would seem un-American to spray or dust such a wonderful insect.

References

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For assistance with a specific problem, contact your local Cooperative Extension center.

This factsheet has not been peer reviewed.

Author

Professor Emeritus
Entomology & Plant Pathology

Publication date: July 11, 2013
Revised: Oct. 14, 2019

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