# Spicebush swallowtail (Papilio troilus) > A medium to large black swallowtail with an iridescent blue-green hindwing band; caterpillars feed on spicebush, sassafras and other laurels and mimic bird droppings or snake eyes. Source: https://insectscanner.com/species/spicebush-swallowtail/ (updated 2026-10-10) ## Is it dangerous? **Non-toxic.** Harmless to people. Adults do not bite or sting. Caterpillars may regurgitate or evert an orange forked gland (osmeterium) when disturbed; this is harmless though it can smell unpleasant. **Pets:** Generally harmless to pets. Dogs or cats might investigate caterpillars but reported poisoning from spicebush swallowtails is not known. Avoid forcing pets to eat wildlife. ## Quick facts - Scientific name: Papilio troilus - Also called: Green-clouded swallowtail - Order: Lepidoptera (Butterflies and moths) - Family: Papilionidae (Swallowtails) - Size: 8-10 cm wingspan - Colours: Black, Iridescent blue-green, Yellow-cream, Orange - Habitat: Woodland edges, swamps, wetlands, gardens and other areas where host plants (spicebush, sassafras and laurels) grow. - Range: Eastern North America: from southern Canada (Ontario, Quebec) south through much of the eastern United States to Florida and east Texas. - Active: Active spring through fall; usually day-flying with peak activity in warm sunny weather. One to three broods per year depending on latitude. - Lifespan: Adults live for about 2-3 weeks in typical conditions; full generation from egg to adult takes several weeks to months depending on temperature and season. - Effect on plants: Host specialist - Pest: no ## Overview Papilio troilus is a swallowtail butterfly native to eastern North America. Adults patrol woodland edges, gardens and wetlands looking for nectar and host plants. Females lay single eggs on leaves of host shrubs; caterpillars go through several striking instars — early instars look like bird droppings while later instars are green with large false eye spots. There are one to three broods per year depending on latitude. Spicebush swallowtails are important pollinators and a familiar sight in native-plant and wildlife gardens. They are not dangerous to people, and both larvae and adults are frequently used in butterfly education and gardening to encourage wildlife-friendly habitats. ## How to identify it Adults have a wingspan about 8-10 cm with black forewings and a broad blue-green iridescent band across the hindwings (blue-green in males, more bluish in females). A row of yellow or cream spots runs along the outer margin of both wings; the hindwing has small orange submarginal spots near the tail. Each hindwing bears a short 'swallowtail' tail. Caterpillars in early instars are brown and white and resemble bird droppings; later instars are bright green with exaggerated false eye spots and a swollen thorax. Pupae are mottled brown or green and hang in a 'head-up' chrysalis posture. - Black swallowtail with a broad iridescent band across the hindwing (blue-green in males, bluer in females). - Row of yellow or cream marginal spots on both forewing and hindwing, plus small orange submarginal spots on hindwing near the tail. - Short swallowtail 'tails' on the hindwings. - Caterpillars: early instars look like bird droppings; later instars are bright green with prominent false eye spots and a swollen thorax. ## Lookalikes - **Eastern tiger swallowtail** (Papilio glaucus): Tiger swallowtail is yellow with black tiger stripes; spicebush swallowtail is mostly black with blue-green hindwing scaling. - **Palamedes swallowtail** (Papilio palamedes): Palamedes has a broad yellow band across both wings and a yellow-striped body; it is largely restricted to swamps and coastal plain of the southeastern U.S. - **Pipevine swallowtail** (Battus philenor): Pipevine swallowtail is uniformly dark with iridescent blue on the hindwing, lacks the cream spots along the forewing margin and has a single row of orange spots on the hindwing underside (spicebush has two). ## Life cycle - **Egg:** Single, pale yellow eggs laid singly on the underside of host leaves; they darken before hatching in about 4-10 days depending on temperature. - **Larva (caterpillar):** Multiple instars: early instars mimic bird droppings; later instars are green with large false eye spots and a swollen thorax. Feeding stage lasts several weeks. - **Pupa (chrysalis):** Pupae attach to a stem or leaf and remain as a mottled green or brown chrysalis for one to several weeks; overwintering occurs as a pupa in colder regions. - **Adult (butterfly):** Winged, nectar-feeding adult that mates and lays eggs to begin the next generation. Adults live about 2-3 weeks. ## Diet and predators - Young eat: Leaves of spicebush (Lindera), sassafras and other Lauraceae and related shrubs. - Adults eat: Nectar from a wide range of flowering plants, including milkweed, phlox, thistles, joe-pye weed and many garden flowers. - Predators of the young: Birds, predatory insects, ants, spiders and parasitoid wasps and flies. - Predators of adults: Birds, dragonflies and some predatory insects; adults also suffer mortality from bad weather and habitat loss. ## Effect on plants and gardens Larvae feed primarily on spicebush (Lindera benzoin) and sassafras (Sassafras albidum), and also use several members of the laurel family and related plants. Adults visit a variety of nectar flowers (milkweed, thistles, phlox, joe-pye weed) and act as pollinators. ## Where and when to find it Look along woodland edges, swamps, stream corridors and native-plant gardens. Eggs and caterpillars are found on spicebush, sassafras and related shrubs; adults visit nearby nectar flowers. - Best time: Best seen from spring through early fall on warm sunny days, especially mid-morning to mid-afternoon. Peak months vary by region but often May-August. - Tips: Walk quietly along woodland edges and watch shrubs with aromatic leaves for eggs and caterpillars. Photograph adults from a distance to avoid disturbance; caterpillars are easier to photograph when feeding or basking on host leaves. ## Fun facts - Early instar caterpillars mimic bird droppings to avoid predators; later instars display large eye spots that can startle birds. - Like other swallowtails, the caterpillar can evert an orange, forked gland called the osmeterium that emits a foul scent to deter attackers. - Older caterpillars spend the day hidden inside a leaf they fold over with silk, coming out to feed at night. ## Frequently asked questions ### Do spicebush swallowtails bite? No. Adults do not bite or sting. Caterpillars are non-biting; they may regurgitate or evert an osmeterium when threatened, which is harmless though smelly. ### Are spicebush swallowtails harmful to my garden? Generally no. Caterpillars feed on host shrubs and seldom cause serious long-term damage. They are considered beneficial as pollinators as adults. ### Why is a spicebush swallowtail in my house? Adults may enter houses while searching for nectar, mates or shelter. Sometimes pupae attached near windows or doors can lead to emergent adults indoors. ### How do I attract spicebush swallowtails to my garden? Plant larval host shrubs such as spicebush (Lindera benzoin), sassafras and native laurels, and provide nectar plants like milkweed, phlox and joe-pye weed. Provide shelter and avoid broad-spectrum insecticides. ### How can I get rid of spicebush swallowtail caterpillars? They are not pests and removal is usually unnecessary. For removal, handpick caterpillars and relocate them away from sensitive ornamental plants, or cover host plants with fine netting. Use Bacillus thuringiensis kurstaki (Btk) cautiously; Btk affects many caterpillars and will also harm non-target butterflies. ### Are spicebush swallowtails endangered? No. Spicebush swallowtails are common in suitable habitats across their range. Local declines can occur where host plants or habitats are lost. --- More about this species: [iNaturalist](https://www.inaturalist.org/taxa/58525), [Wikipedia](https://en.wikipedia.org/wiki/Papilio_troilus). Identify insects and spiders from a photo with the Insect Scanner iPhone app: https://apps.apple.com/app/id1543946563?pt=126685406&ct=web-markdown&mt=8 Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.