They are known for sequestering acids from the plants they feed on in order to defend themselves from predators by being poisonous when consumed.

[9] The pipevine swallowtail was first identified in 1771 by Linnaeus and originally was placed in the genus Papilo, as was typical for butterflies.

The pipevine swallowtail also belongs to the tribe Troidini, a group of butterflies whose larvae all feed on plants of the genus Aristolochia.

In the United States, the butterfly is found in New England down to Florida west to Nebraska, Texas, New Mexico, Arizona, California, and Oregon.

[11][12] The butterfly frequents warmer, more temperate environments, and can be found mostly in open grasslands, woodlands, meadows, and backyard gardens.

[10] This plant genus is known to have active aristolochic acids, which pipevine swallowtail larvae sequester and use for defensive properties.

[14] A common host plant is the Virginia snakeroot, (Aristolochia serpentaria), which can be found in the Eastern United States and in Florida.

Some Aristolochia species are actually toxic or extremely distasteful to larvae and thus may act as death traps for the butterflies.

The female pipevine swallowtail deposits this excretion from a gland above the ovipositor during the egg laying process.

[10] Pipevine swallowtail larvae are around 5 cm in length and vary in color from dark brown to black.

They eat in groups at first but as food sources deplete they become more solitary as they move on in search of fresh host plants.

[10] Pipevine swallowtail pupation takes place many feet off the ground on tree trunks or other suitable spots.

Pupation begins when the larva releases silk to form a support structure so that the chrysalis can hang safely.

[13] The adults from Californian populations of these butterflies have smaller and hairier bodies and are thought to be a subspecies Battus philenor hirsute.

Immediately after emerging from the chrysalis, adult butterflies spend time near the pupa case and dry their wings and remove pupal waste products from their bodies.

As a result of bird predation, this butterfly has evolved a chemical defense using the aristolochic acids found in their host plants.

[10][14] All host plants for the pipevine swallowtail have some form of aristolochic acids, which the larva sequesters while they feed.