One of the much-loved parts of summer is watching butterflies alight on nectar-rich flowers to sup. Through a network of like-minded friends, we are able to help each other out when in need. I’m often contacted around September, when milkweed, Asclepias spp., is in short supply, due to the excess needed with all the monarchs returning to Mexico. We are in their flight path. In early summer, it’s all about the pipevine swallowtails. I’ve never asked for help with the Eastern black swallowtail, Papilio polyxenes. Most of us butterfly gardeners always seem to have enough host plants, those in the carrot family. In our area, in general, we tend to see the most butterfly activity starting in mid-July through October.

My friend, Abby L., always has female Dutchman’s pipe butterflies, Battus philenor, lays her eggs in March, even when a frost is expected. In fact, we tested their tolerance one year when we were expecting a heavy frost. They did fine. For the last four years, when Abby was out of the host plant, I’ve taken as many as I could to support in my garden, but I’ve never had the luck Abby has. I’ve still not seen a pipevine swallowtail in my garden! This year, I shared with The Joslin Garden!

Battus is a New World genus of butterflies that are usually found around pipevine plants, Aristolochia spp.. The caterpillars feed off the poisonous pipevines, resulting in a foul taste that wards off predators.

Battus philenor, the pipevine swallowtail can be found in North American and through Central America. This butterfly is black with iridescent-blue hindwings. On the right, where more blue is noticed, is the female. They are found in many different habitats but are most commonly found in forests. Abby’s garden is forest-like. Maybe mine isn’t so much, but sort of. The Joslin Garden is definitely a wonderful forest, and there is a vast amount of pipevine!

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

Life cycle

EGG

The eggs of the pipevine swallowtail vary in color from red to orange. They are small and are laid on host plant stems or foliage. A distinctive feature of these eggs which is shared by all Aristolochia butterflies is that the outer layer of the egg is covered by a firm and nourishing excretion laid in vertical stripes along the outside. The egg appears bumpy due to the excretion forming large beads along with the bands. The female pipevine swallowtail deposits this excretion from a gland above the ovipositor during the egg-laying process.

LARVAE

Pipevine swallowtail larvae feed on plants within the genus Aristolochia. These are commonly known as pipevine plants, which is where the butterfly gets its common name. This plant genus is known to have active aristolochic acids, which pipevine swallowtail larvae sequester and use for defensive properties.

Larvae spend almost all their time eating the leaves of their host plants. Once they completely remove edible matter from one plant they move to the next one. 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.

CHRYSALIS/PUPAE

Pipevine swallowtail adults use nectar-producing plants as hosts, and thus there are many plants that fit their needs. These butterflies frequent thistle, Cirsium spp., flowers, the pink and purple flowers of the Phlox species, and ironweed of Vernonia species.

The pipevine swallowtail pupae are colored green or brown. They are about two inches in length. These pupae differ from other swallowtail butterfly pupae in that the sides of their pupae bodies widen into a sort of a winged appearance, with distinctive purplish edges along the sides of these extensions.

Pipevine swallowtail pupation takes place many feet off the ground on tree trunks or other suitable spots. Pupation is rare on green surfaces. Pupation begins when the larva releases silk to form a support structure so that the chrysalis can hang safely. In colder climates, it will spend the winter as a pupa, but in warmer climates, pupation only lasts a few weeks. Prior to emerging as an adult, the wing markings of the butterfly can be seen through the chrysalis.

ADULT

Pipevine swallowtail adults have a wingspan from three to five inches. The dorsal wings of an adult male are black with vibrant blue iridescence on the hind wings. Female iridescence is duller in appearance. Bright orange spots are visible on the back end of the ventral wings.

The adult pipevine swallowtail male spends most of his time feeding and searching for mates. Males have also been observed to take moisture and nutrients from mud, a behavior that is motivated by the presence of other males.

Females spend their time feeding, being courted by males, and reproducing. 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. The butterflies are seen during the spring and summer months.