The Pipevine swallowtail butterfly, also known as the Blue swallowtail, is a butterfly that lives in many areas of North America and is unique for its black and iridescent blue color combination and orange spots on the underside of its wings, which serve as a warning to birds.
Pipevine Swallowtail Butterfly Species Summary
| Scientific Name | Battus philenor |
| Family Name | Papilionidae |
| Kingdom | Animalia |
| Genus | Battus |
| Habitat | Open grasslands, woodlands, meadows, backyard gardens |
| Range | North and Central America |
| Host Plants | Pipevine |
| Butterfly Description | Black with one row of pale spots near the wing edges |
| Caterpillar Description | Black with red spots |
Butterfly Physical Description and comparison with other species
The Pipevine swallowtail butterfly is a beautiful butterfly with black dorsal and iridescent blue hind wings. That’s why some call it a blue swallowtail.
You may notice tiny, barely visible white spots on the upper side of its blue-green hind wings. On the other hand, the undersides of its ventral wings are rich in orange spots. The wingspan varies between 2 3/4 to 5 inches (7 to 13 cm). Females lack iridescence and are duller than males.
Other butterflies, such as the Black swallowtail, Spicebush swallowtail, and Red-spotted purple, mimic the patterns of the Pipevine swallowtail to upgrade their defense against predators.
Why are they called a Pipevine Swallowtail Butterfly?
The Pipevine swallowtail butterfly is named after their most popular host plant, the pipevine, on which they are highly dependent.
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Caterpillar Physical Description
Pipevine swallowtail caterpillars are about 2 inches (5 cm) in length. They vary in color, going from dark brown to black. The larval offspring in warmer areas, (Texas and Arizona), are reddish. Larvae also have bright orange spots on the ends of the tubercles. The tubercles are elongated at both ends of their body.
Fully grown larvae are glossy and velvety and have many fine hairs. Larvae will spend most of their time eating the leaves of their host plants. They’ll move to the next plant once they eat all edible matter from the first one.
Initially, they eat in groups but later become more solitary. The larvae feed and roam for a few weeks before finding the best place to pupate.
The Pipevine swallowtail pupae are green or brown, about 2.3 to 2.7 inches (6 to 7 cm) in length. These pupae differ from another swallowtail chrysalis as their bodies widen into a winged look. They also have distinct purple edges on the side of their bodies. Pipevine swallowtails will spend winters as pupae in colder areas.
How long does a pipevine swallowtail live?
| Egg Stage | 4 to 10 days |
| Caterpillar Stage | 21 to 28 days |
| Chrysalis Stage | 10 to 20 days |
| Butterfly Stage | 6 to 14 days |
Ideal Habitat
The Pipevine swallowtail butterfly prefers warmer temperatures. They can be found around open grasslands, woodlands, meadows, and backyard gardens. It’s also present anywhere where pipevine (Aristolochia) is abundant.
Host Plants
The most common host plants where this swallowtail butterfly lays eggs are the following Aristolochia species:
- Pipevine
- Virginia snakeroot
- Dutchman’s pipe
- California Dutchman’s pipe
Diet
Pipevine Swallowtail larvae feed and eat the plants from the genus Aristolochia. These are known as pipevine plants, and they have active aristolochic acids. The caterpillars use these acids for defense.
Adults prefer nectar from the following food plants:
- Swamp milkweed
- Butterfly Bush
- Yellow star thistle
- Phlox species
- Ironweed of Vernonia species
- Bergamot
- Phlox
- Gilias
- California buckeye
- Yerba santa
Behavior
Adult males fly around looking for females. They’ll also visit host plants to find them. Once they do, they’ll hover above her and conduct a courtship display to fan the female with pheromones. After mating, females will proceed to lay eggs in batches on the underside of the host plant leaves.
They’ll pick the right plant based on the leaf shape. The presence of Aristolochic acid may act as an oviposition stimulant. These butterflies produce 2 to 4 broods annually.
Caterpillars feed in small groups while young and become solitary while growing up. The chrysalis overwinters.
Adults spend most of their time feeding and looking for mates. In some cases, males have been observed to suck moisture and nutrients from mud. These butterflies are around during the spring and summer months.
What eats a pipevine swallowtail?
Birds are the largest threat to larvae of Pipevine swallowtails. The Pipevine swallowtail larva has other natural predators, including other butterflies. In addition, parasites can also threaten larvae, especially wasps and flies, which are the most dangerous ones.
Are Pipevine Swallowtail Butterflies Poisonous?
Due to bird predation, the butterfly has evolved to use the chemical defense — with aristolochic acids from their host plants.
All host plants this butterfly uses have some form of this acid. It gets passed onto the eggs, larvae, pupa, and adult butterflies. Eventually, this acid accumulates inside the butterfly, and the insect becomes unpalatable to birds.
The bright orange spots are also a form of defense. They’re supposed to serve as a warning to predators, meaning the larvae have a bad taste. This is why many other species of swallowtail butterflies adopted this defense technique — the Red-spotted purple butterfly, female Eastern tiger swallowtail, Promothea silkmoth males, Eastern black swallowtail butterflies, and the Spicebush swallowtail all use similar mimicry.
Distribution
The Pipevine swallowtails are widely distributed across North America. In the US, they frequent:
- New England
- Florida
- Nebraska
- Texas
- New Mexico
- Arizona
- California
- Oregon
- North Carolina
There are some rare sightings in Mexico.
Do Pipevine Swallowtail Butterflies Migrate?
Pipevine swallowtail butterflies don’t migrate. Its chrysalis overwinters until spring.
Are Pipevine Swallowtail Butterflies Endangered and rare?
Pipevine swallowtail butterflies are not endangered. They are secure by all standards. This species was common in San Francisco Bay. However, due to the loss of habitat, it has become rare.
What to Plant in your Garden to attract Pipevine Swallowtail Butterflies?
Planting any species of pipevine will guarantee a visit from a Pipevine swallowtail. This includes any Aristolochia species, such as:
- Aristolochia serpentaria
- Aristolochia tomentosa
- Aristolochia macrophylla
- Aristolochia californica
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