Pipevine Swallowtail – Battus philenor

Pipevine Swallowtail butterflies (Battus philenor) are found in all or part of about 43 states. Hosting on certain species of pipevine plants, these are quick flying butterflies, darting from spot to spot. Many people find it difficult to take clear photographs of these beauties.

Pipevine Swallowtail butterfly male

Male Pipevine Swallowtail butterfly

Pipevine Swallowtail butterflies lay burgundy eggs on their host plants. On occasion they will lay eggs on the wrong species of pipevine. If young caterpillars aren’t moved to the proper host plant quickly, they will die.

Pipevine Swallowtail butterfly red burgundy eggs Battus philenor

Pipevine Swallowtail butterfly eggs

Pipevine Swallowtail caterpillars dark burgundy and lighter burgundy

Pipevine Swallowtail caterpillars
Left: was eating in a shady location
Right: was exposed to more sunlight

A similar butterfly species, Gold Rim Swallowtail (also called Polydamas Swallowtail) butterflies use pipevine plants as host plants also. Burgundy eggs are from Pipevine Swallowtail butterflies and gold eggs are from Gold Rim Swallowtail butterflies.

Gold Rim and Pipevine Swallowtail butterfly eggs

Gold/yellow Gold Rim Swallowtail eggs
Burgundy/red Pipevine Swallowtail eggs

Young caterpillars tend to be gregarious, staying together as they eat and molt. They are often on the underside of a leaf, not visible as we walk by their plant. The pattern of eating clues us in to the fact that there are caterpillars hidden under the leaf.

Caterpillars exposed to more light tend to lighten in color. Instead of a mid to deep burgundy, almost black color, they become lighter in color.

Pipevine Swallowtail butterfly caterpillars

Pipevine Swallowtail butterfly caterpillars
Left: was living in shade
Right: was living in full sun

As they grow larger, they tend to separate a bit more, often becoming solitary by the time they are late instar caterpillars.

Pipevine Swallowtail caterpillars

Pipevine Swallowtail caterpillars
on White Veined Pipevine

Pipevine Swallowtail osmeterium is yellow/orange. The caterpillars often extend these glands when they are disturbed. The osmeterium are coated with a bad smelling liquid.

Pipevine Swallowtail butterfly caterpillar with extended yellow/orange osmeterium

Pipevine Swallowtail butterfly caterpillar
with extended yellow/orange osmeterium

Pipevine Swallowtail butterfly caterpillar

Pipevine Swallowtail butterfly caterpillar

Pipevine Swallowtail butterfly caterpillar prolegs

Pipevine Swallowtail butterfly caterpillar prolegs

Some species of pipevine, such as the Virginia Snakeroot, may be so small that one caterpillar will need to eat several plants before it grows large enough to pupate.

Pipevine Swallowtail caterpillar on Virginia Snakeroot

Pipevine Swallowtail caterpillar on Virginia Snakeroot

Older Pipevine Swallowtail caterpillar on Virginia Snakeroot

Older Pipevine Swallowtail caterpillar on Virginia Snakeroot

Before pupating, the caterpillar will empty its digestive system in a messy blob. This is known as a ‘frass dump’. It is wet and stains rearing habitats and containers.

Pipevine Swallowtail frass dump before pupation

Pipevine Swallowtail frass dump before pupation

When preparing to pupate, they create a silk pad and silk button. Attaching their anal prolegs to the silk button, they create a silken girdle, made of many loops of silk. Ducking their heads into their girdles, they work the girdle to the middle of their bodies. A day later, they pupate.

Pipevine Swallowtail caterpillar preparing to pupate look silk girdle

Pipevine Swallowtail caterpillar preparing to pupate, ducking into its silk girdle

Freshly pupated, the new chrysalis is often bright yellow. It often changes color as it dries.

Older Pipevine Swallowtail in the midst of pupation

Older Pipevine Swallowtail in the midst of pupation

Fresh Pipevine Swallowtail butterfly chrysalis

Fresh Pipevine Swallowtail butterfly chrysalis

Chrysalises will be brown or green, depending on their surroundings when they pupate

Chrysalises will be brown or green, depending
on their surroundings when they pupate

Male Pipevine Swallowtail butterflies are metallic blue on their hindwings. Females have metallic black in their hindwings.

Female Pipevine Swallowtail's are metallic black

Female Pipevine Swallowtail’s are metallic black

Male Pipevine Swallowtails are metallic blue on their hindwings

Male Pipevine Swallowtails are
metallic blue on their hindwings

Several species of swallowtails have orange spots underneath their hindwings. Pipevine Swallowtail’s orange spots are arranged in a tight J. Other species are arranged in more of a relaxed C.

Pipevine Swallowtail butterfly orange spots tight J

Pipevine Swallowtail butterfly
orange spots form a tight J shape

Pipevine Swallowtail butterflies spend the winter in diapause in chrysalis stage. The last generation of the year will overwinter in chrysalis and emerge in the spring, when pipevine plants put on new leaves.

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