Pipevine Swallowtail Caterpillar
Summary: In general, Pipevine swallowtail caterpillars are not thought of as pests. In fact, some people plant Pipevines in their yard for the sole purpose of attracting the Pipevine swallowtail butterflies that these caterpillars eventually become.
The Pipevine swallowtail is a beautiful black butterfly that can develop a wingspan of more than three inches. As mature butterflies, Pipevine swallowtails are black in color, with metallic blue-green hind wings. Rows of white or yellowish-white dots separate the females from the males of this species. The underside of a Pipevine swallowtail's wings also has a beautiful pattern of bright orange spots, set against a metallic blue-green background. You might see these beautiful butterflies from April to the early fall, flitting about in gardens, meadows, roadsides and fields. If you grow Pipevine plants in your yard, you may even have the pleasure of observing these butterflies from your own kitchen window.
However, before the Pipevine swallowtail becomes a beautiful butterfly, it must first survive as a caterpillar. During breeding season, females of the species lay several rust-colored eggs on a Pipevine plant, typically on the underside of a leaf. Plants in the Pipevine family include Virginia Snakeroot and Dutchman's Pipe. These are the only types of leaves that the newly hatched caterpillars eat, so you won't find their eggs anywhere else.
Pipevine swallowtail caterpillars are unique in being able to eat plants in the Pipevine family, which are poisonous to most animal species. In fact, as the Pipevine swallowtail caterpillars eat these plants, they become poisonous themselves, at least to most predators. These caterpillars are more at risk from predators when they are young, before they have a chance to build up the Pipevine chemicals in their system. Therefore, young caterpillars stick together, eat lots of Pipevine and grow quickly, only venturing out to live on their own when they have become poisonous.
As full-grown caterpillars, Pipevine swallowtails aren't the cute fuzzy caterpillar species that you might let crawl along your finger. This particular species of caterpillar can grow to be more than two inches long and has substantial red spines on its black body. Once full-grown, these rather unattractive caterpillars move away from the host plant and form a cocoon, only to remerge in a few weeks or months (depending on the season) as a beautiful butterfly and start the cycle all over again by mating.
In general, many people enjoy seeing Pipevine swallowtail caterpillars, if only because they grow to be such beautiful butterflies. Some people even grow Pipevine plants in their yards to intentionally attract this species. As mature butterflies, Pipevine swallowtails can also help your flowerbeds because they pollinate plants seeking their sole food source, flower nectar. Pipevine swallowtails even do other butterfly species a favor by warding off predators. You see, even as adults, this species remains poisonous to most predators thanks to all of the Pipevine plants they munched on as caterpillars. Several butterfly species that closely resemble Pipevine swallowtails are avoided by predatory birds exactly for this reason.
When large amounts of these caterpillars are present, they can kill pipeline plants by eating all of the leaves, which could potentially make them a pest in the eyes of some people. However, in most cases, the treat of observing the beautiful Pipevine swallowtail butterfly is well worth any trouble caused by these hungry caterpillars.