Eastern Black Swallowtails

Eastern Black Swallowtails (Papilio polyxenes), commonly known as "those little monsters eating my herb garden!" are found in Central Florida area during late spring and early summer. With a range north to Quebec, south to Florida and west to Colorado and Southern California they are a well known and common Swallowtail species throughout most of the United States. Black Swallowtails are especially interesting to raise, as they go through a variety of "costume changes" as they molt between instars. Eggs are a pearly green or white, and spherical in shape. Initially, the caterpillars resemble the larvae of Giant Swallowtails (Papilio cresphontes), being black with a white patch midway down their bodies.
As they grow and molt, the caterpillars take on a different appearance, with third, fourth, and fifth instars looking quite different from the first two.

Black Swallowtails, like other members of the swallowtail family, have osmeterium, fleshy appendages that they can push out from their heads when they feel threatened. These protuberances are covered in an oil that the caterpillars sequester from their host plants, and give off a fairly awful smell to drive off predators. Black Swallowtails have a smell rather like rotting fresh paint (if you can imagine such a thing).

The chrysalis of this species may be either brown or green in color and both are wonderfully camouflaged on their bright green host plants looking alternately like foliage or a small bit of wood or dead leaf.

Adult butterflies often have a wingspan measuring between 3 1/4 and 4 1/4 inches, making them a fairly large and easy to spot insect. Male Black Swallowtails can often be observed patrolling open fields and marshes, searching for a female of their species. Adult males have a wide band of yellow on their wings while females tend to have much less yellow and more blue coloration. It has been suggested that blue coloring on the females of the species serves to mimic the Pipevine Swallowtail which predators find distasteful. This ensures that females may have a longer lifespan in which to deposit their eggs on host plants. Black Swallowtail butterflies also strongly resemble Spicebush Swallowtails (Papilio troilus), but can be distinguished by the tiny black dots found in the orange spots at the base of the lower wings.

Parsley is the best-known host plant for these caterpillars, who will also eat fennel, dill, Queen Anne's Lace, and other members of the carrot family. Black Swallowtails also use Common Rue (Ruta graevolens) as a host plant, though it seems a secondary choice if others are available. Learn more about their herb host plants here. In the wild, Black Swallowtails also use native Mock Bishop's Weed here in Florida.