Eastern Black Swallowtails

Eastern Black Swallowtails (Papilio polyxenes), commonly known as "those little monsters eating my herb garden!" are one of the most common butterflies found in the home gardens of the Tampa Bay area.

Although they start as tiny brown caterpillars, larvae quickly molt to a appear more white with black stripes and yellow dots. More mature caterpillars take on a pale green coloring instead of white. Larvae consume parsley, dill, fennel, rue celery, Queen Anne's Lace and carrot tops. Caterpillars can quickly defoliate these herbs, but the herbs will often flush back with new leaves after being denuded by many hungry caterpillars.


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.

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 males have a wide band of yellow on their wings and 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.

Male Black Swallowtails can often be observed patrolling open fields and marshes, searching for a female of their species. These 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.

The next time you are out in the garden, take a peek at your kitchen herbs and look for these colorful larvae or even their eggs. Black Swallowtail eggs are tiny white globes that look a great deal like miniature pearls.