native plants
Pawpaws Attract the Elusive Zebra Swallowtail Butterfly by Carol Bales
This is the eleventh of a series of Cape Fear area native plant articles to appear in Going Green. The articles will include stories about common native plants that would enhance any coastal North Carolina garden or landscape. I spotted my first Zebra Swallowtail at the Zilker Botanical Garden in Austin, Texas–a large, 358-acre tract of land that encompasses Barton Springs with a natural spring winding through the park. The gardens attract numerous varieties of butterflies and moths, most of which are native to the geographical area. Butterfly enthusiasts transformed an acre of the garden into a butterfly trail. At my first sighting of this butterfly, I was careful to identify the Zebra as a swallowtail and not a Zebra longwing. Since then, I have been researching this wonderful butterfly in the hopes of learning to attract it to my own yard in North Carolina. I’d like to share some resources you might find helpful if you’d like to get better acquainted with this beautiful butterfly.
The first reference I would like to recommend is Wildflowers & Plant Communities of the Southern Appalachian Mountains and Piedmont—A Naturalist’s Guide to the Carolinas, Virginia, Tennessee, and Georgia by Timothy P. Spira. In the book, he describes the host plant—the pawpaw tree (Asimina triloba)—that Zebra swallowtails use exclusively as the only food for their caterpillars, and that is where they lay their eggs. As Spira reminds us, butterflies have co-evolved with the plants that support their young. Zebra Swallowtail caterpillars eat only pawpaw leaves; Zebra Longwings consume passion vines. Spira says he was sleuthing around the forests looking for native plants and insects when he came upon a pawpaw patch and some Zebra Swallowtail Butterflies. I have been trying to attract Zebra Swallowtail butterflies to my Wilmington yard for at least ten years but haven’t spotted any yet in my gardens. About ten years ago, I planted two sturdy pawpaw saplings in my backyard, knowing that they would not bear any fruit for at least five years. They are now about 30 feet tall, and they produce many delicious pawpaw “Custard apples” that we enjoy eating and sharing with neighbors. A couple of years ago, I joined a UNCW naturalists’ walk through Holly Shelter Game Land and was delighted to spot a beautiful Zebra Swallowtail flitting around some young Pawpaw trees. So, I know that these creatures are close by, and I hope to see one soon near my home. While I wait for spring to come, I have been researching this elusive butterfly. Butterflies are part of the botanical order of Lepidoptera, and the Zebra Swallowtail is part of the species of Kite Wing butterflies, Eurytides philolaur. The botanical order for these butterflies has been changed lately to Protographium marcellas (Cramer). Those who study butterflies are called lepidopterists. These scientists share results of their research by writing books and articles that are available in most bookstores, online and libraries.
photo © Sara Bright
Zebra Swallowtail caterpillars feed only on pawpaw trees, a native tree with distinctively-shaped flowers.
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One reference is The Butterfly Effect: Insects and the making of the Modern World by Edward D. Melillo. This book explains the
Cape Fear’s Going Green • Spring 2022
photo © Sara Bright
Zebra Swallowtails lay their eggs on pawpaw leaves, ensuring the emerging caterpillar will have a ready food source.
proboscis and how butterflies use this organ to feed. The proboscis is an interesting organ that is used after a caterpillar transforms into a butterfly. It is an elongated tube-shaped organ that allows a butterfly to extract nectar from flowers or take up salts and minerals from the ground. Because of the organ’s flexibility, the butterfly can use it to access flower blossoms of all different shapes. The proboscis is in two pieces, as if you’d cut a straw lengthwise. The butterfly uses its front legs to press the two pieces together from root to tip, so it can be used to suck nectar from a flower. When not being used, a butterfly’s proboscis is rolled up out of the way. Another reference I found, Wings in the light: Wild Butterflies in North America by David Lee Myers, is particularly interesting. It has many photos, one of which is a Zebra Swallowtail nectaring on wildflowers below a pawpaw tree. Another is a close-up photo of the butterfly’s proboscis with its sensilla—a sense organ used while visiting nectar sources—at the tip. When I lived in Austin, Texas over 25 years ago, I was fortunate enough to create the Austin Butterfly Forum (ABF), which included a few butterfly enthusiasts and local lepidopterists. It was one of many gardening organizations of Zilker Botanical Garden. The Austin Butterfly Forum was started by a dozen butterfly enthusiasts on a freezing night in February. We met monthly to learn about the butterflies of Travis County. Now, the ABF has grown to about 1,500 members. —Carol Bales (continued on page 7)
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