SWALLOWTAIL BUTTERFLIES

photo by
Judy Gallagher

Swallowtails (Family: Papilionidae, Genera: Papilio, Eurytides, Battus)

Meadow Fritillary - Photo by Judy Gallagher

Common swallowtail species in their natural range in Northern VA include the Tiger Swallowtail (Papilio glaucus), which is the state butterfly of Virginia, the Spicebush Swallowtail (Papilio Troilus), the Black Swallowtail (Papilio polyxenes), the Zebra Swallowtail (Eurytides marcellus), and the Pipevine Swallowtail (Battus philenor). These are representatives of a family that includes the largest butterflies in North America.

Their wingspan is some 2 ½ to 5 inches, and they normally have prominent “tails” on the hindwings. The caterpillars (larvae) are distinctive, typically with forklike horns (osmateria) and many with bright warning coloration or a large eyespot.

Young caterpillars may be mottled, resembling bird droppings. Sexual dimorphism is common (two recognizable forms in a single species). In suburban settings, it is more common to see the Tiger and Black as their host plants are somewhat more widespread. Identification is easy for the Zebra and yellow form Tiger, each with distinctive color and markings. The Pipevine Swallowtail is a species, like the Monarch, that serves as a model that other species mimic. Predators avoid the distasteful

Pipevine and its look-alikes, including dark form female Tiger Swallowtails, Black Swallowtails and Spicebush Swallowtails.

Similar flight behaviors, as well as closely matched physical features have evolved in the mimics to confuse potential predators.

Variegated Fritillary - Photo by Judy Gallagher

What Swallowtail Butterflies Need	How Can We Help
Food and Water: All adult stage Swallowtails seek nectar plants for energy during their short reproductive lives, but they depend on particular plant species to lay eggs and host the hungry caterpillars. Different swallowtail species require different host plants. The Zebra needs pawpaw (Asimina spp.). The Pipevine swallowtail needs pipevine (Aristolochia spp.) The Spicebush swallowtail needs (no surprise) the native spicebush (Lindera benzoin) or sassafras (Sassafras albidum). Black swallowtail caterpillars feed on plants in the carrot family (Apiaciae), including Golden alexander (Zizia aurea), Rattlesnake master (Eryngium yuccifolium), as well as non-native members of the carrot family, such as dill, parsley, fennel and Queen Annes Lace. Tiger Swallowtail caterpillars feed on native deciduous tree species, including willows (Salix spp.), wild cherries (Prunus spp.) and tulip poplar (Liriodendron tulipfera).	Avoid using pesticides; broad spectrum insecticides kill all insects, including caterpillars and adult butterflies. If you are troubled by mosquitoes in your yard, avoid broadcast spraying and try these mosquito control methods instead. Choose sun-loving flowers. Native nectar plants are preferred because swallowtail butterflies recognize them. Recommended choices include coneflowers, milkweed, joe-pye weed, bee balm, sunflowers, blazing star (liatris), ironweed, dogbane, and goldenrods. Provide water. Butterflies will drink from shallow puddles and muddy or sandy areas.
Breeding: All butterflies undergo complete metamorphosis. This family of butterflies commonly produces anywhere from 1 to 3 flights (broods) per year. Eggs are laid singly on host plants, hatching in 4-10 days. Caterpillars mature in 3-4 weeks and the upright pupa stage lasts 10-20 days. The adult butterfly phase of mating and egg laying commonly lasts around 2 weeks.	The host plants mentioned above are required for the larval stage of Swallowtails to survive and thrive. If you have native Black cherry, Spicebush, Sassafras, Tulip poplar, or Pawpaw, growing in your yard, preserve them and you'll increase the populations of Swallowtail butterflies visiting your yard and beyond. If you have an herb garden, plant a few extra plants of dill, parsley, and fennel to support the Black swallowtail caterpillars that are likely to be attracted to these plants. Remember that having butterflies means having caterpillars, and caterpillars eat leaves. This means to support butterflies in your landscape you must tolerate some plant leaves appearing chewed and eaten – that’s good! It means you’ve helped raise a butterfly! Male swallowtails will often gather to extract minerals from the soil to help produce sperm. This is called puddling.
Shelter: Adult Swallowtails are on the move almost constantly during their short lives. They may perch for the night, or during storms, under leaves or branches of shrubs or trees. Eggs and caterpillars (larvae) are vulnerable, not so much to predators, as from simple loss of habitat. They need the plants mentioned above in order to survive. On these plants, the caterpillar spends its life feeding and molting several times as it grows. The final molt produces the pupa, or chrysalis, during which stage it does not feed. Swallowtails over-winter in the pupa stage.	Swallowtail habitat typically includes trees in close proximity to their nectar sources. Woodland edges, fields and meadows are the natural habitat of most of these species, while marshes, water courses and floodplain forests attract the Zebra Swallowtail in particular. Include some large shrubs or small trees on the periphery of your butterfly garden. Along with spicebush and sassafras, many native shrubs grow large enough to provide shelter, for example native cherries (prunus species, such as common chokecherry) and many viburnum species. Inkberry Holly and Eastern Red Cedar provide thick, evergreen cover and windbreaks.
Resources: Want to know about which host plants will attract Swallowtails or other butterfly species? Several organizations publish lists of native Virginia host plants. Other organizations that promote pollinator conservation and provide information about increasing their habitat include Xerces Society and Pollinator Partnership.	Piedmont Environmental Council list of larval host plants of selected lepidoptera in Virginia Virginia Native Plant Society articles about individual butterflies and their host species, such as Pipevine swallowtails. Lewis Ginter Botanical Garden list of host plants. “Butterflies of the Mid-Atlantic” by Robert Blakney and Judy Gallagher.