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Butterflies of Alabama
Glimpses into Their Lives
By Paulette Haywood Ogard, Sara Bright The University of Alabama Press
Copyright © 2010 The University of Alabama Press
All rights reserved.
ISBN: 978-0-8173-9145-4
CHAPTER 1
Using the Species Accounts
The eighty-four accounts that follow are designed to provide a glimpse of each species as we have come to know it through our years of field experience and our additional research. Although some of the information is rather technical, we have chosen to use "plain" language in these narrations so that they are accessible to those with various levels of knowledge. For this reason, we have also chosen to refer to plants and animals by their "common" or vernacular names. While there is no doubt that scientific nomenclature is the most efficient and consistent way to identify any organism, even parenthetically including these names within the accounts made them cumbersome and difficult to read. Therefore, each plant and animal mentioned by its common name within the accounts is listed with its Latin name in "Plant and Animal Associates."
With a few exceptions, we follow the Butterflies of America interactive Web site in its selection of specific butterfly names. In an effort to make this book consistent with the upcoming revision of Wildflowers of Alabama and Adjoining States, plant nomenclature is based on the soon-to-be published Annotated Checklist of the Vascular Plants of Alabama.
Sometimes we share the glimpses of others by quoting their exact words. Appropriate citations are found in the Notes.
It has never been our intent to produce a field guide — we leave that task to others; however, for the convenience of the reader, concise information, additional details that include identification tips, and range maps for each species are included in the Annotated Checklist.
Many of the photographs in this book were taken in Alabama. Sometimes, especially in the case of rare species, that was not possible. We have made every attempt to ensure that when photographed elsewhere, the butterflies, plants, and habitats are consistent with those that occur within this state.
CHAPTER 2
Swallowtails
The Papilionidae
Swallowtails are attention grabbers. Large and showy, these elegant butterflies are also powerful fliers. Each of Alabama's resident species have tailed hindwings that are reminiscent of a swallow's long, forked tails — hence their familiar common name.
Swallowtail caterpillars are also famous for forked appendages. They possess deeply cleft organs called osmeteria that aid in defense against predation. Normally hidden at the back of the head, caterpillars evert and then brandish these structures when danger threatens. Osmeteria emit foul-smelling secretions composed of terpenes, primary constituents of the essential oils found within the species' host plants. Small predators are repulsed, while humans wonder, "What is that funny smell?" Long thought to be unique to the swallowtails, greater fritillary larvae also possess osmeteria, but those of the swallowtails are brighter colored and more visible.
Most swallowtail eggs are large, round, and smooth. Chrysalides resemble broken branch tips or rolled leaves, and may be brown or green, depending on both surface and season. Fall's short day lengths typically generate brown chrysalides that blend with leafless winter landscapes. Longer summer days and smooth, leafy surfaces tend to trigger green pupal color, but brown chrysalides often dangle from rough surfaces like rocks or bark, regardless of season or photoperiod.
Taxonomically, the diverse swallowtail family is divided into three subfamilies. Papilioninae, the largest, is further divided into tribes (groupings of very closely related and similar species). Swallowtails from three tribes reside in Alabama: the Aristolochia Swallowtails, the Kite Swallowtails, and the Fluted Swallowtails.
Pipevine Swallowtails belong to the tribe of Aristolochia Swallowtails, and are its only representative in Alabama. Because they are able to sequester toxic chemicals from their host plants (Aristolochias) and use them defensively against predators, many other butterflies presumably mimic them. Unlike other swallowtails in our region, Pipevines lay their eggs in small clusters, and young caterpillars feed in groups.
Zebra Swallowtails are the only Kite Swallowtails that inhabit Alabama. Typically tropical, their elongated wing shape and tube-like hindwing margins are diagnostic. Pawpaws, shrubs and trees within the Custard-Apple family, function as caterpillar food plants.
The Fluted Swallowtails encompass the majority of Alabama's swallowtail species. The name originated because male hindwing margins are lightly rolled or "fluted." Early instar caterpillars resemble bird droppings and display a white, saddle-like mark on a dark, grainy body. Within this large tribe, Black Swallowtail larvae eat plants from the Carrot/Parsley family; Giants are Citrus family feeders; Palamedes/Spicebush Swallowtails are tied to the Laurels, and the Tigers claim many families as caterpillar hosts.
Pipevine Swallowtail Battus philenor
Pipevine Swallowtails are poisonous, and they openly advertise it. Their black upper hindwings shimmer with metallic blue, but their undersides are emblazoned with dramatic orange spots, a classic warning or aposematic color scheme known in the natural world to signal danger. Constant fluttering, even while nectaring, draws attention to these flashing neon danger signs. Their early warning system is so effective that Pipevine Swallowtails are often considered to be the center of a mimicry ring containing at least five species of butterfly impersonators. Because the copycats are also big, black and blue, orange-spotted butterflies, they all presumably gain some protection from predation.
What makes Pipevine Swallowtails so unpalatable? The answer is contained within their larval food, a group of plants collectively known as pipevines (or aristolochias). Pipevine clamors up treetops along stream and riverbanks. It is covered with large, heart-shaped leaves, and odd flowers (shaped like Sherlock Holmes' pipe) dangle beneath its foliage. Virginia-Snakeroot, another aristolochia, is a small, upright plant that grows sporadically in open woodlands. Both pipevine species contain aristocholic acids and cardiac glycosides, phytochemicals that render them distasteful and harmful to vertebrate predators. Pipevine Swallowtail caterpillars bypass toxic effects by sequestering molecules within their bodies. They keep these poison pouches throughout metamorphosis and into adulthood, passing deleterious effects to any predator inexperienced enough to ingest them. Like their parents, caterpillars employ aposematic warning coloration. Brown or black bodies are covered with two rows of short orange tubercles. Fleshy filaments complete the look. Bypassing typical swallowtail mimicry and camouflage techniques, their early instars do not resemble bird droppings. Emerging from small groups of dark orange eggs, caterpillars initially feed in groups, perhaps maximizing the visibility of their warning signals. Those feeding on pipevines generally have ample food supplies, but Virginia-Snakeroot eaters must scour the woodland floor for additional plants in order to satiate voracious appetites and complete larval development. Chrysalides occur in two color forms and are the only camouflaged life-cycle stage. Brown pupae resemble broken twigs or withered leaves while green chrysalides look like furled foliage.
Warning colors aside, early field guides referred to these butterflies as Blue Swallowtails for good reason. Their iridescent blue hindwings glisten and glimmer as they catch sunlight at different angles. In a world of butterfly mimics, Pipevine Swallowtails are beautiful — but dangerous — originals.
Zebra Swallowtail Eurytides marcellus
A large, black-and-white-striped butterfly flying in Alabama is a Zebra Swallowtail. Long-tailed and unmistakable, it flies in early spring, followed by a longer tailed summer generation. In good years, a third, extremely long-tailed brood is the seasons' finale.
Their tails may be long, but Zebra Swallowtails' proboscises are unusually short, limiting nectar sources to short-tubed flowers such as flowering plums and blackberries. Slender striped wings are adapted for both maneuverability and camouflage, allowing Zebra Swallowtails to flutter and swoop through woodland understories. Visually, their telltale stripes make them difficult to follow as they glide through dappled sunlight and shadows.
Look for Zebra Swallowtails near pawpaws, their only caterpillar food. In most of Alabama, there are two species: Common Pawpaw and Small-Fruit Pawpaw. Common Pawpaws are trees that grow near creeks and rivers and in floodplains. Large leaved and tropical in appearance, they bear meaty fruits that inspired "sweet little Susie to pick 'em up and put 'em in her pocket." Small-Fruit Pawpaws inhabit drier, open woods. As their name implies, foliage, flowers, and fruits are small in scale and can be easily overlooked in woodland vegetation.
Zebra Swallowtails are skilled pawpaw detectors and deposit globe-shaped eggs on twigs, flower buds, and velvety new leaves. Newly hatched caterpillars appear to be solid black specks, but after molting, they display camouflaging stripes. Enlarged thoracic segments create a curious humpbacked appearance, which exaggerates if danger is detected. When alarmed, caterpillars quickly extrude bright yellow osmeteria, blasting out foul-smelling chemicals derived from acetogenins, insecticidal pawpaw chemicals. Fifth instar caterpillars transform into short, stout chrysalides that are "shaped almost like the body of a pig," according to Philip Henry Gosse. Leafy green or bark brown, they are often attached to their pawpaw hosts.
Zebras belong to the worldwide group of Kite Swallowtails, a tropical genus named for its wing shape. They are the sole members that have adapted to our North American, less-than-tropical climate. Fortunately for Alabamians, Zebra Swallowtails are at home in our state wherever pawpaws abound.
Black Swallowtail Papilio polyxenes
Black Swallowtails are at home in gardens throughout Alabama. Drawn by showy, fragrant flowers, they linger in herb and vegetable gardens that include plants in the Carrot/Parsley family, their caterpillar hosts. Cultivated species include parsley, dill, fennel, and caraway. But Black Swallowtails range far beyond the garden. Meadows, prairies, wetlands, and woodland edges that support native carrots such as Hairy Angelica, mock bishopweeds, and naturalized Queen Anne's Lace are also prime Black Swallowtail habitat.
Gardeners who never noticed Black Swallowtail butterflies will be familiar with their striking green-and-black-striped caterpillars. Sometimes called parsley worms, they begin life as brown-and-white bird-dropping mimics but quickly transform into lean, green, eating machines. They devour entire plants, despite the fact that carrot family members are loaded with furanocoumarins, toxic chemicals which interfere with DNA processing. Black Swallowtails ingest large doses, rendering themselves mildly distasteful to hungry predators. Caterpillars do not wait to be tasted, but also engage in a "prevent defense." When danger is detected, they quickly puff up, rear back, and eject bright orange osmeteria from their heads. These organs spray foul-smelling bucolic acid at attackers. If defensive tactics are successful and caterpillars reach maturity, they form either brown or green chrysalides, depending on season and surface texture.
Butterflies retain some toxicity from caterpillar days and maximize this advantage by mimicking more highly poisonous Pipevine Swallowtails. Females are better impersonators. Their dorsal (upper surface) wings are close copies of Pipevine's solid black surface, clouded with shimmery blue. Male butterflies display bright yellow bands and only minimal blue scaling. Like their Pipevine Swallowtail model, both sexes display prominent orange spots on ventral (under surface) hindwings, advertising their bad taste with warning coloration and further confusing predators as to their true identity.
Giant Swallowtail Papilio cresphontes
Giant Swallowtails seem larger than life. With five-inch wingspans, they are not necessarily Alabama's biggest butterflies (female tiger swallowtails claim that distinction), but in the words of Philip Henry Gosse, they have "a magnificent appearance." Viewed from above, chocolate-brown butterflies are festooned with crisscrossed yellow bands. Seen from below, the color scheme is reversed: creamy yellow butterflies are delicately outlined and etched in blackest brown. Flapping wings create a gentle strobe effect, and as Gosse noted, "the contrast between prevailing colours of the upper and under surface is very observable as the insect floats carelessly along."
Giant Swallowtail caterpillars are magnificent in their own right. Like most swallowtails, earliest instars resemble bird droppings, but unlike the others, Giants never completely discard that disguise. Fully mature larvae present an impressive, if disgusting, countenance. Their mottled brown color pattern serves them well. In addition to creating the dung disguise, it also enables larger caterpillars to rest on similarly patterned tree bark, blending invisibly into that background. Gosse compared the color combination to a piebald horse, but it also brings to mind a small, scaly brown snake, perhaps discouraging meal-seeking predators. The frightening effect is accentuated when defensive caterpillars display bright red osmeterial glands, eerily reminiscent of a viper's forked tongue.
Their appetite for cultivated citrus plants is infamous, and Florida's commercial growers curse Giant Swallowtail caterpillars as "Orange Dogs" that damage their cash crops. In Alabama, larvae must rely on little-known Citrus family members for nourishment. Although herb gardeners may find them eating Common Rue, Giant Swallowtail populations depend on native citruses like Hoptree and Southern Prickly-Ash. Superficially, these small trees bear little resemblance to their culinary cousins. Rather than tart, round fruits, Hoptree produces dry, papery-thin, one-seeded fruits called samaras, and Southern Prickly-Ash bears clusters of husk-covered capsules that open to reveal dark, round seeds. Yet they contain the same ethereal oils responsible for typical citrus aromas, as well as the family's bitter-tasting triteripenes, alkaloids, and calcium oxalate crystals, all chemical deterrents to hungry herbivores.
Giant Swallowtails emerge from crusty chrysalides that look like broken branches. They avidly nectar at many different flowers, their constantly fluttering wings blurring their two-toned color scheme. Nonetheless, their appearance is undeniably magnificent.
Appalachian Tiger Swallowtail Papilio appalachiensis
Who would have guessed that hidden within one of America's most widely known and recognizable butterfly species was another similar but separate entity? Lepidopterists had long scratched their heads over unusually large, strangely shaped tiger swallowtails that seemed to fly only in the mountains, but it was not until 2002 that Harry Pavulaan and David Wright described and named a new species, Appalachian Tiger Swallowtail.
At first glance, "Appys," as they are often called, seem virtually identical to Eastern Tiger Swallowtails, but there are relevant and discernable differences in appearance, life history, and range. Appalachian Tigers are as much as 20 percent larger than first-generation Eastern Tigers, a size difference that is particularly noticeable when both species are seen puddling or nectaring side by side. Wing shape also differs. Appalachian hindwings are triangular rather than rounded, and edges appear stair-stepped rather than scalloped. While Eastern Tigers have multiple broods that stretch across temperate months, Appys are univoltine, flying only in spring and possibly into early summer, roughly between Eastern Tigers' first two generations.
Appalachian Tiger Swallowtails avidly seek flower nectar, and males frequently congregate in large puddle clubs in their search for minerals. Unfortunately, females are wary and reclusive, so details regarding reproductive behavior have been slow in coming. Currently, only Black Cherry is a confirmed host plant, but additional hosts are suspected. Range is limited to the Appalachian Mountains, where Appys are seasonally abundant, and at times, the most prevalent tiger swallowtail in the area.
(Continues...)
Excerpted from Butterflies of Alabama by Paulette Haywood Ogard, Sara Bright. Copyright © 2010 The University of Alabama Press. Excerpted by permission of The University of Alabama Press.
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