Spicebush swallowtails excel in deception and camouflage throughout their lifecycle. As adults, they employ Batesian mimicry by imitating the pipevine swallowtail (Battus philenor) . Pipevine swallowtail larvae consume plants with aristolochic acids, which are retained through their life stages, making them unpalatable to predators. By adopting a similar color pattern, spicebush swallowtails confuse potential predators, gaining some protection from being eaten.
But the deception doesn’t end there!
Egg
Females use both visual and chemical cues when finding host plants on which to oviposit her eggs. After landing on a plant, a female confirms the plant as a host plant by drumming the surface of a leaf with her forelegs. She then will lay a single egg on the undersides of leaves of host plants to keep them hidden from wasps and other predators. Eggs are spherical and greenish-white or white in color and transparent.
While the spicebush (Lindera benzoin) plant is the primary host plant for the spicebush swallowtail caterpillars, they can also feed on a few other plant species including sassafras (Sassafras albidum), camphor (Camphora officinarum), redbay (Persea borbonia) and perhaps prickly ash (Zanthoxylum americanum), tulip tree (Liriodendron tulipifera), and sweetbay (Magnolia virginiana).
Caterpillar
All five instars of the spicebush swallowtail caterpillar is marked by visual deception and hiding from detection. The earlier stages of the caterpillar are camouflaged to look like bird droppings. In later stages caterpillars develop two pairs of false eyespots on their body, which are believed to be a mimicry of either green snakes or tree frogs.
Early instar caterpillars look like bird droppings.As the caterpillar grows, it turns green with large, false eyespots that make it look like a small snake, providing further protection from predators.
Spicebush Swallowtail larvae are leaf-rollers. They create shelters for by first cutting and pulling small sections of leaves around themselves to hide from predators. As they grow larger, they wrap up in entire leaves, and fifth-instar caterpillars may even stitch several leaves together. The caterpillar then hides in the shelter during the day and emerges at night to eat. This simple way of rolling a leaf as a shelter is one of the amazing ways that they’ve adapted for survival.
First instar spicebush caterpillars are hidden inside the rolled up leaf.
If their clever camouflage and sheltering tactics fail, they have another defense mechanism. At each larval stage, they possess bright orange, horn-like organs called osmeteria. When disturbed, these organs emerge behind the caterpillar’s head and release an unpleasant odor, helping to repel potential predators.
The caterpillar’s osmeterium further enhances its snake-like appearance.
As the final instar larva prepares for pupation, it dons another cryptic disguise. The caterpillar turns a muted orange-yellow color. It is believed they do this to more closely resemble the leaf litter that it crawls around on when looking for a suitable site in which to anchor itself before forming the chrysalis.
Chrysalis
When the caterpillar is ready to form a chrysalis and pupate, it engages in one final act of mimicry. The chrysalis resembles a curled-up leaf. Caterpillars that pupate early in the season create a green chrysalis to blend in with the predominantly green leaves. However, if they pupate later in the season and will overwinter as pupae, the chrysalis turns brown, mimicking a dead leaf.
Adult
This species displays sexual dimorphism which means that males and females have different coloration. Males have hind wings with a pale green to yellow coloration. Females display a blue iridescent coloration.
Each of the sexes are able to exhibit mimicry of pipevine swallowtail (Battus philenor) successfully, even though the brighter-blue color on female wings is a little more vibrant than the pipevine swallowtail coloring.
The Papilio cresphontes, commonly known as the giant swallowtail, is the largest butterfly in North America. The giant swallowtail is widespread across the United States, from southern New England to southern Canada, and southward to Florida and the Caribbean. They are particularly common in the southeastern regions, including Florida.
Females have an average wingspan of about 5.5 inches (14 cm), while males can reach up to 7.4 inches (19 cm)
I find giant swallowtail butterflies incredibly fascinating due to their diverse adaptations to their environment and their unique defense mechanisms at each stage of their lifecycle.
Ventral view of giant swallowtail nectaring on orange blossom.
Egg
Females lay eggs on the tops of the leaves of one of their preferred host plants. This is because the first larval instars are unable to move from plant to plant, so the mother must select an appropriate plant to support them. One egg is lain at a time, as opposed to in clutches.
Egg found on wild lime (Zanthoxylum fagara).
Caterpillar
The larvae, known as “orange dogs,” have a unique defense mechanism. They resemble bird droppings, which helps them avoid predators.
When threatened, the caterpillars can extend a forked, orange-red gland called an osmeterium from behind their heads. This gland emits a foul-smelling chemical to deter predators.
Chrysalis
The chrysalis is mottled brown and green, resembling a twig or leaf to blend in with its surroundings. The giant swallowtail can only overwinter in warmer climates, such as Florida and the deep South, so in colder regions their pupae will enter a state of diapause to survive the freezing wintertemperatures.
This giant swallowtail chrysalis is perfectly camouflaged making it difficult for predators to detect.
Adult
Adult giant swallowtails have a distinctive, erratic flight pattern. They often glide and flap their wings in a slow, deliberate manner, which can make them appear larger and more intimidating to potential predators.
Male giant swallowtails sometimes engage in puddling, where they gather on moist ground to extract minerals and salts, which are essential for reproduction.
An eastern tiger swallowtail on the left and a giant swallowtail on the right sipping nutrients from mud.
The female swallowtails use a large variety of host plants to sustain their growing population. They use their antennae to detect the scent of the plants, and then use their feet to determine if it is a correct plant to lay their eggs.
Females use a variety of trees and plants to lay their eggs, including Orange (Citrus sinensis), Wild Lime (Zanthoxylum fagara), Hoptree (Ptelea trifoliata), Hercules Club (Zanthoxylum clava-herculis), Common Rue (Ruta graveolens), and Torchwood (Amyris elemifera ).
The giant swallowtail’s ability to adapt to different habitat and climates allows it to flourish across a wide area. Recently, its range has expanded northward, a change attributed to rising temperatures and absence of September frosts in these new regions. This has enabled larvae to survive before pupating. The immediate effects of this warming, as well as their effect on host plants, can explain the giant swallowtail’s range expansion. (Finkbeiner, Susan D.; Reed, Robert D.; Dirig, Robert; Losey, John E. (2011-07-01). “The Role of Environmental Factors in the Northeastern Range Expansion of Papilio cresphontes Cramer (Papilionidae)”. Journal of the Lepidopterists’ Society. 65 (2): 119–125.
The Eastern Tiger Swallowtail butterfly(Papilio glaucus) is a prevalent and stunning butterfly found in the eastern regions of North America. Its range extends from Ontario down to the Gulf Coast and northern Mexico, east of the Rocky Mountains. These butterflies are active from spring to fall, often soaring above deciduous forests, woodlands, and streams. They are also commonly seen in residential gardens, parks, and orchards.
Characteristics
Tiger Swallowtails boast an impressive wingspan of up to 6 inches (15 cm), ranking them among the largest butterflies in North America. Their hindwings feature long, pointed tail extensions, which give them their characteristic swallowtail appearance.
The color of the eastern tiger swallowtail can vary. Males are yellow or yellow-orange with black tiger stripes. Their wings are bordered in black with yellow spots, and they have black “tiger stripes” running across the top of their wings. Their long black tails have blue patches on them.
Females come in two forms. The yellow form resembles the male but has additional blue shading on the hindwings. The black form is called dimorphic coloration, which adds a level of protection by mimicking the distasteful Pipevine Swallowtail. These females often exhibit a shadow of the “tiger” stripes.
Host and Nectar Plants
The Eastern Tiger Swallowtail utilizes a large variety of host plants, mostly trees, such as cottonwood, ash, birch, wild black cherry, tulip tree, sweet bay (magnolia), and willow.Adult Eastern Tiger Swallowtails feed on nectar from flowers. Their long proboscis allows them to access nectar deep within the flowers. They are attracted to a wide variety of flowers, including native milkweeds, phlox, lilac, ironweed, Joe Pye weed, Gayfeather, tall verbena, Mexican sunflowers, pentas, purple coneflowers, and zinnias.
Tiger Swallowtails are solitary, preferring to spend most of their life in the canopy of deciduous trees. Recently hatched larvae spend their days resting in a silken hammock attached to a leaf. At night they will begin feeding on their host plant.
Males will form large groups is when they participate in a behavior called puddling, in which they congregate on mud, damp gravel or puddles. They extract sodium ions and amino acids from these sources which aid in reproduction. Females will occasionally puddle, but do not form congregations. Adults have also been seen feeding on dung, carrion, and urine.
Male Tiger Swallowtail sipping nutrients from feces.
Lifecycle
Egg Stage: Female eastern tiger swallowtail butterflies lay their greenish eggs singly on the upper surface their host plants. Each female can lay up to 250 eggs. The eggs are small, round, and greenish yellow.
Caterpillar Stage: After about a week, the eggs hatch into tiny caterpillars. Initially, the caterpillars are brown and white, resembling bird droppings, which helps protect them from predators. As they grow, they turn bright green with two large, false eyespots on their thorax, which can startle predators.
Like all swallowtails, the caterpillar of Papilio glaucuspossesses an osmeterium, an orange, fleshy organ that emits foul-smelling odor repel predators. Normally hidden, the osmeterium is located on the first segment of the thorax and can be everted when the caterpillar feels threatened. The combination of eyespots and osmeterium makes the caterpillar resemble a snake.
Chrysalis Stage: The chrysalises can range from beige to dark brown to green which helps it to blend in the environment and protect it from predators. The larvae that experience the shortening days of late summer will enter diapause after transforming into pupae. The pupae stop developing throughout the winter and wait for increasing day length and warmer temperatures. They produce glycerol and trehalose, which act like antifreeze to protect them from freezing. These pupae emerge as the first eastern swallowtails you see in the spring.
Adult Stage: The adult butterfly has a lifespan of 2 weeks.
Once considered a single butterfly with a vast range, there are four other distinct species of tiger swallowtails:
Western Tiger Swallowtail (Papilio rutulus)
The normal range of the western tiger swallowtail covers much of western North America, from British Columbia to North Dakota in the north to Baja California and New Mexico in the south.
Two-tailed Swallowtail (Papilio multicadata)
The two-tailed swallowtail is found in western North America from British Columbia to Central America. It is the state butterfly of Arizona
Canadian Tiger Swallowtail (Papilio canadensis)
The Canadian tiger swallowtail is found in North America from central Alaska southeast across Canada and the northern Great Lakes states to northern New England.
The Appalachian tiger swallowtail is a cross between the Eastern tiger swallowtail and the Canadian tiger swallowtail. The butterfly is found in the eastern United States, specifically in the Appalachian Mountains, ranging from Pennsylvania to Georgia.
The tiger swallowtail butterfly is not considered to be a threatened or endangered species. However, as with many other butterfly species, their populations may be declining due to habitat loss and other human activities. It is important to protect and preserve their habitats to maintain healthy populations of tiger swallowtail butterflies. Click here to learn how to create a butterfly garden that will attract these majestic butterflies.
The eastern tiger swallowtail is the state butterfly of Alabama, Delaware, Georgia, North Carolina and South Carolina, and is the state insect of Virginia.
Native plants offer several benefits, making them a great choice for landscaping and gardening. Choose native plants that thrive in your specific region. They’re adapted to local ecosystems, which means they’ll require less water, fertilizer, and maintenance.
Pollinator populations have declined significantly in recent years, mainly due to habitat loss. Homeowners can help by creating pollinator-friendly gardens. Here are some of the best native pollinator plants to include in your yard.
This North American native with cheerful daisy-like flowers provides a food source for many pollinators at a time of year when other food sources are scarce. Endangered monarch butterflies feed on the nectar in preparation for their journey south. Zones: 3-10, depending on variety Exposure: Full sun to partial shade Height/Spread: 1 to 6 feet tall, 1 to 4 feet wide Bloom time: Summer to fall
This native has flowers spikes that provide nectar and pollen for a wide range of bees, butterflies and beneficial moths. The larvae of liatris flower moth feed on the flowers and seeds, while liatris borer moth larvae eat the stems. Zones: 3-9, depending on variety Exposure: Full sun Height/Spread: 1 to 5 feet tall, 6 inches to 2 feet wide Bloom time: Summer to fall.
Whorls of red, purple, pink, or white tubular flowers provide a steady source of food for bees, butterflies, and hummingbirds.
Zones: 3-9 Exposure: Full sun to partial shade Height/Spread: 1 to 4 feet tall, 1 to 3 feet wide Bloom time: Late spring to fall
Rudbeckia has a prolonged bloom time that attracts butterflies and other pollinators. The late season seed heads attract finches and other birds. It is a larval host plant to Wavy-lined Emerald (Synchlora aerata) and to Silvery Checkerspot (Chlosyne nycteis) butterflies. It is an important nectar plant for fall-migrating monarch butterflies.
Zones: 3-9, depending on variety Exposure: Full sun to partial shade Height/Spread: 1 to 3 feet tall, 1 to 3 feet wide Bloom time: Late spring to fall
Famous for its cheerful color and extended bloom time, draw nectar-loving bees and insects, while their seeds attract granivorous birds like sparrows and finches.
Zones: 3-9, depending on variety Exposure: Full sun Height/Spread: 24-30 inches , 24 inches wide Bloom time: Mid-summer to fall
Hawkmoths and bees are attracted to this native and migratory hummingbirds fuel up on the nectar during their journey north. Zones: 3-9 Exposure: Full sun to partial shade Height/Spread: 8 to 36 inches tall, 8 to 24 inches wide Bloom time: Mid-spring to early summer
This native with cone-shaped flowers in an array of colors is one of the best summer bloomers for supporting a wide range of pollinators. Butterflies including monarchs, fritillaries, swallowtails, and painted ladies feed on the sweet nectar. Zones: 3-9 Exposure: Full sun Height/Spread: 1 to 5 feet tall, 1 to 2 feet wide Bloom time: Summer
Goldenrod is an essential native plant with yellow flower plumes that support late season pollinators such as native bees, bumble bees, honey bees, butterflies, beetles, flies, moths, and wasps. Zones: 3-8, with some to Zone 9 Exposure: Full sun to partial shade Height/Spread: 1 to 7 feet tall, 1 to 6 feet wide Bloom time: Late summer to fall
The lavender nectar-rich flowers are highly attractive for butterflies, bees and hummingbirds.
Zones: 3-10, depending on variety Exposure: Full sun Height/Spread: 3 to 8 feet tall, 1 to 3 feet wide Bloom time: Mid-summer to fall
Ironweed is a magnet for butterflies and is listed by the Xerces Society as having special value to native bees. Ironweed is the larval host plants for the Ironweed Borer moth. Zones: 3-10, depending on variety Exposure: Full sun Height/Spread: 2 to 8 feet tall, 3 to 5 feet wide Bloom time: Mid-summer to fall
The showy flowers of this native plant are an essential late season food source for hummingbirds, bumble bees, honey bees, wasps, and butterflies such as swallowtails, skippers, red admirals, and fritillaries. Migrating monarch butterflies feast on the nectar-rich flowers as they make their journey south. Zones: 3-9, depending on variety Exposure: Full sun to partial shade Height/Spread: 3 to 8 feet tall, 1 to 5 feet wide Bloom time: Mid-summer to fall
Milkweed is one of the most important pollinator-friendly plants and the sole food source for monarch butterfly larvae. The flower nectar, pollen, and leaves are food sources for a wide range of bees, wasps, hoverflies, beetles, butterflies, and moths.
Zones: 3-9, depending on variety Exposure: Full sun Height/Spread: 1 to 6 feet tall, 1 to 3 feet wide Bloom time: Summer
Salvia is a mint relative with nectar-rich flowers that appeal to a wide range of pollinators. The colorful tubular or open-faced flowers attract hummingbirds, butterflies, native bees, bumble bees, and honey bees. Zones: 4-10, depending on variety Exposure: Full sun Height/Spread: 1 to 5 feet tall, 1 to 6 feet wide Bloom time: Late winter to fall, depending on variety
The cheerful disc-shaped flowers provide a continuous source of nectar. Pollinating insects that feast on the flowers include carpenter bees, leaf cutter bees, long-horned bees, and sulphur butterflies. Zones: 3-9 Exposure: Full sun Height/Spread: 1 to 4 feet tall, 1 to 3 feet wide Bloom time: Late spring to fall, depending on the variety
The nectar-rich flowers are a feast for the butterflies.
Zones: 3-9 Exposure: Full sun, partial shade Height/Spread: 6-12 inches tall/ 12-36 in. wide Bloom time: Spring-fall, depending on variety
Pollinator Partnership has ecoregional planting guides which are tailored to specific areas of the United States and Canada.
Milkweed has a fascinating pollination mechanism that sets it apart from many other flowering plants! Milkweed flower clusters consist of multiple individual flowers that arise from the stems of a single branch.
Each individual flower consists of five petals that are fused to form a distinct shape, often described as resembling a star or a crown known as the corona. The corona contains specialized structures called hoods and horns. The hoods hold the nectar that attracts bees and butterflies and other pollinators.
Enclosed within the corona is a structure called the gynostegium, or stigmatic chamber. This reproductive chamber has 5 vertical slits called stigmatic slits around its perimeter. These slits allow access to the female ovaries and male pollinia within it.
Instead of being loose grains, as is typical of most flowers, the pollen in milkweed is packaged within sticky structures called pollinia (singular: pollinium) which are masses of pollen grains that stick together and are located in the gynostegium.
Pollinia from common milkweed attached to the hind foot of a bee.
When insects land on the hoods of the flowers to feed on nectar, their foot slips into the stigmatic slit. Inside the stigmatic slit, insects come in contact with the pollinia. The stigmatic slit essentially “captures” the insect’s leg or foot, ensuring effective pollen transfer.
For pollination to occur:
An insect is attracted to the flower’s nectar and lands on one of the five hoods.
The insect’s leg or appendage slips into the stigmatic slit (that acts like a trap door) between the hoods and touches the pollinia.
The insect pulls its leg out, bringing the pollinia with it.
Male conopid fly, Physocephala furcillata, on common milkweed with pollinia on front leg.
The insect visits another milkweed flower and accidentally slides its leg into the slit again.
The insect extracts its leg, dislodging the pollinia, which is then transferred to the flower and completes pollination.
While this method ensures cross-pollination, it can be risky for insects. If their legs get snagged on the filament holding the sticky pollinia sacs, they may become trapped. Smaller bees are especially vulnerable and can perish inside the flowers.
The milkweed’s unique pollination mechanism benefits the plant in several ways:
Cross-Pollination: By requiring pollinators to visit multiple flowers, milkweed promotes cross-pollination. This genetic diversity enhances the plant’s chances of adapting to changing environmental conditions.
Reduced Self-Pollination: The pollinia attachment system prevents self-pollination. This ensures that the plant receives pollen from a different individual, preventing inbreeding and maintaining genetic diversity.
Nectar Reward: Milkweed produces nectar as a reward for pollinators. In exchange for nectar, pollinators inadvertently transfer pollen between flowers, aiding in fertilization.
Seed Production: Successful pollination leads to seed production. Milkweed seeds are equipped with silky hairs that allow them to disperse easily in the wind, increasing the plant’s chances of colonizing new areas.
Overall, this intricate pollination mechanism ensures milkweed’s survival and contributes to the health of its ecosystem.
Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution by Anurag Agrawal. Click here to purchase book.The Milkweed Lands: An Epic Story of One Plant: Its Nature and Ecology by Eric Lee-Mäder (Author), Beverly Duncan (Illustrator) Click here to purchase.
Adult Eastern Tiger Swallowtails feed on nectar from flowers. Their long proboscis allows them to access nectar deep within the flowers. They are attracted to a wide variety of flowers, including 
