''Papilio troilus'', the spicebush swallowtail or green-clouded butterfly, is a common black swallowtail butterfly found in North America."Simply Butterflies," Accessed March 17, 2011, http://www.simplybutterflies.com/Backyard_Butterflies.html It has two subspecies, ''Papilio troilus troilus'' and ''Papilio troilus ilioneus'', the latter found mainly in the Florida peninsula.Hall, Donald; Butler, Jerry (Aug 2007). "Spicebush Swallowtail," ''Institute of Food and Agricultural Sciences, University of Florida''. http://www.edis.ifas.ufl.edu/pdffiles/IN/IN110700.pdf The spicebush swallowtail derives its name from its most common host plant, the

spicebush Dried fruits of ''Lindera neesiana'' used as spice (coll. MHNT) ''Lindera'' is a genus of about 80–100Papilionidae Swallowtail butterflies are large, colorful butterflies in the family Papilionidae, and include over 550 species. Though the majority are tropical, members of the family inhabit every continent except Antarctica. The family includes the larg ...

, or swallowtails, include the largest butterflies in the world. The swallowtails are unique in that even while feeding, they continue to flutter their wings. Unlike other swallowtail butterflies, spicebushes fly low to the ground instead of at great heights.Scott, James. ''Butterflies of North America''. Stanford: Stanford UP, 1986.

Distribution and habitat

The spicebush swallowtail is found only in the eastern US and southern Ontario, but occasionally strays as far as the American Midwest, Cuba, Manitoba and Colorado. While still larvae, spicebush swallowtails remain on the leaf of the plant on which they were laid. As adults, the butterflies do not limit their flight geographically and instead are motivated mostly by availability of water and nectar and mates within the species' range.Mickley, J. and A. Fraser (2006). "Papilio troilus" (On-line), Animal Diversity Web. Accessed March 30, 2011, http://animaldiversity.ummz.umich.edu/site/accounts/information/Papilio_troilus.html This primarily black swallowtail is normally found in deciduous woods or woody swamps, where they can be found flying low and fast through shaded areas. Females tend to stay in open plains,Scriber, J., Y. Tsubaki and R. Lederhouse. ''Swallowtail butterflies: their ecology and evolutionary biology''. Scientific Publishers: Gainesville, Fla. 1995. while males are typically found in swamp areas.

''Papilio troilus troilus''

The more widespread subspecies of spicebush swallowtail is prevalent throughout the Eastern United States, from New England to Wisconsin, west to Illinois, Wisconsin, North Dakota and Nebraska. It also abounds in Texas and Colorado.Hamilton, Tyler A. ''The Swallowtail Butterflies of North America''. Naturegraph: Heraldsburg, Calif., 1975. Temperature may be a limiting factor for the spread of ''P. t. troilus'', as in experimental conditions, they do not fare well at or above 36 °C (97 °F) nor are they capable of flourishing at or below 14 °C (57 °F) .Scriber, J. Mark, Keegan Keefover and S. Nelson, (2002). "Hot summer temperatures may stop movement of ''Papilio Canadensis'' butterflies and genetic introgression south of the hybrid zone in the North American Great Lakes Region." ''Ecography'' 25: 184-192.

''Papilio troilus ilioneus''

The smaller subspecies of ''P. troilus'' is confined to the Southeastern coastal United States, namely throughout Florida and along coastal Georgia and in places in Texas.

Description

''P. t. troilus''

Typically, the wingspan of a spicebush swallowtail ranges from ."Spicebush Swallowtail," Accessed March 14, 2011, Adults are primarily black/brown in color, with a trademark green-blue (male) or bright blue (female) splotch in the shape of a half moon on the hindwings. The forewing has a border of cream-colored, oval spots. In the middle portion of the wing, the spots can be moon shaped and a light blue in color. Both sexes have cream-yellow moon-shaped spots on the edges of the hindwings and a bright orange color spot at the base of the wings.Minno, Marc C.; Minno, Maria. ''Florida Butterfly Gardening: A Complete Guide to Attracting, Identifying, and Enjoying Butterflies of the Lower South''. Gainesville: UP of Florida, 1999. In females, the orange spot at the base of the wings will turn a greenish-white shade in summer, but not the spring. On the underside of the hindwing, there will be a dual row of orange spots, which distinguishes it from the pipevine swallowtail, which only has a single row of spots. In between these rows, there is more blue or green coloring.

''P. t. ilioneus''

The distinguishing difference in color between the two subspecies is evident where the spots, which are blue in color on the hindwing of the ''P. t. troilus,'' are more yellow in color in ''P. t. ilioneus''. Additionally, splashes of blue can trail all the way down the tail of ''P. t. ilioneus''.

Ecology

The host plants of the spicebush swallowtail are most commonly either

spicebush Dried fruits of ''Lindera neesiana'' used as spice (coll. MHNT) ''Lindera'' is a genus of about 80–100white sassafras (''Sassafras albidum'').Klots, Alexander. ''A Field Guide to Butterflies''. Boston: Houghton Mifflin, 1964. Other possible host plants include prickly ash (''Zanthoxylum''),Attributes of ''Papilio Troilus'', Accessed March 17, 2011, http://www.butterfliesandmoths.org/species/Papilio-troilus as well as

tulip tree ''Liriodendron'' () is a genus of two species of characteristically large trees, deciduous over most of their populations, in the magnolia family (Magnoliaceae). These trees are widely known by the common name tulip tree or tuliptree for their ...

(''Liriodendron tulipifera''), sweetbay (''Magnolia virginiana''), camphor (''Cinnamomum camphora'') and redbay (''Persea borbonia''). Redbay and swampbay (''Persea palustris'') are the primary host plants for members of the ''P. t. ilioneus'' strain, while spicebush and sassafras as the primary hosts for ''P. t. troilus''.Nitao, James; Ayres, Matthew; Lederhouse, Robert; Scriber, Mark J. (Aug 1991). "Larval Adaptation to Lauraceous Hosts: Geographic Divergence in the Spicebush Swallowtail Butterfly," Ecology 72 (4): 1428-1435. However, when given the choice between spicebush and sassafras, the ''P. t. troilus'' showed no significant preference for either.Carter, Maureen; Feeny, Paul; Haribal, Meena (1999). "An Oviposition Stimulant for Spicebush Swallowtail Butterfly, ''Papilio Troilus'', From Leaves of ''Sassafras albidum''." Journal of Chemical Ecology 25 (6). Additionally, ''P. t. ilioneus'' live only on redbay because that is the primary host plant within the Southern range. However, in a test of ''P. t. troilus'' and ''P. t. ilioneus'' on redbay, sassafras and spicebush, although the ''P. t. ilioneus'' had higher growth and survival rates on redbay than the ''P. t. troilus'', as a holistic group, both subspecies performed better on sassafras or spicebush over time. In general, spicebush swallowtails tend to stick to plants that are members of the family Lauraceae. The preference for Lauraceae is so consistent among spicebush swallowtails that under experimental conditions, when placed in an environment with leaves other than Lauraceae, ''P. troilus'' died without eating anything.Scriber, J. Mark, Michelle Larsen, Geoff Allen, Paul Walker and Myron Zalucki, (2008). "Interactions between Papilionidae and ancient Australian angiosperms: evolutionary specialization or ecological monophagy?" ''Entomologia Experimentalis et Applicata'' 128: 230-239. This fact is especially noteworthy because Lauraceae are distantly related to the host plants of other species that are food for ''Papilio'' caterpillars."Swallowtail Butterflies," Accessed March 17, 2011, http://www.uky.edu/Ag/CritterFiles/casefile/insects/butterflies/swallowtail/swallowtail.htm The fact that spicebush swallowtails live and feed primarily on Lauraceae only is noteworthy also because most other varieties of swallowtail butterflies are nowhere near as specific. Part of the reason for the selective nature of ''P. troilus'' and host plants may have to do with the requirement of positive stimuli to confirm that a plant is Lauraceae among ''P. troilus'' before they will feed on it, while '' P. glaucus'', for example, will at once try to feed on any plant presented to it. The insistence on feeding primarily on Lauraceae has its advantages for spicebush swallowtails. They are able to feed two to four times more adeptly and efficiently on Lauraceae than ''P. glaucus'' on the same plant, for example, who feed on Lauraceae as well as other types of plants. In addition, there has not been any other Lepidoptera species which feeds as efficiently as the ''P. troilus'' on spicebush. However, none of the host plants of ''Papilio troilus'' occur throughout the full range of the spicebush swallowtail. As stated above, the ''P. t. ilioneus'' strain, found in

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

, mostly feeds on redbay, while ''P. t. troilus'' feeds on either sassafras or spicebush. In a study, it was found that those spicebush swallowtails that normally feed on redbay did not grow as well on spicebush or sassafras during the first

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ...

of development, while all insects studied grew better throughout the larval period on sassafras or spicebush. In addition, the ''P. t. ilioneus'' strain was typically larger in size than the ''P. t. troilus''. In a recent study, 3-''trans''-caffeoyl-muco-quinic acid was found to be the substance that compelled spicebush swallowtails to lay their eggs on members of Lauraceae. However, 3-''trans''-caffeoyl-muco-quinic acid is a component of the extract from sassafras plants but not from spicebush, redbay or camphor tree, the other top three host plants of spicebush swallowtails. This substance is not necessarily itself the stimulant but instead activates another as yet unknown compound that thus compels the spicebush swallowtail to lay eggs. Thus, this substance may hold the link for why some spicebush swallowtails prefer to lay eggs on sassafras rather than spicebush. In addition, 3-''trans''-caffeoyl-muco-quinic acid is a member of a family of acids,

hydroxycinnamic acid Hydroxycinnamic acids (hydroxycinnamates) are a class of aromatic acids or phenylpropanoids having a C6–C3 skeleton. These compounds are hydroxy derivatives of cinnamic acid. In the category of phytochemicals that can be found in food, there ...

s, which are present in oviposition stimulants for some members of all five families of swallowtail butterflies. Hydroxycinnamic acids are also present in the extracts from host plants for two other species within the genus ''Papilio'': the black swallowtail butterfly, '' P. polyxenes'', and '' P. protenor''. Thus, hydroxycinnamic acids may help explain why many types of swallowtails choose to oviposit on the plants that they choose.

Food sources

Spicebush swallowtails gain sustenance from eight major sources.

Joe-Pye weed ''Eutrochium'' is a North American genus of herbaceous flowering plants in the family Asteraceae. They are commonly referred to as Joe-Pye weeds. They are native to the United States and Canada, and have non-dissected foliage and pigmented flowe ...

jewelweed ''Impatiens'' is a genus of more than 1,000 species of flowering plants, widely distributed throughout the Northern Hemisphere and the tropics. Together with the genus ''Hydrocera'' (one species), ''Impatiens'' make up the family Balsaminaceae. ...

, and

honeysuckle Honeysuckles are arching shrubs or twining vines in the genus ''Lonicera'' () of the family Caprifoliaceae, native to northern latitudes in North America and Eurasia. Approximately 180 species of honeysuckle have been identified in both conti ...

are favorite sources of nectar for the adults. They have also been known to drink nectar from

lantana ''Lantana'' () is a genus of about 150 species of perennial flowering plants in the verbena family, Verbenaceae. They are native to tropical regions of the Americas and Africa but exist as an introduced species in numerous areas, especially in ...

s, as well as

thistle Thistle is the common name of a group of flowering plants characterised by leaves with sharp prickles on the margins, mostly in the family Asteraceae. Prickles can also occur all over the planton the stem and on the flat parts of the leaves ...

milkweed ''Asclepias'' is a genus of herbaceous, perennial, flowering plants known as milkweeds, named for their latex, a milky substance containing cardiac glycosides termed cardenolides, exuded where cells are damaged. Most species are toxic to humans ...

s, azalea,

dogbane Dogbane, dog-bane, dog's bane, and other variations, some of them regional and some transient, are names for certain plants that are reputed to kill or repel dogs; "bane" originally meant "slayer", and was later applied to plants to indicate tha ...

mimosa ''Mimosa'' is a genus of about 590 species of herbs and shrubs, in the mimosoid clade of the legume family Fabaceae. The generic name is derived from the Greek word (''mimos''), an "actor" or "mime", and the feminine suffix -''osa'', "resemb ...

, and sweet pepperbush.

Life cycle

When female swallowtails decide which leaf to oviposit on, they frequently will drum their forelegs toward a leaf to identify it. Their forelegs have

chemoreceptor A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemorecept ...

s located in the foretarsi that assess the chemical makeup of the leaf and use that information to decide if it is an acceptable spot. In general, females have shorter and denser sensilla on their forelegs than males, which may be a result of their having to sustain frequent heavy strokes. The eggs of the spicebush swallowtail are greenish white in color, are fairly large and are laid one or two at a time on a spicebush leaf. Once hatched, the young larvae chew through the leaf from the edge to the midrib, about of an inch (19 mm) from the tip of the leaf. The larva lies on the midrib and exudes silk. Upon drying, the silk contracts and causes the leaf to fold up around the larva to form a shelter. At first, young larvae are brownish.Field Notes from the Beiser Field Station: October 7, 2008, The Spicebush Swallowtail, Accessed March 14, 2011, http://www.marietta.edu/~biol/biomes/spicebush.htm. The brown color of the larvae is independent of leaf color and will occur even on a green leaf.Shapiro, A.M., (1976). "Seasonal polyphenism." Evolutionary Biology 9: 229-253. A folded leaf serves as the home for the young larvae. During the day, the larvae remain in the shelter so as to avoid predators and come out at night to feed. Additionally, if larvae are disturbed while rolled up in the leaf, they emit a foul-smelling substance. When these larvae reach later stages, they turn greenish yellow before pupating. Older larvae live in a leaf, rolled up and lined with silk and held together by a line of silk. In order to pupate, the larvae will leave the shelter and find the underside of a leaf near the ground to do so. Upon discovery of a suitable leaf, the larvae begin the pupating process by emitting silk from their salivary glands, which helps attach the larvae to the branch or leaf. Then the larvae turn around while still emitting silk, which creates a "safety harness" for the pupating process."Spicebush Swallowtail," Accessed March 17, 2011, http://www.carolinanature.com/butterflies/spicebushswt.html At the end of the pupating process, the larvae have become pupae which are either brown (winter) or green (summer). The practice of turning either brown in winter or green in summer is called

seasonal polyphenism A polyphenic trait is a trait for which multiple, discrete phenotypes can arise from a single genotype as a result of differing environmental conditions. It is therefore a special case of phenotypic plasticity. There are several types of polyphe ...

. Because the color of the pupa reflects the color of the deciduous host plants, since the leaves will turn brown in winter and green in summer. Even in cases where the leaves are not yet brown, the pupa appear to turn that color in anticipation of the changing colors. Roughly three generations of spicebush swallowtails occur each year. Most develop into adults throughout the range between the months of February and November. The entire development process from egg to adult takes about a month."Tiger Swallowtail Butterfly," Accessed 27 April 2011, http://www.enchantedlearning.com/subjects/butterfly/species/Tigersw.shtml Once they have reached the adult stage, ''Papilio troilus'' can live anywhere from two days to two weeks dependent on resource availability and predator avoidance.

Feeding behavior

Spicebush swallowtails (along with '' P. palamedes'') are able to thermoregulate their thoraxes better than other ''Papilio'' species, perhaps due to their darker body and wing color. This allows them to fly and feed at lower temperatures than their counterparts.

Social behavior

Spicebush swallowtails often engage in '' puddling'', a type of behavior which occurs while adults are flying in search of food or mates. Puddling reflects the fact that while engaging in either feeding or mating behavior, i.e. when they are away from home, spicebush swallowtails tend to stay in groups. These groupings are typically located on the banks of water, such as sandy or moist ridges. When puddling in these groups, the ''Papilio troilus'' will extract moisture from the soil or sand near the water.

Mating behavior

In general, both sexes will copulate with several mates during mating season. However, each time a female mates, she becomes less likely to mate again. One key known form of communication among spicebush swallowtails occurs during mating. Visual cues are important for males to find females, and courtship displays can be elaborate. While these courtship displays occur, the female and male are often in contact, which is likely a way for them to relay information to one another. Additionally, the male butterfly will typically emit pheromones around the female butterfly and the female will use her scent to make her decision about mating. Females can often be found outside the treeline, in areas of direct sun. This may be due to the fact that these areas are in direct sunlight, which allows for higher thoracic temperatures. Males are less concerned with direct sunlight during mating because their thoracic temperature rises while performing vigorous courtship dances. Males may perform these courtship dances both to females perched on host plants as well as those flying freely.

Parental care

Once eggs are laid, formal parental care ceases among spicebush swallowtails. Larvae do have a nutrient-rich egg, which keeps them well fed during the developmental period. Also, as noted above, females are very particular about host plant choice that aids in the success of egg development.

Predators and avoidance

Predators

When threatened, a spicebush swallowtail butterfly exudes red drops of a foul-smelling liquid. Its many predators include

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...

s, robber flies, and

dragonflies A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threa ...

. All of these creatures will try to eat both adult spicebush swallowtail butterflies and youthful larvae. Spicebush swallowtail caterpillar head

Mimicry

The spicebush swallowtail's major form of predator avoidance is through mimicry. Both subspecies and sexes of ''Papilio troilus'' have the ability to perform mimicry both as a larva and as an adult.

Larval mimicry

As larvae, spicebush swallowtails have two stages of mimicry. While the larvae are in the early stages, they are dark brown and thus appear to resemble bird droppings, which encourages predators to leave them alone. When the larvae have progressed to their fourth and last instar and are nearly ready to pupate, they turn a yellow-green color and are marked by two large black dots with a white highlight. The placement of these dots on the swollen thorax creates the illusion that the caterpillars are common green snakes. Mimicking snakes help the caterpillars to ward off predators, specifically birds. The caterpillar spicebush swallowtails enhance the physical resemblance behaviorally, as they have been observed to "rear up and retract the actual caterpillar head." The

osmeterium The osmeterium is a defensive organ found in all papilionid larvae, in all stages. The organ is situated in the prothoracic segment and can be everted when the larva feels threatened. The everted organ resembles a fleshy forked tongue (not unlik ...

of the caterpillar also helps to enhance the resemblance to a snake. When attacked, the larvae will expose the osmeterium, a Y-shaped organ typically folded up within the caterpillar. For many spicebush swallowtails, the osmeterium is red, thus creating the illusion of a snake tongue and even further enhancing the disguise.Brower, Jane Van Zandt (Jun 1958). "Experimental Studies of Mimicry in Some North American Butterflies: Part II. Battus philenor and Papilio Troilus, P. polyxenes and P. glaucus." Evolution 12 (2): 123-136 . Spicebush Swallowtail Papilio troilus Caterpillar 2400px

Spicebush Swallowtail Papilio troilus Caterpillar 2400px

Adult mimicry

Adult spicebush swallowtails practice another type of mimicry, as they resemble the pipevine swallowtail (''Battus philenor''), a foul-tasting butterfly. Each of the sexes are able to exhibit mimicry of ''B. philenor'' successfully, even though the brighter-blue color on female wings is a little more vibrant than the pipevine swallowtail's coloring. As they themselves are not unpalatable and the pipevine are, this is an example of Batesian mimicry. If predators know that the pipevine swallowtail has a foul taste, they are unlikely to eat it and also unlikely to eat the spicebush swallowtail. There are other adult butterflies which mimic the poisonous ''B. philenor'', including '' P. polyxenes'', '' P. glaucus, C. promethea'' and '' L. astyanax'', but ''P. troilus'' most closely resembles it. However, ''P. troilus'' has a greater physical resemblance to the other mimics than it does to ''B. philenor''. Besides mimicry, another form of predator avoidance for spicebush swallowtails is the "club-like extensions from their hind-wings." An attack from a predator focused on the "false head" will leave the butterfly itself unharmed, though with slightly damaged wings.

References

External links

Spicebush swallowtails
BugGuide
Michael Gerber's caterpillar photoButterflies and Moths of North America from The Big Sky Institute at Montana State University and NBII Mountain Prairie Information Node
* ttps://web.archive.org/web/20110303210748/http://www.netstate.com/states/tables/state_insects.htm Official state insects from NETSTATEbr>Spicebush swallowtail
on the

University of Florida The University of Florida (Florida or UF) is a public land-grant research university in Gainesville, Florida. It is a senior member of the State University System of Florida, traces its origins to 1853, and has operated continuously on its ...

/ Institute of Food and Agricultural Sciences Featured Creatures website
Spicebush swallowtail
Butterflies of Canada {{Taxonbar, from=Q149664

troilus Troilus ( or ; grc, Τρωΐλος, Troïlos; la, Troilus) is a legendary character associated with the story of the Trojan War. The first surviving reference to him is in Homer's ''Iliad,'' composed in the late 8th century BCE. In Greek myth ...

Butterflies of North America Butterflies described in 1758 Taxa named by Carl Linnaeus Symbols of Mississippi