A subspecies of Papilio troilus, called Papilio troilus ilioneus, is the dominant type of this butterfly in Florida. The major distinguishing feature of this subspecies is that it has enlarged, light submarginal spots.
Although spicebush swallowtails employ extensive mimicry throughout their lifecycles, mimicking bird droppings and green snakes as caterpillars, and mimicking the poisonous pipevine swallowtail (Battus philenor) as adults, they suffer from extensive predation. Spiders, insect predators such as dragonflies and robber flies, and especially birds, will eat swallowtail butterfly adults and larvae.
Known Predators:
Anti-predator Adaptations: mimic; cryptic
In adults, the upper surface of the forewing is mostly black, with ivory spots along the bottom margin. The upper surface of the hindwing has an orange spot on the costal margin which is unique to spicebush swallowtails. There is also a band of bluish (female) or bluish-green (male) scales on the upper surface of the hindwing. The bottom margin of the hindwing has bluish or ivory spots, and also a “tail” measuring 9 to 12 mm long at the bottom of the wing. This feature is similar to other swallowtails such as black swallowtails (Papilio asterius) and pipevine swallowtails (Battus philenor). However, the "tail" in P. troilus is broader and spatulate. Wingspan ranges from 80 to 115 mm.
The larval or caterpillar form initially resembles bird droppings, but in later instars is green with a pale yellow lateral line running the length of the caterpillar. The underside of the caterpillar is pinkish-brown, and each abdominal segment is ringed by six blue spots outlined in black. One dot on each side is below the yellow lateral line.
Caterpillars have two pairs of false eyespots: one pair is toward the back of the thorax, and is small and yellow. The other pair is closer to the head, and is yellow with a black spot in the middle, and a white spot that resembles the glare off a black eye. The combination of the eyespots and a swollen thorax is believed to be a mimicry of either green snakes or tree frogs.
Female caterpillars are often slightly longer than males. Pupae can be brown or green depending on the season, mimicking leaves of spring and fall, and have a pair of horns at the top of the pupa.
Range wingspan: 80 to 115 mm.
Average wingspan: 100 mm.
Sexual Dimorphism: female larger; sexes colored or patterned differently
Other Physical Features: ectothermic ; bilateral symmetry
Adult swallowtail butterflies live roughly from 2 days to 2 weeks.
Typical lifespan
Status: wild: 2 to 14 days.
The larval form of P. troilus is found in deciduous woodlands, wooded swamps, and pine barrens. The adult form is a fairly common butterfly within its range, that can be seen in woodlands, parks, yards, fields, and roadsides, but prefers the borders of shady woods. Males are often found near moist, sandy areas along roads or streams.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: savanna or grassland ; forest
Wetlands: marsh ; swamp ; bog
Other Habitat Features: urban ; suburban ; agricultural
Spicebush swallowtails (Papilio troilus) are found in eastern North America from southern Canada to Florida, and west to Oklahoma, Manitoba, and central Texas. This species is less common on the western edge of its range, along the southern Mississippi River, as well as in New England. Occasionally these butterflies are found as far west as Colorado, and as far south as Cuba.
Biogeographic Regions: nearctic (Native ); neotropical (Native )
As in many animals that undergo metamorphosis, the diet of the young differs from the diet of the adult.
In P. troilus, larvae feed on the leaves of aromatic trees and shrubs in the family Lauraceae. Their primary hosts are spicebush (Lindera benzoin), sassafras (Sassafras albidum), but they are also known to feed on camphor (Cinnamomum camphora) sweetbay (Magnolia virginiana), and redbay (Persea borbonia). The choice of host plant depends primarily on host availability in a particular part of the range. There is evidence of geographic divergence among populations with larval adaptation to the most common host species.
Adult P. troilus butterflies feed on nectar, and are partial to honeysuckle, clover, and thistle flowers. Their unusually long proboscis allows them to reach nectar in unusually deep flowers such as bee balm. They will also drink nectar from other flowers such as jewelweed, milkweed, azalea, dogbane, mimosa, and sweet pepperbush.
Plant Foods: leaves; nectar
Primary Diet: herbivore (Folivore , Nectarivore )
Spicebush swallowtail larvae are specialist herbivores, feeding on members of the family Lauraceae. Adults are generic pollinators for many flowers, inadvertently pollinating while feeding on nectar.
Ecosystem Impact: pollinates
Species Used as Host:
Mutualist Species:
Swallowtail butterflies have a slow and lazy flight, and because of this, they are easy to catch, making them prime collector's items. They are also popular photography subjects because of their large size, showiness, and slow flight. Since spicebush swallowtails are generic pollinators, they are also beneficial to crops.
Positive Impacts: research and education; pollinates crops
Spicebush swallowtails are not usually considered pests, though their host trees occasionally suffer slightly when planted as ornamentals.
Negative Impacts: crop pest
Spicebush swallowtails lay their eggs on the undersides of leaves. Larvae hatch and initially resemble bird droppings, but come to mimic a snake, complete with eyespots, in later instars. These larvae form pupae which are green (summer) or brown (fall) and metamorphose into butterflies. Some pupae hibernate over winter, and these are usually brown to mimic dead leaves. Shorter photoperiods associated with the coming of winter trigger pupae to assume the brown color, regardless of whether the leaf they live on is green or brown.
Papilio troilus produces two generations per year from April to October, except in Florida, where three are possible between March and December.
Development - Life Cycle: metamorphosis ; diapause
The Nature Conservancy ranks spicebush swallowtails as a G5 species, which means that they are in no danger on a global scale, though may be quite rare in parts of the species' range, especially on the periphery.
US Federal List: no special status
CITES: no special status
Females use both visual and chemical cues when finding hosts plants on which to oviposit. After landing on a plant, a female confirms the plant as a host plant by drumming the surface of the leaf with her forelegs, which have contact chemorecepters located on the foretarsi.
Information on communication between individuals is limited to mating contexts. Males apparently recognize females visually. The courtship display of a male involves many visual elements. In additon, during the process of mating itself, there is some contact, probably relaying information between the individuals.
Communication Channels: visual ; tactile ; chemical
Other Communication Modes: mimicry
Perception Channels: visual ; tactile ; chemical
In order to find females, males patrol flyways on hilltops or host plant sites. When patrolling males meet, they generally fly in opposite directions. Females have much lower representations in these areas. The only areas of equal representation are nectar sources. When a female appears, a male flies towards her and performs a brief courtship ritual, lasting less than a minute. If the female is receptive to the courtship, copulation occurs, often lasting over an hour. Both males and females often copulate with multiple partners. A fertilized female oviposits in the warm portion of the day, laying eggs singly on young host leaves.
Mating System: polygynandrous (promiscuous)
Spicebush swallowtails breed after becoming adults. This takes place during the summer months (April to October, or March to December in the southern part of the range) when there is ample food for the larvae. Though both males and females copulate with multiple partners, females are increasingly less likely to seek another mate with each successful copulation. Females search out host plants by visual and chemical cues, then land on a plant and drum the leaf with their forelegs to "taste" it, and confirm it as a host plant.
Breeding interval: Males mate daily. A females may mate multiple times during her lifetime.
Breeding season: Breeding occurs between April and October.
Key Reproductive Features: semelparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous ; sperm-storing
Care of eggs once they are laid, or of larvae, does not occur in this species. However, females do invest in their young by producing nutrient rich eggs to allow the larvae to develop until hatching. They also select host plants carefully, to help ensure the survival of their young.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female)
Papilio troilus, the spicebush swallowtail or green-clouded butterfly, is a common black swallowtail butterfly found in North America.[2] It has two subspecies, Papilio troilus troilus and Papilio troilus ilioneus, the latter found mainly in the Florida peninsula.[3] The spicebush swallowtail derives its name from its most common host plant, the spicebush, members of the genus Lindera.
The family to which spicebush swallowtails belong, Papilionidae, 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.[4]
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.[4] 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.[5]
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,[6] while males are typically found in swamp areas.[5]
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.[7] 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).[8]
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.[7]
Typically, the wingspan of a spicebush swallowtail ranges from 3 to 4 inches (7.6 to 10.2 cm).[9] 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.[7] 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.[10] 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.[7]
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.[7]
The host plants of the spicebush swallowtail are most commonly either spicebush (Lindera benzoin) or white sassafras (Sassafras albidum).[11] Other possible host plants include prickly ash (Zanthoxylum),[12] as well as tulip tree (Liriodendron tulipifera), sweetbay (Magnolia virginiana), camphor (Cinnamomum camphora) and redbay (Persea borbonia).[9] 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.[13] However, when given the choice between spicebush and sassafras, the P. t. troilus showed no significant preference for either.[14]
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.[6]
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.[15] This fact is especially noteworthy because Lauraceae are distantly related to the host plants of other species that are food for Papilio caterpillars.[16] 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.[6]
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.[15] 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, 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 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.[13]
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 acids, 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.[16]
Spicebush swallowtails gain sustenance from eight major sources. Joe-Pye weed, jewelweed, and honeysuckle are favorite sources of nectar for the adults.[10] They have also been known to drink nectar from lantanas,[2] as well as thistles, milkweeds, azalea, dogbane, mimosa, and sweet pepperbush.[9]
When female swallowtails decide which leaf to oviposit on, they frequently will drum their forelegs toward a leaf to identify it. Their forelegs have chemoreceptors 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.[6]
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 3⁄4 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.[17] The brown color of the larvae is independent of leaf color and will occur even on a green leaf.[18] A folded leaf serves as the home for the young larvae.[4] 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.[5]
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.[4] In order to pupate, the larvae will leave the shelter and find the underside of a leaf near the ground to do so.[17] 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.[19] At the end of the pupating process, the larvae have become pupae which are either brown (winter) or green (summer).[5]
The practice of turning either brown in winter or green in summer is called seasonal polyphenism.[18] 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.[6]
Roughly three generations of spicebush swallowtails occur each year. Most develop into adults throughout the range between the months of February and November.[17] The entire development process from egg to adult takes about a month.[20] 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.[5]
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.[6]
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.[5]
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.[5]
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.[5] 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.[10]
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.[6]
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.[5]
When threatened, a spicebush swallowtail butterfly exudes red drops of a foul-smelling liquid. Its many predators include birds, spiders, robber flies, and dragonflies. All of these creatures will try to eat both adult spicebush swallowtail butterflies and youthful larvae.[5]
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.
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.[3] 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."[19]
The osmeterium 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.[19] For many spicebush swallowtails, the osmeterium is red, thus creating the illusion of a snake tongue and even further enhancing the disguise.[21]
Adult spicebush swallowtails practice another type of mimicry, as they resemble the pipevine swallowtail (Battus philenor), a foul-tasting butterfly.[10] 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.[6] 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.[2] 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.[14]
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.[2]
.jpg)
_(3714906883).jpg)
{{cite web}}: CS1 maint: archived copy as title (link) Papilio troilus, the spicebush swallowtail or green-clouded butterfly, is a common black swallowtail butterfly found in North America. It has two subspecies, Papilio troilus troilus and Papilio troilus ilioneus, the latter found mainly in the Florida peninsula. The spicebush swallowtail derives its name from its most common host plant, the spicebush, members of the genus Lindera.
The family to which spicebush swallowtails belong, Papilionidae, 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.
