The giant swallowtail (''Papilio cresphontes'') is the largest butterfly in North America.
It is abundant through many parts of eastern North America; populations from western North America and down into
Panama
Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Co ...
are now (as of 2014) considered to belong to a different species, ''
Papilio rumiko''.
[A new Heraclides swallowtail (Lepidoptera, Papilionidae) from North America is recognized by the pattern on its neck](_blank)
/ref> Though it is often valued in gardens for its striking appearance, its larval stage can be a serious pest to citrus farms, which has earned its caterpillars the names orange dog or orange puppy. The giant swallowtail caterpillars possess remarkable camouflage from predators by closely resembling bird droppings. They use this, along with their osmeteria, to defend against predators such as wasps, flies, and vertebrates.
Geographic range
The giant swallowtail is common across the United States, reaching as far north as southern New England
New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the Can ...
and southern Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
. South of the United States, it is found in parts of Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
and also found in Jamaica
Jamaica (; ) is an island country situated in the Caribbean Sea. Spanning in area, it is the third-largest island of the Greater Antilles and the Caribbean (after Cuba and Hispaniola). Jamaica lies about south of Cuba, and west of His ...
and Cuba
Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbea ...
. The species was historically considered to occur in the western United States and into South America, but now those populations are treated as a separate species, '' Papilio rumiko'', based largely on DNA evidence.
Habitat
In the United States, ''P. cresphontes'' mostly inhabit deciduous forest
In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, ...
and citrus orchards. They are only capable of overwintering 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 ...
and the deep South.
Description
One of the giant swallowtail's most notable features is its size. Females have an average wingspan of , and up to , while males' average is , and up to .
The wings are black with a horizontal yellow line across the forewing
Insect wings are adult outgrowths of the insect exoskeleton that enable insects to fly. They are found on the second and third thoracic segments (the mesothorax and metathorax), and the two pairs are often referred to as the forewings and hindwi ...
s, and a diagonal yellow line across the hindwing. The underside of the wings is yellow with accents of black. A small patch of red on the ventral wing (within the small blue band) allows for distinction from the similar-looking Schaus' swallowtail.
Food resources
Caterpillars
As well as eating valuable citrus crops, larvae eat a wide variety of plants in the family Rutaceae
The Rutaceae is a family, commonly known as the rue[RUTACEAE](_blank)
in BoDD – Botanical Der ...
(citrus plants), including different types of prickly ash. They also consume some exotic Rutaceae species that have been introduced to North America, such as gasplant and sapote
Sapote (from Nahuatl ''tzapotl'') is a term for a soft, edible fruit. The word is incorporated into the common names of several unrelated fruit-bearing plants native to southern Mexico, Central America and northern parts of South America. It is al ...
.
Feeding specialization
In specific local subpopulations (studied in Wisconsin, Ohio, and Florida), it was found that giant swallowtail caterpillars do better on their local host plant than on other giant swallowtail host plants. The local host caused the larva to develop faster than other plants that were also edible to the larva. However, this feeding specialization hypothesis has not been tested in the species as a whole beyond these three regions.
Adults
Nectar plants for adults include ''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 ...
'', Azaleas, ''Bougainvilla
''Bougainvillea'' ( , ) is a genus of thorny ornamental vines, bushes, and trees belonging to the four o' clock family, Nyctaginaceae. It is native to eastern South America, found from Brazil, west to Peru, and south to southern Argentina. ...
, Saponaria officinalis
''Saponaria officinalis'' is a common perennial plant from the family Caryophyllaceae. This plant has many common names, including common soapwort, bouncing-bet, crow soap, wild sweet William, and soapweed. There are about 20 species of soapwo ...
'', ''Hesperis matronalis
''Hesperis matronalis'' is an herbaceous plant species in the family Brassicaceae. It has numerous common names, including dame's rocket, damask-violet, dame's-violet, dames-wort, dame's gilliflower, night-scented gilliflower, queen's gilliflo ...
'', '', Lonicera japonica
''Lonicera japonica'', known as Japanese honeysuckle and golden-and-silver honeysuckle, is a species of honeysuckle native to eastern Asia. It is often grown as an ornamental plant, but has become an invasive species in a number of countries. Jap ...
'', and '' Asclepias incarnata''. Along with flower nectar, adults can also consume liquid from animal waste.
Life history
Eggs
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. The small egg (1–1.5 mm) is brownish colored, but appears more orange due to a special orange colored secretion.
Caterpillars
Once emerged from the eggs, there are five larval instars, wherein the larva grow to about 2 inches before pupating. Larvae are mostly nocturnal, feeding at night. Their appearance changes slightly throughout the 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 ...
s, with the younger ones having seta
In biology, setae (singular seta ; from the Latin word for " bristle") are any of a number of different bristle- or hair-like structures on living organisms.
Animal setae
Protostomes
Annelid setae are stiff bristles present on the body. ...
e and the older instars lacking setae. The caterpillars have remarkable camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...
patterns.
Pupation
Larvae must find a vertical plant, or sometimes a man-made object, to form their chrysalis on, and often they choose the host plant they already occupy. They attach themselves to their substrate of choice and molt to reveal a brown, mottled chrysalis (resembling a bit of dead twig) in which they remain for approximately 10–12 days.
Mating
Males search for females along set flight paths and near host plants, and mate with females in the afternoon. Male and female then copulate facing away from each other.
Enemies
Parasites
Giant swallowtails are most vulnerable to parasites
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...
when they are in their chrysalis. Common parasites include flies and wasps such as '' Brachymeria robusta'', '' Pteromalus cassotis'', ''Pteromalus vanessae'', and '' Lespesia rileyi''.
Protective coloration and behavior
Larvae have many adaptations to protect themselves from predators.
Coloration
The caterpillars' intricate coloring patterns are an effective camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...
and defense against both vertebrate and invertebrate predators and parasites. It is thought that the coloration was naturally selected for because of its imitation of bird and lizard droppings. The caterpillar mimics certain droppings based on its habitat and which instar it is. The caterpillars' coloration, particularly the saddle pattern, is also thought to be disruptive coloration
Disruptive coloration (also known as disruptive camouflage or disruptive patterning) is a form of camouflage that works by breaking up the outlines of an animal, soldier or military vehicle with a strongly contrasting pattern. It is often comb ...
. This means the coloration makes it harder for a predator to distinguish the shape of the camouflaged prey, which explains the continuation of this coloration pattern in larger instars that are too large to be mistaken for bird droppings. It has also been hypothesized that the older instars' pattern is meant to be reminiscent of a snake.
Other defensive measures
When camouflage is not enough, larvae will employ their osmeteria when they are threatened. The osmeterium is an organ behind the head that “inflates” into an orange/red Y-shaped growth that resembles a snake's forked tongue. By the fourth instar, the osmeterium is more than just a startle mechanism and also has bad-smelling and toxic mixture of acidic chemicals. This is only effective on small invertebrate predators, and the caterpillar will try to rub its osmeterium on the predator to deter it. It has been experimentally tested and found that osmeteria are ineffective at deterring predation from birds.
Physiology
Identifying host plants
Giant swallowtail butterflies must correctly identify their host plants by antennal sensitivity to the specific volatile compounds in the plants. A study found that antennal response to these volatiles depends upon the concentration of the volatiles, the host plant of origin (whether it is a primary or secondary host), and the sex of the butterfly. This last dependency is thought to be because the females, not the males, must identify the correct host plant for egg laying.
Flight
Because of the butterfly's notably large wingspan (14 to 18 cm), giant swallowtails are very strong fliers and are able to glide long distances with very few wing beats.
Interactions with humans
Sometimes referred to as "orange dogs", "orange pups", or "bird poop caterpillars" by farmers, the larva targets all varieties of citrus plants, often causing significant damage to new foliage and younger trees, which they can more thoroughly defoliate. Large mature citrus trees are not generally significantly impacted. Outside of farms, the species is valued for its aesthetic appeal and can also be raised to butterflies successfully at home.
Control
Biological insecticides, such as '' Bacillus thuringiensis'', as well as chemical insecticides, are used to protect trees against larvae. Methionine, an essential amino acid
An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet. Of the 21 amino acids common to all life form ...
in humans, has also been found to be an effective killer of caterpillars, with possible use as a nontoxic pesticide against giant swallowtail larvae.
Effects of climate change
There has been a northern expansion of the range of the giant swallowtail in recent years which has been linked to increasingly warm temperatures, and particularly to a lack of September frosts in regions of expansion starting in 2001. Larvae were then able to withstand a few frosts before they pupated. The immediate effects of this warming, as well as their effect on host plants and predators, can explain the giant swallowtail's range expansion.
Gallery
File:Giant swallowtail egg.jpg, Egg
File:Papilio cresphontes larva defensive.JPG, ''P. cresphontes'' caterpillar showing defensive posture
File:Butterfly House 1.JPG, Adult, underside
File: Papilio cresphontes - The giant swallowtail.webm, In flight. Video clip
References
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External links
Giant swallowtail butterfly life cycle photographs
on the UF / IFAS Featured Creatures Web site
Butterflycorner
Images from Naturhistorisches Museum Wien
The Natural History Museum Vienna (german: Naturhistorisches Museum Wien) is a large natural history museum located in Vienna, Austria. It is one of the most important natural history museums worldwide.
The NHM Vienna is one of the largest museum ...
Giant Swallowtail
Butterflies and Moths of North America
funet.fi
Giant Swallowtail (''Papilio cresphontes'')
CBIF
{{Taxonbar, from=Q950614
cresphontes
In Greek mythology, Cresphontes (; grc, Κρεσφόντης) was a son of Aristomachus, husband of Merope, father of Aepytus and brother of Temenus and Aristodemus. He was a great-great-grandson of Heracles and helped lead the fifth and fin ...
Butterflies described in 1777
Butterflies of North America
Papilionidae of South America
Taxa named by Pieter Cramer
Articles containing video clips