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Butterfly

Butterflies are winged insects from the lepidopteran suborder Rhopalocera, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The group comprises the superfamilies Hedyloidea (moth-butterflies in the Americas) and Papilionoidea (all others). The oldest butterfly fossils have been dated to the Paleocene, about 56 million years ago, though they likely originated in the Late Cretaceous, about 101 million years ago.

Butterflies have a four-stage life cycle, and like other holometabolous insects they undergo complete metamorphosis. Winged adults lay eggs on the food plant on which their larvae, known as caterpillars, will feed. The caterpillars grow, sometimes very rapidly, and when fully developed, pupate in a chrysalis. When metamorphosis is complete, the pupal skin splits, the adult insect climbs out, expands its wings to dry, and flies off.

Some butterflies, especially in the tropics, have several generations in a year, while others have a single generation, and a few in cold locations may take several years to pass through their entire life cycle.

Butterflies are often polymorphic, and many species make use of camouflage, mimicry, and aposematism to evade their predators. Some, like the monarch and the painted lady, migrate over long distances. Many butterflies are attacked by parasites or parasitoids, including wasps, protozoans, flies, and other invertebrates, or are preyed upon by other organisms. Some species are pests because in their larval stages they can damage domestic crops or trees; other species are agents of pollination of some plants. Larvae of a few butterflies (e.g., harvesters) eat harmful insects, and a few are predators of ants, while others live as mutualists in association with ants. Culturally, butterflies are a popular motif in the visual and literary arts. The Smithsonian Institution says "butterflies are certainly one of the most appealing creatures in nature".

Etymology

The Oxford English Dictionary derives the word straightforwardly from Old English butorflēoge, butter-fly; similar names in Old Dutch and Old High German show that the name is ancient, but modern Dutch and German use different words (vlinder and Schmetterling) and the common name often varies substantially between otherwise closely related languages. A possible source of the name is the bright yellow male of the brimstone (Gonepteryx rhamni); another is that butterflies were on the wing in meadows during the spring and summer butter season while the grass was growing.

Paleontology
The earliest Lepidoptera fossils date to the Triassic-Jurassic boundary, around 200million years ago. Butterflies evolved from moths, so while the butterflies are monophyletic (forming a single clade), the moths are not. The oldest known butterfly is Protocoeliades kristenseni from the Palaeocene aged Fur Formation of Denmark, approximately 55million years old, which belongs to the family Hesperiidae (skippers). Molecular clock estimates suggest that butterflies originated sometime in the Late Cretaceous, but only significantly diversified during the Cenozoic, with one study suggesting a North American origin for the group. The oldest American butterfly is the Late Eocene Prodryas persephone from the Florissant Fossil Beds, approximately 34million years old.

Taxonomy and phylogeny
Butterflies are scientifically classified in the macrolepidopteran suborder clade Rhopalocera from the order Lepidoptera, which also includes moths. Traditionally, butterflies have been divided into the superfamily Papilionoidea excluding the smaller groups of the Hesperiidae (skippers) and the more moth-like Hedylidae of America. Phylogenetic analysis suggests that the traditional Papilionoidea is paraphyletic with respect to the other two groups, so they should both be included within Papilionoidea, to form a single butterfly group, thereby synonymous with the clade Rhopalocera.

General description

Butterfly adults are characterized by their four scale-covered wings, which give the Lepidoptera their name (Ancient Greek λεπίς lepís, scale + πτερόν pterón, wing). These scales give butterfly wings their colour: they are pigmented with melanins that give them blacks and browns, as well as uric acid derivatives and flavones that give them yellows, but many of the blues, greens, reds and iridescent colours are created by structural coloration produced by the micro-structures of the scales and hairs.

As in all insects, the body is divided into three sections: the head, thorax, and abdomen. The thorax is composed of three segments, each with a pair of legs. In most families of butterfly the antennae are clubbed, unlike those of moths which may be threadlike or feathery. The long proboscis can be coiled when not in use for sipping nectar from flowers.

Nearly all butterflies are diurnal, have relatively bright colours, and hold their wings vertically above their bodies when at rest, unlike the majority of moths which fly by night, are often cryptically coloured (well camouflaged), and either hold their wings flat (touching the surface on which the moth is standing) or fold them closely over their bodies. Some day-flying moths, such as the hummingbird hawk-moth, are exceptions to these rules.

Butterfly larvae, caterpillars, have a hard (sclerotised) head with strong mandibles used for cutting their food, most often leaves. They have cylindrical bodies, with ten segments to the abdomen, generally with short prolegs on segments 3–6 and 10; the three pairs of true legs on the thorax have five segments each. Many are well camouflaged; others are aposematic with bright colours and bristly projections containing toxic chemicals obtained from their food plants. The pupa or chrysalis, unlike that of moths, is not wrapped in a cocoon.

Many butterflies are sexually dimorphic. Most butterflies have the ZW sex-determination system where females are the heterogametic sex (ZW) and males homogametic (ZZ).

Distribution and migration
Butterflies are distributed worldwide except Antarctica, totalling some 18,500 species. Of these, 775 are Nearctic; 7,700 Neotropical; 1,575 Palearctic; 3,650 Afrotropical; and 4,800 are distributed across the combined Oriental and Australian/Oceania regions. The monarch butterfly is native to the Americas, but in the nineteenth century or before, spread across the world, and is now found in Australia, New Zealand, other parts of Oceania, and the Iberian Peninsula. It is not clear how it dispersed; adults may have been blown by the wind or larvae or pupae may have been accidentally transported by humans, but the presence of suitable host plants in their new environment was a necessity for their successful establishment.

Many butterflies, such as the painted lady, monarch, and several danaine migrate for long distances. These migrations take place over a number of generations and no single individual completes the whole trip. The eastern North American population of monarchs can travel thousands of miles south-west to overwintering sites in Mexico. There is a reverse migration in the spring. It has recently been shown that the British painted lady undertakes a 9,000-mile round trip in a series of steps by up to six successive generations, from tropical Africa to the Arctic Circle — almost double the length of the famous migrations undertaken by monarch. Spectacular large-scale migrations associated with the monsoon are seen in peninsular India. Migrations have been studied in more recent times using wing tags and also using stable hydrogen isotopes.

Butterflies navigate using a time-compensated sun compass. They can see polarized light and therefore orient even in cloudy conditions. The polarized light near the ultraviolet spectrum appears to be particularly important. Many migratory butterflies live in semi-arid areas where breeding seasons are short. The life histories of their host plants also influence butterfly behaviour.

Life cycle

Butterflies in their adult stage can live from a week to nearly a year depending on the species. Many species have long larval life stages while others can remain dormant in their pupal or egg stages and thereby survive winters. The Melissa Arctic (Oeneis melissa) overwinters twice as a caterpillar. Butterflies may have one or more broods per year. The number of generations per year varies from temperate to tropical regions with tropical regions showing a trend towards multivoltinism.

Courtship is often aerial and often involves pheromones. Butterflies then land on the ground or on a perch to mate. Copulation takes place tail-to-tail and may last from minutes to hours. Simple photoreceptor cells located at the genitals are important for this and other adult behaviours. The male passes a spermatophore to the female; to reduce sperm competition, he may cover her with his scent, or in some species such as the Apollos (Parnassius) plugs her genital opening to prevent her from mating again.

The vast majority of butterflies have a four-stage life cycle: egg, larva (caterpillar), pupa (chrysalis) and imago (adult). In the genera Colias, Erebia, Euchloe, and Parnassius, a small number of species are known that reproduce semi-parthenogenetically; when the female dies, a partially developed larva emerges from her abdomen.

Eggs

Butterfly eggs are protected by a hard-ridged outer layer of shell, called the chorion. This is lined with a thin coating of wax which prevents the egg from drying out before the larva has had time to fully develop. Each egg contains a number of tiny funnel-shaped openings at one end, called micropyles; the purpose of these holes is to allow sperm to enter and fertilize the egg. Butterfly eggs vary greatly in size and shape between species, but are usually upright and finely sculptured. Some species lay eggs singly, others in batches. Many females produce between one hundred and two hundred eggs.

Butterfly eggs are fixed to a leaf with a special glue which hardens rapidly. As it hardens it contracts, deforming the shape of the egg. This glue is easily seen surrounding the base of every egg forming a meniscus. The nature of the glue has been little researched but in the case of Pieris brassicae, it begins as a pale yellow granular secretion containing acidophilic proteins. This is viscous and darkens when exposed to air, becoming a water-insoluble, rubbery material which soon sets solid. Butterflies in the genus Agathymus do not fix their eggs to a leaf; instead, the newly laid eggs fall to the base of the plant.

Eggs are almost invariably laid on plants. Each species of butterfly has its own host plant range and while some species of butterfly are restricted to just one species of plant, others use a range of plant species, often including members of a common family. In some species, such as the great spangled fritillary, the eggs are deposited close to but not on the food plant. This most likely happens when the egg overwinters before hatching and where the host plant loses its leaves in winter, as do violets in this example.

The egg stage lasts a few weeks in most butterflies, but eggs laid close to winter, especially in temperate regions, go through a diapause (resting) stage, and the hatching may take place only in spring. Some temperate region butterflies, such as the Camberwell beauty, lay their eggs in the spring and have them hatch in the summer.

Caterpillar larva

Butterfly larvae, or caterpillars, consume plant leaves and spend practically all of their time searching for and eating food. Although most caterpillars are herbivorous, a few species are predators: Spalgis epius eats scale insects, while lycaenids such as Liphyra brassolis are myrmecophilous, eating ant larvae.

Some larvae, especially those of the Lycaenidae, form mutual associations with ants. They communicate with the ants using vibrations that are transmitted through the substrate as well as using chemical signals. The ants provide some degree of protection to these larvae and they in turn gather honeydew secretions. Large blue (Phengaris arion) caterpillars trick Myrmica ants into taking them back to the ant colony where they feed on the ant eggs and larvae in a parasitic relationship.

Caterpillars mature through a series of developmental stages known as instars. Near the end of each stage, the larva undergoes a process called apolysis, mediated by the release of a series of neurohormones. During this phase, the cuticle, a tough outer layer made of a mixture of chitin and specialized proteins, is released from the softer epidermis beneath, and the epidermis begins to form a new cuticle. At the end of each instar, the larva moults, the old cuticle splits and the new cuticle expands, rapidly hardening and developing pigment. Development of butterfly wing patterns begins by the last larval instar.

Caterpillars have short antennae and several simple eyes. The mouthparts are adapted for chewing with powerful mandibles and a pair of maxillae, each with a segmented palp. Adjoining these is the labium-hypopharynx which houses a tubular spinneret which is able to extrude silk. Caterpillars such as those in the genus Calpodes (family Hesperiidae) have a specialized tracheal system on the 8th segment that function as a primitive lung. Butterfly caterpillars have three pairs of true legs on the thoracic segments and up to six pairs of prolegs arising from the abdominal segments. These prolegs have rings of tiny hooks called crochets that are engaged hydrostatically and help the caterpillar grip the substrate. The epidermis bears tufts of setae, the position and number of which help in identifying the species. There is also decoration in the form of hairs, wart-like protuberances, horn-like protuberances and spines. Internally, most of the body cavity is taken up by the gut, but there may also be large silk glands, and special glands which secrete distasteful or toxic substances. The developing wings are present in later stage instars and the gonads start development in the egg stage.

Pupa

When the larva is fully grown, hormones such as prothoracicotropic hormone (PTTH) are produced. At this point the larva stops feeding, and begins "wandering" in the quest for a suitable pupation site, often the underside of a leaf or other concealed location. There it spins a button of silk which it uses to fasten its body to the surface and moults for a final time. While some caterpillars spin a cocoon to protect the pupa, most species do not. The naked pupa, often known as a chrysalis, usually hangs head down from the cremaster, a spiny pad at the posterior end, but in some species a silken girdle may be spun to keep the pupa in a head-up position. Most of the tissues and cells of the larva are broken down inside the pupa, as the constituent material is rebuilt into the imago. The structure of the transforming insect is visible from the exterior, with the wings folded flat on the ventral surface and the two halves of the proboscis, with the antennae and the legs between them.

The pupal transformation into a butterfly through metamorphosis has held great appeal to mankind. To transform from the miniature wings visible on the outside of the pupa into large structures usable for flight, the pupal wings undergo rapid mitosis and absorb a great deal of nutrients. If one wing is surgically removed early on, the other three will grow to a larger size. In the pupa, the wing forms a structure that becomes compressed from top to bottom and pleated from proximal to distal ends as it grows, so that it can rapidly be unfolded to its full adult size. Several boundaries seen in the adult colour pattern are marked by changes in the expression of particular transcription factors in the early pupa.

Adult

The reproductive stage of the insect is the winged adult or imago. The surface of both butterflies and moths is covered by scales, each of which is an outgrowth from a single epidermal cell. The head is small and dominated by the two large compound eyes. These are capable of distinguishing flower shapes or motion but cannot view distant objects clearly. Colour perception is good, especially in some species in the blue/violet range. The antennae are composed of many segments and have clubbed tips (unlike moths that have tapering or feathery antennae). The sensory receptors are concentrated in the tips and can detect odours. Taste receptors are located on the palps and on the feet. The mouthparts are adapted to sucking and the mandibles are usually reduced in size or absent. The first maxillae are elongated into a tubular proboscis which is curled up at rest and expanded when needed to feed. The first and second maxillae bear palps which function as sensory organs. Some species have a reduced proboscis or maxillary palps and do not feed as adults.

Many Heliconius butterflies also use their proboscis to feed on pollen; in these species only 20% of the amino acids used in reproduction come from larval feeding, which allow them to develop more quickly as caterpillars, and gives them a longer lifespan of several months as adults.

The thorax of the butterfly is devoted to locomotion. Each of the three thoracic segments has two legs (among nymphalids, the first pair is reduced and the insects walk on four legs). The second and third segments of the thorax bear the wings. The leading edges of the forewings have thick veins to strengthen them, and the hindwings are smaller and more rounded and have fewer stiffening veins. The forewings and hindwings are not hooked together (as they are in moths) but are coordinated by the friction of their overlapping parts. The front two segments have a pair of spiracles which are used in respiration.

The abdomen consists of ten segments and contains the gut and genital organs. The front eight segments have spiracles and the terminal segment is modified for reproduction. The male has a pair of clasping organs attached to a ring structure, and during copulation, a tubular structure is extruded and inserted into the female's vagina. A spermatophore is deposited in the female, following which the sperm make their way to a seminal receptacle where they are stored for later use. In both sexes, the genitalia are adorned with various spines, teeth, scales and bristles, which act to prevent the butterfly from mating with an insect of another species. After it emerges from its pupal stage, a butterfly cannot fly until the wings are unfolded. A newly emerged butterfly needs to spend some time inflating its wings with hemolymph and letting them dry, during which time it is extremely vulnerable to predators.

Pattern formation
The colourful patterns on many butterfly wings tell potential predators that they are toxic. Hence, the genetic basis of wing pattern formation can illuminate both the evolution of butterflies as well as their developmental biology. The colour of butterfly wings is derived from tiny structures called scales, each of which have their own pigments. In Heliconius butterflies, there are three types of scales: yellow/white, black, and red/orange/brown scales. Some mechanism of wing pattern formation are now being solved using genetic techniques. For instance, a gene called cortex determines the colour of scales: deleting cortex turned black and red scales yellow. Mutations, e.g. transposon insertions of the non-coding DNA around the cortex gene can turn a black-winged butterfly into a butterfly with a yellow wing band.

Mating
When the butterfly Bicyclus anynana is subjected to repeated inbreeding in the laboratory, there is a dramatic decrease in egg hatching. This severe inbreeding depression is considered to be likely due to a relatively high mutation rate to recessive alleles with substantial damaging effects and infrequent episodes of inbreeding in nature that might otherwise purge such mutations. Although B. anynana experiences inbreeding depression when forcibly inbred in the laboratory it recovers within a few generation when allowed to breed freely. During mate selection, adult females do not innately avoid or learn to avoid siblings, implying that such detection may not be critical to reproductive fitness. Inbreeding may persist in B anynana because the probability of encountering close relatives is rare in nature; that is, movement ecology may mask the deleterious effect of inbreeding resulting in relaxation of selection for active inbreeding avoidance behaviors.

Behaviour

Butterflies feed primarily on nectar from flowers. Some also derive nourishment from pollen, tree sap, rotting fruit, dung, decaying flesh, and dissolved minerals in wet sand or dirt. Butterflies are important as pollinators for some species of plants. In general, they do not carry as much pollen load as bees, but they are capable of moving pollen over greater distances. Flower constancy has been observed for at least one species of butterfly.

Adult butterflies consume only liquids, ingested through the proboscis. They sip water from damp patches for hydration and feed on nectar from flowers, from which they obtain sugars for energy, and sodium and other minerals vital for reproduction. Several species of butterflies need more sodium than that provided by nectar and are attracted by sodium in salt; they sometimes land on people, attracted by the salt in human sweat. Some butterflies also visit dung and scavenge rotting fruit or carcasses to obtain minerals and nutrients. In many species, this mud-puddling behaviour is restricted to the males, and studies have suggested that the nutrients collected may be provided as a nuptial gift, along with the spermatophore, during mating.

In hilltopping, males of some species seek hilltops and ridge tops, which they patrol in search for females. Since it usually occurs in species with low population density, it is assumed these landscape points are used as meeting places to find mates.

Butterflies use their antennae to sense the air for wind and scents. The antennae come in various shapes and colours; the hesperiids have a pointed angle or hook to the antennae, while most other families show knobbed antennae. The antennae are richly covered with sensory organs known as sensillae. A butterfly's sense of taste is coordinated by chemoreceptors on the tarsi, or feet, which work only on contact, and are used to determine whether an egg-laying insect's offspring will be able to feed on a leaf before eggs are laid on it. Many butterflies use chemical signals, pheromones; some have specialized scent scales (androconia) or other structures (coremata or "hair pencils" in the Danaidae). Vision is well developed in butterflies and most species are sensitive to the ultraviolet spectrum. Many species show sexual dimorphism in the patterns of UV reflective patches. Colour vision may be widespread but has been demonstrated in only a few species. Some butterflies have organs of hearing and some species make stridulatory and clicking sounds.

Many species of butterfly maintain territories and actively chase other species or individuals that may stray into them. Some species will bask or perch on chosen perches. The flight styles of butterflies are often characteristic and some species have courtship flight displays. Butterflies can only fly when their temperature is above 27 °C; when it is cool, they can position themselves to expose the underside of the wings to the sunlight to heat themselves up. If their body temperature reaches 40 °C, they can orientate themselves with the folded wings edgewise to the sun. Basking is an activity which is more common in the cooler hours of the morning. Some species have evolved dark wingbases to help in gathering more heat and this is especially evident in alpine forms.

As in many other insects, the lift generated by butterflies is more than can be accounted for by steady-state, non-transitory aerodynamics. Studies using Vanessa atalanta in a wind tunnel show that they use a wide variety of aerodynamic mechanisms to generate force. These include wake capture, vortices at the wing edge, rotational mechanisms and the Weis-Fogh 'clap-and-fling' mechanism. Butterflies are able to change from one mode to another rapidly.

Parasitoids, predators, and pathogens

Butterflies are threatened in their early stages by parasitoids and in all stages by predators, diseases and environmental factors. Braconid and other parasitic wasps lay their eggs in lepidopteran eggs or larvae and the wasps' parasitoid larvae devour their hosts, usually pupating inside or outside the desiccated husk. Most wasps are very specific about their host species and some have been used as biological controls of pest butterflies like the large white butterfly. When the small cabbage white was accidentally introduced to New Zealand, it had no natural enemies. In order to control it, some pupae that had been parasitised by a chalcid wasp were imported, and natural control was thus regained. Some flies lay their eggs on the outside of caterpillars and the newly hatched fly larvae bore their way through the skin and feed in a similar way to the parasitoid wasp larvae. Predators of butterflies include ants, spiders, wasps, and birds.

Caterpillars are also affected by a range of bacterial, viral and fungal diseases, and only a small percentage of the butterfly eggs laid ever reach adulthood. The bacterium Bacillus thuringiensis has been used in sprays to reduce damage to crops by the caterpillars of the large white butterfly, and the entomopathogenic fungus Beauveria bassiana has proved effective for the same purpose.

Endangered species
Queen Alexandra's birdwing, found in Papua New Guinea, is the largest butterfly in the world. The species is endangered, and is one of only three insects (the other two being butterflies as well) to be listed on Appendix I of CITES, making international trade illegal.

Black grass-dart butterfly (Ocybadistes knightorum) is a butterfly of the family Hesperiidae. It is endemic to New South Wales. It has a very limited distribution in the Boambee area.

Defences
Butterflies protect themselves from predators by a variety of means.

Chemical defences are widespread and are mostly based on chemicals of plant origin. In many cases the plants themselves evolved these toxic substances as protection against herbivores. Butterflies have evolved mechanisms to sequester these plant toxins and use them instead in their own defence. These defence mechanisms are effective only if they are well advertised; this has led to the evolution of bright colours in unpalatable butterflies (aposematism). This signal is commonly mimicked by other butterflies, usually only females. A Batesian mimic imitates another species to enjoy the protection of that species' aposematism. The common Mormon of India has female morphs which imitate the unpalatable red-bodied swallowtails, the common rose and the crimson rose. Müllerian mimicry occurs when aposematic species evolve to resemble each other, presumably to reduce predator sampling rates; Heliconius butterflies from the Americas are a good example.

Camouflage is found in many butterflies. Some like the oakleaf butterfly and autumn leaf are remarkable imitations of leaves. As caterpillars, many defend themselves by freezing and appearing like sticks or branches. Others have deimatic behaviours, such as rearing up and waving their front ends which are marked with eyespots as if they were snakes. Some papilionid caterpillars such as the giant swallowtail (Papilio cresphontes) resemble bird droppings so as to be passed over by predators. Some caterpillars have hairs and bristly structures that provide protection while others are gregarious and form dense aggregations. Some species are myrmecophiles, forming mutualistic associations with ants and gaining their protection. Behavioural defences include perching and angling the wings to reduce shadow and avoid being conspicuous. Some female Nymphalid butterflies guard their eggs from parasitoidal wasps.

The Lycaenidae have a false head consisting of eyespots and small tails (false antennae) to deflect attack from the more vital head region. These may also cause ambush predators such as spiders to approach from the wrong end, enabling the butterflies to detect attacks promptly. Many butterflies have eyespots on the wings; these too may deflect attacks, or may serve to attract mates.

Auditory defences can also be used, which in the case of the grizzled skipper refers to vibrations generated by the butterfly upon expanding its wings in an attempt to communicate with ant predators.

Many tropical butterflies have seasonal forms for dry and wet seasons. These are switched by the hormone ecdysone. The dry-season forms are usually more cryptic, perhaps offering better camouflage when vegetation is scarce. Dark colours in wet-season forms may help to absorb solar radiation.

Butterflies without defences such as toxins or mimicry protect themselves through a flight that is more bumpy and unpredictable than in other species. It is assumed this behavior makes it more difficult for predators to catch them, and is caused by the turbulence created by the small whirlpools formed by the wings during flight.

Declining numbers
Declining butterfly populations have been noticed in many areas of the world, and this phenomenon is consistent with the rapidly decreasing insect populations around the world. At least in the Western United States, this collapse in the number of most species of butterflies has been determined to be driven by global climate change, specifically, by warmer autumns.

In art and literature

Butterflies have appeared in art from 3500 years ago in ancient Egypt. In hunting scenes, butterflies were sometimes included in a way that suggested life, freedom, and the strength to escape capture, creating a balance to scenes concerned with death and upholding ma'at. They also were suggestive of regeneration or rebirth and protection. Certain butterflies, such as the tiger butterfly, may have been associated with solar deities, particularly Ra. The tiger butterfly also would have a particular resemblance to the ankh, due to its black body and wingtips, that was likely noted by the Ancient Egyptians. Butterflies may also have been understood as one of the deceased's guides in the afterlife.

In the ancient Mesoamerican city of Teotihuacan, the brilliantly coloured image of the butterfly was carved into many temples, buildings, jewellery, and emblazoned on incense burners. The butterfly was sometimes depicted with the maw of a jaguar, and some species were considered to be the reincarnations of the souls of dead warriors. The close association of butterflies with fire and warfare persisted into the Aztec civilisation; evidence of similar jaguar-butterfly images has been found among the Zapotec and Maya civilisations.

Butterflies are widely used in objects of art and jewellery: mounted in frames, embedded in resin, displayed in bottles, laminated in paper, and used in some mixed media artworks and furnishings. The Norwegian naturalist Kjell Sandved compiled a photographic Butterfly Alphabet containing all 26 letters and the numerals 0 to 9 from the wings of butterflies.

Sir John Tenniel drew a famous illustration of Alice meeting a caterpillar for Lewis Carroll's Alice in Wonderland, c. 1865. The caterpillar is seated on a toadstool and is smoking a hookah; the image can be read as showing either the forelegs of the larva, or as suggesting a face with protruding nose and chin. Eric Carle's children's book The Very Hungry Caterpillar portrays the larva as an extraordinarily hungry animal, while also teaching children how to count (to five) and the days of the week.

A butterfly appeared in one of Rudyard Kipling's Just So Stories, "The Butterfly that Stamped".

One of the most popular, and most often recorded, songs by Sweden's eighteenth-century bard, Carl Michael Bellman, is "Fjäriln vingad syns på Haga" (The butterfly wingèd is seen in Haga), one of his Fredman's Songs.

Madam Butterfly is a 1904 opera by Giacomo Puccini about a romantic young Japanese bride who is deserted by her American officer husband soon after they are married. It was based on John Luther Long's short story written in 1898.

In mythology and folklore
According to Lafcadio Hearn, a butterfly was seen in Japan as the personification of a person's soul; whether they be living, dying, or already dead. One Japanese superstition says that if a butterfly enters your guest room and perches behind the bamboo screen, the person whom you most love is coming to see you. Large numbers of butterflies are viewed as bad omens. When Taira no Masakado was secretly preparing his famous revolt, a vast a swarm of butterflies appeared in Kyoto. The people were frightened, thinking the apparition to be a portent of coming evil.

Diderot's Encyclopédie cites butterflies as a symbol for the soul. A Roman sculpture depicts a butterfly exiting the mouth of a dead man, representing the Roman belief that the soul leaves through the mouth. In line with this, the ancient Greek word for "butterfly" is ψυχή (psȳchē), which primarily means "soul" or "mind". According to Mircea Eliade, some of the Nagas of Manipur claim ancestry from a butterfly. In some cultures, butterflies symbolise rebirth. The butterfly is a symbol of being transgender, because of the transformation from caterpillar to winged adult. In the English county of Devon, people once hurried to kill the first butterfly of the year, to avoid a year of bad luck. In the Philippines, a lingering black or dark butterfly or moth in the house is taken to mean an impending or recent death in the family. Several American states have chosen an official state butterfly.

Collecting, recording, and rearing

"Collecting" means preserving dead specimens, not keeping butterflies as pets. Collecting butterflies was once a popular hobby; it has now largely been replaced by photography, recording, and rearing butterflies for release into the wild. The zoological illustrator Frederick William Frohawk succeeded in rearing all the butterfly species found in Britain, at a rate of four per year, to enable him to draw every stage of each species. He published the results in the folio sized handbook The Natural History of British Butterflies in 1924.

Butterflies and moths can be reared for recreation or for release.

In technology
Study of the structural coloration of the wing scales of swallowtail butterflies has led to the development of more efficient light-emitting diodes, and is inspiring nanotechnology research to produce paints that do not use toxic pigments and the development of new display technologies.

Regional lists

 * North America
 * Africa: Ghana
 * Asia: Singapore Israel Indo-China Sulawesi (Southeastern Sulawesi) Turkey

title: Butterfly


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Parachute

A parachute is a device used to slow the motion of an object through an atmosphere by creating drag or, in a ram-air parachute, aerodynamic lift. A major application is to support people, for recreation or as a safety device for aviators, who can exit from an aircraft at height and descend safely to earth.

A parachute is usually made of a light, strong fabric. Early parachutes were made of silk. The most common fabric today is nylon. A parachute's canopy is typically dome-shaped, but some are rectangles, inverted domes, and other shapes.

A variety of loads are attached to parachutes, including people, food, equipment, space capsules, and bombs.

Middle Ages
In 852, in Córdoba, Spain, the Moorish man Armen Firman attempted unsuccessfully to fly by jumping from a tower while wearing a large cloak. It was recorded that "there was enough air in the folds of his cloak to prevent great injury when he reached the ground."

Early Renaissance

The earliest evidence for the true parachute dates back to the Renaissance period. The oldest parachute design appears in a manuscript from the 1470s attributed to Taccola (British Library, Add MS 34113, fol. 200v), showing a free-hanging man clutching a crossbar frame attached to a conical canopy. As a safety measure, four straps ran from the ends of the rods to a waist belt. Although the surface area of the parachute design appears to be too small to offer effective air resistance and the wooden base-frame is superfluous and potentially harmful, the basic concept of a working parachute is apparent.

The design is a marked improvement over another folio (189v), which depicts a man trying to break the force of his fall using two long cloth streamers fastened to two bars, which he grips with his hands.

Shortly after, a more sophisticated parachute was sketched by the polymath Leonardo da Vinci in his Codex Atlanticus (fol. 381v) dated to c. 1485. Here, the scale of the parachute is in a more favorable proportion to the weight of the jumper. A square wooden frame, which alters the shape of the parachute from conical to pyramidal, held open Leonardo's canopy. It is not known whether the Italian inventor was influenced by the earlier design, but he may have learned about the idea through the intensive oral communication among artist-engineers of the time. The feasibility of Leonardo's pyramidal design was successfully tested in 2000 by Briton Adrian Nicholas and again in 2008 by the Swiss skydiver Olivier Vietti-Teppa. According to historian of technology Lynn White, these conical and pyramidal designs, much more elaborate than early artistic jumps with rigid parasols in Asia, mark the origin of "the parachute as we know it."

The Croatian polymath and inventor Fausto Veranzio, or Faust Vrančić (1551–1617), examined da Vinci's parachute sketch and kept the square frame but replaced the canopy with a bulging sail-like piece of cloth that he came to realize decelerates a fall more effectively. A now-famous depiction of a parachute that he dubbed Homo Volans (Flying Man), showing a man parachuting from a tower, presumably St Mark's Campanile in Venice, appeared in his book on mechanics, Machinae Novae ("New Machines", published in 1615 or 1616), alongside a number of other devices and technical concepts.

It was once widely believed that in 1617, Veranzio, then aged 65 and seriously ill, implemented his design and tested the parachute by jumping from St Mark's Campanile, from a bridge nearby, or from St Martin's Cathedral in Bratislava. Various publications incorrectly claimed the event was documented some thirty years later by John Wilkins, one of the founders of, and secretary of, the Royal Society in London, in his book Mathematical Magick or, the Wonders that may be Performed by Mechanical Geometry, published in London in 1648. However, Wilkins wrote about flying, not parachutes, and does not mention Veranzio, a parachute jump, or any event in 1617. Doubts about this test, which include a lack of written evidence, suggest it never occurred, and was instead a misreading of historical notes.

18th and 19th centuries
The modern parachute was invented in the late 18th century by Louis-Sébastien Lenormand in France, who made the first recorded public jump in 1783. Lenormand also sketched his device beforehand.

Two years later, in 1785, Lenormand coined the word "parachute" by hybridizing an Italian prefix para, an imperative form of parare = to avert, defend, resist, guard, shield or shroud, from paro = to parry, and chute, the French word for fall, to describe the aeronautical device's real function.

Also in 1785, Jean-Pierre Blanchard demonstrated it as a means of safely disembarking from a hot-air balloon. While Blanchard's first parachute demonstrations were conducted with a dog as the passenger, he later claimed to have had the opportunity to try it himself in 1793 when his hot air balloon ruptured, and he used a parachute to descend. (This event was not witnessed by others).

On 12 October 1799, Jeanne Geneviève Garnerin ascended in a gondola attached to a balloon. At 900 meters she detached the gondola from the balloon and descended in the gondola by parachute. In doing so, she became the first woman to parachute. She went on to complete many ascents and parachute descents in towns across France and Europe.

Subsequent development of the parachute focused on it becoming more compact. While the early parachutes were made of linen stretched over a wooden frame, in the late 1790s, Blanchard began making parachutes from folded silk, taking advantage of silk's strength and light weight. In 1797, André Garnerin made the first descent of a "frameless" parachute covered in silk. In 1804, Jérôme Lalande introduced a vent in the canopy to eliminate violent oscillations. In 1887, Park Van Tassel and Thomas Scott Baldwin invented a parachute in San Francisco, California, with Baldwin making the first successful parachute jump in the western United States.

Eve of World War I
In 1907 Charles Broadwick demonstrated two key advances in the parachute he used to jump from hot air balloons at fairs: he folded his parachute into a backpack, and the parachute was pulled from the pack by a static line attached to the balloon. When Broadwick jumped from the balloon, the static line became taut, pulled the parachute from the pack, and then snapped.

In 1911 a successful test took place with a dummy at the Eiffel Tower in Paris. The puppet's weight was 75 kg; the parachute's weight was 21 kg. The cables between the puppet and the parachute were 9 m long. On February 4, 1912, Franz Reichelt jumped to his death from the tower during initial testing of his wearable parachute.

Also in 1911, Grant Morton made the first parachute jump from an airplane, a Wright Model B piloted by Phil Parmalee, at Venice Beach, California. Morton's device was of the "throw-out" type where he held the parachute in his arms as he left the aircraft. In the same year (1911), Russian Gleb Kotelnikov invented the first knapsack parachute, although Hermann Lattemann and his wife Käthe Paulus had been jumping with bagged parachutes in the last decade of the 19th century.

In 1912, on a road near Tsarskoye Selo, years before it became part of St. Petersburg, Kotelnikov successfully demonstrated the braking effects of a parachute by accelerating a Russo-Balt automobile to its top speed and then opening a parachute attached to the back seat, thus also inventing the drogue parachute.

On 1 March 1912, U.S. Army Captain Albert Berry made the first (attached-type) parachute jump in the United States from a fixed-wing aircraft, a Benoist pusher, while flying above Jefferson Barracks, St. Louis, Missouri. The jump utilized a parachute stored or housed in a cone-shaped casing under the airplane and attached to a harness on the jumper's body.

Štefan Banič patented an umbrella-like design in 1914, and sold (or donated) the patent to the United States military, which later modified his design, resulting in the first military parachute. Banič had been the first person to patent the parachute, and his design was the first to properly function in the 20th century.

On June 21, 1913, Georgia Broadwick became the first woman to parachute-jump from a moving aircraft, doing so over Los Angeles, California. In 1914, while doing demonstrations for the U.S. Army, Broadwick deployed her chute manually, thus becoming the first person to jump free-fall.

World War I
The first military use of the parachute was by artillery observers on tethered observation balloons in World War I. These were tempting targets for enemy fighter aircraft, though difficult to destroy, due to their heavy anti-aircraft defenses. Because it was difficult to escape from them, and dangerous when on fire due to their hydrogen inflation, observers would abandon them and descend by parachute as soon as enemy aircraft were seen. The ground crew would then attempt to retrieve and deflate the balloon as quickly as possible. The main part of the parachute was in a bag suspended from the balloon with the pilot wearing only a simple waist harness attached to the main parachute. When the balloon crew jumped the main part of the parachute was pulled from the bag by the crew's waist harness, first the shroud lines, followed by the main canopy. This type of parachute was first adopted on a large scale for their observation balloon crews by the Germans, and then later by the British and French. While this type of unit worked well from balloons, it had mixed results when used on fixed-wing aircraft by the Germans, where the bag was stored in a compartment directly behind the pilot. In many instances where it did not work the shroud lines became entangled with the spinning aircraft. Although this type of parachute saved a number of famous German fighter pilots, including Hermann Göring, no parachutes were issued to the crews of Allied "heavier-than-air" aircraft. It has been claimed that the reason was to avoid pilots jumping from the plane when hit rather than trying to save the aircraft, but Air Vice Marshall Arthur Gould Lee, himself a pilot during the war, examined the British War Office files after the war and found no evidence of such claim. Airplane cockpits at that time also were not large enough to accommodate a pilot and a parachute, since a seat that would fit a pilot wearing a parachute would be too large for a pilot not wearing one. This is why the German type was stowed in the fuselage, rather than being of the "backpack" type. Weight was – at the very beginning – also a consideration since planes had limited load capacity. Carrying a parachute impeded performance and reduced the useful offensive and fuel load.

In the UK, Everard Calthrop, a railway engineer and breeder of Arab horses, invented and marketed through his Aerial Patents Company a "British Parachute" and the "Guardian Angel" parachute. As part of an investigation into Calthrop's design, on 13 January 1917, test pilot Clive Franklyn Collett successfully jumped from a Royal Aircraft Factory BE.2c flying over Orford Ness Experimental Station at 180 m. He repeated the experiment several days later.

Following on from Collett, balloon officer Thomas Orde-Lees, known as the "Mad Major", successfully jumped from Tower Bridge in London, which led to the balloonists of the Royal Flying Corps using parachutes, though they were issued for use in aircraft.

In 1911, Solomon Lee Van Meter, Jr. of Lexington, Kentucky, submitted an application for, and in July 1916 received, a patent for a backpack style parachute – the Aviatory Life Buoy. His self-contained device featured a revolutionary quick-release mechanism – the ripcord – that allowed a falling aviator to expand the canopy only when safely away from the disabled aircraft.

Otto Heinecke, a German airship ground crewman, designed a parachute which the German air service introduced in 1918, becoming the world's first air service to introduce a standard parachute. Schroeder company of Berlin manufactured Heinecke's design. The first successful use of this parachute was by Leutnant Helmut Steinbrecher of Jagdstaffel 46, who bailed on 27 June 1918 from his stricken fighter airplane to become the first pilot in history to successfully do so. Although many pilots were saved by the Heinecke design, their efficacy was relatively poor. Out of the first 70 German airmen to bail out, around a third died, These fatalities were mostly due to the chute or ripcord becoming entangled in the airframe of their spinning aircraft or because of harness failure, a problem fixed in later versions.

The French, British, American and Italian air services later based their first parachute designs on the Heinecke parachute to varying extents.

In the UK, Sir Frank Mears, who was serving as a Major in the Royal Flying Corps in France (Kite Balloon section), registered a patent in July 1918 for a parachute with a quick release buckle, known as the "Mears parachute", which was in common use from then onwards.

Post-World War I
The experience with parachutes during the war highlighted the need to develop a design that could be reliably used to exit a disabled airplane. For instance, tethered parachutes did not work well when the aircraft was spinning. After the war, Major Edward L. Hoffman of the United States Army led an effort to develop an improved parachute by bringing together the best elements of multiple parachute designs. Participants in the effort included Leslie Irvin and James Floyd Smith. The team eventually created the Airplane Parachute Type-A. This incorporated three key elements:
 * storing the parachute in a soft pack worn on the back, as demonstrated by Charles Broadwick in 1906;
 * a ripcord for manually deploying the parachute at a safe distance from the airplane, from a design by Albert Leo Stevens; and
 * a pilot chute that draws the main canopy from the pack.

In 1919, Irvin successfully tested the parachute by jumping from an airplane. The Type-A parachute was put into production and over time saved a number of lives. The effort was recognized by the awarding of the Robert J. Collier Trophy to Major Edward L. Hoffman in 1926.

Irvin became the first person to make a premeditated free-fall parachute jump from an airplane. An early brochure of the Irvin Air Chute Company credits William O'Connor as having become, on 24 August 1920, at McCook Field near Dayton, Ohio, the first person to be saved by an Irvin parachute. Test pilot Lt. Harold R. Harris made another life-saving jump at McCook Field on 20 October 1922. Shortly after Harris' jump, two Dayton newspaper reporters suggested the creation of the Caterpillar Club for successful parachute jumps from disabled aircraft.

Beginning with Italy in 1927, several countries experimented with using parachutes to drop soldiers behind enemy lines. The regular Soviet Airborne Troops were established as early as 1931 after a number of experimental military mass jumps starting from 2 August 1930. Earlier the same year, the first Soviet mass jumps led to the development of the parachuting sport in the Soviet Union. By the time of World War II, large airborne forces were trained and used in surprise attacks, as in the battles for Fort Eben-Emael and The Hague, the first large-scale, opposed landings of paratroopers in military history, by the Germans. This was followed later in the war by airborne assaults on a larger scale, such as the Battle of Crete and Operation Market Garden, the latter being the largest airborne military operation ever. Aircraft crew were routinely equipped with parachutes for emergencies as well.

In 1937, drag chutes were used in aviation for the first time, by Soviet airplanes in the Arctic that were providing support for the polar expeditions of the era, such as the first drifting ice station, North Pole-1. The drag chute allowed airplanes to land safely on smaller ice floes.

Most parachutes were made of silk until World War II cut off supplies from Japan. After Adeline Gray made the first jump using a nylon parachute in June 1942, the industry switched to nylon.

Types
Today's modern parachutes are classified into two categories – ascending and descending canopies. All ascending canopies refer to paragliders, built specifically to ascend and stay aloft as long as possible. Other parachutes, including ram-air non-elliptical, are classified as descending canopies by manufacturers.

Some modern parachutes are classified as semi-rigid wings, which are maneuverable and can make a controlled descent to collapse on impact with the ground.

Round

Round parachutes are purely a drag device (that is, unlike the ram-air types, they provide no lift) and are used in military, emergency and cargo applications (e.g. airdrops). Most have large dome-shaped canopies made from a single layer of triangular cloth gores. Some skydivers call them "jellyfish 'chutes" because of the resemblance to the marine organisms. Modern sports parachutists rarely use this type. The first round parachutes were simple, flat circulars. These early parachutes suffered from instability caused by oscillations. A hole in the apex helped to vent some air and reduce the oscillations. Many military applications adopted conical, i.e., cone-shaped, or parabolic (a flat circular canopy with an extended skirt) shapes, such as the United States Army T-10 static-line parachute. A round parachute with no holes in it is more prone to oscillate and is not considered to be steerable. Some parachutes have inverted dome-shaped canopies. These are primarily used for dropping non-human payloads due to their faster rate of descent.

Forward speed (5–13 km/h) and steering can be achieved by cuts in various sections (gores) across the back, or by cutting four lines in the back, thereby modifying the canopy shape to allow air to escape from the back of the canopy, providing limited forward speed. Other modifications sometimes used are cuts in various gores to cause some of the skirt to bow out. Turning is accomplished by forming the edges of the modifications, giving the parachute more speed from one side of the modification than the other. This gives the jumpers the ability to steer the parachute (such as the United States Army MC series parachutes), enabling them to avoid obstacles and to turn into the wind to minimize horizontal speed at landing.

Cruciform
The unique design characteristics of cruciform parachutes decrease oscillation (its user swinging back and forth) and violent turns during descent. This technology will be used by the United States Army as it replaces its older T-10 parachutes with T-11 parachutes under a program called Advanced Tactical Parachute System (ATPS). The ATPS canopy is a highly modified version of a cross/ cruciform platform and is square in appearance. The ATPS system will reduce the rate of descent by 30 percent from 21 ft/s to 15.75 ft/s. The T-11 is designed to have an average rate of descent 14% slower than the T-10D, thus resulting in lower landing injury rates for jumpers. The decline in the rate of descent will reduce the impact energy by almost 25% to lessen the potential for injury.

Pull-down apex

A variation on the round parachute is the pull-down apex parachute, invented by a Frenchman named Pierre-Marcel Lemoigne. The first widely used canopy of this type was called the Para-Commander (made by the Pioneer Parachute Co.), although there are many other canopies with a pull-down apex produced in the years thereafter - these had minor differences in attempts to make a higher performance rig, such as different venting configurations. They are all considered 'round' parachutes, but with suspension lines to the canopy apex that apply load there and pull the apex closer to the load, distorting the round shape into a somewhat flattened or lenticular shape when viewed from the side. And while called rounds, they generally have an elliptical shape when viewed from above or below, with the sides bulging out more than the for'd-and-aft dimension, the chord (see the lower photo to the right and you likely can ascertain the difference).

Due to their lenticular shape and appropriate venting, they have a considerably faster forward speed than, say, a modified military canopy. And due to controllable rear-facing vents in the canopy's sides, they also have much snappier turning capabilities, though they are decidedly low-performance compared to today's ram-air rigs. From about the mid-1960s to the late-1970s, this was the most popular parachute design type for sport parachuting (prior to this period, modified military 'rounds' were generally used and after, ram-air 'squares' became common). Note that the use of the word elliptical for these 'round' parachutes is somewhat dated and may cause slight confusion, since some 'squares' (i.e. ram-airs) are elliptical nowadays, too.

Annular
Some designs with a pull-down apex have the fabric removed from the apex to open a hole through which air can exit (most, if not all, round canopies have at least a small hole to allow easier tie-down for packing - these aren't considered annular), giving the canopy an annular geometry. This hole can be very pronounced in some designs, taking up more 'space' than the parachute. They also have decreased horizontal drag due to their flatter shape and, when combined with rear-facing vents, can have considerable forward speed. Truly annular designs - with a hole large enough that the canopy can be classified as ring-shaped - are uncommon.

Rogallo wing
Sport parachuting has experimented with the Rogallo wing, among other shapes and forms. These were usually an attempt to increase the forward speed and reduce the landing speed offered by the other options at the time. The ram-air parachute's development and the subsequent introduction of the sail slider to slow deployment reduced the level of experimentation in the sport parachuting community. The parachutes are also hard to build.

Ribbon and ring

Ribbon and ring parachutes have similarities to annular designs. They are frequently designed to deploy at supersonic speeds. A conventional parachute would instantly burst upon opening and be shredded at such speeds. Ribbon parachutes have a ring-shaped canopy, often with a large hole in the centre to release the pressure. Sometimes the ring is broken into ribbons connected by ropes to leak air even more. These large leaks lower the stress on the parachute so it does not burst or shred when it opens. Ribbon parachutes made of Kevlar are used on nuclear bombs, such as the B61 and B83.

Ram-air
The principle of the Ram-Air Multicell Airfoil was conceived in 1963 by Canadian Domina "Dom" C. Jalbert, but serious problems had to be solved before a ram-air canopy could be marketed to the sport parachuting community. Ram-air parafoils are steerable (as are most canopies used for sport parachuting), and have two layers of fabric—top and bottom—connected by airfoil-shaped fabric ribs to form "cells". The cells fill with higher-pressure air from vents that face forward on the leading edge of the airfoil. The fabric is shaped and the parachute lines trimmed under load such that the ballooning fabric inflates into an airfoil shape. This airfoil is sometimes maintained by use of fabric one-way valves called airlocks. "The first jump of this canopy (a Jalbert Parafoil) was made by International Skydiving Hall of Fame member Paul 'Pop' Poppenhager."

Varieties

Personal ram-air parachutes are loosely divided into two varieties – rectangular or tapered – commonly called "squares" or "ellipticals", respectively. Medium-performance canopies (reserve-, BASE-, canopy formation-, and accuracy-type) are usually rectangular. High-performance, ram-air parachutes have a slightly tapered shape to their leading and/or trailing edges when viewed in plan form, and are known as ellipticals. Sometimes all the taper is on the leading edge (front), and sometimes in the trailing edge (tail).

Ellipticals are usually used only by sport parachutists. They often have smaller, more numerous fabric cells and are shallower in profile. Their canopies can be anywhere from slightly elliptical to highly elliptical, indicating the amount of taper in the canopy design, which is often an indicator of the responsiveness of the canopy to control input for a given wing loading, and of the level of experience required to pilot the canopy safely.

The rectangular parachute designs tend to look like square, inflatable air mattresses with open front ends. They are generally safer to operate because they are less prone to dive rapidly with relatively small control inputs, they are usually flown with lower wing loadings per square foot of area, and they glide more slowly. They typically have a lower glide ratio.

Wing loading of parachutes is measured similarly to that of aircraft, comparing exit weight to area of parachute fabric. Typical wing loading for students, accuracy competitors, and BASE jumpers is less than 5 kg per square meter – often 0.3 kilograms per square meter or less. Most student skydivers fly with wing loading below 5 kg per square meter. Most sport jumpers fly with wing loading between 5 and 7 kg per square meter, but many interested in performance landings exceed this wing loading. Professional canopy pilots compete with wing loading of 10 to over 15 kilograms per square meter. While ram-air parachutes with wing loading higher than 20 kilograms per square meter have been landed, this is strictly the realm of professional test jumpers.

Smaller parachutes tend to fly faster for the same load, and ellipticals respond faster to control input. Therefore, small, elliptical designs are often chosen by experienced canopy pilots for the thrilling flying they provide. Flying a fast elliptical requires much more skill and experience. Fast ellipticals are also considerably more dangerous to land. With high-performance elliptical canopies, nuisance malfunctions can be much more serious than with a square design, and may quickly escalate into emergencies. Flying highly loaded, elliptical canopies is a major contributing factor in many skydiving accidents, although advanced training programs are helping to reduce this danger.

High-speed, cross-braced parachutes, such as the Velocity, VX, XAOS, and Sensei, have given birth to a new branch of sport parachuting called "swooping." A race course is set up in the landing area for expert pilots to measure the distance they are able to fly past the 1.5 m tall entry gate. Current world records exceed 180 m.

Aspect ratio is another way to measure ram-air parachutes. Aspect ratios of parachutes are measured the same way as aircraft wings, by comparing span with chord. Low aspect ratio parachutes, i.e., span 1.8 times the chord, are now limited to precision landing competitions. Popular precision landing parachutes include Jalbert (now NAA) Para-Foils and John Eiff's series of Challenger Classics. While low aspect ratio parachutes tend to be extremely stable, with gentle stall characteristics, they suffer from steep glide ratios and a small tolerance, or "sweet spot", for timing the landing flare.

Because of their predictable opening characteristics, parachutes with a medium aspect ratio around 2.1 are widely used for reserves, BASE, and canopy formation competition. Most medium aspect ratio parachutes have seven cells.

High aspect ratio parachutes have the flattest glide and the largest tolerance for timing the landing flare, but the least predictable openings. An aspect ratio of 2.7 is about the upper limit for parachutes. High aspect ratio canopies typically have nine or more cells. All reserve ram-air parachutes are of the square variety, because of the greater reliability, and the less-demanding handling characteristics.

Paragliders
Paragliders - virtually all of which use ram-air canopies - are more akin to today's sport parachutes than, say, parachutes of the mid-1970s and earlier. Technically, they are ascending parachutes, though that term is not used in the paragliding community, and they have the same basic airfoil design of today's 'square' or 'elliptical' sports parachuting canopy, but generally have more sectioned cells, higher aspect ratio and a lower profile. Cell count varies widely, typically from the high 20s to the 70s, while aspect ratio can be 8 or more, though aspect ratio (projected) for such a canopy might be down at 6 or so - both outrageously higher than a representative skydiver's parachute. The wing span is typically so great that it's far closer to a very elongated rectangle or ellipse than a square and that term is rarely used by paraglider pilots. Similarly, span might be ~15 m with span (projected) at 12 m. Canopies are still attached to the harness by suspension lines and (four or six) risers, but they use lockable carabiners as the final connection to the harness. Modern high-performance paragliders often have the cell openings closer to the bottom of the leading edge and the end cells might appear to be closed, both for aerodynamic streamlining (these apparently closed end cells are vented and inflated from the adjacent cells, which have venting in the cell walls).

The main difference is in paragliders' usage, typically longer flights that can last all day and hundreds of kilometres in some cases. The harness is also quite different from a parachuting harness and can vary dramatically from ones for the beginner (which might be just a bench seat with nylon material and webbing to ensure the pilot is secure, no matter the position), to seatboardless ones for high altitude and cross-country flights (these are usually full-body cocoon- or hammock-like devices to include the outstretched legs - called speedbags, aerocones, etc. - to ensure aerodynamic efficiency and warmth). In many designs, there will be protection for the back and shoulder areas built-in, and support for a reserve canopy, water container, etc. Some even have windshields.

Because paragliders are made for foot- or ski-launch, they aren't suitable for terminal velocity openings and there is no slider to slow down an opening (paraglider pilots typically start with an open but uninflated canopy). To launch a paraglider, one typically spreads out the canopy on the ground to closely approximate an open canopy with the suspension lines having little slack and less tangle - see more in Paragliding. Depending on the wind, the pilot has three basic options: 1) a running forward launch (typically in no wind or slight wind), 2) a standing launch (in ideal winds) and 3) a reverse launch (in higher winds). In ideal winds, the pilot pulls on the top risers to have the wind inflate the cells and simply eases the brakes down, much like an aircraft's flaps, and takes off. Or if there is no wind, the pilot runs or skis to make it inflate, typically at the edge of a cliff or hill. Once the canopy is above one's head, it's a gentle pull down on both toggles in ideal winds, a tow (say, behind a vehicle) on flat ground, a continued run down the hill, etc. Ground handling in a variety of winds is important and there are even canopies made strictly for that practice, to save on wear and tear of more expensive canopies designed for say, XC, competition or just recreational flying.

General characteristics
Main parachutes used by skydivers today are designed to open softly. Overly rapid deployment was an early problem with ram-air designs. The primary innovation that slows the deployment of a ram-air canopy is the slider; a small rectangular piece of fabric with a grommet near each corner. Four collections of lines go through the grommets to the risers (risers are strips of webbing joining the harness and the rigging lines of a parachute). During deployment, the slider slides down from the canopy to just above the risers. The slider is slowed by air resistance as it descends and reduces the rate at which the lines can spread. This reduces the speed at which the canopy can open and inflate.

At the same time, the overall design of a parachute still has a significant influence on the deployment speed. Modern sport parachutes' deployment speeds vary considerably. Most modern parachutes open comfortably, but individual skydivers may prefer harsher deployment.

The deployment process is inherently chaotic. Rapid deployments can still occur even with well-behaved canopies. On rare occasions, deployment can even be so rapid that the jumper suffers bruising, injury, or death. Reducing the amount of fabric decreases the air resistance. This can be done by making the slider smaller, inserting a mesh panel, or cutting a hole in the slider.

Deployment
Reserve parachutes usually have a ripcord deployment system, which was first designed by Theodore Moscicki, but most modern main parachutes used by sports parachutists use a form of hand-deployed pilot chute. A ripcord system pulls a closing pin (sometimes multiple pins), which releases a spring-loaded pilot chute, and opens the container; the pilot chute is then propelled into the air stream by its spring, then uses the force generated by passing air to extract a deployment bag containing the parachute canopy, to which it is attached via a bridle. A hand-deployed pilot chute, once thrown into the air stream, pulls a closing pin on the pilot chute bridle to open the container, then the same force extracts the deployment bag. There are variations on hand-deployed pilot chutes, but the system described is the more common throw-out system.

Only the hand-deployed pilot chute may be collapsed automatically after deployment—by a kill line reducing the in-flight drag of the pilot chute on the main canopy. Reserves, on the other hand, do not retain their pilot chutes after deployment. The reserve deployment bag and pilot chute are not connected to the canopy in a reserve system. This is known as a free-bag configuration, and the components are sometimes not recovered after a reserve deployment.

Occasionally, a pilot chute does not generate enough force either to pull the pin or to extract the bag. Causes may be that the pilot chute is caught in the turbulent wake of the jumper (the "burble"), the closing loop holding the pin is too tight, or the pilot chute is generating insufficient force. This effect is known as "pilot chute hesitation," and, if it does not clear, it can lead to a total malfunction, requiring reserve deployment.

Paratroopers' main parachutes are usually deployed by static lines that release the parachute, yet retain the deployment bag that contains the parachute—without relying on a pilot chute for deployment. In this configuration, the deployment bag is known as a direct-bag system, in which the deployment is rapid, consistent, and reliable.

Safety
A parachute is carefully folded, or "packed" to ensure that it will open reliably. If a parachute is not packed properly it can result in a malfunction where the main parachute fails to deploy correctly or fully. In the United States and many developed countries, emergency and reserve parachutes are packed by "riggers" who must be trained and certified according to legal standards. Sport skydivers are always trained to pack their own primary "main" parachutes.

Exact numbers are difficult to estimate because parachute design, maintenance, loading, packing technique and operator experience all have a significant impact on malfunction rates. Approximately one in a thousand sport main parachute openings malfunctions, requiring the use of the reserve parachute, although some skydivers have many thousands of jumps and never needed to use their reserve parachute.

Reserve parachutes are packed and deployed somewhat differently. They are also designed more conservatively, favouring reliability over responsiveness and are built and tested to more exacting standards, making them more reliable than main parachutes. Regulated inspection intervals, coupled with significantly less use contributes to reliability as wear on some components can adversely affect reliability. The safety advantage of a reserve parachute comes from the small probability of a main malfunction being multiplied by the even smaller probability of a reserve malfunction. This yields an even smaller probability of a double malfunction, although there is also a small possibility of a malfunctioning main parachute not being able to be released and thus interfering with the reserve parachute. In the United States, the 2017 average fatality rate is recorded to be 1 in 133,571 jumps.

Injuries and fatalities in sport skydiving are possible even under a fully functional main parachute, such as may occur if the skydiver makes an error in judgment while flying the canopy which results in a high-speed impact either with the ground or with a hazard on the ground, which might otherwise have been avoided, or results in collision with another skydiver under canopy.

Malfunctions
Below are listed the malfunctions specific to round parachutes:
 * A "Mae West" or "blown periphery" is a type of round parachute malfunction that contorts the shape of the canopy into the outward appearance of a large brassiere, named after the generous proportions of the late actress Mae West. The column of nylon fabric, buffeted by the wind, rapidly heats from friction and opposite sides of the canopy can fuse together in a narrow region, removing any chance of it opening fully.
 * A "streamer" is the main chute which becomes entangled in its lines and fails to deploy, taking the shape of a paper streamer. The parachutist cuts it away to provide space and clean air for deploying the reserve.
 * An "inversion" occurs when one skirt of the canopy blows between the suspension lines on the opposite side of the parachute and then catches air. That portion then forms a secondary lobe with the canopy inverted. The secondary lobe grows until the canopy turns completely inside out.
 * A "barber's pole" describes having a tangle of lines behind the jumper's head, who cuts away the main and opens his reserve.
 * The "horseshoe" is an out-of-sequence deployment, when the parachute lines and bag are released before the bag drogue and bridle. This can cause the lines to become tangled or a situation where the parachute drogue is not released from the container.
 * "Jumper-In-Tow" involves a static line that does not disconnect, resulting in a jumper being towed behind the aircraft.

Records

On August 16, 1960, Joseph Kittinger, in the Excelsior III test jump, set the previous world record for the highest parachute jump. He jumped from a balloon at an altitude of 102800 ft (which was also a piloted balloon altitude record at the time). A small stabilizer chute deployed successfully, and Kittinger fell for 4 minutes and 36 seconds, also setting a still-standing world record for the longest parachute free-fall, if falling with a stabilizer chute is counted as free-fall. At an altitude of 17500 ft, Kittinger opened his main chute and landed safely in the New Mexico desert. The whole descent took 13 minutes and 45 seconds. During the descent, Kittinger experienced temperatures as low as -94 °F. In the free-fall stage, he reached a top speed of 614 mph (988 km/h or 274 m/s), or Mach 0.8.

According to Guinness World Records, Yevgeni Andreyev, a colonel in the Soviet Air Force, held the official FAI record for the longest free-fall parachute jump (without drogue chute) after falling for 24,500 m (80,380 ft) from an altitude of 25,457 m (83,523 ft) near the city of Saratov, Russia on November 1, 1962, until broken by Felix Baumgartner in 2012.

Felix Baumgartner broke Joseph Kittinger's record on October 14, 2012, with a jump from an altitude of 127,852 feet (38,969.3 m) and reaching speeds up to 833.9 mph (1,342.0 km/h or 372.8 m/s), or nearly Mach 1.1. Kittinger was an advisor for Baumgartner's jump.

Alan Eustace made a jump from the stratosphere on October 24, 2014, from an altitude of 135,889.108 feet (41,419 m). However, because Eustace's jump involved a drogue parachute while Baumgartner's did not, their vertical speed and free fall distance records remain in different record categories.

Uses
In addition to the use of a parachute to slow the descent of a person or object, a drogue parachute is used to aid horizontal deceleration of a land or air vehicle, including fixed-wing aircraft and drag racers, provide stability, as to assist certain types of light aircraft in distress, tandem free-fall; and as a pilot triggering deployment of a larger parachute.

Parachutes are also used as play equipment.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Parachute