Lepidoptera

Lepidoptera Temporal range:Early Jurassic–Present,
Peacock butterfly (Aglais io)
Adhemarius gannascus,a species ofsphinx moth
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
(unranked):	Amphiesmenoptera
Order:	Lepidoptera Linnaeus,1758
Suborders
Aglossata Glossata Heterobathmiina Rhopalocera Zeugloptera

Lepidoptera(/ˌlɛpɪˈdɒptərə/LEP-ih-DOP-tər-ə) orlepidopteransis anorderofwinged insectswhich includesbutterfliesandmoths.About 180,000speciesof the Lepidoptera have been described, representing 10% of the total described species of living organisms,making it the second largest insect order (behindColeoptera) with 126familiesand 46superfamilies,and one of the most widespread and widely recognizable insect orders in the world.

Lepidopteran species are characterized by more than three derived features. The most apparent is the presence ofscalesthat cover thebodies,large triangularwings,and aproboscisforsiphoningnectars.The scales are modified, flattened "hairs", and give butterflies and moths their wide variety of colors and patterns. Almost all species have some form of membranous wings, except for a few that have reduced wings or are wingless.Matingand the laying of eggs is normally performed near or on host plants for thelarvae.Like most other insects, butterflies and moths areholometabolous,meaning they undergocomplete metamorphosis.The larvae are commonly calledcaterpillars,and are completely different from their adult moth or butterfly forms, having a cylindrical body with a well-developed head, mandible mouth parts, three pairs of thoracic legs and from none up to five pairs ofprolegs.As they grow, these larvae change in appearance, going through a series of stages calledinstars.Once fully matured, the larva develops into apupa.A few butterflies and many moth species spin asilkcasing orcocoonfor protection prior to pupating, while others do not, instead going underground.A butterfly pupa, called achrysalis,has a hard skin, usually with no cocoon. Once the pupa has completed its metamorphosis, a sexually mature adult emerges.

Lepidopterans first appeared in fossil record in theTriassic-Jurassicboundary and havecoevolvedwithflowering plantssince theangiosperm boomin theMiddle/Late Cretaceous.They show many variations of the basic body structure that have evolved to gain advantages in lifestyle and distribution. Recent estimates suggest the order may have more species than earlier thought,and is among the five most species-rich orders (each with over 100,000 species) along withColeoptera(beetles),Diptera(flies),Hymenoptera(ants,bees,waspsandsawflies) andHemiptera(cicadas,aphidsand other true bugs).They have, over millions of years, evolved a wide range of wing patterns and coloration ranging from drab moths akin to the related orderTrichoptera,to the brightly colored and complex-patterned butterflies.Accordingly, this is the most recognized and popular of insect orders with many people involved in the observation, study, collection, rearing of, and commerce in these insects. A person who collects or studies this order is referred to as alepidopterist.

Butterflies and moths are mostlyherbivorous(folivorous) as caterpillars andnectarivorousas adults. They play an important role in the natural ecosystem aspollinatorsand serve asprimary consumersin thefood chain;conversely, their larvae (caterpillars) are considered very problematic to vegetation in agriculture, as they consume large quantity of plant matter (mostlyfoliage) to sustain growth. In many species, the female may produce from 200 to 600 eggs, while in others, the number may approach 30,000 eggs in one day. The caterpillars hatching from these eggs can cause significant damage to crops within a very short period of time. Many moth and butterfly species are of economic interest by virtue of their role as pollinators, thesilkin their cocoon, or forexterminationaspestspecies.

Etymology

The term Lepidoptera was used in 1746 byCarl Linnaeusin hisFauna Svecica.The word is derived fromGreekλεπίςlepís,gen.λεπίδοςlepídos( "scale") andπτερόν( "wing" ).Sometimes, the termRhopalocerais used for thecladeof all butterfly species, derived from the Ancient Greekῥόπαλον(rhopalon)andκέρας(keras)meaning "club" and "horn", respectively, coming from the shape of theantennaeof butterflies.

The origins of the common names "butterfly" and "moth" are varied and often obscure. TheEnglishword butterfly is fromOld Englishbuttorfleoge,with many variations in spelling. Other than that, the origin is unknown, although it could be derived from the pale yellow color of many species' wings suggesting the color of butter.The species ofHeteroceraare commonly calledmoths.The origins of the English word moth are clearer, deriving from Old Englishmoððe(cf.Northumbrian dialectmohðe) from Common Germanic (compareOld Norsemotti,DutchmotandGermanMotteall meaning "moth" ). Perhaps its origins are related to Old Englishmaðameaning "maggot"or from the root of"midge",which until the 16th century was used mostly to indicate the larva, usually in reference to devouring clothes.

The etymological origins of the word "caterpillar", the larval form of butterflies and moths, are from the early 16th century, fromMiddle Englishcatirpel,catirpeller,probably an alteration ofOld North Frenchcatepelose(from Latincattus,"cat" +pilosus,"hairy" ).

Distribution and diversity

Main article:Lists of Lepidoptera by region

The Lepidoptera are among the most successful groups of insects. They are found on all continents, exceptAntarctica,and inhabit all terrestrial habitats ranging from desert to rainforest, from lowland grasslands to mountain plateaus, but almost always associated with higher plants, especially angiosperms (flowering plants).Among the most northern dwelling species of butterflies and moths is the Arctic Apollo (Parnassius arcticus), which is found in the Arctic Circle in northeasternYakutia,at an altitude of 1,500 metres (4,900 ft) above sea level.In theHimalayas,various Apollo species such asParnassius epaphushave been recorded to occur up to an altitude of 6,000 metres (20,000 ft) above sea level.

Some lepidopteran species exhibitsymbiotic,phoretic,orparasiticlifestyles, inhabiting the bodies of organisms rather than the environment.Coprophagouspyralidmoth species, calledsloth moths,such asBradipodicola hahneliandCryptoses choloepi,are unusual in that they are exclusively found inhabiting the fur ofsloths,mammals found inCentralandSouth America.Two species ofTineamoths have been recorded as feeding on horny tissue and have been bred from the horns of cattle. The larva ofZenodochiumcoccivorellais an internal parasite of thecoccidKermesspecies. Many species have been recorded as breeding in natural materials or refuse such as owl pellets, bat caves, honeycombs or diseased fruit.

As of 2007, there were roughly 174,250 lepidopteran species described, with butterflies andskippersestimated to comprise around 17,950, and moths making up the rest.The vast majority of Lepidoptera are to be found in the tropics, but substantial diversity exists on most continents. North America has over 700 species of butterflies and over 11,000 species of moths,while about 400 species of butterflies and 14,000 species of moths are reported from Australia.The diversity of Lepidoptera in eachfaunal regionhas been estimated by John Heppner in 1991 based partly on actual counts from the literature, partly on the card indices in theNatural History Museum(London) and theNational Museum of Natural History(Washington), and partly on estimates:

Diversity of Lepidoptera in each faunal region

	Palearctic	Nearctic	Neotropic	Afrotropic	Indo-Australian (comprisingIndomalayan,Australasian,andOceanian realms)
Estimated number of species	22,465	11,532	44,791	20,491	47,287

External morphology

Main article:External morphology of Lepidoptera

Further information:Glossary of entomology termsandComparison of butterflies and moths

Parts of an adult butterfly

A – head, B – thorax, C – abdomen, 1 – prothoracic shield, 2 – spiracle, 3 – true legs, 4 – midabdominal prolegs, 5 – anal proleg, 6 – anal plate, 7 – tentacle, a – eye, b – stemmata (ocelli), c – antenna, d – mandible, e – labrum, f – frontal triangle.

Lepidoptera are morphologically distinguished from other orders principally by the presence ofscaleson the external parts of the body and appendages, especially thewings.Butterflies and moths vary in size frommicrolepidopteraonly a few millimeters long, to conspicuous animals with a wingspan greater than 25 centimetres (9.8 in), such as theQueen Alexandra's birdwingandAtlas moth. Lepidopterans undergo a four-stagelife cycle:egg;larvaorcaterpillar;pupaorchrysalis;andimago (plural: imagines)/ adult and show many variations of the basic body structure, which give these animals advantages for diverse lifestyles and environments.

Head

Face of a caterpillar with the mouthparts showing

The head is where many sensing organs and the mouth parts are found. Like the adult, the larva also has a toughened, orsclerotizedhead capsule.Here, twocompound eyes,andchaetosema,raised spots or clusters of sensory bristles unique to Lepidoptera, occur, though many taxa have lost one or both of these spots. The antennae have a wide variation in form among species and even between different sexes. The antennae of butterflies are usually filiform and shaped like clubs, those of the skippers are hooked, while those of moths have flagellar segments variously enlarged or branched. Some moths have enlarged antennae or ones that are tapered and hooked at the ends.

Themaxillary galeaeare modified and form an elongatedproboscis.The proboscis consists of one to five segments, usually kept coiled up under the head by small muscles when it is not being used to suck up nectar from flowers or other liquids. Somebasalmoths still havemandibles,or separate moving jaws, like their ancestors, and these form the familyMicropterigidae.

The larvae, calledcaterpillars,have a toughened head capsule. Caterpillars lack the proboscis and have separate chewingmouthparts.These mouthparts, calledmandibles,are used to chew up the plant matter that the larvae eat. The lower jaw, or labium, is weak, but may carry aspinneret,an organ used to create silk. The head is made of large lateral lobes, each having an ellipse of up to six simple eyes.

Thorax

The thorax is made of three fused segments, theprothorax,mesothorax,andmetathorax,each with a pair of legs. The first segment contains the first pair of legs. In some males of the butterfly familyNymphalidae,the forelegs are greatly reduced and are not used for walking or perching.The three pairs of legs are covered with scales. Lepidoptera also have olfactory organs on their feet, which aid the butterfly in "tasting" or "smelling" out its food.In the larval form there are 3 pairs of true legs, with up to 11 pairs of abdominal legs (usually eight) and hooklets, called apical crochets.

The two pairs of wings are found on the middle and third segments, ormesothoraxandmetathorax,respectively. In the more recent genera, the wings of the second segment are much more pronounced, although some more primitive forms have similarly sized wings of both segments. The wings are covered in scales arranged like shingles, which form an extraordinary variety of colors and patterns. The mesothorax has more powerful muscles to propel the moth or butterfly through the air, with the wing of this segment (forewing) having a stronger vein structure.The largest superfamily, theNoctuoidea,has their wings modified to act astympanal or hearing organs.

The caterpillar has an elongated, soft body that may have hair-like or other projections, three pairs of true legs, with none to 11 pairs of abdominal legs (usually eight) and hooklets, called apical crochets.The thorax usually has a pair of legs on each segment. The thorax is also lined with many spiracles on both the mesothorax and metathorax, except for a few aquatic species, which instead have a form ofgills.

Abdomen

See also:Lepidoptera genitalia

Caterpillar prolegs onPapilio machaon

The abdomen, which is less sclerotized than the thorax, consists of 10 segments with membranes in between, allowing for articulated movement. The sternum, on the first segment, is small in some families and is completely absent in others. The last two or three segments form the external parts of the species' sex organs. Thegenitaliaof Lepidoptera are highly varied and are often the only means of differentiating between species. Male genitals include avalva,which is usually large, as it is used to grasp the female during mating. Female genitalia include three distinct sections.

The females of basal moths have only one sex organ, which is used forcopulationand as anovipositor,or egg-laying organ. About 98% of moth species have a separate organ for mating, and an external duct that carries the sperm from the male.

The abdomen of the caterpillar has four pairs of prolegs, normally located on the third to sixth segments of the abdomen, and a separate pair of prolegs by the anus, which have a pair of tiny hooks called crotchets. These aid in gripping and walking, especially in species that lack many prolegs (e. g. larvae ofGeometridae). In some basal moths, these prolegs may be on every segment of the body, while prolegs may be completely absent in other groups, which are more adapted to boring and living in sand (e. g.,ProdoxidaeandNepticulidae,respectively).

Scales

Wing scales form the color and pattern on wings. The scales shown here are lamellar. The pedicel can be seen attached to a few loose scales.

The wings, head, and parts of the thorax and abdomen of Lepidoptera are covered with minute scales, a feature from which the order derives its name. Most scales arelamellar,or blade-like, and attached with a pedicel, while other forms may be hair-like or specialized as secondary sexual characteristics.

The lumen or surface of the lamella has a complex structure. It gives color either by coloredpigmentsit contains, or throughstructural colorationwith mechanisms that includephotonic crystalsanddiffraction gratings.

Scales function in insulation, thermoregulation, producingpheromones(in males only),and aiding gliding flight, but the most important is the large diversity of vivid or indistinctpatternsthey provide, which help the organism protect itself bycamouflageormimicry,and which act as signals to other animals including rivals andpotential mates.

Electron microscopy images of scales

A patch of wing (×50)

Scales close up (×200)

A single scale (×1000)

Microstructure of a scale (×5000)

Internal morphology

Reproductive system

In thereproductive system of butterflies and moths,the malegenitaliaare complex and unclear. In females the three types of genitalia are based on the relating taxa: 'monotrysian', 'exoporian', and 'ditrysian'. In the monotrysian type is an opening on the fused segments of the sterna 9 and 10, which act as insemination and oviposition. In the exoporian type (inHepialoideaandMnesarchaeoidea) are two separate places for insemination and oviposition, both occurring on the same sterna as the monotrysian type, i.e. 9 and 10.The ditrysian groups have an internal duct that carries sperm, with separate openings for copulation and egg-laying.In most species, the genitalia are flanked by two soft lobes, although they may be specialized and sclerotized in some species for ovipositing in area such as crevices and inside plant tissue.Hormones and the glands that produce them run the development of butterflies and moths as they go through their life cycles, called theendocrine system.The first insect hormoneprothoracicotropic hormone(PTTH) operates the species life cycle anddiapause.This hormone is produced bycorpora allataandcorpora cardiaca,where it is also stored. Some glands are specialized to perform certain task such as producing silk or producing saliva in the palpi.While the corpora cardiaca produce PTTH, the corpora allata also produces juvenile hormones, and the prothorocic glands produce moulting hormones.

Digestive system

In thedigestive system,the anterior region of the foregut has been modified to form a pharyngeal sucking pump as they need it for the food they eat, which are for the most part liquids. Anesophagusfollows and leads to the posterior of the pharynx and in some species forms a form of crop. The midgut is short and straight, with the hindgut being longer and coiled.Ancestors of lepidopteran species, stemming fromHymenoptera,had midgut ceca, although this is lost in current butterflies and moths. Instead, all the digestive enzymes, other than initial digestion, are immobilized at the surface of the midgut cells. In larvae, long-necked and stalkedgoblet cellsare found in the anterior and posterior midgut regions, respectively. In insects, the goblet cells excrete positivepotassiumions, which are absorbed from leaves ingested by the larvae. Most butterflies and moths display the usual digestive cycle, but species with different diets require adaptations to meet these new demands.Some, like theluna moth,exhibit no digestive system whatsoever; they survive as adults from stored energy consumed as larvae and live for no longer than 7-10 days.

Internal morphology of adult male in the familyNymphalidae,showing most of the major organ systems, with characteristic reduced forelegs of that family: The corpora include the corpus allatum and the corpus cardiaca.

Circulatory system

In thecirculatory system,hemolymph,or insect blood, is used to circulate heat in a form ofthermoregulation,where muscles contraction produces heat, which is transferred to the rest of the body when conditions are unfavorable. In lepidopteran species, hemolymph is circulated through the veins in the wings by some form of pulsating organ, either by the heart or by the intake of air into thetrachea.

Respiratory system

Air is taken in through spiracles along the sides of the abdomen and thorax supplying the trachea with oxygen as it goes through the lepidopteran'srespiratory system.Three different tracheaes supply and diffuse oxygen throughout the species' bodies. The dorsal tracheae supply oxygen to the dorsal musculature and vessels, while the ventral tracheae supply the ventral musculature and nerve cord, and the visceral tracheae supply the guts, fat bodies, and gonads.

Polymorphism

Main article:Polymorphism in Lepidoptera

Sexually dimorphic bagworm moths (Thyridopteryx ephemeraeformis) mating: The female is flightless.

TheHeliconiusbutterflies from the tropics of the Western Hemisphere are the classical model forMüllerian mimicry.

Polymorphism is the appearance of forms or "morphs", which differ in color and number of attributes within a single species.In Lepidoptera, polymorphism can be seen not only between individuals in a population, but also between the sexes assexual dimorphism,between geographically separated populations ingeographical polymorphism,and between generations flying at different seasons of the year (seasonal polymorphismorpolyphenism). In some species, the polymorphism is limited to one sex, typically the female. This often includes the phenomenon ofmimicrywhen mimetic morphs fly alongside nonmimetic morphs in a population of a particular species. Polymorphism occurs both at specific level with heritable variation in the overall morphological adaptations of individuals, as well as in certain specific morphological or physiological traits within a species.

Environmental polymorphism, in whichtraitsare not inherited, is often termed as polyphenism, which in Lepidoptera is commonly seen in the form of seasonal morphs, especially in the butterfly families ofNymphalidaeandPieridae.An Old World pierid butterfly, the common grass yellow (Eurema hecabe) has a darker summer adult morph, triggered by a long day exceeding 13 hours in duration, while the shorter diurnal period of 12 hours or less induces a paler morph in the postmonsoon period.Polyphenism also occurs in caterpillars, an example being the peppered moth,Biston betularia.

Geographical isolation causes a divergence of a species into different morphs. A good example is the Indian white admiralLimenitis procris,which has five forms, each geographically separated from the other by large mountain ranges.An even more dramatic showcase of geographical polymorphism is theApollo butterfly(Parnassius apollo). Because the Apollos live in small local populations, thus having no contact with each other, coupled with their strong stenotopic nature and weak migration ability, interbreeding between populations of one species practically does not occur; by this, they form over 600 different morphs, with the size of spots on the wings of which varies greatly.

Seasonal diphenism in the common grass yellow,Eurema hecabe

Dry-season form

Wet-season form

Sexual dimorphism is the occurrence of differences between males and females in a species. In Lepidoptera, it is widespread and almost completely set by genetic determination.Sexual dimorphism is present in all families of the Papilionoidea and more prominent in theLycaenidae,Pieridae,and certain taxa of theNymphalidae.Apart from color variation, which may differ from slight to completely different color-pattern combinations, secondary sexual characteristics may also be present.Different genotypes maintained by natural selection may also be expressed at the same time.Polymorphic and/or mimetic females occur in the case of some taxa in thePapilionidaeprimarily to obtain a level of protection not available to the male of their species. The most distinct case of sexual dimorphism is that of adult females of manyPsychidaespecies which have only vestigial wings, legs, and mouthparts as compared to the adult males that are strong fliers with well-developed wings and feathery antennae.

Reproduction and development

Mating pair ofLaothoe populi(poplar hawk-moth) showing two different color variants

Species of Lepidoptera undergoholometabolismor "complete metamorphosis". Their life cycle normally consists of anegg,alarva,apupa,and animagoor adult.The larvae are commonly calledcaterpillars,and the pupae of moths encapsulated in silk are calledcocoons,while the uncovered pupae of butterflies are calledchrysalides.

Lepidopterans in diapause

Unless the species reproduces year-round, a butterfly or moth may enterdiapause,a state of dormancy that allows the insect to survive unfavorable environmental conditions.

Mating

See also:Lepidoptera genitalia

Males usually starteclosion(emergence) earlier than females and peak in numbers before females. Both of the sexes are sexually mature by the time of eclosion.Butterflies and moths normally do not associate with each other, except for migrating species, staying relatively asocial. Mating begins with an adult (female or male) attracting a mate, normally using visual stimuli, especially indiurnalspecies like most butterflies. However, the females of most nocturnal species, including almost all moth species, usepheromonesto attract males, sometimes from long distances.Some species engage in a form of acoustic courtship, or attract mates using sound or vibration such as the polka-dot wasp moth,Syntomeida epilais.

Adaptations include undergoing one seasonal generation, two or even more, calledvoltinism(Univoltism, bivoltism, and multivism, respectively). Most lepidopterans intemperate climatesare univoltine, while in tropical climates most have two seasonal broods. Some others may take advantage of any opportunity they can get, and mate continuously throughout the year. These seasonal adaptations are controlled by hormones, and these delays in reproduction are calleddiapause.Many lepidopteran species, after mating and laying their eggs, die shortly afterwards, having only lived for a few days after eclosion. Others may still be active for several weeks and then overwinter and become sexually active again when the weather becomes more favorable, or diapause. The sperm of the male that mated most recently with the female is most likely to have fertilized the eggs, but the sperm from a prior mating may still prevail.

Life cycle

The four stages of the life cycle of ananise swallowtail

Eggs

Lepidoptera usually reproduce sexually and areoviparous(egg-laying), though some species exhibit live birth in a process calledovoviviparity.A variety of differences inegg-laying and the number of eggs laid occur. Some species simply drop their eggs in flight (these species normally have polyphagous larvae, meaning they eat a variety of plants e. g.,hepialidsand somenymphalids)while most lay their eggs near or on the host plant on which the larvae feed. The number of eggs laid may vary from only a few to several thousand.The females of both butterflies and moths select the host plant instinctively, and primarily, by chemical cues.

The eggs are derived from materials ingested as a larva and in some species, from the spermatophores received from males during mating.An egg can only be 1/1000 the mass of the female, yet she may lay up to her own mass in eggs. Females lay smaller eggs as they age. Larger females lay larger eggs.The egg is covered by a hard-ridged protective outer layer of shell, called thechorion.It is lined with a thin coating ofwax,which prevents the egg from drying out. Each egg contains a number ofmicropyles,or tiny funnel-shaped openings at one end, the purpose of which is to allow sperm to enter and fertilize the egg. Butterfly and moth eggs vary greatly in size between species, but they are all either spherical or ovate.

The egg stage lasts a few weeks in most butterflies, but eggs laid prior to winter, especially intemperate regions,go throughdiapause,and hatching may be delayed until spring. Other butterflies may lay their eggs in the spring and have them hatch in the summer. These butterflies are usually temperate species (e. g.Nymphalis antiopa).

Larvae

Main article:Caterpillar

Larval form typically lives and feeds on plants

The larvae or caterpillars are the first stage in the life cycle after hatching. Caterpillars are "characteristicpolypodlarvae with cylindrical bodies, short thoracic legs, and abdominal prolegs (pseudopods) ".They have a sclerotized head capsule with an adfrontal suture formed by medial fusion of the sclerites,mandibles (mouthparts)for chewing, and a soft tubular, segmented body, that may have hair-like or other projections, three pairs of true legs, and additionalprolegs(up to five pairs).The body consists of thirteen segments, of which three are thoracic and ten are abdominal.Most larvae areherbivores,but a few arecarnivores(some eat ants or other caterpillars) anddetritivores.

Different herbivorous species have adapted to feed on every part of the plant and are normally considered pests to their host plants; some species have been found to lay their eggs on the fruit and other species lay their eggs on clothing or fur (e. g.,Tineola bisselliella,the common clothes moth). Some species are carnivorous, and others are even parasitic. Somelycaenidspecies such asPhengaris rebeliaresocial parasitesofMyrmicaant nests.A species ofGeometridaefromHawaiihas carnivorous larvae that catch and eat flies.Some pyralid caterpillars are aquatic.

The larvae develop rapidly with several generations in a year; however, some species may take up to 3 years to develop, and exceptional examples likeGynaephora groenlandicatake as long as seven years.The larval stage is where the feeding and growing stages occur, and the larvae periodically undergo hormone-inducedecdysis,developing further with eachinstar,until they undergo the final larval-pupal molt.

The larvae of both butterflies and moths exhibit mimicry to deter potential predators. Some caterpillars have the ability to inflate parts of their heads to appear snake-like. Many have false eye-spots to enhance this effect. Some caterpillars have special structures calledosmeteria(familyPapilionidae), which are exposed to produce smelly chemicals used in defense. Host plants often have toxic substances in them, and caterpillars are able to sequester these substances and retain them into the adult stage. This helps make them unpalatable to birds and other predators. Such unpalatability is advertised using bright red, orange, black, or white warning colors. The toxic chemicals in plants are often evolved specifically to prevent them from being eaten by insects. Insects, in turn, develop countermeasures or make use of these toxins for their own survival. This "arms race" has led to the coevolution of insects and their host plants.

Wing development

No form of wing is externally visible on the larva, but when larvae are dissected, developing wings can be seen as disks, which can be found on the second and third thoracic segments, in place of the spiracles that are apparent on abdominal segments. Wing disks develop in association with a trachea that runs along the base of the wing, and are surrounded by a thin peripodial membrane, which is linked to the outer epidermis of the larva by a tiny duct. Wing disks are very small until the last larval instar, when they increase dramatically in size, are invaded by branchingtracheaefrom the wing base that precede the formation of the wing veins and begin to develop patterns associated with several landmarks of the wing.

Near pupation, the wings are forced outside the epidermis under pressure from thehemolymph,and although they are initially quite flexible and fragile, by the time the pupa breaks free of the larval cuticle, they have adhered tightly to the outer cuticle of the pupa (in obtect pupae). Within hours, the wings form a cuticle so hard and well-joined to the body that pupae can be picked up and handled without damage to the wings.

Pupa

Eclosion ofPapilio dardanus

After about five to seven instars,or molts, certain hormones, like PTTH, stimulate the production ofecdysone,which initiates insect molting. The larva starts to develop into thepupa:body parts specific to the larva, such as the abdominal prolegs, degenerate, while others such as the legs and wings undergo growth. After finding a suitable place, the animal sheds its last larval cuticle, revealing the pupal cuticle underneath.

Depending on the species, the pupa may be covered in a silk cocoon, attached to different types of substrates, buried in the ground, or may not be covered at all. Features of theimagoare externally recognizable in the pupa. All the appendages on the adult head and thorax are found cased inside the cuticle (antennae,mouthparts,etc.), with the wings wrapped around, adjacent to the antennae.The pupae of some species have functional mandibles, while the pupal mandibles are not functional in others.

Although the pupal cuticle is highly sclerotized, some of the lower abdominal segments are not fused, and are able to move using small muscles found in between the membrane. Moving may help the pupa, for example, escape the sun, which would otherwise kill it. The pupa of theMexican jumping beanmoth (Cydia saltitans) does this. The larvae cut a trapdoor in the bean (species ofSebastiania) and use the bean as a shelter. With a sudden rise in temperature, the pupa inside twitches and jerks, pulling on the threads inside. Wiggling may also help to deterparasitoidwasps from laying eggs on the pupa. Other species of moths are able to make clicks to deter predators.

The length of time before the pupa ecloses (emerges) varies greatly. The monarch butterfly may stay in its chrysalis for two weeks, while other species may need to stay for more than 10 months in diapause. The adult emerges from the pupa either by using abdominal hooks or from projections located on the head. The mandibles found in the most primitive moth families are used to escape from their cocoon (e. g.,Micropterigoidea).

Adult

Most lepidopteran species do not live long after eclosion, only needing a few days to find a mate and then lay their eggs. Others may remain active for a longer period (from one to several weeks) or go through diapause and overwintering as monarch butterflies do, or waiting out environmental stress. Some adult species of microlepidoptera go through a stage where no reproductive-related activity occurs, lasting through summer and winter, followed by mating and oviposition in the early spring.

While most butterflies and moths areterrestrial,many species ofAcentropinae(Crambidae) are trulyaquaticwith all stages except the adult occurring in water. Many species from other families such asErebidae,Nepticulidae,Cosmopterigidae,Tortricidae,Olethreutidae,Noctuidae,Cossidae,andSphingidaeare aquatic orsemiaquatic.

Video gallery of butterfly life cycle (Pieris rapae,the common cabbage white)

• Emerging from egg and first feedings.
• Second instar larvae eating. Speeded up 50 times to illustrate feeding behavior. Nearly transparent body shows internal digestion.
• This second instar larvae sheds skin in under 20 minutes.
• Larvae eating remainder of a leaf. Six hours speeded up one hundred times.
• Segments of the last two hours of the larvae shedding its 4th instar skin, after starting a few hours earlier.
• Fifth instarwhite cabbagelarvae walking on broccoli stem and on glass, showing it laying down silk it then walks on.
• Parasitized larvae showing wasp larvae exiting its body, spinning cocoons. Playback at double speed. Adult wasps at normal speed.
• Larvae shedding skin, becoming a chrysalis. Recorded over fifteen hours. Closeups at two times speed. Other clips at ten times speed.
• Emerging from chrysalis into an adult.
• Butterflies flying. Later clips in slow motion.
• Male butterfliesmud-puddlingto concentrate salts for female reproduction.
• Butterflies depositing eggs under leaves. Each repeated in slow motion.

Behavior

Flight

Flight is an important aspect of the lives of butterflies and moths, and is used for evading predators, searching for food, and finding mates in a timely manner, as most lepidopteran species do not live long after eclosion. It is the main form of locomotion in most species. In Lepidoptera, the forewings and hindwings are mechanically coupled and flap in synchrony. Flight is anteromotoric, or being driven primarily by action of the forewings. Although lepidopteran species reportedly can still fly when their hindwings are cut off, it reduces their linear flight and turning capabilities.

Lepidopteran species have to be warm, about 77 to 79 °F (25 to 26 °C), to fly. They depend on their body temperature being sufficiently high and since they cannot regulate it themselves, this is dependent on their environment. Butterflies living in cooler climates may use their wings to warm their bodies. They will bask in the sun, spreading out their wings so that they get maximum exposure to the sunlight. In hotter climates butterflies can easily overheat, so they are usually active only during the cooler parts of the day, early morning, late afternoon or early evening. During the heat of the day, they rest in the shade. Some larger thick-bodied moths (e.g. Sphingidae) can generate their own heat to a limited degree by vibrating their wings. The heat generated by the flight muscles warms the thorax while the temperature of the abdomen is unimportant for flight. To avoid overheating, some moths rely on hairy scales, internal air sacs, and other structures to separate the thorax and abdomen and keep the abdomen cooler.

Some species of butterflies can reach fast speeds, such as thesouthern dart,which can go as fast as 48.4 kilometres per hour (30.1 mph). Sphingids are some of the fastest flying insects, some are capable of flying at over 50 kilometres per hour (31 mph), having a wingspan of 35–150 millimetres (1.4–5.9 in).In some species, sometimes a gliding component to their flight exists. Flight occurs either as hovering, or as forward or backward motion.In butterfly and moth species, such ashawk moths,hovering is important as they need to maintain a certain stability over flowers when feeding on the nectar.

Navigation

Main article:Animal navigation

Long exposure image of flying moths, attracted to the floodlights

Navigationis important to Lepidoptera species, especially for those that migrate. Butterflies, which have more species that migrate, have been shown to navigate using time-compensated sun compasses. They can seepolarized light,so can orient even in cloudy conditions. The polarized light in the region close to the ultraviolet spectrum is suggested to be particularly important.Most migratory butterflies are those that live in semiarid areas where breeding seasons are short.The life histories of their host plants also influence the strategies of the butterflies.Other theories include the use of landscapes. Lepidoptera may use coastal lines, mountains, and even roads to orient themselves. Above sea, the flight direction is much more accurate if the coast is still visible.

Many studies have also shown that moths navigate. One study showed that many moths may use theEarth's magnetic fieldto navigate, as a study of theheart and dartmoth suggests.Another study, of the migratory behavior of thesilver Y,showed, even at high altitudes, the species can correct its course with changing winds, and prefers flying with favourable winds, suggesting a great sense of direction.Aphrissa statirainPanamaloses its navigational capacity when exposed to a magnetic field, suggesting it uses the Earth's magnetic field.

Moths exhibit a tendency to circle artificial lights repeatedly. This suggests they use a technique ofcelestial navigationcalledtransverse orientation.By maintaining a constant angular relationship to a bright celestial light, such as theMoon,they can fly in a straight line. Celestial objects are so far away, even after traveling great distances, the change in angle between the moth and the light source is negligible; further, the moon will always be in the upper part of the visual field or on thehorizon.When a moth encounters a much closer artificial light and uses it for navigation, the angle changes noticeably after only a short distance, in addition to being often below the horizon. The moth instinctively attempts to correct by turning toward the light, causing airborne moths to come plummeting downwards, and at close range, which results in a spiral flight path that gets closer and closer to the light source.Other explanations have been suggested, such as the idea that moths may be impaired with a visual distortion called aMach bandby Henry Hsiao in 1972. He stated that they fly towards the darkest part of the sky in pursuit of safety, thus are inclined to circle ambient objects in the Mach band region.

Migration

Main article:Lepidoptera migration

Monarch butterflies,seen in a cluster inSanta Cruz,California,where the western population migrates for the winter

Lepidopteran migration is typicallyseasonal,as the insects moving to escape dry seasons or other disadvantageous conditions. Most lepidopterans that migrate are butterflies, and the distance travelled varies. Some butterflies that migrate include themourning cloak,painted lady,American lady,red admiral,and thecommon buckeye.A notable species of moth that migrates long distances is thebogong moth.The most well-known migrations are those of the eastern population of themonarch butterflyfrom Mexico to northern United States and southern Canada, a distance of about 4,000–4,800 km (2,500–3,000 mi). Other well-known migratory species include the painted lady and several of thedanainebutterflies. Spectacular and large-scale migrations associated with themonsoonsare seen in peninsular India.Migrations have been studied in more recent times using wing tags and stable hydrogen isotopes.

Moths also undertake migrations, an example being theuraniids.Urania fulgensundergoes population explosions and massive migrations that may be not surpassed by any other insect in theNeotropics.InCosta RicaandPanama,the first population movements may begin in July and early August and depending on the year, may be very massive, continuing unabated for as long as five months.

Communication

Group ofMelitaea athalianearWarka,Poland

Pheromones are commonly involved in mating rituals among species, especially moths, but they are also an important aspect of other forms of communication. Usually, the pheromones are produced by either the male or the female and detected by members of the opposite sex with their antennae.In many species, a gland between the eighth and ninth segments under the abdomen in the female produces the pheromones.Communication can also occur through stridulation, or producing sounds by rubbing various parts of the body together.

Moths are known to engage in acoustic forms of communication, most often as courtship, attracting mates using sound or vibration. Like most other insects, moths pick up these sounds using tympanic membranes in their abdomens.An example is that of thepolka-dot wasp moth(Syntomeida epilais), which produces sounds with a frequency above that normally detectable by humans (about 20 kHz). These sounds also function as tactile communication, or communication through touch, as they stridulate, or vibrate a substrate like leaves and stems.

Most moths lack bright colors, as many species use coloration ascamouflage,but butterflies engage in visual communication. Femalecabbage butterflies,for example, use ultraviolet light to communicate, with scales colored in this range on the dorsal wing surface. When they fly, each down stroke of the wing creates a brief flash of ultraviolet light which the males apparently recognize as the flight signature of a potential mate. These flashes from the wings may attract several males that engage in aerial courtship displays.

Ecology

Moths and butterflies are important in the natural ecosystem. They are integral participants in the food chain; having co-evolved with flowering plants and predators, lepidopteran species have formed a network oftrophicrelationships betweenautotrophsandheterotrophs,which are included in the stages of Lepidoptera larvae, pupae, and adults. Larvae and pupae are links in the diets of birds and parasiticentomophagousinsects. The adults are included in food webs in a much broader range of consumers (including birds, small mammals, reptiles, etc.).

Defense and predation

Main article:Defense in insects

Papilio machaoncaterpillar showing theosmeterium,which emits unpleasant smells to ward off predators

This Lepidoptera larvae disposes of itsfrassthat might attract predators or parasites.

Lepidopteran species are soft bodied, fragile, and almost defenseless, while the immature stages move slowly or are immobile, hence all stages are exposed topredation.Adult butterflies and moths are preyed upon bybirds,bats,lizards,amphibians,dragonflies,andspiders.One spider species,Argiope argentata,eats butterflies and moths and exhibits a long bite when preying on them rather than wrapping them in silk first. This is theorized to serve as an immobilization tactic.Caterpillars and pupae fall prey not only to birds, but also to invertebrate predators and small mammals, as well as fungi and bacteria.Parasitoidandparasiticwasps andfliesmay lay eggs in the caterpillar, which eventually kill it as they hatch inside its body and eat its tissues. Insect-eating birds are probably the largest predators. Lepidoptera, especially the immature stages, are an ecologically important food to many insectivorous birds, such as thegreat titin Europe.

An "evolutionary arms race"can be seen between predator and prey species. The Lepidoptera have developed a number of strategies for defense and protection, including evolution of morphological characters and changes in ecological lifestyles and behaviors. These includeaposematism,mimicry,camouflage,and development of threat patterns and displays.Only a few birds, such as thenightjars,hunt nocturnal lepidopterans. Their main predators arebats.Again, an "evolutionary race" exists, which has led to numerous evolutionary adaptations of moths to escape from their main predators, such as the ability to hear ultrasonic sounds, or even to emit sounds in some cases. Lepidopteran eggs are also preyed upon. Some caterpillars, such as thezebra swallowtail butterflylarvae, are cannibalistic.

Some species of Lepidoptera are poisonous to predators, such as the monarch butterfly in the Americas,Atrophaneuraspecies (roses, windmills, etc.) in Asia, as well asPapilio antimachus,and thebirdwings,the largest butterflies in Africa and Asia, respectively. They obtain their toxicity by sequestering the chemicals from the plants they eat into their own tissues. Some Lepidoptera manufacture their own toxins. Predators that eat poisonous butterflies and moths may become sick and vomit violently, learning not to eat those species. A predator which has previously eaten a poisonous lepidopteran may avoid other species with similar markings in the future, thus saving many other species, as well.Toxic butterflies and larvae tend to develop bright colors and striking patterns as an indicator to predators about their toxicity. This phenomenon is known asaposematism.Some caterpillars, especially members ofPapilionidae,contain anosmeterium,a Y-shaped protrusibleglandfound in theprothoracicsegment of the larvae.When threatened, the caterpillar emits unpleasant smells from the organ to ward off the predators.

Camouflage is also an important defense strategy, which involves the use of coloration or shape to blend into the surrounding environment. Some lepidopteran species blend with their surroundings, making them difficult to spot by predators. Caterpillars can exhibit shades of green that match its host plant. Caterpillars have been demonstrated to be able to detect the color of their surroundings and substrate using organs on their feet.Some caterpillars look like inedible objects, such as twigs or leaves. For instance, themourning cloakfades into the backdrop of trees when it folds its wings back. The larvae of some species, such as the common Mormon (Papilio polytes) and thewestern tiger swallowtaillook like bird droppings.For example, adultSesiidaespecies (also known as clearwing moths) have a general appearance sufficiently similar to awasporhornetto make it likely the moths gain a reduction in predation byBatesian mimicry.Eyespotsare a type ofautomimicryused by some butterflies and moths. In butterflies, the spots are composed of concentric rings of scales in different colors. The proposed role of the eyespots is to deflect attention of predators. Their resemblance to eyes provokes the predator's instinct to attack these wing patterns.

BatesianandMüllerianmimicry complexes are commonly found in Lepidoptera. Genetic polymorphism and natural selection give rise to otherwise edible species (the mimic) gaining a survival advantage by resembling inedible species (the model). Such a mimicry complex is referred to as Batesian and is most commonly known in the example between thelimenitidineviceroy butterflyin relation to the inedibledanainemonarch. The viceroy is, in fact, more toxic than the monarch and this resemblance should be considered as a case of Müllerian mimicry.In Müllerian mimicry, inedible species, usually within a taxonomic order, find it advantageous to resemble each other so as to reduce the sampling rate by predators that need to learn about the insects' inedibility. Taxa from the toxic genusHeliconiusform one of the most well-known Müllerian complexes.The adults of the various species now resemble each other so well, the species cannot be distinguished without close morphological observation and, in some cases, dissection or genetic analysis.

Moths are able to hear the range emitted by bats, which in effect causes flying moths to make evasive maneuvers because bats are a main predator of moths. Ultrasonic frequencies trigger a reflex action in thenoctuidmoth that cause it to drop a few inches in its flight to evade attack.Tiger mothsin a defense emit clicks within the same range of the bats, which interfere with the bats and foil their attempts to echolocate it.

Pollination

Further information:EntomophilyandPollination syndrome

A day-flyinghummingbird hawk-mothdrinking nectar from a species ofDianthus

Most species of Lepidoptera engage in some form ofentomophily(more specifically psychophily and phalaenophily for butterflies and moths, respectively), or thepollinationof flowers.Most adult butterflies and moths feed on thenectarinside flowers, using their probosces to reach the nectar hidden at the base of the petals. In the process, the adults brush against the flowers'stamens,on which the reproductivepollenis made and stored. The pollen is transferred on appendages on the adults, which fly to the next flower to feed and unwittingly deposit the pollen on thestigmaof the next flower, where the pollengerminatesand fertilizes the seeds.

Flowers pollinated by butterflies tend to be large and flamboyant, pink or lavender in color, frequently having a landing area, and usually scented, as butterflies are typically day-flying. Since butterflies do notdigestpollen (except forheliconid species,) more nectar is offered than pollen. The flowers have simple nectar guides, with the nectaries usually hidden in narrow tubes or spurs, reached by the long "tongue" of the butterflies. Butterflies such asThymelicus flavushave been observed to engage inflower constancy,which means they are more likely to transfer pollen to other conspecific plants. This can be beneficial for the plants being pollinated, as flower constancy prevents the loss of pollen during different flights and the pollinators from clogging stigmas with pollen of other flower species.

Among the more important moth pollinator groups are thehawk mothsof thefamilySphingidae. Their behavior is similar tohummingbirds,i.e., using rapid wing beats to hover in front of flowers. Most hawk moths arenocturnalorcrepuscular,so moth-pollinated flowers (e.g.,Silene latifolia) tend to be white, night-opening, large, and showy with tubularcorollaeand a strong, sweet scent produced in the evening, night, or early morning. A lot of nectar is produced to fuel the highmetabolic ratesneeded to power their flight.Other moths (e.g.,noctuids,geometrids,pyralids) fly slowly and settle on the flower. They do not require as much nectar as the fast-flying hawk moths, and the flowers tend to be small (though they may be aggregated in heads).

Mutualism

Tobacco hornworm caterpillar (Manduca sexta) parasitized byBraconidaewasp larvae

Mutualismis a form ofbiological interactionwherein each individual involved benefits in some way. An example of a mutualistic relationship would be that shared byyucca moths(Tegeculidae) and their host,yucca flowers(Asparagaceae). Female yucca moths enter the host flowers, collect the pollen into a ball using specialized maxillary palps, then move to the apex of the pistil, where pollen is deposited on the stigma, and lay eggs into the base of the pistil where seeds will develop. The larvae develop in the fruit pod and feed on a portion of the seeds. Thus, both insect and plant benefit, forming a highly mutualistic relationship.Another form of mutualism occurs between some larvae of butterflies and certain species ofants(e.g.Lycaenidae). The larvae communicate with the ants using vibrations transmitted through a substrate, such as the wood of a tree or stems, as well as using chemical signals.The ants provide some degree of protection to these larvae and they in turn gatherhoneydew secretions.

Parasitism

Parasitoid larva exits from the fox moth caterpillar

Only 42 species ofparasitoidlepidopterans are known (1Pyralidae;40Epipyropidae).The larvae of thegreaterandlesser wax mothsfeed on thehoneycombinsidebeenests and may becomepests;they are also found inbumblebeeandwaspnests, albeit to a lesser extent. In northern Europe, the wax moth is regarded as the most serious parasitoid of the bumblebee and is found only in bumblebee nests. In some areas in southern England, as much as 80% of nests can be destroyed.Other parasitic larvae are known to prey uponcicadasandleaf hoppers.

The different parasitoids affecting the spongy moth (Lymantaria dispar): The stage they affect and eventually kill and its duration are denoted by arrows.

In reverse, moths and butterflies may be subject toparasitic waspsandflies,which may lay eggs on the caterpillars, which hatch and feed inside its body, resulting in death. Although, in a form of parasitism called idiobiont, the adult paralyzes the host, so as not to kill it but for it to live as long as possible, for the parasitic larvae to benefit the most. In another form of parasitism, koinobiont, the species live off their hosts while inside (endoparasitic). These parasites live inside the host caterpillar throughout its life cycle or may affect it later on as an adult. In other orders, koinobionts include flies, a majority ofcoleopteran,and manyhymenopteranparasitoids.Some species may be subject to a variety of parasites, such as thespongy moth(Lymantaria dispar), which is attacked by a series of 13 species, in six different taxa throughout its life cycle.

In response to a parasitoid egg or larva in the caterpillar's body, theplasmatocytes,or simply the host's cells can form a multilayered capsule that eventually causes the endoparasite toasphyxiate.The process, called encapsulation, is one of the caterpillar's only means of defense against parasitoids.

Other biological interactions

A few species of Lepidoptera are secondary consumers, orpredators.These species typically prey upon the eggs of other insects, aphids, scale insects, or ant larvae.Some caterpillars are cannibals, and others prey on caterpillars of other species (e.g. HawaiianEupithecia). Those of the 15 species inEupitheciathat mirror inchworms, are the only known species of butterflies and moths that are ambush predators.Four species are known to eat snails. For example, the Hawaiian caterpillar (Hyposmocoma molluscivora) uses silk traps, in a manner similar to that of spiders, to capture certain species of snails (typicallyTornatellides).

Larvae of some species of moths in theTineidae,Gelechiidae,andNoctuidae,besides others, feed ondetritus,or dead organic material, such as fallen leaves and fruit, fungi, and animal products, and turn it intohumus.Well-known species include thecloth moths(Tineola bisselliella,Tinea pellionella,andTrichophaga tapetzella), which feed on detritus containingkeratin,includinghair,feathers,cobwebs,bird nests(particularly ofdomestic pigeons,Columba livia domestica) and fruits or vegetables. These species are important to ecosystems as they remove substances that would otherwise take a long time to decompose.

In 2015 it was reported that waspbracovirusDNA was present in Lepidoptera such as monarch butterflies, silkworms and moths.These were described in some newspaper articles as examples of a naturally occurringgenetically engineeredinsects.

Evolution and systematics

History of study

Main article:Lepidopterology

Lepidoptera collection in Cherni Osam Natural Sciences Museum,Troyan,Bulgaria

Linnaeus inSystema Naturae(1758) recognized three divisions of the Lepidoptera:Papilio,SphinxandPhalaena,with seven subgroups inPhalaena.These persist today as 9 of the superfamilies of Lepidoptera. Other works on classification followed including those byMichael Denis&Ignaz Schiffermüller(1775),Johan Christian Fabricius(1775) andPierre André Latreille(1796).Jacob Hübnerdescribed many genera, and the lepidopteran genera were catalogued byFerdinand OchsenheimerandGeorg Friedrich Treitschkein a series of volumes on the lepidopteran fauna of Europe published between 1807 and 1835.Gottlieb August Wilhelm Herrich-Schäffer(several volumes, 1843–1856), andEdward Meyrick(1895) based their classifications primarily on wing venation. SirGeorge Francis Hampsonworked on the microlepidoptera during this period andPhilipp Christoph ZellerpublishedThe Natural History of the Tineinaealso on microlepidoptera (1855).

Among the first entomologists to study fossil insects and their evolution wasSamuel Hubbard Scudder(1837–1911), who worked on butterflies.He published a study of the Florissant deposits of Colorado, including the exceptionally preservedProdryas persephone.Andreas V. Martynov(1879–1938) recognized the close relationship between Lepidoptera and Trichoptera in his studies on phylogeny.

Major contributions in the 20th century included the creation of the monotrysia and ditrysia (based on female genital structure) by Borner in 1925 and 1939.Willi Hennig(1913–1976) developed thecladisticmethodology and applied it to insect phylogeny. Niels P. Kristensen, E. S. Nielsen and D. R. Davis studied the relationships amongmonotrysianfamilies and Kristensen worked more generally on insectphylogenyand higher Lepidoptera too.While it is often found that DNA-based phylogenies differ from those based onmorphology,this has not been the case for the Lepidoptera; DNA phylogenies correspond to a large extent to morphology-based phylogenies.

Many attempts have been made to group the superfamilies of the Lepidoptera into natural groups, most of which fail because one of the two groups is notmonophyletic:Microlepidoptera and Macrolepidoptera, Heterocera and Rhopalocera, Jugatae and Frenatae, Monotrysia and Ditrysia.

A 2024 genetic study found that thegenomesof butterflies and moths have remained largely unchanged over the past 250 million years.

Fossil record

Main article:Prehistoric Lepidoptera

1887 engraving ofProdryas persephone,a fossil lepidopteran from theEocene.

The fossil record for Lepidoptera is lacking in comparison to other winged species and tends not to be as common as some other insects in habitats that are most conducive to fossilization, such as lakes and ponds; their juvenile stage has only the head capsule as a hard part that might be preserved. Also, the scales covering their wings arehydrophobicand prevents their body from sinking when they end up on the water's surface.Lepidopteran bodies tend to come apart after death, and decompose quickly, so fossil remains are often extremely fragmentary. Of the fossils known, only an estimated 7% have been described.The location and abundance of the most common moth species are indicative that mass migrations of moths occurred over the PalaeogeneNorth Sea,which is why there is a serious lack of moth fossils.Yet there are fossils, some preserved in amber and some in very fine sediments.Leaf minesare also seen in fossil leaves, although the interpretation of them is tricky.

Putative fossil stem group representatives ofAmphiesmenoptera(the clade comprising Trichoptera and Lepidoptera) are known from theTriassic.The earliest known lepidopteran fossils are fossilized scales from theTriassic-Jurassic boundary.They were found as rarepalynologicalelements in the sediments of the Triassic-Jurassic boundary from the cored Schandelah-1 well, drilled nearBraunschweigin northernGermany.This pushes back the fossil record and origin ofglossatanlepidopterans by about 70 million years, supporting molecular estimates of aNorian(ca 212 million years) divergence of glossatan and non-glossatan lepidopterans. The findings were reported in 2018 in the journalScience Advances.The authors of the study proposed that lepidopterans evolved a proboscis as an adaptation to drink from droplets and thin films of water for maintaining theirfluid balancein the hot and aridclimateof theTriassic.

The earliest named lepidopteran taxon isArchaeolepis mane,a primitive moth-like species from theEarly Jurassic,dated back to around190million years ago,and known only from three wings found in theCharmouth MudstoneofDorset,UK.The wings show scales with parallel grooves under a scanning electron microscope and a characteristic wing venation pattern shared withTrichoptera(caddisflies).Only two more sets of Jurassic lepidopteran fossils have been found, as well as 13 sets from theCretaceous,which all belong to primitive moth-like families.

Many more fossils are found from the Tertiary, and particularly theEoceneBaltic amber.The oldest genuine butterflies of the superfamily Papilionoidea have been found in thePaleoceneMoClayorFur FormationofDenmark.The best preserved fossil lepidopteran is the EoceneProdryas persephonefrom theFlorissant Fossil Beds.

Phylogeny

Phylogenetic hypothesis of major lepidopteran lineages superimposed on the geologic time scale. Radiation ofangiospermsspans130 to 95million years agofrom their earliest forms to domination of vegetation.

Lepidoptera andTrichoptera(caddisflies) aresister groups,sharing many similarities that are lacking in others; for example the females of both orders areheterogametic,meaning they have two differentsex chromosomes,whereas in most species the males are heterogametic and the females have two identical sex chromosomes. The adults in both orders display a particular wing venation pattern on their forewings. The larvae in the two orders have mouth structures and glands with which they make and manipulatesilk.Willi Henniggrouped the two orders into the superorderAmphiesmenoptera;together they are sister to the extinct orderTarachoptera.Lepidoptera descend from a diurnal moth-like common ancestor that either fed on dead or living plants.

Thecladogram,based on molecular analysis, shows the order as aclade,sister to the Trichoptera, and more distantly related to theDiptera(true flies) andMecoptera(scorpionflies).

Holometabola	Hymenoptera(sawflies, wasps) Aparaglossata Neuropteroidea Coleopterida Coleoptera(beetles) Strepsiptera(twisted-wing parasites) Neuropterida Raphidioptera(snakeflies) Megaloptera(alderflies and allies) Neuroptera(Lacewings and allies) Panorpida Amphiesmenoptera Lepidoptera(butterflies, moths) Trichoptera(caddisflies) Antliophora Diptera Mecoptera(scorpionflies) Siphonaptera(fleas)

Micropterigidae,AgathiphagidaeandHeterobathmiidaeare the oldest and mostbasallineages of Lepidoptera. The adults of these families do not have the curled tongue orproboscis,that are found in most members of the order, but instead have chewingmandiblesadapted for a special diet. Micropterigidae larvae feed onleaves,fungi,orliverworts(much like theTrichoptera).Adult Micropterigidae chew the pollen or spores of ferns. In the Agathiphagidae, larvae live insidekauri pinesand feed on seeds. In Heterobathmiidae the larvae feed on the leaves ofNothofagus,the southern beech tree. These families also have mandibles in the pupal stage, which help the pupa emerge from the seed or cocoon aftermetamorphosis.

TheEriocraniidaehave a short coiled proboscis in the adult stage, and though they retain their pupal mandibles with which they escaped the cocoon, their mandibles are non-functional thereafter.Most of these non-ditrysian families, are primarilyleaf minersin the larval stage. In addition to the proboscis, there is a change in the scales among these basal lineages, with later lineages showing more complex perforated scales.

With the evolution of theDitrysiain the mid-Cretaceous, there was a major reproductive change. The Ditrysia, which comprise 98% of the Lepidoptera, have two separate openings for reproduction in the females (as well as a third opening for excretion), one for mating, and one for laying eggs. The two are linked internally by a seminal duct. (In more basal lineages there is onecloaca,or later, two openings and an external sperm canal.) Of the early lineages of Ditrysia,GracillarioideaandGelechioideaare mostly leaf miners, but more recent lineages feed externally. In theTineoidea,most species feed on plant and animal detritus and fungi, and build shelters in the larval stage.

TheYponomeutoideais the first group to have significant numbers of species whose larvae feed on herbaceous plants, as opposed to woody plants.They evolved about the time that flowering plants underwent an expansiveadaptive radiationin the mid-Cretaceous,and the Gelechioidea that evolved at this time also have great diversity. Whether the processes involvedcoevolutionor sequential evolution, the diversity of the Lepidoptera and the angiosperms increased together.

In the so-called "macrolepidoptera",which constitutes about 60% of lepidopteran species, there was a general increase in size, better flying ability (via changes in wing shape and linkage of the forewings and hindwings), reduction in the adult mandibles, and a change in the arrangement of the crochets (hooks) on the larval prolegs, perhaps to improve the grip on the host plant.Many also havetympanal organs,that allow them to hear. These organs evolved eight times, at least, because they occur on different body parts and have structural differences. The main lineages in the macrolepidoptera are theNoctuoidea,Bombycoidea,Lasiocampidae,Mimallonoidea,GeometroideaandRhopalocera.Bombycoidea plus Lasiocampidae plus Mimallonoidea may be amonophyleticgroup.The Rhopalocera, comprising thePapilionoidea(butterflies),Hesperioidea(skippers), and theHedyloidea(moth-butterflies), are the most recently evolved.There is quite a good fossil record for this group, with the oldest skipper dating from56million years ago.

Taxonomy

Main articles:Taxonomy of the LepidopteraandLepidopteran diversity

Taxonomy is the classification of species in selected taxa, the process of naming being callednomenclature.There are over 120 families in Lepidoptera, in 45 to 48 superfamilies. Lepidoptera have always been, historically, classified in five suborders, one of which is of primitive moths that never lost the morphological features of their ancestors. The rest of the moths and butterflies make up ninety-eight percent of the other taxa, makingDitrysia.More recently, findings of new taxa, larvae and pupa have aided in detailing the relationships of primitive taxa, phylogenetic analysis showing the primitive lineages to beparaphyleticcompared to the rest of Lepidoptera lineages. Recently, lepidopterists have abandoned clades like suborders, and those between orders and superfamilies.

• Zeuglopterais a clade withMicropterigoideabeing its only superfamily, containing the single family Micropterigidae. Species of Micropterigoidea are practically living fossils, being one of the most primitive lepidopteran groups, still retaining chewing mouthparts (mandibles) in adults, unlike other clades of butterflies and moths. About 120 species are known worldwide, with more than half the species in the genusMicropterixin the Palearctic region. There are only two known in North America (Epimartyria), with many more being found in Asia and the southwest Pacific, particularly New Zealand with about 50 species.
• Aglossatais the second most primitivelineageof Lepidoptera; being first described in 1952 byLionel Jack Dumbleton.Agathiphagidaeis the only family in Aglossata and contains two species in its only genus,Agathiphaga.Agathiphaga queenslandensisandAgathiphaga vitiensisare found along the north-eastern coast ofQueensland,Australia,and inFijitoVanuatuand theSolomon Islands,respectively.
• Heterobathmiinawas first described by Kristensen and Nielsen in 1979.Heterobathmiidaeis the only family and includes about 10 species, which are day-flying, metallic moths, confined to southern South America, the adults eat the pollen ofNothofagusor southern beech and the larvae mine the leaves.
• Glossatacontains a majority of the species, with the most obvious difference being non-functioning mandibles, and elongated maxillary galeae or the proboscis. Thebasal cladesstill retaining some of the ancestral features of the wings such as similarly shaped fore- and hindwings with relatively complete venation. Glossata also contains the divisionDitrysia,which contains 98% of all described species in Lepidoptera.

Relationship to people

Culture

Death's-head hawkmoth(Acherontia lachesis), an old bleached specimen still showing the classical skull pattern on the thorax

Artistic depictions of butterflies have been used in many cultures including as early as 3500 years ago, in Egyptian hieroglyphs.Today, butterflies are widely used in various objects of art and jewelry: mounted in frames, embedded in resin, displayed in bottles, laminated in paper, and in some mixed media artworks and furnishings.Butterflies have also inspired the "butterfly fairy"as an art and fictional character.

In many cultures the soul of a dead person is associated with the butterfly, for example inAncient Greece,where the word for butterflyψυχή(psyche) also meanssoulandbreath.InLatin,as in Ancient Greece, the word for "butterfly"papiliowas associated with the soul of the dead.The skull-like marking on the thorax of thedeath's-head hawkmothhas helped these moths, particularlyA. atropos,earn a negative reputation, such as associations with the supernatural and evil. The moth has been prominently featured in art and movies such asUn Chien Andalou(byBuñuelandDalí) andThe Silence of the Lambs,and in the artwork of the Japanese metal bandSigh's albumHail Horror Hail.According toKwaidan: Stories and Studies of Strange Things,byLafcadio Hearn,a butterfly was seen in Japan as thepersonificationof a person's soul; whether they be living, dying, or already dead. One Japanese superstition says that if a butterfly enters your guestroom and perches behind thebambooscreen, the person whom you most love is coming to see you. However, large numbers of butterflies are viewed as badomens.WhenTaira no Masakadowas secretly preparing for his famous revolt, there appeared inKyotoso vast a swarm of butterflies that the people were frightened—thinking the apparition to be a portent of coming evil.

In the ancientMesoamericancity ofTeotihuacan,the brilliantly colored image of the butterfly was carved into many temples, buildings, jewelry, and emblazoned onincense burnersin particular. The butterfly was sometimes depicted with the maw of ajaguarand some species were considered to be the reincarnations of the souls of dead warriors. The close association of butterflies tofireand warfare persisted through to theAztec civilizationand evidence of similar jaguar-butterfly images has been found among theZapotec,andMaya civilizations.

Pests

Caterpillar hatchling of thegrey dagger(Acronicta psi) eating leaves from a tree

Thelarvaeof many lepidopteran species are major pests inagriculture.Some of the major pests includeTortricidae,Noctuidae,andPyralidae.The larvae of the Noctuidae genusSpodoptera(armyworms),Helicoverpa(corn earworm), orPieris brassicaecan cause extensive damage to certain crops.Helicoverpa zealarvae (cotton bollworms or tomato fruitworms) arepolyphagous,meaning they eat a variety of crops, includingtomatoesandcotton.Peridroma saucia(variegated cutworms) are described as one of the most damaging pests to gardens, with the ability to destroy entire gardens and fields in a matter of days.

Butterflies and moths are one of the largest taxa to solely feed and be dependent on living plants, in terms of the number of species, and they are in many ecosystems, making up the largest biomass to do so. In many species, the female may produce anywhere from 200 to 600 eggs, while in some others it may go as high as 30,000 eggs in one day. This can create many problems for agriculture, where many caterpillars can affect acres of vegetation. Some reports estimate that there have been over 80,000 caterpillars of several different taxa feeding on a single oak tree. In some cases, phytophagous larvae can lead to the destruction of entire trees in relatively short periods of time.

Ecological ways of removing pest Lepidoptera species are becoming more economically viable, as research has shown ways like introducing parasitic wasps and flies. For example,Sarcophaga aldrichi,a fly which deposited larvae feed upon the pupae of theforest tent caterpillar moth.Pesticides can affect other species other than the species they are targeted to eliminate, damaging the natural ecosystem.Another good biological pest control method is the use ofpheromone traps.A pheromone trap is a type ofinsect trapthat usespheromonesto lureinsects.Sex pheromones and aggregating pheromones are the most common types used. A pheromone-impregnated lure is encased in a conventional trap such as a Delta trap,water-pan trap,or funnel trap.

Species of moths that aredetritivoreswould naturally eatdetrituscontainingkeratin,such ashairsorfeathers.Well known species arecloth moths(T. bisselliella,T. pellionella,andT. tapetzella), feeding on foodstuffs that people find economically important, such ascotton,linen,silkand woolfabricsas well asfurs;furthermore they have been found on shedfeathersandhair,bran,semolinaandflour(possibly preferringwheatflour),biscuits,casein,andinsectspecimens inmuseums.

Beneficial insects

Even though some butterflies and moths affect the economy negatively, many species are a valuable economic resource. The most prominent example is that of thedomesticated silkworm moth(Bombyx mori), the larvae of which make their cocoons out ofsilk,which can be spun into cloth. Silk is and has been an important economic resourcethroughout history.The speciesBombyx morihas been domesticated to the point where it is completely dependent on mankind for survival.A number of wild moths such asBombyx mandarina,andAntheraeaspecies, besides others, provide commercially important silks.

The preference of the larvae of most lepidopteran species to feed on a single species or limited range of plants is used as a mechanism for biological control ofweedsin place of herbicides. Thepyralidcactus mothwas introduced from Argentina to Australia, where it successfully suppressed millions of acres ofprickly pear cactus.Another species of the Pyralidae, called thealligator weed stem borer(Arcola malloi), was used to control theaquatic plantknown asalligator weed(Alternanthera philoxeroides) in conjunction with thealligator weed flea beetle;in this case, the two insects work insynergyand the weed rarely recovers.

Breeding butterflies and moths, orbutterfly gardening/rearing, has become an ecologically viable process of introducing species into the ecosystem to benefit it.Butterfly ranching in Papua New Guineapermits nationals of that country to "farm" economically valuable insect species for the collectors market in an ecologically sustainable manner.

Food

Beondegi,silkwormpupae steamed or boiled and seasoned for taste, for sale by a street vendor in South Korea

Lepidoptera feature prominently inentomophagyas food items on almost every continent. While in most cases, adults, larvae or pupae are eaten as staples by indigenous people,beondegiorsilkwormpupaeare eaten as a snack inKorean cuisinewhileMaguey wormis considered a delicacy inMexico.In some parts ofHuasteca,the silk nests of theMadrone butterflyare maintained on the edge of roof tops of houses for consumption.In theCarniaregion of Italy, children catch and eatingluviesof the toxicZygaenamoths in early summer. The ingluvies, despite having a very low cyanogenic content, serve as a convenient, supplementary source of sugar to the children who can include this resource as a seasonal delicacy at minimum risk. Outside of this instance, adult Lepidoptera are rarely consumed by humans, with the sole exception of theBogong moth.

Health

Some larvae of both moths and butterflies have a form of hair that has been known to be a cause of human health problems. Caterpillar hairs sometimes have toxins in them and species from approximately 12 families of moths or butterflies worldwide can inflict serious human injuries (urticarialdermatitis andatopicasthmatoosteochondritis,consumptioncoagulopathy,renalfailure, andintracerebralhemorrhage).Skin rashes are the most common, but there have been fatalities.Lonomiais a frequent cause of envenomation in humans in Brazil, with 354 cases reported between 1989 and 2005. Lethality ranging up to 20% with death caused most often by intracranial hemorrhage.

These hairs have also been known to causekeratoconjunctivitis.The sharp barbs on the end of caterpillar hairs can get lodged in soft tissues andmucous membranessuch as the eyes. Once they enter such tissues, they can be difficult to extract, often exacerbating the problem as they migrate across the membrane.This becomes a particular problem in an indoor setting. The hairs easily enter buildings through ventilation systems and accumulate in indoor environments because of their small size, which makes it difficult for them to be vented out. This accumulation increases the risk of human contact in indoor environments.

See also

• Lepidoptera in the 10th edition of Systema Naturae
• McGuire Center for Lepidoptera and Biodiversity,University of Florida
• Societas Europaea Lepidopterologica

Lists

• Lists of Lepidoptera by region
• Taxonomy of the Lepidoptera

Further reading

• Kristensen, N. P. (ed.) 1999. Lepidoptera, Moths and Butterflies. Volume 1: Evolution, Systematics, and Biogeography.Handbuch der Zoologie. Eine Naturgeschichte der Stämme des Tierreiches / Handbook of Zoology. A Natural History of the phyla of the Animal Kingdom.Band / Volume IV Arthropoda: Insecta Teilband / Part 35: 491 pp. Walter de Gruyter, Berlin, New York.
• Nemos, F. (c. 1895).Europas bekannteste Schmetterlinge. Beschreibung der wichtigsten Arten und Anleitung zur Kenntnis und zum Sammeln der Schmetterlinge und Raupen[Europe's best known butterflies. Description of the most important species and instructions for recognising and collecting butterflies and caterpillars](PDF).Berlin: Oestergaard Verlag. Archived fromthe original(PDF)on 24 July 2011.
• Nye, I. W. B. & Fletcher, D. S. 1991.Generic Names of Moths of the World.Volume 6: xxix + 368 pp. Trustees of the British Museum (Natural History), London.
• O'Toole, Christopher. 2002.Firefly Encyclopedia of Insects and Spiders.ISBN1-55297-612-2.

Bibliography

• Lamas, Gerardo (1990)."An Annotated List of Lepidopterological Journals"(PDF).The Journal of Research on the Lepidoptera.29(1–2): 92–104.doi:10.5962/p.266621.S2CID108756448.Archived fromthe original(PDF)on 27 August 2016.Retrieved22 November2012.

External links

• Natural History Museum archived database of host plants
• Historic Moth illustrations
• Lepidopteraat Insects (Insecta) of the World
• "Lepidoptera".Integrated Taxonomic Information System.
• Caught Between the Pages: Treasures from the Franclemont CollectionOnline virtual exhibit featuring a selection of historic entomological writings and images from the Comstock Library of Entomology at Cornell University

Regional sites

• British Butterflies and Moths
• Butterflies of BulgariaArchived5 April 2008 at theWayback Machine
• Butterflies of Canada
• Photography of European Butterflies and Moths
• Lepidoptera of French Antilles
• Butterflies of India
• A Check List of Butterflies in Indo-China
• Moths of Jamaica
• JapmothJapanese moths. Access images via the numbers on the left.
• Butterflies and Moths in the Netherlands
• Butterflies and Moths of Northern IrelandArchived1 August 2015 at theWayback Machine
• Butterflies of Asian RussiaArchived31 August 2007 at theWayback Machine
• Photos of Larvae and Pupae butterflies and moths. SpainArchived28 July 2013 at theWayback Machine
• Butterflies of Asturias – Spain
• Swedish Moths and Butterflies Lepidoptera (English)
• Butterflies of Turkey