View source for Lepidoptera

{{Short description|Order of insects including moths and butterflies}}
{{Use dmy dates|date=January 2018}} 
{{good article}}
{{Automatic taxobox
| fossil_range = [[Early Jurassic]]–[[Holocene|Present]], {{fossilrange|200|0|earliest=236}} Possible [[Late Triassic]] records
| image = Peacock butterfly (Aglais io) 2.jpg
| image_alt = 
| image_caption = Peacock butterfly (''[[Aglais io]]'')
| image2 = Deilephila elpenor 04.jpg
| image2_alt = 
| image2_caption = Elephant hawk moth (''[[Deilephila elpenor]]'')
| taxon = Lepidoptera
| authority = [[Linnaeus]], [[10th edition of Systema Naturae|1758]]
| subdivision_ranks = Subdivisions
| subdivision = [[Aglossata]]<br/>
[[Glossata]]<br/>
[[Heterobathmiina]]<br/>
[[Zeugloptera]]
}}

'''Lepidoptera''' ({{IPAc-en|ˌ|l|ɛ|p|ɪ|ˈ|d|ɒ|p|t|ər|ə}} {{respell|LEP|ih|DOP|tər|ə}}) or '''lepidopterans''' are an [[order (biology)|order]] of [[winged insect]]s which include [[Butterfly|butterflies]] and [[moth]]s. About 180,000 [[species]] of the Lepidoptera have been described, representing 10% of the total described species of living organisms,<ref name="Taxome1">{{cite web |url=http://www.ucl.ac.uk/taxome/lepnos.html |title=Taxonomy of Lepidoptera: the scale of the problem |author=Mallet, Jim |date=12 June 2007 |work=The Lepidoptera Taxome Project |publisher=University College, London |access-date=8 February 2011 |archive-url=https://web.archive.org/web/20110605000548/http://www.ucl.ac.uk/taxome/lepnos.html |archive-date=5 June 2011 |url-status=live }}</ref><ref>{{cite web | title = Lepidoptera Taxome Project | publisher = Lepidoptera Taxome Project | url = http://www.ucl.ac.uk/taxome/ | access-date = 25 February 2015 | archive-url = https://web.archive.org/web/20110805155650/http://www.ucl.ac.uk/taxome/ | archive-date = 5 August 2011 | url-status = live }}</ref><!-- over 160,000 described species, {{rp|699}} --> making it the second largest insect order (behind [[Coleoptera]]) with 126 [[family (biology)|families]]<ref name="Capinera">{{Cite book |last=Capinera |first=John L. |title=Encyclopedia of Entomology |publisher=[[Springer Science+Business Media|Springer]] |year=2008 |edition=2nd |volume=4 |pages=626–672 |chapter=Butterflies and moths |isbn=978-1-4020-6242-1 |chapter-url=https://books.google.com/books?id=i9ITMiiohVQC |access-date=22 September 2016 |archive-date=24 June 2016 |archive-url=https://web.archive.org/web/20160624051424/https://books.google.com/books?id=i9ITMiiohVQC |url-status=live }}</ref> and 46 [[Taxonomic rank|superfamilies]],<ref name="Taxome1"/> and one of the most widespread and widely recognizable insect orders in the world.<ref name="Resh & Carde">{{cite book|last1=Powell |first1=Jerry A. |editor2-last=Cardé|editor2-first=Ring T.|editor1-first=Vincent H. |editor1-last=Resh |title=Encyclopedia of Insects |edition=2 (illustrated) |pages=557–587|year=2009 |publisher=Academic Press |isbn=978-0-12-374144-8 |chapter=Lepidoptera}}</ref>

Lepidopteran species are characterized by more than three derived features. The most apparent is the presence of [[scale (anatomy)|scale]]s that cover the [[torso|bodies]], large triangular [[Insect wing|wings]], and a [[proboscis]] for [[siphon]]ing [[nectar]]s. 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. [[Mating]] and the laying of eggs is normally performed near or on host plants for the [[larva]]e. Like most other insects, butterflies and moths are [[holometabolous]], meaning they undergo [[complete metamorphosis]]. The larvae are commonly called [[caterpillar]]s, 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 of [[proleg]]s. As they grow, these larvae change in appearance, going through a series of stages called [[instar]]s. Once fully matured, the larva develops into a [[pupa]]. A few butterflies and many moth species spin a [[silk]] casing or [[cocoon (silk)|cocoon]] for protection prior to pupating, while others do not, instead going underground.<ref name="Resh & Carde"/> A butterfly pupa, called a [[chrysalis]], 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 the [[Triassic]]-[[Jurassic]] boundary and have [[coevolve]]d with [[flowering plant]]s since the [[Cretaceous Terrestrial Revolution|angiosperm boom]] in the [[Middle Cretaceous|Middle]]/[[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,<ref name="Inventory">{{cite book |editor1=Z.-Q. Zhang |editor2=W. A. Shear |year=2007 |title=Linnaeus Tercentenary: Progress in Invertebrate Taxonomy (Zootaxa:1668) |publisher=Magnolia Press |isbn=978-0-12-690647-9 |chapter-url=http://www.lepidoptera.ee/images/lingid/Zootaxa1668p699.pdf |access-date=2 March 2010 |last1=Kristensen |first1=Niels P. |last2=Scoble |first2=M. J. |last3=Karsholt |first3=Ole |chapter=Lepidoptera phylogeny and systematics: the state of inventorying moth and butterfly diversity |pages=699–747 |archive-date=15 May 2013 |archive-url=https://web.archive.org/web/20130515015416/http://www.lepidoptera.ee/images/lingid/Zootaxa1668p699.pdf }}</ref> and is among the five most species-rich orders (each with over 100,000 species) along with [[Coleoptera]] (beetles), [[Diptera]] (flies), [[Hymenoptera]] ([[ant]]s, [[bee]]s, [[wasp]]s and [[sawflies]]) and [[Hemiptera]] ([[cicada]]s, [[aphid]]s and other true bugs).<ref name="Resh & Carde"/> They have, over millions of years, evolved a wide range of wing patterns and coloration ranging from drab moths akin to the related order [[Trichoptera]], to the brightly colored and complex-patterned butterflies.<ref name="Capinera"/> 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 a [[lepidopterist]].

Butterflies and moths are mostly [[herbivorous]] ([[folivorous]]) as caterpillars and [[nectarivorous]] as adults. They play an important role in the natural ecosystem as [[pollinator]]s and serve as [[consumer (food chain)#Levels of the food chain|primary consumer]]s in the [[food chain]]; conversely, their larvae (caterpillars) are considered very problematic to vegetation in agriculture, as they consume large quantity of plant matter (mostly [[foliage]]) 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, the [[silk]] in their cocoon, or for [[pest control|extermination]] as [[pest (organism)|pest]] species.

== Etymology ==
The term Lepidoptera was used in 1746 by [[Carl Linnaeus]] in his ''[[Fauna Svecica]]''.<ref>{{cite book | last=Linnaeus | first=Carl | author-link=Carl Linnaeus | year=1746 | title=Fauna Svecica: sistens animalia Sveciæ regni: qvadrupedia, aves, amphibia, pisces, insecta, vermes, distributa per classes & ordines, genera & species. Cum differentiis specierum, synonymis autorum, nominibus incolarum, locis habitationum, descriptionibus insectorum | language=la | place=Lugduni Batavorum [Leiden] | publisher=C. Wishoff et G.J. Wishoff | page=232 | url=https://www.biodiversitylibrary.org/page/24848873 | access-date=8 August 2020 | archive-date=18 September 2020 | archive-url=https://web.archive.org/web/20200918151150/https://www.biodiversitylibrary.org/page/24848873 | url-status=live }}</ref><ref name="EngelKristensen2013">{{cite journal |last1=Engel |first1=Michael S. |last2=Kristensen |first2=Niels P. |title=A History of Entomological Classification |journal=Annual Review of Entomology |volume=58 |issue=1 |year=2013 |pages=585–607 |issn=0066-4170 |doi=10.1146/annurev-ento-120811-153536|pmid=23317047 }}</ref> The word is derived from [[Ancient Greek|Greek]] {{lang |grc |[[wikt:λεπίς|λεπίς]]}} {{Transliteration|grc|lepís}}, [[Genitive case|gen.]] {{lang |grc |[[wikt:λεπίδος|λεπίδος]]}} {{Transliteration|grc |lepídos}} ("[[scale (insect anatomy)|scale]]") and {{lang |grc| [[wikt:πτερόν|πτερόν]]}} ("wing").<ref name="Etymology">{{OEtymD|lepidoptera}}</ref><ref>{{LSJ|lepi/s|λεπίς}}, {{LSJ|ptero/n|πτερόν|ref}}.</ref> Sometimes, the term [[Rhopalocera]] is used for the [[clade]] of all butterfly species, derived from the Ancient Greek {{lang |grc |[[wikt:ῥόπαλον|ῥόπαλον]]}} (''{{lang |grc |rhopalon}}'')<ref name="Partridge">{{cite book |title=Origins: an etymological dictionary of modern English |last=Partridge |first=Eric |year=2009 |publisher=Routledge |isbn=978-0-203-42114-7  |url=https://books.google.com/books?id=xA9dxrhfa5kC}}</ref>{{rp |4150}} and {{lang |grc |[[wikt:κέρας|κέρας]]}} (''{{lang |grc |keras}}'')<ref name="Partridge"/>{{rp |3993}} meaning "club" and "horn", respectively, coming from the shape of the [[antenna (biology)|antenna]]e of butterflies.

The origins of the common names "butterfly" and "moth" are varied and often obscure. The [[English language|English]] word butterfly is from [[Old English]] ''{{lang|ang|buttorfleoge}}'', 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.<ref name=autogenerated3>{{cite web |url=http://www.etymonline.com/ |title=Online Etymological Dictionary |last=Harpe |first=Douglas |author2=Dan McCormack |date=November 2001 |publisher=LogoBee |page=1 |access-date=6 December 2009 |archive-url=https://web.archive.org/web/20120825071940/http://www.etymonline.com/ |archive-date=25 August 2012 |url-status=live}}</ref><ref name="Arnett">{{Cite book |last=Arnett |first=Ross H. |title=American insects: a handbook of the insects of America north of Mexico |publisher=[[CRC Press]] |date=28 July 2000 |edition=2nd |page=631 |chapter=Part I: 27 |isbn=978-0-8493-0212-1 |chapter-url=https://books.google.com/books?id=4M0v0Ye54MYC&q=leidoptera |access-date=8 October 2020 |archive-date=31 May 2021 |archive-url=https://web.archive.org/web/20210531114653/https://books.google.com/books?id=4M0v0Ye54MYC&q=leidoptera |url-status=live}}</ref> The species of [[Heterocera]] are commonly called [[moth]]s. The origins of the English word moth are clearer, deriving from Old English ''{{lang|ang|moððe}}'' (cf. [[Northumbrian dialect]] ''{{lang |ang |mohðe}}'') from Common Germanic (compare [[Old Norse]] ''{{lang|non|motti}}'', [[Dutch language|Dutch]] ''{{Lang|nl|mot}}'' and [[German language|German]] ''{{lang|de|Motte}}'' all meaning "moth"). Perhaps its origins are related to Old English ''{{lang|ang|maða}}'' meaning "[[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.<ref name="Etymology2">{{cite dictionary |url=http://www.etymonline.com/index.php?search=moth&searchmode=none |title=moth |last=Harper |first=Douglas |dictionary=The Online Etymology Dictionary |access-date=31 March 2011 |archive-url=https://web.archive.org/web/20110606064211/http://www.etymonline.com/index.php?search=moth&searchmode=none |archive-date=6 June 2011 |url-status=live}}</ref>

The etymological origins of the word "caterpillar", the larval form of butterflies and moths, are from the early 16th century, from [[Middle English]] {{lang|enm|catirpel}}, {{lang|enm|catirpeller}}, probably an alteration of [[Old French|Old North French]] {{lang|fro|catepelose}} (from Latin {{lang|la|cattus}}, "cat" + {{lang|la|pilosus}}, "hairy").<ref>{{cite dictionary |url=http://dictionary.reference.com/browse/caterpillar |title=Caterpillar |access-date=5 October 2011 |dictionary=Dictionary.com |archive-url=https://web.archive.org/web/20110909053143/http://dictionary.reference.com/browse/caterpillar |archive-date=9 September 2011 |url-status=live}}</ref>

== Distribution and diversity ==
{{main|Lists of Lepidoptera by region}}

The Lepidoptera are among the most successful groups of insects. They are found on all continents, except [[Antarctica]], 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 plant]]s).<ref name="cgillott">{{Cite book |last=Gullan |first=P. J. |author2=P. S. Cranston |title=The insects: an outline of entomology |publisher=Wiley-Blackwell |date=13 September 2004 |edition=3 |pages=[https://archive.org/details/isbn_9781405111133/page/198 198–199] |chapter=7 |isbn=978-1-4051-1113-3 |chapter-url=https://books.google.com/books?id=qHtMPvaAfKIC&q=Lepidoptera%20larva |url=https://archive.org/details/isbn_9781405111133/page/198 }}</ref> Among the most northern dwelling species of butterflies and moths is the Arctic Apollo (''[[Parnassius arcticus]]''), which is found in the Arctic Circle in northeastern [[Yakutia]], at an altitude of {{Convert|1500|m|ft}} above sea level.<ref>{{cite web |url=http://rusinsects.com/p-arct.htm |title=Parnassius arctica Eisner, 1968 |first=Felix |last=Stumpe |work=Russian-Insects.com |access-date=9 November 2010 |archive-url=https://web.archive.org/web/20110715214958/http://rusinsects.com/p-arct.htm |archive-date=15 July 2011 }}</ref> In the [[Himalayas]], various Apollo species such as ''[[Parnassius epaphus]]'' have been recorded to occur up to an altitude of {{Convert|6000|m|ft}} above sea level.<ref>{{cite book |title=Ecology and Biogeography of High Altitude Insects |last=Mani |first=M. S. |year=1968 |publisher=Springer |series=Volume 4 of Series entomologica |isbn=978-90-6193-114-0 |page=530 |url=https://books.google.com/books?id=n4qSTCkniZoC&pg=PA221 |access-date=9 November 2010 |archive-date=19 July 2021 |archive-url=https://web.archive.org/web/20210719043454/https://books.google.com/books?id=n4qSTCkniZoC&pg=PA221 |url-status=live }}</ref>{{rp|221}}

Some lepidopteran species exhibit [[symbiotic]], [[Commensalism|phoretic]], or [[parasitic]] lifestyles, inhabiting the bodies of organisms rather than the environment. [[Coprophagous]] [[Pyralidae|pyralid]] moth species, called [[sloth moth]]s, such as ''[[Bradipodicola hahneli]]'' and ''[[Cryptoses choloepi]]'', are unusual in that they are exclusively found inhabiting the fur of [[sloth]]s, mammals found in [[Central America|Central]] and [[South America]].<ref>{{cite journal |url=http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/10046/terra2008Spring.pdf?sequence=1 |title=An OSU scientist braves an uncharted rainforest in a search for rare and endangered species |last=Sherman |first=Lee |journal=Terra |year=2008 |publisher=Oregon State University |volume=3 |issue=2 |access-date=14 February 2011 |archive-url=https://web.archive.org/web/20110919170258/http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/10046/terra2008Spring.pdf?sequence=1 |archive-date=19 September 2011 }}</ref><ref name="Rau">{{cite journal |last1=Rau |first1=P |year=1941 |title=Observations on certain lepidopterous and hymenopterous parasites of Polistes wasps|doi=10.1093/aesa/34.2.355 |journal=Annals of the Entomological Society of America |volume=34 |issue=2 |pages=355–366(12)}}</ref> Two species of ''[[Tinea (moth)|Tinea]]'' moths have been recorded as feeding on horny tissue and have been bred from the horns of cattle. The larva of ''[[Zenodochium]] coccivorella'' is an internal parasite of the [[coccid]] ''[[Kermes (insect)|Kermes]]'' species. Many species have been recorded as breeding in natural materials or refuse such as owl pellets, bat caves, honeycombs or diseased fruit.<ref name="Rau"/>

As of 2007, there were roughly 174,250 lepidopteran species described, with butterflies and [[Skipper (butterfly)|skippers]] estimated to comprise around 17,950, and moths making up the rest.<ref name="Taxome1"/><ref name="Taxome2">{{cite web |url=http://www.ucl.ac.uk/taxome/rhopnos.html |title=Taxonomy of butterflies: the scale of the problem |author=Mallet, Jim |date=12 June 2007 |work=The Lepidoptera Taxome Project |publisher=University College, London |access-date=8 February 2011 |archive-url=https://web.archive.org/web/20110514043409/http://www.ucl.ac.uk/taxome/rhopnos.html |archive-date=14 May 2011 |url-status=live }}</ref> 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,<ref>{{cite book |title=Kaufman field guide to insects of North America |last=Eaton |first=Eric R. |author2=Kaufman, Kenn |year=2007 |publisher=Houghton Mifflin Harcourt |isbn=978-0-618-15310-7 |page=391 |url=https://books.google.com/books?id=aWVi0IF_jcQC |access-date=22 September 2016 |archive-url=https://web.archive.org/web/20190724170825/https://books.google.com/books?id=aWVi0IF_jcQC |archive-date=24 July 2019 |url-status=live }}</ref><ref>{{cite book |title=The wild silk moths of North America: a natural history of the Saturniidae of the United States and Canada |last=Tuskes |first=Paul M. |author2=Tuttle, James P. |author3=Collins, Michael M.|year=1996 |publisher=Cornell University Press |series=The Cornell series in arthropod biology|edition=illustrated|isbn=978-0-8014-3130-2 |page=250 |url=https://books.google.com/books?id=3vqpGATXU2oC |access-date=12 February 2011}}</ref> while about 400 species of butterflies and 14,000 species of moths are reported from Australia.<ref>{{cite book |title=Wildlife of the Australian snow-country: a comprehensive guide to alpine fauna |last=Green |first=Ken |author2=Osborne, William S.  |year=1994 |publisher=Reed |edition=illustrated|isbn=978-0-7301-0461-2 |page=200 |url=https://books.google.com/books?id=-wZFAAAAYAAJ}}</ref> The diversity of Lepidoptera in each [[biogeographic realm|faunal region]] has been estimated by John Heppner in 1991 based partly on actual counts from the literature, partly on the card indices in the [[Natural History Museum, London|Natural History Museum]] (London) and the [[National Museum of Natural History]] (Washington), and partly on estimates:<ref name="Inventory"/>

{| class="wikitable" style="text-align: center; width:80%;"
|+ Diversity of Lepidoptera in each faunal region
|-
|
! scope="col" | [[Palearctic]]
! scope="col" | [[Nearctic]]
! scope="col" | [[Neotropic]]
! scope="col" | [[Afrotropic]]
! scope="col" | Indo-Australian<br/>(comprising [[Indomalayan]], [[Australasian realm|Australasian]], and [[Oceanian realm]]s)
|-
! scope="row" | Estimated number of species
| 22,465
| 11,532
| 44,791
| 20,491
| 47,287
|}

== External morphology ==
{{main|External morphology of Lepidoptera}}
{{further|Glossary of entomology terms|Comparison of butterflies and moths}}
[[File:Butterfly parts.svg|thumb|upright=1.4|Parts of an adult butterfly]]
[[File:Caterpillar morphology diagram.svg|thumb|upright=1.4|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 of [[scale (Lepidoptera)|scale]]s on the external parts of the body and appendages, especially the [[Insect wing|wings]]. Butterflies and moths vary in size from [[microlepidoptera]] only a few millimeters long, to conspicuous animals with a wingspan greater than {{Convert|25|cm|in}}, such as the [[Queen Alexandra's birdwing]] and [[Atlas moth]].<ref name="Gillot">{{cite book |title=Entomology |last=Gillot |first=C. |edition=2 |year=1995 |isbn=978-0-306-44967-3 |pages=246–266 |chapter-url=https://books.google.com/books?id=DrTKxvZq_IcC |access-date=14 November 2010 |chapter=Butterflies and moths |publisher=Springer |archive-date=10 March 2017 |archive-url=https://web.archive.org/web/20170310082058/https://books.google.com/books?id=DrTKxvZq_IcC |url-status=live }}</ref>{{Rp|246}}
Lepidopterans undergo a four-stage [[Biological life cycle|life cycle]]: [[egg]]; [[larva]] or [[caterpillar]]; [[pupa]] or [[chrysalis]]; and [[imago|imago (plural: imagines)]] / adult and show many variations of the basic body structure, which give these animals advantages for diverse lifestyles and environments.

=== Head ===
[[File:Caterpillar face close up.jpg|thumb|left|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, or [[sclerite|sclerotized]] head capsule.<ref name="scoble_heads">Scoble (1995). Section ''The Adult Head – Feeding and Sensation'', (pp. 4–22).</ref> Here, two [[compound eye]]s, and ''chaetosema'', 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.<ref name="Resh and Carde">{{cite book |last=Resh |first=Vincent H. |author2=Ring T. Carde  |title=Encyclopedia of Insects |publisher=Academic Press |location=U. S. A. |date=1 July 2009 |edition=2 |isbn=978-0-12-374144-8}}</ref>{{Rp|559–560}}

The [[Galea (insects)|maxillary galeae]] are modified and form an elongated [[proboscis]]. 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. Some [[basal (phylogenetics)|basal]] moths still have [[mandible (insect mouthpart)|mandible]]s, or separate moving jaws, like their ancestors, and these form the family [[Micropterigidae]].<ref name="scoble_heads"/><ref name="Resh and Carde"/>{{Rp|560}}<ref name="Firefly">{{Cite book|last=Christopher|first=O'Toole|title=Firefly Encyclopedia of Insects and Spiders|edition=1|isbn=978-1-55297-612-8|url=https://archive.org/details/fireflyencyclope0000unse_k0d2|year=2002|publisher=Firefly Books |url-access=registration}}</ref>

The larvae, called [[caterpillar]]s, have a toughened head capsule. Caterpillars lack the proboscis and have separate chewing [[Insect mouthparts|mouthparts]].<ref name="scoble_heads"/> These mouthparts, called [[mandible (insect mouthpart)|mandible]]s, are used to chew up the plant matter that the larvae eat. The lower jaw, or labium, is weak, but may carry a [[spinneret]], an organ used to create silk. The head is made of large lateral lobes, each having an ellipse of up to six simple eyes.<ref name="Resh and Carde"/>{{Rp|562–563}}

=== Thorax ===
The thorax is made of three fused segments, the [[prothorax]], [[mesothorax]], and [[metathorax]], each with a pair of legs. The first segment contains the first pair of legs. In some males of the butterfly family [[Nymphalidae]], the forelegs are greatly reduced and are not used for walking or perching.<ref name="Resh and Carde"/>{{Rp|586}} 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.<ref name="Heppner">{{cite book |last1=Heppner |first1=J. B. |editor1-first=John L. |editor1-last=Capinera |title=Encyclopedia of Entomology |url=https://books.google.com/books?id=i9ITMiiohVQC |edition=2 |series=Gale virtual reference library |volume=4 |year=2008 |publisher=Springer Reference |isbn=978-1-4020-6242-1 |page=4345 |chapter=Butterflies and moths |chapter-url=https://books.google.com/books?id=i9ITMiiohVQC&pg=PA626 |access-date=22 September 2016 |archive-url=https://web.archive.org/web/20160624051424/https://books.google.com/books?id=i9ITMiiohVQC |archive-date=24 June 2016 |url-status=live }}</ref> 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.<ref name="cgillott"/>

The two pairs of wings are found on the middle and third segments, or [[mesothorax]] and [[metathorax]], 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.<ref name="Resh and Carde"/>{{Rp|560}} The largest superfamily, the [[Noctuoidea]], has their wings modified to act as [[Tympanal organ|tympanal or hearing organ]]s.<ref name="Scoble">{{cite book |last1=Scoble|first1=MJ. |title=The Lepidoptera: Form, function, and diversity. |url=https://archive.org/details/lepidopteraformf0000scob|url-access=registration|year=1992 |publisher=Oxford Univ. Press|isbn=978-1-4020-6242-1}}</ref><!-- could include the case of fringed wings -->

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.<ref name="cgillott"/> 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 of [[gill]]s.<ref name="Resh and Carde"/>{{Rp|563}}

=== Abdomen ===
{{See also|Lepidoptera genitalia}}
[[File:Chenille de Grand porte queue (macaon) Fausses pattes.jpg|thumb|Caterpillar prolegs on ''[[Papilio 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. The [[Lepidoptera genitalia|genitalia]] of Lepidoptera are highly varied, and are often the only means of differentiating between species. Male genitals include a [[valva]], 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 for [[copulation (zoology)|copulation]] and as an [[ovipositor]], 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.<ref name="Resh and Carde"/>{{Rp|561}}

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 of [[Geometridae]]). 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., [[Prodoxidae]] and [[Nepticulidae]], respectively).<ref name="Resh and Carde"/>{{Rp|563}}

=== Scales ===
[[File:Mottenflügel in Mikroskop.jpg|thumb|right|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 are [[lamella (anatomy)|lamella]]r, or blade-like, and attached with a pedicel, while other forms may be hair-like or specialized as secondary sexual characteristics.<ref name="Scoble scale">Scoble (1995). Section ''Scales'', (pp. 63–66).</ref>

The lumen or surface of the lamella has a complex structure. It gives color either by colored [[pigment]]s it contains, or through [[structural coloration]] with mechanisms that include [[photonic crystal]]s and [[diffraction grating]]s.<ref name="Vukusic (2006)">{{cite journal |last1=Vukusic |first1=P. |year=2006 |title=Structural color in Lepidoptera |journal=Current Biology |pmid=16920604 |volume=16 |issue=16 |pages=R621–3 |doi=10.1016/j.cub.2006.07.040 |s2cid=52828850 |doi-access=free |bibcode=2006CBio...16.R621V }}</ref>

Scales function in insulation, thermoregulation, producing [[pheromones]] ([[androconia|in males only]]),<ref>{{cite journal |last1=Hall |first1=Jason P. W. |last2=Harvey |first2=Donald J. |year=2002 |title=A survey of androconial organs in the Riodinidae (Lepidoptera) |journal=[[Zoological Journal of the Linnean Society]] |volume=136 |issue=2 |pages=171–197 |doi=10.1046/j.1096-3642.2002.00003.x |doi-access=free }}</ref> and aiding gliding flight, but the most important is the large diversity of vivid or indistinct [[patterns in nature|patterns]] they provide, which help the organism protect itself by [[camouflage]] or [[mimicry]], and which act as signals to other animals including rivals and [[sexual selection|potential mates]].<ref name="Scoble scale"/>
{{Multiple image
| direction=horizontal
| align = left
| width = 180
| header = Electron microscopy images of scales
| image1 = SEM_image_of_a_Peacock_wing%2C_slant_view_1.JPG
| caption1 = A patch of wing (×50)
| image2 = SEM_image_of_a_Peacock_wing,_slant_view_2.JPG
| caption2 = Scales close up (×200)
| image3 = SEM_image_of_a_Peacock_wing,_slant_view_3.JPG
| caption3 = A single scale (×1000)
| image4 = SEM_image_of_a_Peacock_wing,_slant_view_4.JPG
| caption4 = Microstructure of a scale (×5000)
}}{{Clear}}

== Internal morphology ==

===Reproductive system===
In the [[Lepidoptera genitalia|reproductive system of butterflies and moths]], the male [[genitalia]] are 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 (in [[Hepialoidea]] and [[Mnesarchaeoidea]]) are two separate places for insemination and oviposition, both occurring on the same sterna as the monotrysian type, i.e. 9 and 10.<ref name="Gillot"/> The ditrysian groups have an internal duct that carries sperm, with separate openings for copulation and egg-laying.<ref name="Resh & Carde"/> 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.<ref name="Gillot"/> Hormones and the glands that produce them run the development of butterflies and moths as they go through their life cycles, called the [[endocrine system]]. The first insect hormone [[prothoracicotropic hormone]] (PTTH) operates the species life cycle and [[#Diapause|diapause]].<ref>{{cite journal|doi=10.2307/1538279|pmid=20268135|year=1947|last1=Williams|first1=C. M.|title=Physiology of insect diapause. ii. interaction between the pupal brain and prothoracic glands in the metamorphosis of the giant silkworm, ''Platysamia cecropia''|journal=The Biological Bulletin|volume=93|issue=2|pages=89–98|jstor=1538279|url=https://www.biodiversitylibrary.org/part/34159}}</ref> This hormone is produced by [[corpora allata]] and [[corpus cardiacum|corpora cardiaca]], where it is also stored. Some glands are specialized to perform certain task such as producing silk or producing saliva in the palpi.<ref name="Gullan">{{cite book |last=Gullan |first=P. J. |author2=P. S. Cranston |title=The Insects: An Outline of Entomology |url=https://books.google.com/books?id=S7yGZasJ7nEC&q=Insects |publisher=Wiley, John & Sons, Incorporated |location=Oxford |date=22 March 2010 |edition=4 |isbn=978-1-4443-3036-6 |access-date=8 October 2020 |archive-date=1 June 2021 |archive-url=https://web.archive.org/web/20210601163209/https://books.google.com/books?id=S7yGZasJ7nEC&q=Insects |url-status=live }}</ref>{{Rp|65, 75}} While the corpora cardiaca produce PTTH, the corpora allata also produces juvenile hormones, and the prothorocic glands produce moulting hormones.

===Digestive system===
In the [[digestive system]], the anterior region of the foregut has been modified to form a pharyngeal <!-- no link as pharynx and pharyngeal articles are human-oriented --> sucking pump as they need it for the food they eat, which are for the most part liquids. An [[esophagus]] follows 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.<ref name="Gillot"/> Ancestors of lepidopteran species, stemming from [[Hymenoptera]], 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 stalked [[goblet cell]]s are found in the anterior and posterior midgut regions, respectively. In insects, the goblet cells excrete positive [[potassium]] ions, 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.<ref name="Resh and Carde"/>{{Rp|279}}  Some, like the [[luna 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.<ref name=Tuskes1996>{{Citation |vauthors= Tuskes PM, Tuttle JP, Collins MM |year= 1996 |title= The Wild Silk Moths of North America: A Natural History of the Saturniidae of the United States and Canada |publisher= Cornell University Press |location= Ithaca, New York |pages= 182–184 |url= https://books.google.com/books?id=3vqpGATXU2oC&q=Phalena+plumata+caudata&pg=PA182|access-date=30 July 2018|isbn= 978-0-8014-3130-2 }}.</ref>

[[File:Internal morphology of Lepidoptera.svg|500px|thumb|center|Internal morphology of adult male in the family [[Nymphalidae]], 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 the [[circulatory system]], [[hemolymph]], or insect blood, is used to circulate heat in a form of [[thermoregulation]], where muscles contraction produces heat, which is transferred to the rest of the body when conditions are unfavorable.<ref name=Lighton>{{cite journal |author1=Lighton J. R. B. |author2=Lovegrove B. G. | year = 1990 | title = A temperature-induced switch from diffusive to convective ventilation in the honeybee | journal = Journal of Experimental Biology | volume = 154 | issue = 1| pages = 509–516 |doi=10.1242/jeb.154.1.509 | url=http://jeb.biologists.org/cgi/reprint/154/1/509.pdf| doi-access = free |bibcode=1990JExpB.154..509L }}</ref> 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 the [[Invertebrate trachea|trachea]].<ref name="Gullan"/>{{Rp|69}}

===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's [[respiratory 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.<ref name="Gullan"/>{{Rp|71, 72}}

== Polymorphism ==
{{Main|Polymorphism in Lepidoptera}}
[[File:Bagworm Moths Mating.jpg|thumb|upright|Sexually dimorphic bagworm moths (''[[Thyridopteryx ephemeraeformis]]'') mating: The female is flightless.]]
[[File:Heliconius mimicry.png|right|thumb|upright|The ''Heliconius'' butterflies from the tropics of the Western Hemisphere are the classical model for [[Müllerian mimicry]].]]

Polymorphism is the appearance of forms or "morphs", which differ in color and number of attributes within a single species.<ref name="cgillott"/>{{rp|163}}<ref>{{cite journal |author=Ford, E. B. |year=1965 |title=Genetic polymorphism |journal=Proceedings of the Royal Society of London. Series B, Biological Sciences |volume=164 |issue=995 |pages=350–61 |publisher=[[Oxford University Press]] |doi=10.1098/rspb.1966.0037 |pmid=4379524 |s2cid=202575235 |author-link=E. B. Ford}}</ref> In Lepidoptera, polymorphism can be seen not only between individuals in a population, but also between the sexes as [[sexual dimorphism]], between geographically separated populations in [[geographical polymorphism]], and between generations flying at different seasons of the year ([[seasonal polymorphism]] or [[polyphenism]]). In some species, the polymorphism is limited to one sex, typically the female. This often includes the phenomenon of [[mimicry]] when 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.<ref name="cgillott"/>

Environmental polymorphism, in which [[trait (biology)|trait]]s are not inherited, is often termed as polyphenism, which in Lepidoptera is commonly seen in the form of seasonal morphs, especially in the butterfly families of [[Nymphalidae]] and [[Pieridae]]. 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.<ref name="G&C"/> Polyphenism also occurs in caterpillars, an example being the peppered moth, ''[[Biston betularia]]''.<ref>{{Cite journal|last1=Noor|first1=Mohamed A. F.|last2=Parnell|first2=Robin S.|last3=Grant|first3=Bruce S. |title=A reversible color polyphenism in American Peppered Moth (''Biston betularia cognataria'') caterpillars |journal=[[PLoS ONE]] |volume=3 |issue=9 |article-number=e3142 |year=2008 |pmid=18769543 |doi=10.1371/journal.pone.0003142 |pmc=2518955|bibcode = 2008PLoSO...3.3142N |doi-access=free}}</ref>

Geographical isolation causes a divergence of a species into different morphs. A good example is the Indian white admiral ''[[Limenitis procris]]'', which has five forms, each geographically separated from the other by large mountain ranges.<ref name=Kunte/>{{rp|26}} An even more dramatic showcase of geographical polymorphism is the [[Apollo 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.<ref>Ivy I. G., Morgun D. V., Dovgailo K. E., Rubin N. I., Solodovnikov I. A. ''Дневные бабочки'' (Hesperioidea and Papilionoidea, Lepidoptera) Восточной Европы. " CD determinant, database and software package "Lysandra". Minsk, Kiev, Moscow: 2005. In Russian</ref>

{{Multiple image
| align = right
| direction = horizontal
| header = Seasonal diphenism in the common grass yellow, ''[[Eurema hecabe]]''
| image1 = Common Grass Yellow (Eurema hecabe) in Kawal WS, AP W IMG 1784.jpg
| width1 = 170
| caption1 = Dry-season form
| image2 = Common Grass yellow Im IMG 7069.jpg
| width2 = 200
| caption2 = 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.<ref name="G&C">{{cite book |author=Gullan & Cranston |year=2005 |chapter=Polymorphism and polyphenism |pages=[https://archive.org/details/isbn_9781405111133/page/163 163–164]|title= The Insects: An Outline of Entomology|publisher=Wiley |isbn=978-1-4051-1113-3 |url=https://archive.org/details/isbn_9781405111133 |url-access=registration }}</ref> Sexual dimorphism is present in all families of the Papilionoidea and more prominent in the [[Lycaenidae]], [[Pieridae]], and certain taxa of the [[Nymphalidae]]. Apart from color variation, which may differ from slight to completely different color-pattern combinations, secondary sexual characteristics may also be present.<ref name=Kunte>Kunte, Krushnamegh (2000). ''Butterflies of Peninsular India''. Part of Project lifescape. Orient Blackswan. {{ISBN|81-7371-354-5}}, {{ISBN|978-81-7371-354-5}}.</ref>{{rp|25}} Different genotypes maintained by natural selection may also be expressed at the same time.<ref name="G&C"/> Polymorphic and/or mimetic females occur in the case of some taxa in the [[Papilionidae]] primarily 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 many [[Psychidae]] species 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.<ref>{{cite web |url = http://bugguide.net/node/view/122 |title = Psychidae at Bug Guide |access-date = 19 January 2010 |publisher = [[Iowa State University]] |archive-url = https://web.archive.org/web/20120210200949/http://bugguide.net/node/view/122 |archive-date = 10 February 2012 |url-status = live }}</ref>

== Reproduction and development ==

[[File:Joined moths.JPG|thumb|right|upright|Mating pair of ''[[Laothoe populi]]'' (poplar hawk-moth) showing two different color variants]]

Species of Lepidoptera undergo [[holometabolism]] or "complete metamorphosis". Their life cycle normally consists of an [[egg]], a [[larva]], a [[pupa]], and an [[imago]] or adult.<ref name="cgillott"/> The larvae are commonly called [[caterpillar]]s, and the pupae of moths encapsulated in silk are called [[cocoon (silk)|cocoon]]s, while the uncovered pupae of butterflies are called [[chrysalides]].

=== Lepidopterans in diapause ===

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

=== Mating ===
{{see also|Lepidoptera genitalia}}
Males usually start [[eclosion]] (emergence) earlier than females and peak in numbers before females. Both of the sexes are sexually mature by the time of eclosion.<ref name="Resh and Carde"/>{{Rp|564}} 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 in [[Diurnality|diurnal]] species like most butterflies. However, the females of most nocturnal species, including almost all moth species, use [[pheromone]]s to attract males, sometimes from long distances.<ref name="cgillott"/> 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]]''.<ref name="Sanderford">{{Cite journal |last=Sanderford |first=M. V.|author2=W. E. Conner  |date=July 1990 |title=Courtship sounds of the polka-dot wasp moth, ''Syntomeida epilais'' |journal=[[Naturwissenschaften]] |volume=77 |issue=7 |pages=345–347 |doi=10.1007/BF01138395|bibcode = 1990NW.....77..345S |s2cid=1359112}}</ref>

Adaptations include undergoing one seasonal generation, two or even more, called [[voltinism]] (Univoltism, bivoltism, and multivism, respectively). Most lepidopterans in [[temperate climate]]s are 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 called [[diapause]].<ref name="Resh and Carde"/>{{Rp|567}} 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.<ref name="Resh and Carde"/>{{Rp|564}}

=== Life cycle ===

[[File:Anise Swallowtail Life Cycle.svg|thumb|left|The four stages of the life cycle of an [[anise swallowtail]]]]

==== Eggs ====

Lepidoptera usually reproduce sexually and are [[oviparous]] (egg-laying), though some species exhibit live birth in a process called [[ovoviviparity]]. A variety of differences in [[egg]]-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., [[hepialid]]s and some [[Nymphalidae|nymphalids]])<ref name="Wiklund">{{Cite journal |last=Wiklund |first=Christer |date=July 1984 |title=Egg-laying patterns in butterflies in relation to their phenology and the visual apparency and abundance of their host plants |journal=[[Oecologia]] |volume=63 |issue=1 |pages=23–29|doi=10.1007/BF00379780|pmid=28311161 |bibcode=1984Oecol..63...23W |s2cid=29210301 }}</ref> 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.<ref name="cgillott"/> The females of both butterflies and moths select the host plant instinctively, and primarily, by chemical cues.<ref name="Resh and Carde"/>{{Rp|564}}

The eggs are derived from materials ingested as a larva and in some species, from the spermatophores received from males during mating.<ref>{{cite book |last1=Oberhauser |first1=Karen S. |author-link1=Karen Oberhauser |last2=Solensky |first2=Michelle J |title=The Monarch Butterfly: Biology and Conservation |year=2004 |publisher=Cornell University Press |location=Ithaca NY |isbn=978-0-8014-4188-2 |edition=First |ref={{harvid|Oberhauser2004}} |url=https://archive.org/details/monarchbutterfly00mich }}</ref> 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.{{sfn|Oberhauser|2004|p=24}} The egg is covered by a hard-ridged protective outer layer of shell, called the [[chorion]]. It is lined with a thin coating of [[wax]], which prevents the egg from drying out. Each egg contains a number of [[micropyle (zoology)|micropyles]], 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 in [[temperate region]]s, go through [[diapause]] 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|Caterpillar}}
[[File:Arctiidae caterpillar edit.jpg|thumb|upright|right|Larval form typically lives and feeds on plants]]

The larvae or caterpillars are the first stage in the life cycle after hatching. Caterpillars are "characteristic [[Wiktionary:polypod|polypod]] larvae with cylindrical bodies, short thoracic legs, and abdominal prolegs (pseudopods)".<ref name="Gullan_Cranston_2010">{{cite book |author1=Gullan, P. J.  |author2=Cranston, P. S. |year=2010|title=The Insects: an Outline of Entomology |edition=4th |isbn=978-1-4443-3036-6|publisher=[[Wiley-Blackwell]]|chapter=Life-history patterns and phases |pages=156–164}}</ref> They have a sclerotized head capsule with an adfrontal suture formed by medial fusion of the sclerites, [[Mandible (insect mouthpart)|mandibles (mouthparts)]] for chewing, and a soft tubular, segmented body, that may have hair-like or other projections, three pairs of true legs, and additional [[proleg]]s (up to five pairs).<ref name="Dugdale"/> The body consists of thirteen segments, of which three are thoracic and ten are abdominal.<ref name="Triplehorn & Johnson (2005)">{{cite book |title=Borror and Delong's Introduction to the Study of Insects |last=Triplehorn |first=Charles A.|author2=Johnson, Norman F.  |year=2005 |publisher=Thomson Brooks/Cole |location=Belmont, California|isbn=978-0-03-096835-8 |url=https://books.google.com/books?id=_uFkQgAACAAJ}}</ref> Most larvae are [[herbivore]]s, but a few are [[carnivore]]s (some eat ants or other caterpillars) and [[detritivore]]s.<ref name="Dugdale">{{cite journal |last1=Dugdale |first1=J. S. |year=1996 |title=Natural history and identification of litter-feeding Lepidoptera larvae (Insecta) in beech forests, Orongorongo Valley, New Zealand, with especial reference to the diet of mice (''Mus musculus'') |journal=Journal of the Royal Society of New Zealand |volume=26 |issue=4 |pages=251–274 |url=http://www.royalsociety.org.nz/media/publications-journals-nzjr-1996-058.pdf |doi=10.1080/03014223.1996.9517513 |bibcode=1996JRSNZ..26..251D |access-date=14 November 2010 }}{{dead link|date=December 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

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. Some [[lycaenid]] species such as ''[[Phengaris rebeli]]'' are [[social parasitism (biology)|social parasites]] of ''[[Myrmica]]'' ant nests.<ref>{{cite journal |last1=Elmes |first1=G.W. |last2=Wardlaw |first2=J.C. |last3=Schönrogge |first3= K. |last4= Thomas |first4= J.A. |last5=Clarke |first5=R.T. |title=Food stress causes differential survival of socially parasitic caterpillars of Maculinea rebeli integrated in colonies of host and non-host Myrmica ant species
 |journal=Entomologia Experimentalis et Applicata |volume=110 |issue=1 |pages=53–63 |doi= 10.1111/j.0013-8703.2004.00121.x|year=2004 |bibcode=2004EEApp.110...53E |s2cid=86427983 }}</ref> A species of [[Geometridae]] from [[Hawaii]] has carnivorous larvae that catch and eat flies.<ref name=autogenerated4>{{Cite book|last=Arnett|first=Ross H. Jr.|title=American Insects. A Handbook of the Insects of America North of Mexico|publisher=CRC press LLC|date=28 July 2000|edition=2|pages=631–632|isbn=978-0-8493-0212-1|url=https://books.google.com/books?id=4M0v0Ye54MYC&q=lepidopera|access-date=8 October 2020|archive-date=31 May 2021|archive-url=https://web.archive.org/web/20210531113739/https://books.google.com/books?id=4M0v0Ye54MYC&q=lepidopera|url-status=live}}</ref> Some pyralid caterpillars are aquatic.<ref>{{Cite journal |author=Berg, Clifford O. |year=1950 |title=Biology of certain aquatic caterpillars (Pyralididae: ''Nymphula'' spp.) which feed on ''Potamogeton'' |journal=Transactions of the American Microscopical Society |volume=69 |issue=3 |pages=254–266 |jstor=3223096 |doi=10.2307/3223096}}</ref>

The larvae develop rapidly with several generations in a year; however, some species may take up to 3 years to develop, and exceptional examples like ''[[Gynaephora groenlandica]]'' take as long as seven years.<ref name="cgillott"/> The larval stage is where the feeding and growing stages occur, and the larvae periodically undergo hormone-induced [[ecdysis]], developing further with each [[instar]], 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 called [[osmeteria]] (family [[Papilionidae]]), 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.<ref>{{cite journal | doi = 10.2307/2406212 | last1 = Ehrlich | first1 = P. R. | last2 = Raven | first2 = P. H. | year = 1964 | title = Butterflies and plants: a study in coevolution| journal = Evolution | volume = 18 | issue = 4| pages = 586–608 | jstor = 2406212}}</ref>

==== 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 branching [[Invertebrate trachea|tracheae]] from the wing base that precede the formation of the wing veins and begin to develop patterns associated with several landmarks of the wing.<ref name="Nijhout">{{Cite book |last=Nijhout |first=H. Frederik |title=The Development and Evolution of Butterfly Wing Patterns(Smithsonian Series in Comparative Evolutionary Biology) |publisher=Smithsonian Institution Scholarly Press |date=17 August 1991 |edition=1 |pages=2–4 |isbn=978-0-87474-917-5 |url=https://books.google.com/books?id=4M0v0Ye54MYC&q=lepidopera |access-date=8 October 2020 |archive-date=31 May 2021 |archive-url=https://web.archive.org/web/20210531113739/https://books.google.com/books?id=4M0v0Ye54MYC&q=lepidopera |url-status=live }}</ref>

Near pupation, the wings are forced outside the epidermis under pressure from the [[hemolymph]], 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.<ref name="Nijhout"/>

==== Pupa ====

[[File:Papilio dardanus emerging.ogv|left|thumb|Eclosion of ''[[Papilio dardanus]]'']]

After about five to seven instars,<ref name="Dole">{{Cite book |last=Dole |first=Claire Hagen |title=The Butterfly Gardener's Guide |publisher=Brooklyn Botanic Garden |date=28 May 2003|isbn=978-1-889538-58-7 |url=https://archive.org/details/butterflygardene00clai|url-access=registration |page=[https://archive.org/details/butterflygardene00clai/page/26 26] |quote=metamorphosis butterfly. }}</ref>{{rp|26–28}} or molts, certain hormones, like PTTH, stimulate the production of [[ecdysone]], which initiates insect molting. The larva starts to develop into the [[pupa]]: 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 the [[imago]] are externally recognizable in the pupa. All the appendages on the adult head and thorax are found cased inside the cuticle ([[antenna (biology)|antenna]]e, [[Insect mouthparts|mouthpart]]s, etc.), with the wings wrapped around, adjacent to the antennae.<ref name="Resh and Carde"/>{{Rp|564}} The pupae of some species have functional mandibles, while the pupal mandibles are not functional in others.<ref name="scoble_heads" />

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 the [[Mexican jumping bean]] moth (''[[Cydia saltitans]]'') does this. The larvae cut a trapdoor in the bean (species of ''[[Sebastiania]]'') 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 deter [[parasitoid]] wasps from laying eggs on the pupa. Other species of moths are able to make clicks to deter predators.<ref name="Resh and Carde"/>{{Rp|564, 566}}

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]]).<ref name="cgillott"/><ref name="Resh and Carde"/>{{Rp|564}}

==== 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.<ref name="Resh and Carde"/>{{Rp|564}}

While most butterflies and moths are [[Terrestrial animal|terrestrial]], many species of [[Acentropinae]] ([[Crambidae]]) are truly [[Aquatic animal|aquatic]] with all stages except the adult occurring in water. Many species from other families such as [[Erebidae]], [[Nepticulidae]], [[Cosmopterigidae]], [[Tortricidae]], [[Olethreutidae]], [[Noctuidae]], [[Cossidae]], and [[Sphingidae]] are aquatic or [[:wikt:semi-aquatic|semiaquatic]].<ref name="Ward">{{cite book |author1=Ward, James V. |author2=Ward, Peter E. |year=1992 |title=Aquatic Insect Ecology, Biology And Habitat |publisher=John Wiley & Sons |isbn=978-0-471-55007-5}}</ref>{{rp|22}}

{{clear}}

== Video gallery of butterfly life cycle ([[Pieris rapae]], the common cabbage white) ==
{{gallery
|File:White cabbage from egg.webm|Emerging from egg and first feedings.

|File:2nd Instar eating.webm|Second instar larvae eating. Speeded up 50 times to illustrate feeding behavior. Nearly transparent body shows internal digestion.

|File:White 2nd InstarTo 3rd.webm|This second instar larvae sheds skin in under 20 minutes.

|File:White eating leaf.webm|Larvae eating remainder of a leaf. Six hours speeded up one hundred times.

|File:Cabbbage white shedding 4th instar skin.webm|Segments of the last two hours of the larvae shedding its 4th instar skin, after starting a few hours earlier.

|File:Larvae walking on glass.webm|Fifth instar [[Pieris rapae|white cabbage]] larvae walking on broccoli stem and on glass, showing it laying down silk it then walks on.

|File:White cabbage paraistiized larvae.webm|Parasitized larvae showing wasp larvae exiting its body, spinning cocoons. Playback at double speed. Adult wasps at normal speed.

|File:White cabbage to chrysalis.webm|Larvae shedding skin, becoming a chrysalis. Recorded over fifteen hours. Closeups at two times speed. Other clips at ten times speed.

|File:White cabbage to adult butterfly.webm|Emerging from chrysalis into an adult.

|File:White cabbage butterflies flying.webm|Butterflies flying. Later clips in slow motion.

|File:Whites puddling.webm|Male butterflies [[mud-puddling]] to concentrate salts for female reproduction.

|File:Whites cabbage egg depositing.webm|Butterflies depositing eggs under leaves. Each repeated in slow motion.
}}
{{clear}}

== 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.<ref>{{cite journal |author1=Benjamin Jantzen |author2=Thomas Eisner |date=28 July 2008 |title=Hindwings are unnecessary for flight but essential for execution of normal evasive flight in Lepidoptera|journal=[[Proceedings of the National Academy of Sciences]] |volume=105 |issue = 43 |pages=16636–16640 |pmid=18936482 |doi=10.1073/pnas.0807223105 |pmc=2575472 |bibcode = 2008PNAS..10516636J |doi-access=free }}</ref>

Lepidopteran species have to be warm, about {{convert|77|to|79|F|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.{{citation needed|date=August 2022}}

Some species of butterflies can reach fast speeds, such as the [[southern dart]], which can go as fast as {{Convert|48.4|km/h|mi/h}}. Sphingids are some of the fastest flying insects, some are capable of flying at over {{Convert|50|km/h|mi/h}}, having a wingspan of {{Convert|35-150|mm|in}}.<ref name="Capinera"/><ref>{{cite web |url=http://www.speedofanimals.com/insect |title=Speed of animals |author=Reisner, Alex |publisher=speedofanimals.com |access-date=20 February 2011 |archive-url=https://web.archive.org/web/20110225124115/http://www.speedofanimals.com/insect |archive-date=25 February 2011 }}</ref> In some species, sometimes a gliding component to their flight exists. Flight occurs either as hovering, or as forward or backward motion.<ref name=autogenerated2>{{Cite book |last=Scoble |first=Malcolm |title=The Lepidoptera: Form, Function and Diversity |publisher=Oxford University Press, 1995 |pages=66–67 |isbn=978-0-19-854952-9 |url=https://books.google.com/books?id=gnpd_5iNTiwC&pg=PA66 |date=1995 |access-date=11 September 2020 |archive-date=1 June 2021 |archive-url=https://web.archive.org/web/20210601163848/https://books.google.com/books?id=gnpd_5iNTiwC&pg=PA66 |url-status=live }}</ref> In butterfly and moth species, such as [[hawk moth]]s, hovering is important as they need to maintain a certain stability over flowers when feeding on the nectar.<ref name="Capinera"/>

==== Navigation ====
{{main|Animal navigation}}
[[File:Moths attracted by floodlight.jpg|thumb|right|Long exposure image of flying moths, attracted to the floodlights]]

[[Animal navigation|Navigation]] is 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 see [[polarized 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.<ref name="Saumam">{{Cite journal |last=Sauman |first=Ivo |author2=Adriana D. Briscoe |author3=Haisun Zhu |author4=Dingding Shi |author5=Oren Froy |author6=Julia Stalleicken |author7=Quan Yuan |author8=Amy Casselman |author9=Steven M. Reppert   |date=5 May 2005 |title=Connecting the Navigational Clock to Sun Compass Input in Monarch Butterfly Brain |journal=Neuron |volume=46 |issue=3 |pages=457–467 |doi=10.1016/j.neuron.2005.03.014 |pmid=15882645|s2cid=17755509 |doi-access=free }}</ref> Most migratory butterflies are those that live in semiarid areas where breeding seasons are short.<ref name="Southwood">{{Cite journal |last=Southwood |first=T. R. E. |year=1962 |title=Migration of terrestrial arthropods in relation to habitat |journal=[[Biological Reviews]] |volume=37 |issue=2 |pages=171–211 |doi=10.1111/j.1469-185X.1962.tb01609.x|s2cid=84711127 }}</ref> The life histories of their host plants also influence the strategies of the butterflies.<ref name="Dennis">{{Cite journal |last=Dennis |first=Roger L. H.|author2=Tim G. Shreeve |author3=Henry R. Arnold |author4=David B. Roy  |date = September 2005|title=Does diet breadth control herbivorous insect distribution size? Life history and resource outlets for specialist butterflies |journal=Journal of Insect Conservation |volume=9 |issue= 3 |pages=187–200 |doi=10.1007/s10841-005-5660-x|bibcode=2005JICon...9..187D |s2cid=20605146}}</ref> 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.<ref name="Made">{{Cite book |last=Made |first=J. G. van der|author2=Josef Blab |author3=Rudi Holzberger |author4=H. van den Bijtel  |title=Actie voor Vlinders, zo kunnen we ze redden. |publisher=Weert: M & P cop. |year=1989 |page=192|isbn=978-90-6590-303-7|language=nl}}</ref>

Many studies have also shown that moths navigate. One study showed that many moths may use the [[Earth's magnetic field]] to navigate, as a study of the [[heart and dart]] moth suggests.<ref name="heart-and-dart">{{Cite journal |last=Baker |first=R. Robin |date = February 1987|title=Integrated use of moon and magnetic compasses by the heart-and-dart moth, ''Agrotis exclamationis'' |journal=Animal Behaviour |volume=35 |issue=1 |pages=94–101 |doi=10.1016/S0003-3472(87)80214-2|s2cid=54314728 }}</ref> Another study, of the migratory behavior of the [[silver 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.<ref>{{Cite news |url=http://www.gre.ac.uk/pr/articles/2008news/a1537---moths |title=Scientists make compass discovery in migrating moths |last=Breen |first=Amanda |date=7 May 2008 |publisher=University of Greenwich at Medway |page=1 |access-date=9 December 2009 |archive-url=https://archive.today/20120530141617/http://www.gre.ac.uk/pr/articles/2008news/a1537---moths |archive-date=30 May 2012 }}</ref><ref name="Chapman">{{Cite journal |last1=Chapman |first1=Jason W. |first2=Don R. |last2=Reynolds |first3=Henrik |last3=Mouritsen |first4=Jane K. |last4=Hill |first5=Joe R. |last5=Riley |first6=Duncan |last6=Sivell |first7=Alan D. |last7=Smith |first8=Ian P. |last8=Woiwod |date=8 April 2008 |title=Wind selection and drift compensation optimize migratory pathways in a high-flying moth |journal=Current Biology |volume=18 |issue=7 |pages=514–518 |doi=10.1016/j.cub.2008.02.080 |pmid=18394893 |bibcode=2008CBio...18..514C |s2cid=3236142 |url=https://repository.rothamsted.ac.uk/download/1b0eb17b2e2cb34d1483a5a45159f6f47d94e99744eb7b325170de28434fbdbd/117278/PIIS096098220800362X.pdf |access-date=11 September 2020 |archive-date=31 May 2021 |archive-url=https://web.archive.org/web/20210531114608/https://repository.rothamsted.ac.uk/download/1b0eb17b2e2cb34d1483a5a45159f6f47d94e99744eb7b325170de28434fbdbd/117278/PIIS096098220800362X.pdf |url-status=live }}</ref> ''[[Aphrissa statira]]'' in [[Panama]] loses its navigational capacity when exposed to a magnetic field, suggesting it uses the Earth's magnetic field.<ref>{{Cite journal |last1=Srygley |first1=Robert B.|first2=Evandro G. |last2=Oliveira |first3=Andre J. |last3=Riveros  |year=2005 |title=Experimental evidence for a magnetic sense in Neotropical migrating butterflies (Lepidoptera: Pieridae) |journal=The British Journal of Animal Behaviour |volume=71 |issue=1 |pages=183–191 |url=http://users.ox.ac.uk/~zool0206/AnimBeh06.pdf |archive-url=https://web.archive.org/web/20091104100719/http://users.ox.ac.uk/~zool0206/AnimBeh06.pdf |archive-date=4 November 2009 |doi=10.1016/j.anbehav.2005.04.013|s2cid=25203050}}</ref>

Moths exhibit a tendency to circle artificial lights repeatedly. This suggests they use a technique of [[celestial navigation]] called [[transverse orientation]]. By maintaining a constant angular relationship to a bright celestial light, such as the [[Moon]], 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 the [[horizon]]. 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.<ref>{{Cite news |url=https://www.npr.org/templates/story/story.php?storyId=12903572 |title=Why are Moths Attracted to Flame? (audio) |last1=Elliot |first1=Debbie |first2=May |last2=Berenbaum |date=18 August 2007 |publisher=National Public Radio |page=1 |access-date=12 December 2009 |archive-url=https://web.archive.org/web/20090108215236/http://www.npr.org/templates/story/story.php?storyId=12903572 |archive-date=8 January 2009 |url-status=live }}</ref> Other explanations have been suggested, such as the idea that moths may be impaired with a visual distortion called a [[Mach band]] by 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.<ref>{{Cite book |last=Hsiao |first=Henry S. |title=Attraction of moths to light and to infrared radiation |publisher=San Francisco Press |year=1972|isbn=978-0-911302-21-9}}</ref>

==== Migration ====
{{Main|Lepidoptera migration}}
[[File:Monarch butterflies in Santa Cruz-11.jpg|left|thumb|[[Monarch (butterfly)|Monarch butterflies]], seen in a cluster in [[Santa Cruz, California|Santa Cruz]], [[California]], where the western population migrates for the winter]]

Lepidopteran migration is typically [[season]]al, 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 the [[mourning cloak]], [[painted lady]], [[American lady]], [[Vanessa atalanta|red admiral]], and the [[common buckeye]].<ref name="Dole"/>{{rp|29–30}} A notable species of moth that migrates long distances is the [[bogong moth]].<ref>{{cite journal |last1=Warrant |first1=Eric |last2=Frost |first2=Barrie |author2-link=Barrie Frost |last3=Green |first3=Ken |last4=Mouritsen |first4=Henrik |last5=Dreyer |first5=David |last6=Adden |first6=Andrea |last7=Brauburger |first7=Kristina |last8=Heinze |first8=Stanley |year=2016 |title=The Australian Bogong Moth ''Agrotis infusa'': A Long-Distance Nocturnal Navigator |journal=Frontiers in Behavioral Neuroscience |volume=10 |article-number=77 |doi=10.3389/fnbeh.2016.00077|pmid=27147998 |pmc=4838632 |doi-access=free }}</ref> The most well-known migrations are those of the eastern population of the [[monarch butterfly]] from Mexico to northern United States and southern Canada, a distance of about {{convert|4000|-|4800|km|abbr=on}}. Other well-known migratory species include the painted lady and several of the [[Danainae|danaine]] butterflies. Spectacular and large-scale migrations associated with the [[monsoons]] are seen in peninsular India.<ref>{{cite journal |author=Williams, C. B. |year=1927 |title=A study of butterfly migration in south India and Ceylon, based largely on records by Messrs. G. Evershed, E. E. Green, J. C. F. Fryer and W. Ormiston |journal=[[Transactions of the Royal Entomological Society of London]] |volume=75 |issue=1 |pages=1–33 |doi=10.1111/j.1365-2311.1927.tb00054.x |bibcode=1927EcoEn..75....1W }}</ref> Migrations have been studied in more recent times using wing tags and stable hydrogen isotopes.<ref>{{cite journal |author1=Urquhart, F. A.  |author2=N. R. Urquhart |year=1977 |title=Overwintering areas and migratory routes of the Monarch butterfly (''Danaus p. plexippus'', Lepidoptera: Danaidae) in North America, with special reference to the western population |journal=[[Canadian Entomologist]] |volume=109 |issue=12 |pages=1583–1589 |doi=10.4039/ent1091583-12|s2cid=86198255 }}</ref><ref>{{cite journal |doi=10.1073/pnas.95.26.15436 |author1=Wassenaar L. I. |author2=K. A. Hobson |year=1998 |title=Natal origins of migratory monarch butterflies at wintering colonies in Mexico: new isotopic evidence |journal=[[Proceedings of the National Academy of Sciences]] |volume=95 |issue=26 |pages=15436–15439 |pmid=9860986 |pmc=28060|bibcode = 1998PNAS...9515436W |doi-access=free }}</ref>

Moths also undertake migrations, an example being the [[Uraniidae|uraniids]]. ''[[Urania fulgens]]'' undergoes population explosions and massive migrations that may be not surpassed by any other insect in the [[Neotropic]]s. In [[Costa Rica]] and [[Panama]], 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.<ref name="Smith N. G. ">{{Cite book |last1=Smith |first1=N. G. |editor-last=Janzen |editor-first= D. H. |title=''Urania fulgens'' (Calipato Verde, Green Urania) |publisher=[[University of Chicago Press]] |location=Chicago |year=1983 |series=Costa Rican Natural History |page=816}}</ref>

=== Communication ===
[[File:Group of Melitaea athalia near Warka, Poland.PNG|thumb|Group of ''Melitaea athalia'' near [[Warka]], [[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.<ref name=autogenerated1>{{Cite book |last=Chapman |first=R. F. |title=The Insects: Structure and Function |url=https://archive.org/details/insectsstructure0000chap |url-access=registration |quote=Insects. |edition=4 |year=1998 |publisher=Cambridge University Press |location=New York |isbn=978-0-521-57890-5 |page=[https://archive.org/details/insectsstructure0000chap/page/715 715]}}</ref> In many species, a gland between the eighth and ninth segments under the abdomen in the female produces the pheromones.<ref name="cgillott"/> Communication can also occur through stridulation, or producing sounds by rubbing various parts of the body together.<ref name="Chapman"/>

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.<ref name="communications web">{{cite web |url=http://www.cals.ncsu.edu/course/ent425/tutorial/Communication/sound.html |title=Acoustic Communication |author=Meyer, John R. |year=2006 |publisher=Department of Entomology, C State University |access-date=25 February 2011 |archive-url=https://web.archive.org/web/20110720011820/http://www.cals.ncsu.edu/course/ent425/tutorial/Communication/sound.html |archive-date=20 July 2011 }}</ref> An example is that of the [[polka-dot wasp moth]] (''Syntomeida epilais''), which produces sounds with a frequency above that normally detectable by humans (about 20&nbsp;kHz). These sounds also function as tactile communication, or communication through touch, as they stridulate, or vibrate a substrate like leaves and stems.<ref name="Sanderford"/>

Most moths lack bright colors, as many species use coloration as [[camouflage]], but butterflies engage in visual communication. Female [[cabbage butterfly|cabbage 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.<ref name="communications web"/>

== 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 of [[Trophic level|trophic]] relationships between [[autotroph]]s and [[heterotroph]]s, which are included in the stages of Lepidoptera larvae, pupae, and adults. Larvae and pupae are links in the diets of birds and parasitic [[entomophagous]] insects. The adults are included in food webs in a much broader range of consumers (including birds, small mammals, reptiles, etc.).<ref name="Resh and Carde"/>{{Rp|567}}

=== Defense and predation ===
{{Main|Defense in insects}}
[[File:01 chenille machaon (detail).jpg|thumb|upright=0.87|''[[Papilio machaon]]'' caterpillar showing the [[osmeterium]], which emits unpleasant smells to ward off predators]]
[[File:Throw frass.webm|thumb|thumbtime=87|This Lepidoptera larvae disposes of its [[frass]] that 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 to [[predation]]. Adult butterflies and moths are preyed upon by [[bird]]s, [[bat]]s, [[lizard]]s, [[amphibian]]s, [[dragonflies]], and [[spider]]s. 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.<ref>{{Cite journal|last=Robinson|first=Michael H.|date=1969|title=Predatory Behavior of ''Argiope argentata'' (Fabricius)|journal=American Zoologist|volume=9|issue=1|pages=161–173|doi=10.1093/icb/9.1.161|jstor=3881502|issn=0003-1569|doi-access=free}}</ref> Caterpillars and pupae fall prey not only to birds, but also to invertebrate predators and small mammals, as well as fungi and bacteria. [[Parasitoid]] and [[parasitic]] wasps and [[flies]] may 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 the [[great tit]] in 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 include [[aposematism]], [[mimicry]], [[camouflage]], and development of threat patterns and displays.<ref name="Enchanted">{{cite web |url=http://www.enchantedlearning.com/subjects/butterfly/allabout/Defense.shtml |title=Caterpillar and Butterfly Defense Mechanisms |publisher=EnchantedLearning.com |access-date=7 December 2009 |archive-url=https://web.archive.org/web/20090328122619/http://www.enchantedlearning.com/subjects/butterfly/allabout/Defense.shtml |archive-date=28 March 2009 }}</ref> Only a few birds, such as the [[nightjar]]s, hunt nocturnal lepidopterans. Their main predators are [[bat]]s. 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 the [[zebra swallowtail butterfly]] larvae, are cannibalistic.

Some species of Lepidoptera are poisonous to predators, such as the monarch butterfly in the Americas, ''[[Atrophaneura]]'' species (roses, windmills, etc.) in Asia, as well as ''[[Papilio antimachus]]'', and the [[birdwing]]s, 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.<ref name=Enchanted/><ref name="ANC">{{Cite book |last=Kricher |first=John |title=A Neotropical Companion |pages=157–158 |chapter=6 |chapter-url=https://books.google.com/books?id=Z3pgdvrSmG8C&q=defense+protection+butterflies&pg=PA158 |publisher=[[Princeton University Press]] |isbn=978-0-691-00974-2 |date=16 August 1999 |access-date=8 October 2020 |archive-date=31 May 2021 |archive-url=https://web.archive.org/web/20210531114847/https://books.google.com/books?id=Z3pgdvrSmG8C&q=defense+protection+butterflies&pg=PA158 |url-status=live }}</ref> Toxic butterflies and larvae tend to develop bright colors and striking patterns as an indicator to predators about their toxicity. This phenomenon is known as [[aposematism]].<ref name="Santos & Cannatella (2003)">{{cite journal |last1=Santos |first1=J. C. |last2=Cannatella |first2=D. C. |year=2003 |title=Multiple, recurring origins of aposematism and diet specialization in poison frogs |journal=Proceedings of the National Academy of Sciences |volume=100 |issue=22 |pages=12792–12797  |doi=10.1073/pnas.2133521100 |pmid=14555763 |last3=Cannatella |first3=DC |pmc=240697|bibcode = 2003PNAS..10012792S |doi-access=free }} (Abstract).</ref> Some caterpillars, especially members of [[Papilionidae]], contain an [[osmeterium]], a Y-shaped protrusible [[gland]] found in the [[prothoracic]] segment of the larvae.<ref name=Enchanted/> When threatened, the caterpillar emits unpleasant smells from the organ to ward off the predators.<ref>{{cite web |url=http://www.merriam-webster.com/dictionary/osmeterium |title=osmeterium |publisher=Merriam-Webster, Incorporated |access-date=9 December 2009 |archive-url=https://web.archive.org/web/20100220065342/http://www.merriam-webster.com/dictionary/osmeterium |archive-date=20 February 2010 |url-status=live }}</ref><ref name="About">{{cite web |url=http://insects.about.com/od/entomologyglossary/g/def_osmeterium.htm |title=Osmeterium |last=Hadley |first=Debbie |publisher=About.com Guide |access-date=9 December 2009 |archive-url=https://web.archive.org/web/20080723145419/http://insects.about.com/od/entomologyglossary/g/def_osmeterium.htm |archive-date=23 July 2008 }}</ref>

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.<ref>{{Cite journal |last1=Eacock |first1=Amy |last2=Rowland |first2=Hannah M. |last3=van't Hof |first3=Arjen E. |last4=Yung |first4=Carl J. |last5=Edmonds |first5=Nicola |last6=Saccheri |first6=Ilik J. |date=2019 |title=Adaptive colour change and background choice behaviour in peppered moth caterpillars is mediated by extraocular photoreception |journal=Communications Biology |language=en |volume=2 |issue=1 |page=286 |doi=10.1038/s42003-019-0502-7 |issn=2399-3642 |pmc=6677728 |pmid=31396566}}</ref> Some caterpillars look like inedible objects, such as twigs or leaves. For instance, the [[mourning cloak]] fades into the backdrop of trees when it folds its wings back. The larvae of some species, such as the common Mormon (''[[Papilio polytes]]'') and the [[western tiger swallowtail]] look like bird droppings.<ref name=Enchanted/><ref>{{Cite book |last=Latimer |first=Jonathan P. |author2=Karen Stray Nolting  |title=Butterflies |publisher=Houghton Mifflin Harcourt Trade & Reference Publishers |date=30 May 2000 |page=[https://archive.org/details/butterflies0000lati/page/12 12]|isbn=978-0-395-97944-0 |url=https://archive.org/details/butterflies0000lati|url-access=registration |quote=Tiger swallowtail. }}</ref> For example, adult [[Sesiidae]] species (also known as clearwing moths) have a general appearance sufficiently similar to a [[wasp]] or [[hornet]] to make it likely the moths gain a reduction in predation by [[mimicry|Batesian mimicry]].<ref>{{Cite book |title=Insects and Spiders of the World |publisher=Marshall Cavendish |date=January 2003 |volume=10 |pages=292–293 |isbn=978-0-7614-7344-2 |url=https://books.google.com/books?id=uvdpiSQUuesC&q=clearwing+moths+mimicry&pg=PA592 |access-date=8 October 2020 |archive-date=31 May 2021 |archive-url=https://web.archive.org/web/20210531113954/https://books.google.com/books?id=uvdpiSQUuesC&q=clearwing+moths+mimicry&pg=PA592 |url-status=live }}</ref> [[Eyespot (mimicry)|Eyespot]]s are a type of [[automimicry]] used 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.<ref name="Caroll">{{Cite book |last=Carroll |first=Sean |title=Endless forms most beautiful: the new science of evo devo and the making of the animal kingdom |pages=[https://archive.org/details/endlessformsmost00carr_0/page/205 205]–210|isbn=978-0-393-06016-4 |url=https://archive.org/details/endlessformsmost00carr_0 |url-access=registration |quote=Butterfly eyespots defense. |publisher=W. W. Norton & Co |year=2005}}</ref>

[[Batesian]] and [[Müllerian mimicry|Müllerian]] mimicry 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 the [[Limenitidinae|limenitidine]] [[viceroy butterfly]] in relation to the inedible [[Danainae|danaine]] monarch. The viceroy is, in fact, more toxic than the monarch and this resemblance should be considered as a case of Müllerian mimicry.<ref>{{Cite journal |last=Ritland |first=D. B.|author2=L. P. Brower |author-link2=Lincoln Brower |year=1991 |title=The viceroy butterfly is not a Batesian mimic |journal=[[Nature (journal)|Nature]] |volume=350 |issue=6318 |pages=497–498 |doi=10.1038/350497a0 |bibcode=1991Natur.350..497R |s2cid=28667520|quote=Viceroys are as unpalatable as monarchs, and significantly more unpalatable than queens from representative Florida populations. }}</ref> 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 genus ''[[Heliconius]]'' form one of the most well-known Müllerian complexes.<ref>{{cite journal |author=Meyer, A. |year=2006 |title=Repeating patterns of mimicry |journal=[[PLOS Biology]] |volume=4 |issue=10 |article-number=e341 |doi=10.1371/journal.pbio.0040341 |pmid=17048984 |pmc=1617347 |doi-access=free }}</ref> 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 the [[noctuid]] moth that cause it to drop a few inches in its flight to evade attack.<ref>{{cite journal| last = Jones| first = G|author2=D A Waters | title = Moth hearing in response to bat echolocation calls manipulated independently in time and frequency| doi = 10.1098/rspb.2000.1188| year = 2000| journal = Proceedings of the Royal Society B: Biological Sciences| volume = 267| pages = 1627–32| pmid = 11467425| issue = 1453| pmc = 1690724}}</ref> [[Arctiidae|Tiger moth]]s in a defense emit clicks within the same range of the bats, which interfere with the bats and foil their attempts to echolocate it.<ref>{{cite journal|last=Ratcliffe |first=John M. |author2=Fullard, James H. |author3=Arthur, Benjamin J. |author4=Hoy, Ronald R. |url=https://hoylab.cornell.edu/arthur/ratcliffe_fullard_arthur_hoy2009.pdf |title=Tiger moths and the threat of bats: decision-making based on the activity of a single sensory neuron |doi=10.1098/rsbl.2009.0079 |access-date=11 February 2011 |year=2009 |journal=Biology Letters |volume=5 |pages=368–371 |issue=3 |pmid=19324625 |pmc=2679932 |archive-url=https://web.archive.org/web/20110719175800/http://hoylab.cornell.edu/arthur/ratcliffe_fullard_arthur_hoy2009.pdf |archive-date=19 July 2011 }}</ref>

=== Pollination ===
{{Further|Entomophily|Pollination syndrome}}
[[File:Hummingbird hawkmoth a.jpg|thumb|left|A day-flying [[hummingbird hawk-moth]] drinking nectar from a species of ''[[Dianthus]]'']]

Some species of Lepidoptera engage in some form of [[entomophily]] (more specifically psychophily and phalaenophily for butterflies and moths, respectively), or the [[pollination]] of flowers.<ref name="Gilbert">{{Cite journal|last=Gilbert |first=L. E. |year=1972 |title= Pollen feeding and reproductive biology of ''Heliconius'' butterflies |journal=[[Proceedings of the National Academy of Sciences]] |volume=69 |pages=1402–1407 |doi=10.1073/pnas.69.6.1403|pmid=16591992 |issue=6|bibcode = 1972PNAS...69.1403G |pmc=426712 |doi-access=free }}</ref> Most adult butterflies and moths feed on the [[nectar]] inside flowers, using their probosces to reach the nectar hidden at the base of the petals. In the process, the adults may brush against the flowers' [[stamen]]s, on which the reproductive [[pollen]] is 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 the [[stigma (botany)|stigma]] of the next flower, where the pollen [[germinates]] and fertilizes the seeds.<ref name="Resh and Carde"/>{{Rp|813–814}}

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 not [[digestion|digest]] pollen (except for [[Heliconius|heliconid species]],<ref name="Gilbert"/>) 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 as ''[[Thymelicus|Thymelicus flavus]]'' have been observed to engage in [[flower constancy]], which means they are more likely to transfer pollen to other conspecific plants, because it reduces the loss of pollen during foraging, and the stigmas receive less pollen from other flower species.<ref>{{Cite journal|year=1997 |title= Foraging strategies in the small skipper butterfly, ''Thymelicus flavus'': when to switch?|journal=Animal Behaviour |volume=53 |pages=1009–1016|last1=Goulson |first1=D. |first2=J. |last2=Ollerton |first3=C.  |last3=Sluman|doi=10.1006/anbe.1996.0390|issue=5|s2cid= 620334}}</ref> However, most butterflies are very poor pollinators despite high rates of floral visitation; for example, [[Monarch butterfly|monarch butterflies]] contribute almost nothing to seed set in [[Asclepias|milkweeds]] that they visit for nectar.<ref>{{cite book |url=https://books.google.com/books?id=PAhpDQAAQBAJ |title=Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution |last=Agrawal|first=Anurag |date=2017-03-07 |publisher=[[Princeton University Press]] |isbn=978-1-4008-8476-6 |language=en}}</ref>

Among the more important moth pollinator groups are the [[hawk moth]]s of the [[family (biology)|family]] Sphingidae. Their behavior is similar to [[hummingbird]]s, i.e., using rapid wing beats to hover in front of flowers. Most hawk moths are [[nocturnal]] or [[crepuscular]], so moth-pollinated flowers (e.g., ''[[Silene latifolia]]'' ) tend to be white, night-opening, large, and showy with tubular [[Corollaceous|corollae]] and a strong, sweet scent produced in the evening, night, or early morning. A lot of nectar is produced to fuel the high [[metabolic rate]]s needed to power their flight.<ref>{{cite journal |author1=Helen J. Young |author2=Lauren Gravitz |year=2002 |title=The effects of stigma age on receptivity in ''Silene alba'' (Caryophyllaceae) |journal=American Journal of Botany |volume=89 |pages=1237–1241|doi=10.3732/ajb.89.8.1237 |issue=8 |pmid=21665724|bibcode=2002AmJB...89.1237Y |doi-access= }}</ref> Other moths (e.g., [[noctuids]], [[Geometer moth|geometrids]], [[Pyraloidea|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).<ref>{{cite journal |author1=Oliveira PE |author2=PE Gibbs |author3=AA Barbosa |year=2004 |title=Moth pollination of woody species in the Cerrados of Central Brazil: a case of so much owed to so few? |journal=Plant Systematics and Evolution |volume=245 |issue=1–2 |pages=41–54 |doi=10.1007/s00606-003-0120-0|bibcode=2004PSyEv.245...41O |s2cid=21936259 }}</ref>

=== Mutualism ===

[[File:Tomato Hornworm Parasitized by Braconid Wasp.jpg|thumb|right|Tobacco hornworm caterpillar (''[[Manduca sexta]]'') parasitized by [[Braconidae]] wasp larvae]]

[[Mutualism (biology)|Mutualism]] is a form of [[biological interaction]] wherein each individual involved benefits in some way. An example of a mutualistic relationship would be that shared by [[Tegeticula|yucca moths]] (Tegeculidae) and their host, [[yucca|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.<ref name="Resh and Carde"/>{{Rp|814}} Another form of mutualism occurs between some larvae of butterflies and certain species of [[ant]]s (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.<ref>{{cite journal |doi=10.1111/j.1096-3642.1988.tb01201.x |title=The larval ant-organs of ''Thisbe irenea'' (Lepidoptera: Riodinidae) and their effects upon attending ants |year=1988 |author=Devries, P. J. |journal=Zoological Journal of the Linnean Society |volume=94 |pages=379–393 |issue=4}}</ref> The ants provide some degree of protection to these larvae and they in turn gather [[Honeydew (secretion)|honeydew secretions]].<ref>{{cite journal |pmid=17733373 |date=Jun 1990 |author=Devries, Pj |title=Enhancement of Symbioses Between Butterfly Caterpillars and Ants by Vibrational Communication |volume=248 |issue=4959 |pages=1104–1106 |doi=10.1126/science.248.4959.1104 |journal=Science|bibcode = 1990Sci...248.1104D |s2cid=35812411 }}</ref>

=== Parasitism ===
[[File:Macrothylacia rubi caterpillar with parasitoid larvae - Niitvälja bog.jpg|thumbnail|Parasitoid larva exits from the fox moth caterpillar]]
Only 42 species of [[parasitoid]] lepidopterans are known (1 [[Pyralidae]]; 40 [[Epipyropidae]]).<ref name="Resh and Carde"/>{{Rp|748}} The larvae of the [[Galleria mellonella|greater]] and [[lesser wax moth]]s feed on the [[honeycomb]] inside [[bee]] nests and may become [[pest (organism)|pest]]s; they are also found in [[bumblebee]] and [[wasp]] nests, 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.<ref>{{cite book|last= Benton|first= Frank|title= The honey bee: a manual of instruction in apiculture|trans-title= Europe's best known butterflies. Description of the most important species and instructions for recognizing and collecting butterflies and caterpillars|publisher= Oestergaard Verlag|volume= 1–6, 33|pages= 113–114|year= 1895|url= https://books.google.com/books?id=VqZbAAAAMAAJ&pg=PA113|access-date= 11 September 2020|archive-date= 31 May 2021|archive-url= https://web.archive.org/web/20210531114818/https://books.google.com/books?id=VqZbAAAAMAAJ&pg=PA113|url-status= live}}</ref> Other parasitic larvae are known to prey upon [[cicada]]s and [[leaf hopper]]s.<ref name="Rubinoff">{{cite journal|last1=Rubinoff|first1= Daniel|last2= Haines|first2= William P.|year= 2005|title=Web-spinning caterpillar stalks snails|volume= 309|issue= 5734|page= 575|journal= Science|doi= 10.1126/science.1110397|pmid= 16040699|s2cid= 42604851}}</ref>

<!--something VERY wrong with imagemap, only gives Compsilura concinnata wherever cursor points; file size nominally 796 × 671 pixels. The common name for this species is also outdated and they are now known as Spongy Moths. -->
<imagemap> 
File: Parasitism_in_Gypsy_moths.svg|thumb|center|500px| The different parasitoids affecting the spongy moth (''Lymantaria dispar''): The stage they affect and eventually kill and its duration are denoted by arrows.
rect 11 106 222 135 [[Brachymeria intermedia]]
rect 11 146 222 176 [[Coccygomimus instigator]] 
rect 3 515 222 535 [[Compsilura concinnata]]
rect 3 540 222 560[[Parasetigena|Parasetigena silvestris]]
rect 185 600 385 650 [[Blepharipa|Blepharipa pratensis]]
rect 370 560 650 610 [[Aphantorhaphopsis samerensis]]
rect 370 612 650 630 [[Glyptapanteles liparidis]]
rect 370 632 650 650 [[Meteorus pulchricornis]]
rect 600 100 770 150 [[Anastatus disparis]]
rect 450 400 780 440 [[Cotesia melanoscelus]]
rect 450 442 780 465 [[Glyptapanteles porthetriae]]
rect 450 467 780 490 [[Hyposoter tricoloripes]]
rect 450 492 780 520 [[Phobocampe disparis]]
desc bottom-left
</imagemap>

In reverse, moths and butterflies may be subject to [[parasitic wasp]]s and [[flies]], 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 of [[coleopteran]], and many [[hymenoptera]]n parasitoids.<ref name="Resh and Carde"/>{{Rp|748–749}} Some species may be subject to a variety of parasites, such as the [[spongy moth]] (''Lymantaria dispar''), which is attacked by a series of 13 species, in six different taxa throughout its life cycle.<ref name="Resh and Carde"/>{{Rp|750}}

In response to a parasitoid egg or larva in the caterpillar's body, the [[Hemocyte|plasmatocyte]]s, or simply the host's cells can form a multilayered capsule that eventually causes the endoparasite to [[asphyxiate]]. The process, called encapsulation, is one of the caterpillar's only means of defense against parasitoids.<ref name="Resh and Carde"/>{{Rp|748}}

=== Other biological interactions ===

A few species of Lepidoptera are secondary consumers, or [[predator]]s. These species typically prey upon the eggs of other insects, aphids, scale insects, or ant larvae.<ref name="Resh and Carde"/>{{Rp|567}} Some caterpillars are cannibals, and others prey on caterpillars of other species (e.g. Hawaiian ''[[Eupithecia]]'' ). Those of the 15 species in ''Eupithecia'' that mirror inchworms, are the only known species of butterflies and moths that are ambush predators.<ref name="pierce">{{cite journal|author=Pierce, N. E.|year=1995|title=Predatory and parasitic Lepidoptera: Carnivores living on plants|journal=Journal of the Lepidopterists' Society|volume= 49|issue=4|pages= 412–453}}</ref> 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 (typically [[Tornatellides]]).<ref name="Rubinoff"/>

Larvae of some species of moths in the [[Tineidae]], [[Gelechiidae]], and [[Noctuidae]], besides others, feed on [[detritus]], or dead organic material, such as fallen leaves and fruit, fungi, and animal products, and turn it into [[humus]].<ref name="Resh and Carde"/>{{Rp|567}} Well-known species include the [[Tineidae|cloth moth]]s (''[[Tineola bisselliella]]'', ''[[Tinea pellionella]]'', and ''[[Trichophaga tapetzella]]''), which feed on detritus containing [[keratin]], including [[hair]], [[feather]]s, [[cobweb]]s, [[bird nest]]s (particularly of [[domestic pigeon]]s, ''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.<ref name="Garbe (1994)">{{cite book| last= Grabe| first=Albert| title=Eigenartige Geschmacksrichtungen bei Kleinschmetterlingsraupen ("Strange tastes among micromoth caterpillars")| url=http://www.biologiezentrum.at/pdf_frei_remote/ZOEV_27_0105-0109.pdf| series=27| year= 1942| language=de| pages=105–109}}</ref>

In 2015 it was reported that wasp [[bracovirus]] DNA was present in Lepidoptera such as monarch butterflies, silkworms and moths.<ref>{{Cite journal|last1=Gasmi|first1=Laila|last2=Boulain|first2=Helene|last3=Gauthier|first3=Jeremy|last4=Hua-Van|first4=Aurelie|last5=Musset|first5=Karine|last6=Jakubowska|first6=Agata K.|last7=Aury|first7=Jean-Marc|last8=Volkoff|first8=Anne-Nathalie|last9=Huguet|first9=Elisabeth|date=17 September 2015|title=Recurrent Domestication by Lepidoptera of Genes from Their Parasites Mediated by Bracoviruses|journal=PLOS Genet|volume=11|issue=9|article-number=e1005470|doi=10.1371/journal.pgen.1005470|pmc=4574769|pmid=26379286 |doi-access=free }}</ref> These were described in some newspaper articles as examples of a naturally occurring [[genetically engineered]] insects.<ref>{{cite web|url=http://www.the-scientist.com/?articles.view/articleNo/44016/title/Parasite-s-Genes-Persist-in-Host-Genomes/|title=Parasite's Genes Persist in Host Genomes {{!}} The Scientist Magazine®|last=Shaikh-Lesko|first=Rina|date=17 September 2015|website=The Scientist|access-date=13 July 2016|archive-url=https://web.archive.org/web/20161221235759/http://www.the-scientist.com/?articles.view%2FarticleNo%2F44016%2Ftitle%2FParasite-s-Genes-Persist-in-Host-Genomes%2F|archive-date=21 December 2016|url-status=live}}</ref>

== Evolution and systematics ==
<!-- The redirect Evolution of Lepidoptera targets this section. If removing or renaming, please retarget the redirect -->

=== History of study ===
{{main|Lepidopterology}}
[[File:Natural-Sciences-Museum-in-Cherni-Osam.jpg|thumb|Lepidoptera collection in Cherni Osam Natural Sciences Museum, [[Troyan]], [[Bulgaria]]]]

Linnaeus in ''[[Systema Naturae]]'' (1758) recognized three divisions of the Lepidoptera: ''Papilio'', ''Sphinx'' and ''[[Phalaena]]'', with seven subgroups in ''Phalaena''.<ref name="scoble"/> These persist today as 9 of the superfamilies of Lepidoptera. Other works on classification followed including those by [[Michael Denis]] & [[Ignaz Schiffermüller]] (1775), [[Johan Christian Fabricius]] (1775) and [[Pierre André Latreille]] (1796). [[Jacob Hübner]] described many genera, and the lepidopteran genera were catalogued by [[Ferdinand Ochsenheimer]] and [[Georg Friedrich Treitschke]] in a series of volumes on the lepidopteran fauna of Europe published between 1807 and 1835.<ref name="scoble"/> [[Gottlieb August Wilhelm Herrich-Schäffer]] (several volumes, 1843–1856), and [[Edward Meyrick]] (1895) based their classifications primarily on wing venation. Sir [[George Francis Hampson]] worked on the microlepidoptera during this period and [[Philipp Christoph Zeller]] published ''The Natural History of the Tineinae'' also on microlepidoptera (1855).

Among the first entomologists to study fossil insects and their evolution was [[Samuel Hubbard Scudder]] (1837–1911), who worked on butterflies.<ref name="grimaldi">{{Cite book |author-link1=David Grimaldi (entomologist)|last1=Grimaldi|first1=D.|author-link2=Michael S. Engel|last2=Engel|first2=M. S.|title=Evolution of the Insects |year=2005 |publisher=[[Cambridge University Press]] |isbn=978-0-521-82149-0}}</ref> He published a study of the Florissant deposits of Colorado, including the exceptionally preserved ''[[Prodryas persephone]]''. [[Andreas V. Martynov]] (1879–1938) recognized the close relationship between Lepidoptera and Trichoptera in his studies on phylogeny.<ref name="grimaldi"/>

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.<ref name="scoble"/> [[Willi Hennig]] (1913–1976) developed the [[cladistic]] methodology and applied it to insect phylogeny. Niels P. Kristensen, E. S. Nielsen and D. R. Davis studied the relationships among [[monotrysia]]n families and Kristensen worked more generally on insect [[phylogeny]] and higher Lepidoptera too.<ref name="scoble"/><ref name="grimaldi"/> While it is often found that DNA-based phylogenies differ from those based on [[morphology (biology)|morphology]], this has not been the case for the Lepidoptera; DNA phylogenies correspond to a large extent to morphology-based phylogenies.<ref name="grimaldi"/>

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 not [[monophyletic]]: Microlepidoptera and Macrolepidoptera, Heterocera and Rhopalocera, Jugatae and Frenatae, Monotrysia and Ditrysia.<ref name="scoble"/>

A 2024 genetic study found that the [[genome]]s of butterflies and moths have remained largely unchanged over the past 250 million years.<ref>{{cite journal|author=Charlotte J. Wright, Lewis Stevens, Alexander Mackintosh, Mara Lawniczak, Mark Blaxter|date=21 February 2024|url=https://www.researchgate.net/publication/378370076|title=Comparative genomics reveals the dynamics of chromosome evolution in Lepidoptera|journal=Nature Ecology & Evolution|volume=8 |issue=4 |pages=777–790 |doi=10.1038/s41559-024-02329-4|doi-access=free|pmid=38383850 |pmc=11009112|bibcode=2024NatEE...8..777W }}</ref>

=== Fossil record ===
{{main|Prehistoric Lepidoptera}}
[[File:Prodryas.png|thumb|right|1887 engraving of ''[[Prodryas persephone]]'', a fossil lepidopteran from the [[Eocene]].]]
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 are [[hydrophobic]] and prevents their body from sinking when they end up on the water's surface.<ref>{{Cite journal|url=https://academic.oup.com/biolinnean/article/138/2/143/6936511?login=false|title=Illusion of flight? Absence, evidence and the age of winged insects|first1=Sandra R|last1=Schachat|first2=Paul Z|last2=Goldstein|first3=Rob|last3=Desalle|first4=Dean M|last4=Bobo|first5=C Kevin|last5=Boyce|first6=Jonathan L|last6=Payne|first7=Conrad C|last7=Labandeira|date=1 February 2023|journal=Biological Journal of the Linnean Society|volume=138|issue=2|pages=143–168|via=Silverchair|doi=10.1093/biolinnean/blac137|doi-access=free}}</ref> 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.<ref name="Sohn2015">Sohn, JC., Labandeira, C.C. & Davis, D.R. [https://bmcecolevol.biomedcentral.com/articles/10.1186/s12862-015-0290-8 The fossil record and taphonomy of butterflies and moths (Insecta, Lepidoptera): implications for evolutionary diversity and divergence-time estimates.] {{Webarchive|url=https://web.archive.org/web/20210307215700/https://bmcecolevol.biomedcentral.com/articles/10.1186/s12862-015-0290-8 |date=7 March 2021 }} BMC Evol Biol 15, 12 (2015). https://doi.org/10.1186/s12862-015-0290-8</ref> The location and abundance of the most common moth species are indicative that mass migrations of moths occurred over the Palaeogene [[North Sea]], which is why there is a serious lack of moth fossils.<ref>{{cite journal |last=Rust |first=Jest |year=2000 |title=Palaeontology: Fossil record of mass moth migration|journal=Nature |volume=405 |pages=530–531|doi=10.1038/35014733  |issue=6786 |pmid=10850702 |bibcode=2000Natur.405..530R|s2cid=4374137 }}</ref> Yet there are fossils, some preserved in amber and some in very fine sediments. [[Leaf mines]] are also seen in fossil leaves, although the interpretation of them is tricky.<ref name="grimaldi"/>

Putative fossil stem group representatives of [[Amphiesmenoptera]] (the clade comprising Trichoptera and Lepidoptera) are known from the [[Triassic]].<ref name="Resh and Carde"/>{{Rp|567}} The earliest known probable lepidopteran fossils are fossilized scales found in approximately 236 million years old fossilized herbivore dung in Argentina that are thought to have been incidentally ingested.<ref>{{Cite journal |last1=Fiorelli |first1=Lucas E. |last2=Vera |first2=Ezequiel I. |last3=Perez Loinaze |first3=Valeria S. |last4=Torréns |first4=Javier |last5=Ezcurra |first5=Martín D. |last6=Lara |first6=María B. |last7=Desojo |first7=Julia B. |date=2025-08-15 |title=Back to the poop: the oldest hexapod scales discovered within a Triassic coprolite from Argentina |url=https://www.sciencedirect.com/science/article/pii/S0895981125002469 |journal=Journal of South American Earth Sciences |volume=162 |article-number=105584 |doi=10.1016/j.jsames.2025.105584 |bibcode=2025JSAES.16205584F |issn=0895-9811|url-access=subscription }}</ref> The next oldest fossils are from the [[Triassic–Jurassic extinction event|Triassic-Jurassic boundary]] (ca 201 million years ago). They were found as rare [[palynological]] elements in the sediments of the Triassic-Jurassic boundary from the cored Schandelah-1 well, drilled near [[Braunschweig]] in northern [[Germany]]. This pushes back the fossil record and origin of [[glossata]]n lepidopterans by about 70-90 million years, supporting molecular estimates of a [[Norian]] (ca 212 million years) divergence of glossatan and non-glossatan lepidopterans. The findings were reported in 2018 in the journal ''[[Science 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 their [[fluid balance]] in the hot and arid [[climate]] of the [[Triassic]].<ref name="TriJurScales">{{cite journal | doi = 10.1126/sciadv.1701568 | pmid = 29349295 | pmc = 5770165 | title = A Triassic-Jurassic window into the evolution of Lepidoptera | date = 10 January 2018 | first1=Timo J. B.| last1=van Eldijk| first2=Torsten| last2=Wappler| first3=Paul K.| last3=Strother|first4=Carolien M. H.| last4= van der Weijst| first5=Hossein| last5= Rajaei| first6=Henk| last6= Visscher| first7=Bas| last7= van de Schootbrugge| journal = Science Advances | volume = 4 | article-number = e1701568 | number=1| bibcode= 2018SciA....4.1568V}}</ref>

The earliest named lepidopteran taxon is ''[[Archaeolepis mane]]'', a primitive moth-like species from the [[Early Jurassic]], dated back to around {{Ma|190}}, and known only from three wings found in the [[Charmouth Mudstone]] of [[Dorset]], [[UK]]. The wings show scales with parallel grooves under a scanning electron microscope and a characteristic wing venation pattern shared with [[Trichoptera]] (caddisflies).<ref name="GrimaldiEngel2005">{{cite book|last1=Grimaldi|first1=David A.|author2=Michael S. Engel|title=Evolution of the insects|url=https://books.google.com/books?id=Ql6Jl6wKb88C&pg=PA561|access-date=15 July 2011|year=2005|publisher=Cambridge University Press|isbn=978-0-521-82149-0|page=561|archive-url=https://web.archive.org/web/20140108020829/http://books.google.com/books?id=Ql6Jl6wKb88C&pg=PA561|archive-date=8 January 2014|url-status=live}}</ref><ref name="DaviesButler2008">{{cite book|last1=Davies|first1=Hazel|last2=Butler|first2=Carol A.|title=Do butterflies bite?: fascinating answers to questions about butterflies and moths|url=https://books.google.com/books?id=6bOI4-tfxJkC&pg=PA48|access-date=15 July 2011|date=June 2008|publisher=Rutgers University Press|isbn=978-0-8135-4268-3|page=48|archive-url=https://web.archive.org/web/20140108020521/http://books.google.com/books?id=6bOI4-tfxJkC&pg=PA48|archive-date=8 January 2014|url-status=live}}</ref> Only two more sets of Jurassic lepidopteran fossils have been found, as well as 13 sets from the [[Cretaceous]], which all belong to primitive moth-like families.<ref name="grimaldi"/>

Many more fossils are found from the Tertiary, and particularly the [[Eocene]] [[Baltic amber]]. The oldest genuine butterflies of the superfamily Papilionoidea have been found in the [[Paleocene]] [[MoClay]] or [[Fur Formation]] of [[Denmark]]. The best preserved fossil lepidopteran is the Eocene ''[[Prodryas persephone]]'' from the [[Florissant Fossil Beds]].

=== Phylogeny ===

[[File:Phylogenetic chart of Lepidoptera.svg|right|thumb|upright=1.2|Phylogenetic hypothesis of major lepidopteran lineages superimposed on the geologic time scale. Radiation of [[angiosperm]]s spans {{Ma|130|95}} from their earliest forms to domination of vegetation.]]

Lepidoptera and [[Trichoptera]] (caddisflies) are [[sister group]]s, sharing many similarities that are lacking in others; for example the females of both orders are [[ZW sex-determination system|heterogametic]], meaning they have two different [[gamete|sex 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 manipulate [[silk]]. [[Willi Hennig]] grouped the two orders into the superorder [[Amphiesmenoptera]]; together they are sister to the extinct order [[Tarachoptera]].<ref name=Tarachoptera>{{Cite journal |author1=Wolfram Mey |author2=Wilfried Wichard |author3=Patrick Müller |author4=Bo Wang |year=2017 |title=The blueprint of the Amphiesmenoptera – Tarachoptera, a new order of insects from Burmese amber (Insecta, Amphiesmenoptera) |journal=Fossil Record |volume=20 |issue=2 |pages=129–145 |doi=10.5194/fr-20-129-2017 |doi-access=free |bibcode=2017FossR..20..129M }}</ref> Lepidoptera descend from a diurnal moth-like common ancestor that either fed on dead or living plants.<ref>{{cite journal|last=Kaila|first=Lauri|author2=Marko Mutanen |author3=Tommi Nyman |title=Phylogeny of the mega-diverse Gelechioidea (Lepidoptera): Adaptations and determinants of success|journal=Molecular Phylogenetics and Evolution|date=27 August 2011|volume=61|pages=801–809|pmid=21903172|doi=10.1016/j.ympev.2011.08.016|issue=3|bibcode=2011MolPE..61..801K }}</ref>

The [[cladogram]], based on molecular analysis, shows the order as a [[clade]], sister to the Trichoptera, and more distantly related to the [[Diptera]] (true flies) and [[Mecoptera]] (scorpionflies).<ref name=Kjer>{{Cite journal |last1=Kjer |first1=Karl M. |last2=Simon |first2=Chris|author2-link=Chris Simon (biologist) |last3=Yavorskaya |first3=Margarita |last4=Beutel |first4=Rolf G. |date=2016 |title=Progress, pitfalls and parallel universes: a history of insect phylogenetics |journal=Journal of the Royal Society Interface |volume=13 |issue=121 |page=121 |doi=10.1098/rsif.2016.0363 |pmid=27558853 |name-list-style=amp |pmc=5014063 }}</ref>

{{clade
|label1=[[Holometabola]]
|1={{clade
   |label1=[[Hymenopterida]]
   |1=[[Hymenoptera]] (sawflies, wasps) [[File:European wasp white bg.jpg|70px]]
   |label2=[[Aparaglossata]]
   |2={{clade
      |label1=[[Neuropteroidea]]      
      |1={{clade
         |label1=[[Coleopterida]]
         |1={{clade
            |1=[[Coleoptera]] (beetles) [[File:Pseudacrossus przewalskyi (Reitter, 1887).jpg|50px]]
            |2=[[Strepsiptera]] (twisted-wing parasites) [[File:Elenchus koebelei.jpg|70px]]
          }}
         |label2=[[Neuropterida]]
         |2={{clade
            |1=[[Raphidioptera]] (snakeflies) [[File:Raphidia icon.png|70px]]
            |label2=
            |2={{clade
               |1=[[Megaloptera]] (alderflies and allies) [[File:Corydalus cornutus illustration (rotated).png|70px]]
               |2=[[Neuroptera]] (Lacewings and allies) [[File:Osmylus_(white_background).jpg|70px]]
             }}
          }}
       }}
      |label2=[[Panorpida]]
      |2={{clade
         |label1=[[Amphiesmenoptera]]
         |1={{clade
            |1='''Lepidoptera''' (butterflies, moths) [[File:Arctia villica SLU.JPG|70px]]
            |2=[[Trichoptera]] (caddisflies) [[File:RHYACOPHILA DORSALIS Male Pont Forge de Sailly Watigny 02 MHNT.jpg|70px]] 
          }}
         |label2=Antliophora
         |2={{clade 
            |1=[[Diptera]] [[File:Common house fly, Musca domestica.jpg|70px]] 
            |2={{clade
               |1=[[Mecoptera]] (scorpionflies)  [[File:Scorpionfly (white background).jpg|70px]]
               |2=[[Siphonaptera]] (fleas) [[File:Pulex irritans female ZSM (white background).jpg|40px]]
             }}
          }}
       }}
    }}
 }}
}}

The internal phylogeny of Lepidoptera is still being resolved. While many large clades have been established, interfamilial and superfamilial relationships are poorly understood. A large scale study by Regier et al. attempts to resolve these relationships using three different analysis methods, which is shown in the following cladogram.<ref>{{cite journal |author1=Regier, Jerome |display-authors=etal |title=A Large-Scale, Higher-Level, Molecular Phylogenetic Study of the Insect Order Lepidoptera (Moths and Butterflies) |journal=PLOS ONE |date=12 March 2013|volume=8 |issue=3 |article-number=e58568 |doi=10.1371/journal.pone.0058568 |doi-access=free |pmid=23554903 |pmc=3595289 |bibcode=2013PLoSO...858568R }}</ref>

{{clade
|label1='''Lepidoptera'''
|1={{clade
   |1=[[Micropterigoidea]]
   |2={{clade
      |1=[[Agathiphagoidea]]
      |2={{clade
         |1=[[Heterobathmioidea]]
         |label2=[[Glossata]]
         |2={{clade
            |1=[[Eriocranioidea]]
            |label2=[[Coelolepida]]
            |2={{clade
               |1={{clade
                  |1=[[Lophocoronoidea]]
                  |label2=[[Exoporia]]
                  |2={{clade
                     |1=[[Hepialoidea]]
                     |2=[[Mnesarchaeoidea]]
                     }}
                  }}
               |2={{clade
                  |1=[[Neopseustoidea]] <small>(incl. [[Acanthopteroctetidae]])</small>
                  |label2=[[Heteroneura]]
                  |2={{clade
                     |1=[[Nepticuloidea]]
                     |label2=[[Eulepidoptera]]
                     |2={{clade
                        |1={{clade
                           |1=[[Adeloidea]]
                           |2=[[Andesianoidea]]
                           }}
                        |2={{clade
                           |1={{clade
                              |1=[[Tischerioidea]]
                              |2={{clade
                                 |1=''[[Azaleodes]]''
                                 |2=''[[Ptyssoptera]]''
                                 }}
                              }}
                           |2={{clade
                              |1=''[[Palaephatus (moth)|Palaephatus]]''
                              |label2=[[Ditrysia]]
                              |2={{clade
                                 |1=[[Meessiinae]] <small>(traditionally in Tineidae)</small>
                                 |2={{clade
                                    |1=[[Psychidae]]
                                    |2={{clade
                                       |1=[[Eriocottidae]]
                                       |2={{clade
                                          |1=[[Tineidae]]
                                          |2={{clade
                                             |1={{clade
                                                |1=[[Roeslerstammiidae]]
                                                |2={{clade
                                                   |1=[[Gracillariidae]]
                                                   |2=[[Yponomeutoidea]] <small>(incl. [[Bucculatricidae]])</small>
                                                   }}
                                                }}
                                             |2='''[[Apoditrysia]]''' <small>(cont.)</small>
                                             }}
                                          }}
                                       }}
                                    }}
                                 }}
                              }}
                           }}
                        }}
                     }}
                  }}
               }}
            }}
         }}
      }}
   }}
}}

{{clade
|label1='''Apoditrysia'''
|1={{clade
   |1=[[Urodoidea]]
   |2={{clade
      |1={{clade
         |1=[[Choreutoidea]]
         |2={{clade
            |1=[[Douglasiidae]]
            |2=[[Schreckensteinioidea]]
            }}
         }}
      |2={{clade
         |1={{clade
            |1=[[Immoidea]]
            |2=[[Millieriidae]]
            }}
         |2={{clade
            |1={{clade
               |1={{clade
                  |1=[[Tortricoidea]]
                  |2={{clade
                     |1=[[Galacticoidea]]
                     |2=[[Heliocosma|Heliocosmidae]]
                     }}
                  }}
               |2={{clade
                  |1=[[Zygaenoidea]]
                  |2={{clade
                     |1=[[Cossoidea]] ''sensu lato'' <small>(including traditional [[Sesioidea]])</small>
                     |2=[[Cyclotornidae]] <small>(traditionally in Zygaenoidea)</small>
                     }}
                  }}
               }}
            |label2=[[Obtectomera]]
            |2={{clade
               |1=[[Gelechioidea]]
               |2={{clade
                  |1={{clade
                     |1=[[Pyraloidea]]
                     |label2=[[Macroheterocera]]
                     |2={{clade
                        |1=[[Drepanoidea]] <small>(incl. [[Mimallonoidea]])</small>
                        |2={{clade
                           |1=[[Geometroidea]]
                           |2={{clade
                              |1=[[Noctuoidea]]
                              |2={{clade
                                 |1=[[Bombycoidea]]
                                 |2=[[Lasiocampidae]]
                                 }}
                              }}
                           }}
                        }}
                     }}
                  |2={{clade
                     |1={{clade
                        |1=[[Butterfly|Papilionoidea]]
                        |2=[[Pterophoroidea]]
                        }}
                     |2={{clade
                        |1={{clade
                           |1=''[[Pseudurgis]]''
                           |2=[[Thyridoidea]]
                           }}
                        |2={{clade
                           |1={{clade
                              |1=[[Aluctoidea]]
                              |2={{clade
                                 |1=[[Carposinoidea]]
                                 |2=[[Epermenioidea]]
                                 }}
                              }}
                           |2={{clade
                              |1=[[Calliduloidea]]
                              |2={{clade
                                 |1=[[Hyblaeoidea]]
                                 |2=[[Macropiratidae]]
                                 }}
                              }}
                           }}
                        }}
                     }}
                  }}
               }}
            }}
         }}
      }}
   }}
}}

[[Micropterigidae]], [[Agathiphagidae]] and [[Heterobathmiidae]] are the oldest and most [[basal (phylogenetics)|basal]] lineages of Lepidoptera. The adults of these families do not have the curled tongue or [[proboscis]], that are found in most members of the order, but instead have chewing [[mandible (insect mouthpart)|mandible]]s adapted for a special diet. Micropterigidae larvae feed on [[leaves]], [[fungi]], or [[liverworts]] (much like the [[Trichoptera]]).<ref name="scoble">{{Cite book |last=Scoble |first=Malcolm J. |title=The Lepidoptera: Form, Function and Diversity |publisher=Oxford University Press |location=Oxford University |date=September 1995 |edition=1 |pages=4–5 |chapter=2 |isbn=978-0-19-854952-9 |chapter-url=https://books.google.com/books?id=gnpd_5iNTiwC |access-date=11 September 2020 |archive-date=26 June 2020 |archive-url=https://web.archive.org/web/20200626195110/https://books.google.com/books?id=gnpd_5iNTiwC |url-status=live }}</ref> Adult Micropterigidae chew the pollen or spores of ferns. In the Agathiphagidae, larvae live inside [[kauri pine]]s and feed on seeds. In Heterobathmiidae the larvae feed on the leaves of ''[[Nothofagus]]'', the southern beech tree. These families also have mandibles in the pupal stage, which help the pupa emerge from the seed or cocoon after [[metamorphosis]].<ref name="scoble"/>

The [[Eriocraniidae]] have 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.<ref name="scoble"/> Most of these non-ditrysian families, are primarily [[leaf miner]]s in 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.<ref name="grimaldi"/>

With the evolution of the [[Ditrysia]] in 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 one [[cloaca]], or later, two openings and an external sperm canal.) Of the early lineages of Ditrysia, [[Gracillarioidea]] and [[Gelechioidea]] are mostly leaf miners, but more recent lineages feed externally. In the [[Tineoidea]], most species feed on plant and animal detritus and fungi, and build shelters in the larval stage.<ref name="grimaldi"/>

The [[Yponomeutoidea]] is the first group to have significant numbers of species whose larvae feed on herbaceous plants, as opposed to woody plants.<ref name="grimaldi"/> They evolved about the time that flowering plants underwent an expansive [[adaptive radiation]] in the mid-[[Cretaceous]], and the Gelechioidea that evolved at this time also have great diversity. Whether the processes involved [[coevolution]] or 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.<ref name="grimaldi"/> Many also have [[tympanal organ]]s, that allow them to hear. These organs evolved eight times, at least, because they occur on different body parts and have structural differences.<ref name="grimaldi"/>
The main lineages in the macrolepidoptera are the [[Noctuoidea]], [[Bombycoidea]], [[Lasiocampidae]], [[Mimallonoidea]], [[Geometroidea]] and [[Rhopalocera]]. Bombycoidea plus Lasiocampidae plus Mimallonoidea may be a [[monophyletic]] group.<ref name="grimaldi"/> The Rhopalocera, comprising the [[Papilionoidea]] (butterflies), [[Hesperioidea]] (skippers), and the [[Hedyloidea]] (moth-butterflies), are the most recently evolved.<ref name="scoble"/> There is quite a good fossil record for this group, with the oldest skipper dating from {{Ma|56}}.<ref name="grimaldi"/>

=== Taxonomy ===
{{Main|Taxonomy of the Lepidoptera|Lepidopteran diversity}}

Taxonomy involves the [[Biological classification|classification]] of species into hierarchical taxa, while the process of assigning scientific names is known as nomenclature. There are over 120 recognized families in Lepidoptera, distributed across 45 to 48 superfamilies. Historically, lepidopterists classified the order into five suborders, with one encompassing the so-called "primitive" moths—groups that were long viewed as relics, retaining morphological features reminiscent of their distant ancestors without significant evolutionary "advancement." This perspective, now largely outdated, portrayed these lineages as static holdovers from the past, a notion that overlooks the dynamic adaptations all living taxa undergo over millions of years. In contrast, the vast majority of moths and butterflies—accounting for approximately 98% of all lepidopteran species—fall within the dominant suborder [[Ditrysia]], characterized by "advanced" reproductive and morphological traits. More recent discoveries of new taxa, along with detailed studies of larvae and pupae, have refined our understanding of these basal relationships among Lepidoptera. Phylogenetic analyses, drawing on molecular and morphological data, have revealed that these early-diverging lineages are [[paraphyletic]] relative to the more derived groups within Lepidoptera, challenging the rigid subordinal framework and highlighting the bushy, reticulated nature of insect evolution. Consequently, contemporary lepidopterists have largely abandoned intermediate clades such as suborders, favoring a more flexible system of superfamilies and clades that better captures the order's deep evolutionary history.<ref name="Resh and Carde"/>{{Rp|569}}

The basal clades of Lepidoptera represent early-diverging lineages that retain ancestral traits, providing key insights into the order's evolutionary origins. These groups are paraphyletic and form successive sister relationships leading to the dominant Glossata. Below is an overview of the major non-Glossatan clades:

; [[Zeugloptera]]
: This clade comprises the single superfamily [[Micropterigoidea]], which includes only the family Micropterigidae. Sometimes referred to as "living fossils" (a largely outdated, shaky concept), Micropterigidae species represent one of the earliest-diverging lineages in Lepidoptera, with adults retaining functional chewing mouthparts (mandibles)—a trait lost in all other butterflies and moths. Approximately 120 species are known worldwide, with over half belonging to the genus ''[[Micropterix]]'' in the Palearctic region. Only two species occur in North America (genus ''[[Epimartyria]]''), while Asia and the southwest Pacific host the majority, including about 50 species in New Zealand.<ref name="Resh and Carde"/>{{Rp|569}}

; [[Aglossata]]
: The next basal lineage after Zeugloptera, Aglossata was first described in 1952 by [[Lionel Jack Dumbleton]]. It contains a single family, [[Agathiphagidae]], with two species in the genus ''[[Agathiphaga]]'': ''[[Agathiphaga queenslandensis]]'', found along the north-eastern coast of [[Queensland]], [[Australia]]; and ''[[Agathiphaga vitiensis]]'', distributed from [[Fiji]] through [[Vanuatu]] to the [[Solomon Islands]]. These moths lack a functional proboscis, reflecting their early divergence, and their caterpillars feed exclusively on the wood of kauri trees (genus ''[[Agathis]]'').<ref name="Resh and Carde"/>{{Rp|569}}<ref>{{cite book |author=Kristensen, N. P. |year=1999 |chapter=The non-Glossatan moths |pages=41–49 |editor=N. P. Kristensen |title=Lepidoptera, Moths and Butterflies Volume 1: Evolution, Systematics, and Biogeography |series=Handbook of Zoology. A Natural History of the phyla of the Animal Kingdom. Volume IV Arthropoda: Insecta Part 35 |publisher=[[Walter de Gruyter]]}}</ref><ref>{{cite web |url=http://www.environment.gov.au/biodiversity/abrs/online-resources/fauna/afd/taxa/Agathiphaga_queenslandensis |title=Species ''Agathiphaga queenslandensis'' Dumbleton, 1952 |work=[[Australian Faunal Directory]] |date=9 October 2008 |publisher=[[Department of the Environment, Water, Heritage and the Arts]] |access-date=31 August 2010 |archive-url=https://web.archive.org/web/20110405014327/http://environment.gov.au/biodiversity/abrs/online-resources/fauna/afd/taxa/Agathiphaga_queenslandensis |archive-date=5 April 2011 |url-status=live }}</ref><ref>{{LepIndex |id=137590 |name=Agathiphaga vitiensis |access-date=May 8, 2018}}</ref>

; [[Heterobathmiina]]
: First described by Kristensen and Nielsen in 1979, this clade includes the single family [[Heterobathmiidae]], with around 10 species of day-flying, metallic moths restricted to southern South America. Adults feed on pollen from ''[[Nothofagus]]'' (southern beech) trees, while the larvae mine leaves. Like other basal groups, they lack a functional proboscis but exhibit specialized adaptations to their temperate forest habitats.<ref name="Resh and Carde"/>{{Rp|569}}<ref>{{LepIndex |id=137659 |name=Heterobathmia |access-date=May 8, 2018}}</ref>

; [[Glossata]]
: Encompassing the majority of lepidopteran species, Glossata is distinguished by the loss of functional mandibles and the development of elongated maxillary galeae forming a proboscis for liquid feeding. Basal clades within Glossata retain ancestral wing features, such as similarly shaped fore- and hindwings with relatively complete venation. This infraorder includes the suborder [[Ditrysia]], which accounts for 98% of all described Lepidoptera species and features further innovations in reproductive morphology.<ref name="Resh and Carde"/>{{Rp|569}}

== Relationship to people ==

=== Culture ===

[[File:Acherontia lachesis MHNT Female Nîlgîri (Tamil Nadu) Dorsal.jpg|thumb|left|[[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.<ref>{{Cite journal |last= Larsen |first= Torben B. |year= 1994 |title= Butterflies of Egypt |journal= [[Saudi Aramco World]] |volume= 45 |issue= 5 |pages= 24–27 |url= http://www.saudiaramcoworld.com/issue/199405/butterflies.of.egypt.htm |access-date= 18 December 2009 |archive-url= https://web.archive.org/web/20100113084254/http://saudiaramcoworld.com/issue/199405/butterflies.of.egypt.htm |archive-date= 13 January 2010 }}</ref> 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.<ref>{{cite web |url=http://mfjoe.com/tag/furniture/ |title=Table complete with real butterflies embedded in resin |publisher=Mfjoe.com |date=18 December 2009 |access-date=28 April 2012 |archive-url=https://web.archive.org/web/20100506094545/http://mfjoe.com/tag/furniture/ |archive-date=6 May 2010}}</ref> Butterflies have also inspired the "[[fairy|butterfly fairy]]" as an art and fictional character.

In many cultures the soul of a dead person is associated with the butterfly, for example in [[Ancient Greece]], where the word for butterfly [[wikt:ψυχή|ψυχή]] (psyche) also means ''[[soul]]'' and ''[[breath]]''. In [[Latin]], as in Ancient Greece, the word for "butterfly" [[wikt:Papilio|papilio]] was associated with the soul of the dead.<ref>{{cite web |url= http://www.insects.org/ced4/etymology.html |title= Butterfly Etymology |work= [[Cultural Entomology Digest]] 4 |first= Matthew |last= Rabuzzi |date= November 1997 |publisher= Bugbios |location= Cupertino, California |page= 4 |access-date= 18 December 2009 |archive-url= https://web.archive.org/web/19981203024144/http://www.insects.org/ced4/etymology.html |archive-date= 3 December 1998 }}</ref> The skull-like marking on the thorax of the [[death's-head hawkmoth]] has helped these moths, particularly ''A. atropos'', earn a negative reputation, such as associations with the supernatural and evil. The moth has been prominently featured in art and movies such as ''{{lang|fr|[[Un Chien Andalou]]}}'' (by [[Luis Buñuel|Buñuel]] and [[Dalí]]) and ''[[The Silence of the Lambs (film)|The Silence of the Lambs]]'', and in the artwork of the Japanese metal band [[Sigh (band)|Sigh]]'s album ''[[Hail Horror Hail]]''. According to ''[[Kwaidan: Stories and Studies of Strange Things]]'', by [[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 guestroom and perches behind the [[bamboo]] screen, the person whom you most love is coming to see you. However, large numbers of butterflies are viewed as bad [[omen]]s. When [[Taira no Masakado]] was secretly preparing for his famous revolt, there appeared in [[Kyoto]] so vast a swarm of butterflies that the people were frightened—thinking the apparition to be a portent of coming evil.<ref>{{cite book | last = Hearn | first = Lafcadio | author-link = Lafcadio Hearn | year = 1904 | title = Kwaidan: Stories and Studies of Strange Thing | publisher = Dover Publications, Inc. | isbn = 978-0-486-21901-1}}</ref>

In the ancient [[Mesoamerica]]n city of [[Teotihuacan]], the brilliantly colored image of the butterfly was carved into many temples, buildings, jewelry, and emblazoned on [[Censer|incense burners]] in particular. 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 to [[fire]] and warfare persisted through to the [[Aztec civilization]] and evidence of similar jaguar-butterfly images has been found among the [[Zapotec civilization|Zapotec]], and [[Maya civilization]]s.<ref>{{cite book| last=Miller| first=Mary| title=The Gods and Symbols of Ancient Mexico and the Maya.| year=1993| publisher=Thames & Hudson| isbn=978-0-500-27928-1| url=https://archive.org/details/isbn_9780500279281}}</ref>

=== Pests ===
[[File:Acronicta psi - caterpillar 320px.ogv|thumb|right|Caterpillar hatchling of the [[grey dagger]] (''Acronicta psi'') eating leaves from a tree]]
The [[larva]]e of many lepidopteran species are major pests in [[agriculture]]. Some of the major pests include [[Tortricidae]], [[Noctuidae]], and [[Pyralidae]]. The larvae of the Noctuidae genus ''[[Spodoptera]]'' (armyworms), ''[[Helicoverpa]]'' (corn earworm), or ''[[Pieris brassicae]]'' can cause extensive damage to certain crops.<ref name="scoble"/> ''[[Helicoverpa zea]]'' larvae (cotton bollworms or tomato fruitworms) are [[polyphagous]], meaning they eat a variety of crops, including [[tomato]]es and [[cotton]].<ref>{{cite web |url=http://www.ipm.uiuc.edu/fieldcrops/insects/corn_earworm/index.html |title=IPM: Field Crops: Corn Earworm (Heliothis Zea) |first=Kelly A. |last=Cook |author2=Weinzier, R. |year=2004 |publisher=IPM |page=1 |access-date=17 January 2009 |archive-url=https://web.archive.org/web/20090209184546/http://www.ipm.uiuc.edu/fieldcrops/insects/corn_earworm/index.html |archive-date=9 February 2009 }}</ref> ''[[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.<ref>{{Cite book|title=Encyclopedia of Entomology|last=Capinera|first=John L.|date=2008|publisher=Springer Netherlands|isbn=978-1-4020-6242-1|editor-last=Capinera|editor-first=John L.|pages=4038–4041|language=en|doi=10.1007/978-1-4020-6359-6_3936|chapter = Variegated Cutworm, Peridroma saucia (Hübner) (Lepidoptera: Noctuidae)}}</ref>

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.<ref name="Resh and Carde"/>{{Rp|567}}

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 the [[forest tent caterpillar moth]]. Pesticides can affect other species other than the species they are targeted to eliminate, damaging the natural ecosystem.<ref>{{cite journal |title=Friendly Flies: Good News, Bad News |author=Hahn, Jeff |url=http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-June1503.html |publisher=[[University of Minnesota]] |journal=Yard & Garden Line News |volume=5 |issue=9 |date=15 June 2003 |archive-url=https://web.archive.org/web/20110720092257/http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-June1503.html |archive-date=20 July 2011 }}</ref> Another good biological pest control method is the use of [[pheromone trap]]s. A pheromone trap is a type of [[insect trap]] that uses [[pheromone]]s to lure [[insect]]s. 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, [[pan trap|water-pan trap]], or funnel trap.<ref>{{cite journal|title=Insect Attractants and Traps |author1=Weinzierl, R. |author2=Henn, T. |author3=Koehler, P. G. |author4=Tucker, C. L. |url=http://edis.ifas.ufl.edu/in080 |publisher=Office of Agricultural Entomology, University of Illinois at Urbana-Champaign |journal=Alternatives in Insect Management |series=Entomology and Nematology Department, University of Florida |date=June 2005 |archive-url=https://web.archive.org/web/20110311182351/http://edis.ifas.ufl.edu/in080 |archive-date=11 March 2011 }}</ref>

Species of moths that are [[detritivore]]s would naturally eat [[detritus]] containing [[keratin]], such as [[hair]]s or [[feather]]s. Well known species are [[Tineidae|cloth moth]]s (''[[Tineola bisselliella|T. bisselliella]]'', ''[[Tinea pellionella|T. pellionella]]'', and ''[[Trichophaga tapetzella|T. tapetzella]]''), feeding on foodstuffs that people find economically important, such as [[cotton]], [[linen]], [[silk]] and wool [[fabric]]s as well as [[fur]]s; furthermore they have been found on shed [[feather]]s and [[hair]], [[bran]], [[semolina]] and [[flour]] (possibly preferring [[wheat]] flour), [[biscuit]]s, [[casein]], and [[insect]] specimens in [[museum]]s.<ref name="Garbe (1994)"/>

=== 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 the [[Bombyx mori|domesticated silkworm moth]] (''Bombyx mori''), the larvae of which make their cocoons out of [[silk]], which can be spun into cloth. Silk is and has been an important economic resource [[History of silk|throughout history]]. The species ''Bombyx mori'' has been domesticated to the point where it is completely dependent on mankind for survival.<ref>{{cite journal |author1=Goldsmith M. R. |author2=T. Shimada |author3=H. Abe |year=2005 |title=The genetics and genomics of the silkworm, ''Bombyx mori'' |journal=[[Annual Review of Entomology]] |volume=50 |pages=71–100 |pmid=15355234 |doi=10.1146/annurev.ento.50.071803.130456|s2cid=44514698 |url=https://digitalcommons.uri.edu/bio_facpubs/337 |url-access=subscription }}</ref> A number of wild moths such as ''[[Bombyx mandarina]]'', and ''[[Antheraea]]'' species, besides others, provide commercially important silks.<ref>{{Cite journal|author=Yoshitake, N. |year=1968 |title= Phylogenetic aspects on the origin of Japanese race of the silkworm, ''Bombyx mori'' |journal=Journal of Sericological Sciences of Japan |volume=37 |pages=83–87}}</ref>

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 of [[noxious weed|weed]]s in place of herbicides. The [[Pyralidae|pyralid]] [[cactus moth]] was introduced from Argentina to Australia, where it successfully suppressed millions of acres of [[prickly pear cactus]].<ref name="Resh and Carde"/>{{Rp|567}} Another species of the Pyralidae, called the [[alligator weed stem borer]] (''Arcola malloi''), was used to control the [[aquatic plant]] known as [[alligator weed]] (''Alternanthera philoxeroides'') in conjunction with the [[alligator weed flea beetle]]; in this case, the two insects work in [[synergy]] and the weed rarely recovers.<ref>{{cite book |last=Coombs |first=E. M. |title=Biological Control of Invasive Plants in the United States |publisher=Oregon State University Press |location=Corvallis |year=2004 |isbn=978-0-87071-029-2 |page=146}}</ref>

Breeding butterflies and moths, or [[butterfly gardening]]/rearing, has become an ecologically viable process of introducing species into the ecosystem to benefit it. [[Butterfly ranching in Papua New Guinea]] permits nationals of that country to "farm" economically valuable insect species for the collectors market in an ecologically sustainable manner.<ref>[http://www.butterfliesandart.com/Butterfly_Farms/Butterfly_Farms.htm Butterfly Farms | Rainforest Conservation | Butterfly Ranching] {{webarchive|url=https://web.archive.org/web/20080122110443/http://www.butterfliesandart.com/Butterfly_Farms/Butterfly_Farms.htm |date=22 January 2008 }}. butterfliesandart.com</ref>

=== Food ===

[[File:silkworm snack.jpg|thumb|right|[[Beondegi]], [[silkworm]] pupae steamed or boiled and seasoned for taste, for sale by a street vendor in South Korea]]

Lepidoptera feature prominently in [[entomophagy]] as food items on almost every continent. While in most cases, adults, larvae or pupae are eaten as staples by indigenous people, [[beondegi]] or [[silkworm]] [[pupa]]e are eaten as a snack in [[Korean cuisine]]<ref name="Korea">Robinson, Martin; Bartlett, Ray and Whyte, Rob (2007) ''Korea''. Lonely Planet publications, {{ISBN|978-1-74104-558-1}}. (pg 63)</ref> while [[Maguey worm]] is considered a delicacy in [[Mexico]].<ref>{{cite journal |first1=Ana María |last1=Acuña |first2=Laura |last2=Caso |first3=Mario M. |last3=Aliphat |first4=Carlos H. |last4=Vergara |year=2011 |title=Edible insects as part of the traditional food system of the Popoloca town of Los Reyes Metzontla, Mexico |journal=[[Journal of Ethnobiology]] |volume=31 |issue=1 |pages=150–169 |doi=10.2993/0278-0771-31.1.150 |s2cid=53963758 }}</ref> In some parts of [[Huasteca]], the silk nests of the [[Madrone butterfly]] are maintained on the edge of roof tops of houses for consumption.<ref>{{Cite journal|last1=Ramos-Elorduy|first1=Julieta|last2=Moreno|first2=José MP|last3=Vázquez|first3=Adolfo I.|last4=Landero|first4=Ivonne|last5=Oliva-Rivera|first5=Héctor|last6=Camacho|first6=Víctor HM|date=6 January 2011|title=Edible Lepidoptera in Mexico: Geographic distribution, ethnicity, economic and nutritional importance for rural people|journal=Journal of Ethnobiology and Ethnomedicine|volume=7|article-number=2|doi=10.1186/1746-4269-7-2|pmid=21211040|pmc=3034662|issn=1746-4269 |doi-access=free }}</ref> In the [[Carnia]] region of Italy, children catch and eat [[Crop (anatomy)|ingluvies]] of the toxic ''[[Zygaena]]'' moths 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 the [[Bogong moth]].<ref>{{cite journal |first1=Mika |last1=Zagrobelny |first2=Angelo Leandro |last2=Dreon |first3=Tiziano |last3=Gomiero |first4=Gian Luigi |last4=Marcazzan |first5=Mikkel Andreas |last5=Glaring |first6=Birger Lindberg |last6=Møller |first7=Maurizio G. |last7=Paoletti |year=2009 |title=Toxic moths: source of a truly safe delicacy |journal=[[Journal of Ethnobiology]] |volume=29 |issue=1 |pages=64–76 |doi=10.2993/0278-0771-29.1.64 |s2cid=73665731 }}</ref>

=== 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 ([[urticaria]]l dermatitis and [[atopic]] [[asthma]] to [[osteochondritis]], consumption [[coagulopathy]], [[renal]] failure, and [[brain|intracerebral]] [[hemorrhage]]).<ref>{{cite journal|author=Diaz, HJ|year=2005|title=The evolving global epidemiology, syndromic classification, management, and prevention of caterpillar envenoming|pmid=15772333|journal=[[American Journal of Tropical Medicine and Hygiene]] |volume=72|pages=347–357|issue=3|doi=10.4269/ajtmh.2005.72.347|doi-access=free}}</ref> Skin rashes are the most common, but there have been fatalities.<ref>{{cite journal|last1=Redd|first1=J.|last2=Voorhees|first2= R. |last3=Török|first3=T.|title= Outbreak of lepidopterism at a Boy Scout camp|journal= Journal of the American Academy of Dermatology|volume=56|issue=6|pages=952–955|doi=10.1016/j.jaad.2006.06.002|pmid=17368636|year=2007}}</ref> ''[[Lonomia]]'' is 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.<ref>{{cite journal|doi=10.1590/S0004-282X2006000600029|pmid=17221019|date=December 2006|last1=Kowacs|first1=P. A.|last2=Cardoso|first2=J.|last3=Entres|first3=M.|last4=Novak|first4=E. M.|last5=Werneck|first5=L. C.|title=Fatal intracerebral hemorrhage secondary to ''Lonomia obliqua'' caterpillar envenoming: case report|volume=64|issue=4|pages=1030–2|journal=Arquivos de Neuro-Psiquiatria|doi-access=free}} Free full text.</ref>

These hairs have also been known to cause [[keratoconjunctivitis]]. The sharp barbs on the end of caterpillar hairs can get lodged in soft tissues and [[mucous membrane]]s such as the eyes. Once they enter such tissues, they can be difficult to extract, often exacerbating the problem as they migrate across the membrane.<ref>{{cite journal|vauthors=Patel RJ, Shanbhag RM|title=Ophthalmia nodosa – (a case report)|url=http://www.ijo.in/text.asp?1973/21/4/208/34632|journal=Indian Journal of Ophthalmology|year=1973|volume=21|page=208|issue=4|access-date=17 November 2018|archive-url=https://web.archive.org/web/20190912004614/http://www.ijo.in/text.asp?1973%2F21%2F4%2F208%2F34632|archive-date=12 September 2019}}</ref> 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.<ref>{{cite journal |first1=Corrine R. |last1=Balit |first2=Helen C. |last2=Ptolemy |first3=Merilyn J. |last3=Geary |first4=Richard C. |last4=Russell |first5=Geoffrey K. |last5=Isbister |pmid=11837874 |year=2001 |title=Outbreak of caterpillar dermatitis caused by airborne hairs of the mistletoe browntail moth (''Euproctis edwardsi'') |volume=175 |issue=11–12 |pages=641–3 |journal=The Medical Journal of Australia |url=http://www.mja.com.au/public/issues/175_12_171201/balit/balit.html |access-date=25 February 2011 |archive-url=https://web.archive.org/web/20110404211547/https://mja.com.au/public/issues/175_12_171201/balit/balit.html |archive-date=4 April 2011 |url-status=live |doi=10.5694/j.1326-5377.2001.tb143760.x |s2cid=26910462 |url-access=subscription }}. Free full text.</ref>

== See also ==
{{Portal|Arthropods|Animals|Biology}}
* [[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]]

== References ==
{{Reflist|30em}}

== 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.
* {{cite book |author=Nemos, F. |title=Europas bekannteste Schmetterlinge. Beschreibung der wichtigsten Arten und Anleitung zur Kenntnis und zum Sammeln der Schmetterlinge und Raupen |trans-title=Europe's best known butterflies. Description of the most important species and instructions for recognising and collecting butterflies and caterpillars |publisher=Oestergaard Verlag |location=Berlin |date=c. 1895 |url=http://epic.awi.de/Publications/Dem1895a.pdf |archive-url=https://web.archive.org/web/20110724175753/http://epic.awi.de/Publications/Dem1895a.pdf |archive-date=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''. {{ISBN|1-55297-612-2}}.
; Bibliography
* {{cite journal | last1 = Lamas | first1 = Gerardo | year = 1990 | title = An Annotated List of Lepidopterological Journals | url = http://lepidopteraresearchfoundation.org/journals/29/PDF29/29-092.pdf | journal = [[The Journal of Research on the Lepidoptera]] | volume = 29 | issue = 1–2 | pages = 92–104 | doi = 10.5962/p.266621 | s2cid = 108756448 | access-date = 22 November 2012 | archive-url = https://web.archive.org/web/20160827214204/http://lepidopteraresearchfoundation.org/journals/29/PDF29/29-092.pdf | archive-date = 27 August 2016 }}

== External links ==
{{Wikispecies}}
{{Wikibooks|Dichotomous Key|Lepidoptera}}
{{Commons}}

* [https://data.nhm.ac.uk/dataset/hosts Natural History Museum archived database of host plants]
* [http://bcrc.bio.umass.edu/kunkel/Moths/ Historic Moth illustrations]
* [https://web.archive.org/web/20170405020312/http://insecta.pro/taxonomy/1 Lepidoptera] at Insects (Insecta) of the World
* {{ITIS |id=117232 |taxon=Lepidoptera}}
* [https://exhibits.mannlib.cornell.edu/franclemont/ Caught Between the Pages: Treasures from the Franclemont Collection] Online virtual exhibit featuring a selection of historic entomological writings and images from the Comstock Library of Entomology at Cornell University
; Regional sites<!-- Please maintain alphabetical order. -->
* [http://butterfly-conservation.org/50/Identify-abutterfly.html/ British Butterflies and Moths]
* [http://www.butterfliesofbulgaria.com/ Butterflies of Bulgaria] {{Webarchive|url=https://web.archive.org/web/20080405225314/http://www.butterfliesofbulgaria.com/ |date=5 April 2008 }}
* [http://www.cbif.gc.ca/eng/species-bank/butterflies-of-canada/alphabetical-index/ Butterflies of Canada]
* [http://home.hccnet.nl/bernard.fransen/0testsite/0testsite/ Photography of European Butterflies and Moths]
* [https://web.archive.org/web/20070629191807/http://www.inra.fr/internet/Produits/PAPILLON/index.htm Lepidoptera of French Antilles]
* [http://www.ifoundbutterflies.org/#!/tx/472-Apaturini Butterflies of India]
* [http://yutaka.it-n.jp/papi.html A Check List of Butterflies in Indo-China]
* [http://www.mbarnes.force9.co.uk/jamaicamoths/jamaicahome.htm Moths of Jamaica]
* [http://www.jpmoth.org/ Japmoth] Japanese moths. Access images via the numbers on the left.
* [https://web.archive.org/web/20070622044831/http://www.leps.nl/ Butterflies and Moths in the Netherlands] 
* [http://www.habitas.org.uk/moths/ Butterflies and Moths of Northern Ireland] {{Webarchive|url=https://web.archive.org/web/20150801025150/http://www.habitas.org.uk/moths/ |date=1 August 2015 }}
* [http://pisum.bionet.nsc.ru/kosterin/korgor/index.htm Butterflies of Asian Russia] {{Webarchive|url=https://web.archive.org/web/20070831024957/http://pisum.bionet.nsc.ru/kosterin/korgor/index.htm |date=31 August 2007 }}
* [http://gil-t.comze.com/indgalo.htm Photos of Larvae and Pupae butterflies and moths. Spain] {{Webarchive|url=https://web.archive.org/web/20130728150726/http://gil-t.comze.com/indgalo.htm |date=28 July 2013 }}
* [http://www.imagenesdeasturias.com/web/panoramicas_graonet/mariposas_de_asturias/index_mariposas.htm Butterflies of Asturias – Spain]
* [http://www.lepidoptera.se/en/ Swedish Moths and Butterflies Lepidoptera (English)]
* [https://web.archive.org/web/20110727194040/http://leptr.org/ Butterflies of Turkey]

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[[Category:Lepidoptera| ]]
[[Category:Articles containing video clips]]
[[Category:Extant Early Jurassic first appearances]]
[[Category:Insect orders]]
[[Category:Pliensbachian first appearances]]
[[Category:Animal taxa named by Carl Linnaeus]]
[[Category:Insects in culture]]
[[Category:Amphiesmenoptera]]