Editing Butterfly (section)

===Life cycle===

<!-- NOTE: two redirects ("Butterfly life cycle" & "Life cycles of butterflies") target this section. If renaming the section, please retarget those -->
[[File:Butterfly life cycle diagram in English.svg|thumb|Life cycle of the monarch butterfly]]

Butterflies in their adult stage can live from a week to nearly a year depending on the species. Many species have long larval life stages while others can remain [[Diapause|dormant]] in their pupal or egg stages and thereby survive winters.<ref>{{cite journal |last1=Powell |first1=J. A. |year=1987 |title=Records of Prolonged Diapause in Lepidoptera |journal=[[The Journal of Research on the Lepidoptera]] |volume=25 |issue=2 |pages=83–109| doi=10.5962/p.266734 |s2cid=248727391 |doi-access=free }}</ref> The [[Oeneis melissa|Melissa Arctic]] (''Oeneis melissa'') overwinters twice as a caterpillar.<ref>{{cite web |url=http://www.butterfliesandmoths.org/species/Oeneis-melissa |title=Melissa Arctic |work=Butterflies and Moths of North America |access-date=15 September 2015 |archive-date=28 October 2015 |archive-url=https://web.archive.org/web/20151028164705/http://www.butterfliesandmoths.org/species/Oeneis-melissa |url-status=live }}</ref> Butterflies may have one or more broods per year. The number of generations per year varies from [[Temperateness|temperate]] to [[Tropics|tropical regions]] with tropical regions showing a trend towards [[voltinism|multivoltinism]].<ref>{{cite book |author=Timothy Duane Schowalter |title=Insect Ecology: An Ecosystem Approach |url=https://books.google.com/books?id=2KzokTLIysQC&pg=PA159 |year=2011 |publisher=Academic Press |isbn=978-0-12-381351-0 |page=159 |access-date=8 January 2016 |archive-date=25 April 2016 |archive-url=https://web.archive.org/web/20160425180814/https://books.google.com/books?id=2KzokTLIysQC&pg=PA159 |url-status=live }}</ref>

[[File:Mating Pair of Spotted Fritillaries on Greater Pignut.JPG|thumb|left|Mating pair of [[Melitaea didyma|spotted fritillaries]] on [[Bunium bulbocastanum|greater pignut]]]]
[[File:Thymelicus sylvestris m1.JPG|thumb|left|The male small skipper (''[[Thymelicus sylvestris]]'') has [[pheromone]]-releasing "sex brands" (dark line) on the upperside of its forewings.]]

[[courtship display|Courtship]] is often aerial and often involves [[pheromone]]s. Butterflies then land on the ground or on a perch to mate.<ref name=Gullan/> Copulation takes place tail-to-tail and may last from minutes to hours. Simple photoreceptor cells located at the genitals are important for this and other adult behaviours.<ref>{{cite journal |last1=Arikawa |first1=Kentaro |title=Hindsight of Butterflies: The Papilio butterfly has light sensitivity in the genitalia, which appears to be crucial for reproductive behavior |journal=BioScience |volume=51|issue=3 |pages=219–225 |doi=10.1641/0006-3568(2001)051[0219:HOB]2.0.CO;2 |year=2001 |doi-access=free }}</ref> The male passes a [[spermatophore]] to the female; to reduce sperm competition, he may cover her with his scent, or in some species such as the Apollos (''[[Parnassius]]'') [[Mating plug|plugs her genital opening]] to prevent her from mating again.<ref>{{cite book |last=Schlaepfer |first=Gloria G. |title=Butterflies |url=https://archive.org/details/butterflies0000schl |url-access=registration |year=2006 |publisher=Marshall Cavendish |isbn=978-0-7614-1745-3 |page=[https://archive.org/details/butterflies0000schl/page/52 52]}}</ref>

The vast majority of butterflies have a four-stage life cycle: [[egg]], [[larva]] (caterpillar), [[pupa]] (chrysalis) and [[imago]] (adult). In the genera ''[[Colias]]'', ''[[Erebia]]'', ''[[Euchloe]]'', and ''Parnassius'', a small number of species are known that reproduce [[Parthenogenesis|semi-parthenogenetically]]; when the female dies, a partially developed larva emerges from her abdomen.<ref name=Capinera640/>

====Eggs====

[[File:2012-06-27 Aporia crataegi eggs Malus domestica.JPG|thumb|Eggs of black-veined white (''[[Aporia crataegi]]'') on [[apple]] leaf]]
[[File:Butterfly laying eggs underneath a leaf.jpg|thumb|A butterfly from the genus ''[[Euploea]]'', laying eggs underneath the leaf]]

Butterfly eggs are protected by a hard-ridged outer layer of shell, called the ''chorion''. This is lined with a thin coating of wax which prevents the egg from drying out before the larva has had time to fully develop. Each egg contains a number of tiny funnel-shaped openings at one end, called ''micropyles''; the purpose of these holes is to allow sperm to enter and fertilize the egg. Butterfly eggs vary greatly in size and shape between species, but are usually upright and finely sculptured. Some species lay eggs singly, others in batches. Many females produce between one hundred and two hundred eggs.<ref name=Capinera640>{{cite book |author=Capinera, John L. |title=Encyclopedia of Entomology |url=https://books.google.com/books?id=i9ITMiiohVQC&pg=PA640 |year=2008 |publisher=Springer Science & Business Media |isbn=978-1-4020-6242-1 |page=640 |access-date=8 January 2016 |archive-date=20 May 2016 |archive-url=https://web.archive.org/web/20160520021643/https://books.google.com/books?id=i9ITMiiohVQC&pg=PA640 |url-status=live }}</ref>

Butterfly eggs are fixed to a leaf with a special glue which hardens rapidly. As it hardens it contracts, deforming the shape of the egg. This glue is easily seen surrounding the base of every egg forming a meniscus. The nature of the glue has been little researched but in the case of ''[[Pieris brassicae]]'', it begins as a pale yellow granular secretion containing acidophilic proteins. This is viscous and darkens when exposed to air, becoming a water-insoluble, rubbery material which soon sets solid.<ref>{{cite journal |author1=Beament, J.W.L. |author2=Lal, R. |year=1957 |title=Penetration Through the Egg-shell of ''Pieris brassicae'' |journal=Bulletin of Entomological Research |volume=48 |issue=1 |pages=109–125 |doi=10.1017/S0007485300054134}}</ref> Butterflies in the genus ''[[Agathymus]]'' do not fix their eggs to a leaf; instead, the newly laid eggs fall to the base of the plant.<ref name=Scott121>{{cite book |author=Scott, James A. |title=The Butterflies of North America: A Natural History and Field Guide |url=https://books.google.com/books?id=Oa5m8gZcGjMC&pg=PA121 |year=1992 |publisher=Stanford University Press |isbn=978-0-8047-2013-7 |page=121 |access-date=8 January 2016 |archive-date=18 May 2016 |archive-url=https://web.archive.org/web/20160518162206/https://books.google.com/books?id=Oa5m8gZcGjMC&pg=PA121 |url-status=live }}</ref>

Eggs are almost invariably laid on plants. Each species of butterfly has its own host plant range and while some species of butterfly are restricted to just one species of plant, others use a range of plant species, often including members of a common family.<ref>{{cite book |author=Capinera, John L. |title=Encyclopedia of Entomology |url=https://books.google.com/books?id=i9ITMiiohVQC&pg=PA676 |year=2008 |publisher=Springer Science & Business Media |isbn=978-1-4020-6242-1 |page=676 |access-date=8 January 2016 |archive-date=2 May 2016 |archive-url=https://web.archive.org/web/20160502065723/https://books.google.com/books?id=i9ITMiiohVQC&pg=PA676 |url-status=live }}</ref> In some species, such as the [[great spangled fritillary]], the eggs are deposited close to but not on the food plant. This most likely happens when the egg overwinters before hatching and where the host plant loses its leaves in winter, as do [[Viola (plant)|violets]] in this example.<ref name=Shepard55>{{cite book |author1=Shepard, Jon |author2=Guppy, Crispin |title=Butterflies of British Columbia: Including Western Alberta, Southern Yukon, the Alaska Panhandle, Washington, Northern Oregon, Northern Idaho, and Northwestern Montana |url=https://books.google.com/books?id=il6rJ7glHNQC&pg=PA55 |year=2011 |publisher=UBC Press |isbn=978-0-7748-4437-6 |page=55 |access-date=8 January 2016 |archive-date=13 May 2016 |archive-url=https://web.archive.org/web/20160513010746/https://books.google.com/books?id=il6rJ7glHNQC&pg=PA55 |url-status=live }}</ref>

The egg stage lasts a few weeks in most butterflies, but eggs laid close to winter, especially in temperate regions, go through a [[diapause]] (resting) stage, and the hatching may take place only in spring.<ref>{{cite web |title=British Butterflies: Education: Butterflies in Winter |url=http://www.britishbutterflies.co.uk/winter.asp |access-date=12 September 2015 |archive-url=https://web.archive.org/web/20170107044348/http://www.britishbutterflies.co.uk/winter.asp |archive-date=7 January 2017 |url-status=dead }}</ref> Some temperate region butterflies, such as the [[Nymphalis antiopa|Camberwell beauty]], lay their eggs in the spring and have them hatch in the summer.<ref>{{cite web |title=Camberwell Beauty |url=http://www.luontoportti.com/suomi/en/perhoset/camberwell-beauty |publisher=NatureGate |access-date=12 September 2015 |archive-url=https://web.archive.org/web/20170421061806/http://www.luontoportti.com/suomi/en/perhoset/camberwell-beauty |archive-date=21 April 2017 |url-status=dead }}</ref>

====Caterpillar larva====

[[File:Papilionidae - Papilio machaon-2.JPG|thumb|[[Aposematism|Aposematic]] caterpillar of ''[[Papilio machaon]]'', in threat pose]]

Butterfly larvae, or caterpillars, consume plant leaves and spend practically all of their time searching for and eating food. Although most caterpillars are herbivorous, a few species are [[Predation|predators]]: ''[[Spalgis epius]]'' eats [[scale insect]]s,<ref>{{cite journal |author1=Venkatesha, M. G. |author2=Shashikumar, L. |author3=Gayathri Devi, S.S. |year=2004 |title=Protective Devices of the Carnivorous Butterfly, ''Spalgis epius'' (Westwood) (Lepidoptera: Lycaenidae) |journal=Current Science |volume=87 |issue=5 |pages=571–572}}</ref> while lycaenids such as ''[[Liphyra brassolis]]'' are [[myrmecophily|myrmecophilous]], eating ant larvae.<ref name="Bingham">{{cite book |last1=Bingham |first1=C.T. |author-link=Charles Thomas Bingham |title=The Fauna of British India, Including Ceylon and Burma |url=https://archive.org/details/butterflies02bingiala |volume=II |edition=1st |publisher= [[Taylor & Francis|Taylor and Francis, Ltd.]] |location=London |year=1907 }}</ref>

[[File:Catapaecilma major by Balakrishnan Valappil (7385361012).jpg|thumb|left|[[Mutualism (biology)|Mutualism]]: ant tending a [[Lycaenidae|lycaenid]] caterpillar, ''[[Catapaecilma major]]'']]

Some larvae, especially those of the [[Lycaenidae]], form [[Mutualism (biology)|mutual associations]] with ants. They communicate with the ants using vibrations that are transmitted through the [[Substrate (biology)|substrate]] as well as using chemical signals.<ref>{{cite journal |last=Devries |first=P. J. |title=The larval Ant-organs of Thisbe irenea (Lepidoptera: Riodinidae) and Their Effects Upon Attending Ants |year=1988 |journal=Zoological Journal of the Linnean Society |volume=94 |issue=4 |doi=10.1111/j.1096-3642.1988.tb01201.x |pages=379–393}}</ref><ref>{{cite journal |last=Devries |first=P. J. |title=Enhancement of Symbioses Between Butterfly Caterpillars and Ants by Vibrational Communication |date=June 1990 |journal=Science |volume=248 |issue=4959 |doi=10.1126/science.248.4959.1104 |pmid=17733373 |pages=1104–1106|bibcode=1990Sci...248.1104D |s2cid=35812411 }}</ref> The ants provide some degree of protection to these larvae and they in turn gather [[Honeydew (secretion)|honeydew secretions]]. [[Large blue]] (''Phengaris arion'') caterpillars trick ''[[Myrmica]]'' ants into taking them back to the [[ant colony]] where they feed on the ant eggs and larvae in a parasitic relationship.<ref name="Corruption">{{cite journal |last1=Thomas |first1=Jeremy |last2=Schönrogge |first2=Karsten |last3=Bonelli |first3=Simona |last4=Barbero |first4=Francesca |last5=Balletto |first5=Emilio |title=Corruption of Ant Acoustical Signals by Mimetic Social Parasites |journal=Communicative and Integrative Biology |year=2010 |volume=3 |issue=2 |pages=169–171 |pmid=20585513 |pmc=2889977 |doi=10.4161/cib.3.2.10603}}</ref>

[[File:Four-horned Sphinx (Elm Sphinx).jpg|thumb|[[Camouflage|Cryptic]] [[countershading|countershaded]] caterpillar of a hawkmoth, ''[[Ceratomia amyntor]]'']]

Caterpillars mature through a series of developmental stages known as [[instar]]s. Near the end of each stage, the larva undergoes a process called [[apolysis]], mediated by the release of a series of [[neurohormone]]s. During this phase, the [[cuticle]], a tough outer layer made of a mixture of [[chitin]] and specialized [[protein]]s, is released from the softer [[Squamous epithelium|epidermis]] beneath, and the epidermis begins to form a new cuticle. At the end of each instar, the larva [[ecdysis|moults]], the old cuticle splits and the new cuticle expands, rapidly hardening and developing pigment.<ref name=Klowden>{{cite book |author=Klowden, Marc J. |title=Physiological Systems in Insects |url=https://books.google.com/books?id=CABp1YL0F8gC&pg=PA114 |year=2013 |publisher=Academic Press |isbn=978-0-12-415970-9 |page=114 |access-date=8 January 2016 |archive-date=1 May 2016 |archive-url=https://web.archive.org/web/20160501221755/https://books.google.com/books?id=CABp1YL0F8gC&pg=PA114 |url-status=live }}</ref> <!--Development of butterfly wing patterns begins by the last larval instar.-->

Caterpillars have short antennae and several [[Simple eye in invertebrates|simple eyes]]. The [[Insect mouthparts|mouthparts]] are adapted for chewing with powerful mandibles and a pair of maxillae, each with a segmented palp. Adjoining these is the labium-hypopharynx which houses a tubular spinneret which is able to extrude silk.<ref name=Formfunction/> Caterpillars such as those in the genus ''[[Calpodes]]'' (family Hesperiidae) have a specialized tracheal system on the 8th segment that function as a primitive lung.<ref name="Locke 1997">{{cite journal |last=Locke |first=Michael |title=Caterpillars have evolved lungs for hemocyte gas exchange |journal=Journal of Insect Physiology |volume=44 |issue=1 |year=1997 |doi=10.1016/s0022-1910(97)00088-7 |pmid=12770439 |pages=1–20 |bibcode=1997JInsP..44....1L |url=https://www.academia.edu/33633960/Caterpillars_have_evolved_lungs_for_hemocyte_gas_exchange<!--full text, unlike DOI--> |access-date=19 June 2018 |archive-date=19 July 2021 |archive-url=https://web.archive.org/web/20210719044641/https://www.academia.edu/33633960/Caterpillars_have_evolved_lungs_for_hemocyte_gas_exchange |url-status=live }}</ref> Butterfly caterpillars have three pairs of true legs on the thoracic segments and up to six pairs of [[proleg]]s arising from the abdominal segments. These prolegs have rings of tiny hooks called crochets that are engaged hydrostatically and help the caterpillar grip the substrate.<ref>{{cite web |url=http://www.naturemuseum.org/online/thebutterflylab/anatomy/larva.html |archive-url=https://web.archive.org/web/20120319072020/http://www.naturemuseum.org/online/thebutterflylab/anatomy/larva.html |archive-date=19 March 2012 |title=Peggy Notebaert Nature Museum |publisher=Chicago Academy of Sciences |work=Larva Legs |access-date=7 June 2012}}</ref> The epidermis bears tufts of [[seta]]e, the position and number of which help in identifying the species. There is also decoration in the form of hairs, wart-like protuberances, horn-like protuberances and spines. Internally, most of the body cavity is taken up by the gut, but there may also be large silk glands, and special glands which secrete distasteful or toxic substances. The developing wings are present in later stage instars and the [[gonad]]s start development in the egg stage.<ref name=Formfunction/>

====Pupa====

[[File:Chrysalis5504.jpg|thumb|upright|[[Chrysalis]] of [[gulf fritillary]]]]

When the larva is fully grown, hormones such as [[prothoracicotropic hormone]] (PTTH) are produced. At this point the larva stops feeding, and begins "wandering" in the quest for a suitable pupation site, often the underside of a leaf or other concealed location. There it spins a button of silk which it uses to fasten its body to the surface and moults for a final time. While some caterpillars spin a [[Pupa#Cocoon|cocoon]] to protect the pupa, most species do not. The naked pupa, often known as a chrysalis, usually hangs head down from the cremaster, a spiny pad at the posterior end, but in some species a silken girdle may be spun to keep the pupa in a head-up position.<ref name=Capinera640/> Most of the tissues and cells of the larva are broken down inside the pupa, as the constituent material is rebuilt into the imago. The structure of the transforming insect is visible from the exterior, with the wings folded flat on the ventral surface and the two halves of the proboscis, with the antennae and the legs between them.<ref name=Formfunction>{{cite encyclopedia |url=https://www.britannica.com/animal/lepidopteran/Form-and-function |title=Lepidopteran: Form and function |author=Culin, Joseph |encyclopedia=Encyclopædia Britannica |access-date=8 September 2015 |archive-date=21 September 2017 |archive-url=https://web.archive.org/web/20170921192451/https://www.britannica.com/animal/lepidopteran/Form-and-function |url-status=live }}</ref>

The pupal transformation into a butterfly through [[metamorphosis]] has held great appeal to mankind. To transform from the miniature wings visible on the outside of the pupa into large structures usable for flight, the pupal wings undergo rapid mitosis and absorb a great deal of nutrients. If one wing is surgically removed early on, the other three will grow to a larger size. In the pupa, the wing forms a structure that becomes compressed from top to bottom and pleated from proximal to distal ends as it grows, so that it can rapidly be unfolded to its full adult size. Several boundaries seen in the adult colour pattern are marked by changes in the expression of particular transcription factors in the early pupa.<ref name="pmid11676917">{{cite journal |author1=Brunetti, Craig R. |author2=Selegue, Jayne E. |author3=Monteiro, Antonia |author4=French, Vernon |author5=Brakefield, Paul M. |author6=Carroll, Sean B. |year=2001 |title=The Generation and Diversification of Butterfly Eyespot Color Patterns |journal=Current Biology |volume=11 |issue=20 |pages=1578–1585 |doi=10.1016/S0960-9822(01)00502-4 |pmid=11676917|s2cid=14290399 |doi-access=free |bibcode=2001CBio...11.1578B }}</ref>

====Adult====

[[File:ParthenosSylviaButterfly.jpg|thumb|An adult ''[[Parthenos sylvia]]'' butterfly]]

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

Many ''[[Heliconius]]'' butterflies also use their proboscis to feed on pollen;<ref>{{Cite journal|pmid = 25958827|year = 2015|last1 = Harpel|first1 = D.|title = Pollen feeding proteomics: Salivary proteins of the passion flower butterfly, Heliconius melpomene|journal = Insect Biochemistry and Molecular Biology|volume = 63|pages = 7–13|last2 = Cullen|first2 = D. A.|last3 = Ott|first3 = S. R.|last4 = Jiggins|first4 = C. D.|last5 = Walters|first5 = J. R.|doi = 10.1016/j.ibmb.2015.04.004| bibcode=2015IBMB...63....7H |s2cid=39086740 |url = https://lirias.kuleuven.be/handle/123456789/509592|access-date = 8 November 2018|archive-date = 19 July 2021|archive-url = https://web.archive.org/web/20210719044718/https://limo.libis.be/primo-explore/fulldisplay?docid=LIRIAS528183&context=L&vid=Lirias&search_scope=Lirias&tab=default_tab&lang=en_US&fromSitemap=1|url-status = live|hdl = 2381/37010|hdl-access = free}}</ref> in these species only 20% of the amino acids used in reproduction come from larval feeding, which allow them to develop more quickly as caterpillars, and gives them a longer lifespan of several months as adults.<ref>{{cite web |url=https://sta.uwi.edu/fst/lifesciences/sites/default/files/lifesciences/documents/ogatt/Heliconius_ethilla%20-%20Ethilia%20Longwing%20Butterfly.pdf |title=The Online Guide to the Animals of Trinidad and Tobago {{!}} ''Heliconius ethilla'' (Ethilia Longwing Butterfly) |publisher=UWI St. Augustine |access-date=28 May 2018 |archive-date=28 May 2018 |archive-url=https://web.archive.org/web/20180528215909/https://sta.uwi.edu/fst/lifesciences/sites/default/files/lifesciences/documents/ogatt/Heliconius_ethilla%20-%20Ethilia%20Longwing%20Butterfly.pdf |url-status=live }}</ref>

The thorax of the butterfly is devoted to locomotion. Each of the three thoracic segments has two legs (among [[Nymphalidae|nymphalids]], the first pair is reduced and the insects walk on four legs). The second and third segments of the thorax bear the wings. The leading edges of the forewings have thick veins to strengthen them, and the hindwings are smaller and more rounded and have fewer stiffening veins. The forewings and hindwings are not hooked together ([[Wing coupling (Lepidoptera anatomy)|as they are in moths]]) but are coordinated by the friction of their overlapping parts. The front two segments have a pair of [[Spiracle (arthropods)|spiracle]]s which are used in respiration.<ref name=Formfunction/>

The abdomen consists of ten segments and contains the gut and genital organs. The front eight segments have spiracles and the terminal segment is modified for reproduction. The male has a pair of clasping organs attached to a ring structure, and during copulation, a tubular structure is extruded and inserted into the female's vagina. A [[spermatophore]] is deposited in the female, following which the sperm make their way to a seminal receptacle where they are stored for later use. In both sexes, the genitalia are adorned with various spines, teeth, scales and bristles, which act to prevent the butterfly from mating with an insect of another species.<ref name=Formfunction/> After it emerges from its pupal stage, a butterfly cannot fly until the wings are unfolded. A newly emerged butterfly needs to spend some time inflating its wings with [[hemolymph]] and letting them dry, during which time it is extremely vulnerable to predators.<ref>{{cite book |last=Woodbury |first=Elton N. |title=Butterflies of Delmarva |url=https://books.google.com/books?id=cDNHAAAAYAAJ |year=1994 |publisher=Delaware Nature Society; Tidewater Publishers |isbn=978-0-87033-453-5 |page=22 |access-date=8 January 2016 |archive-date=9 May 2016 |archive-url=https://web.archive.org/web/20160509035428/https://books.google.com/books?id=cDNHAAAAYAAJ |url-status=live }}</ref>

==== Pattern formation ====

The colourful patterns on many butterfly wings tell potential predators that they are toxic. Hence, the genetic basis of wing [[pattern formation]] can illuminate both the [[evolution]] of butterflies as well as their [[developmental biology]]. The colour of butterfly wings is derived from tiny structures called scales, each of which have their own [[pigment]]s. In ''[[Heliconius]]'' butterflies, there are three types of scales: yellow/white, black, and red/orange/brown scales. Some mechanism of wing pattern formation are now being solved using genetic techniques. For instance, a [[gene]] called ''cortex'' determines the colour of scales: deleting ''cortex'' turned black and red scales yellow. Mutations, e.g. [[Transposable element|transposon insertions]] of the [[non-coding DNA]] around the ''cortex'' gene can turn a black-winged butterfly into a butterfly with a yellow wing band.<ref>{{Cite journal |last1=Livraghi |first1=Luca |last2=Hanly |first2=Joseph J |last3=Van Bellghem |first3=Steven M |last4=Montejo-Kovacevich |first4=Gabriela |last5=van der Heijden |first5=Eva SM |last6=Loh |first6=Ling Sheng |last7=Ren |first7=Anna |last8=Warren |first8=Ian A |last9=Lewis |first9=James J |last10=Concha |first10=Carolina |last11=Hebberecht |first11=Laura |date=2021-07-19 |title=Cortex cis-regulatory switches establish scale colour identity and pattern diversity in Heliconius |journal=eLife |volume=10 |pages=e68549 |doi=10.7554/eLife.68549 |pmid=34280087 |issn=2050-084X |pmc=8289415 |doi-access=free }}</ref>