Editing Migratory locust

{{Short description|Species of grasshopper}}
{{Speciesbox
| image = Wanderheuschrecke-03.jpg
| image_caption = Female migratory locust
| status = LC
| status_system = IUCN3.1
| display_parents = 3
| genus = Locusta
| parent_authority = [[Carl Linnaeus|Linnaeus]], 1758
| species = migratoria
| authority = ([[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]])
| synonyms =
* ''Acridium migratorium'' <small> </small>
* ''Acridium plorans'' <small> </small>
* ''Pachytylus australis'' <small>(Saussure, 1884) </small>
* ''Pachytylus migratorius'' <small>(Linnaeus, 1758) </small>
* ''Pachytylus migratorioides'' <small>(Fairmaire & L.J. Reiche, 1849) </small>
}}
{{Listen |filename=Locusta migratoria - sound.oga|title=Sound of ''Locusta migratoria'' |description=Field recording in the Netherlands 21s}}
[[File:Locusta migratoria -- Europäische Wanderheuschrecke.webm|thumb|Close-Up of a Locusta migratoria]]
The '''migratory locust''' ('''''Locusta migratoria''''') is the most widespread [[locust]] species, and the [[monotypic|only species]] in the [[genus]] '''''Locusta'''''. It occurs throughout Africa, Europe, Asia, Australia and New Zealand. Because of the vast geographic area it occupies, which comprises many different ecological zones, numerous [[subspecies]] have been described. However, not all experts agree on the validity of some of these subspecies. While it reaches plague proportions in drier areas, it is solitary in northern Australia savannas.<ref>{{Cite book |last=Rentz |first=David C. |url=https://www.worldcat.org/title/ocm55753685 |title=A guide to Australian grasshoppers and locusts |date=2003 |publisher=Natural History Publications (Borneo) |others=Natural History Publications (Borneo), Australian Plague Locust Commission, Orthopterists' Society |isbn=978-983-812-074-6 |location=Kota Kinabalu |oclc=ocm55753685}}</ref>

Many other [[species]] of [[grasshopper]] with [[gregarious behaviour|gregarious]] and possibly [[Insect migration|migratory behaviour]] are referred to as 'locusts' in the vernacular, including the widely distributed [[desert locust]].

At 6.5 [[Base pair|Gbp]],<ref name="WangFang2014">{{cite journal|last1=Wang|first1=Xianhui|last2=Fang|first2=Xiaodong|last3=Yang|first3=Pengcheng|last4=Jiang|first4=Xuanting|last5=Jiang|first5=Feng|last6=Zhao|first6=Dejian|last7=Li|first7=Bolei|last8=Cui|first8=Feng|last9=Wei|first9=Jianing|last10=Ma|first10=Chuan|last11=Wang|first11=Yundan|last12=He|first12=Jing|last13=Luo|first13=Yuan|last14=Wang|first14=Zhifeng|last15=Guo|first15=Xiaojiao|last16=Guo|first16=Wei|last17=Wang|first17=Xuesong|last18=Zhang|first18=Yi|last19=Yang|first19=Meiling|last20=Hao|first20=Shuguang|last21=Chen|first21=Bing|last22=Ma|first22=Zongyuan|last23=Yu|first23=Dan|last24=Xiong|first24=Zhiqiang|last25=Zhu|first25=Yabing|last26=Fan|first26=Dingding|last27=Han|first27=Lijuan|last28=Wang|first28=Bo|last29=Chen|first29=Yuanxin|last30=Wang|first30=Junwen|last31=Yang|first31=Lan|last32=Zhao|first32=Wei|last33=Feng|first33=Yue|last34=Chen|first34=Guanxing|last35=Lian|first35=Jinmin|last36=Li|first36=Qiye|last37=Huang|first37=Zhiyong|last38=Yao|first38=Xiaoming|last39=Lv|first39=Na|last40=Zhang|first40=Guojie|last41=Li|first41=Yingrui|last42=Wang|first42=Jian|last43=Wang|first43=Jun|last44=Zhu|first44=Baoli|last45=Kang|first45=Le|title=The locust genome provides insight into swarm formation and long-distance flight|journal=Nature Communications|volume=5|pages=2957|year=2014|issn=2041-1723|doi=10.1038/ncomms3957|pmid=24423660|pmc=3896762|bibcode=2014NatCo...5.2957W}}</ref> the migratory locust possesses one of the largest known insect [[genome]]s.<ref name="LiZhu2018">{{cite journal|last1=Li|first1=Sheng|last2=Zhu|first2=Shiming|last3=Jia|first3=Qiangqiang|last4=Yuan|first4=Dongwei|last5=Ren|first5=Chonghua|last6=Li|first6=Kang|last7=Liu|first7=Suning|last8=Cui|first8=Yingying|last9=Zhao|first9=Haigang|last10=Cao|first10=Yanghui|last11=Fang|first11=Gangqi|last12=Li|first12=Daqi|last13=Zhao|first13=Xiaoming|last14=Zhang|first14=Jianzhen|last15=Yue|first15=Qiaoyun|last16=Fan|first16=Yongliang|last17=Yu|first17=Xiaoqiang|last18=Feng|first18=Qili|last19=Zhan|first19=Shuai|title=The genomic and functional landscapes of developmental plasticity in the American cockroach|journal=Nature Communications|volume=9|issue=1|pages=1008|year=2018|issn=2041-1723|doi=10.1038/s41467-018-03281-1|pmid=29559629|pmc=5861062|bibcode=2018NatCo...9.1008L}} [[File:CC-BY icon.svg|50px]] This article contains quotations from this source, which is available under the [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International (CC BY 4.0)] license</ref>

==Polyphenism==
The migratory locust is [[Polyphenism|polyphenic]]. It transitions between two main phenotypes in response to population density; the solitary phase and the gregarious phase. As the density of the population increases the locust transforms progressively from the solitary phase towards the gregarious phase with intermediate phases:

{{block indent|1=Solitaire = solitary phase → {{lang|la|transiens congregans}} (intermediate form) → gregarious phase → {{lang|la|transiens dissocians}} (intermediate form) → solitaire = solitary phase.}}

Pigmentation and size of the migratory locust vary according to its phase (gregarious or solitary form) and its age. Gregarious nymphs have a yellow to orange covering with black spots; solitary nymphs are green or brown. The gregarious adult is brownish with yellow, the latter colour becoming more intense and extensive on maturation. The solitary adult is brown with varying extent of green colour depending on the colour of the vegetation. Gregarious adults vary in size between 40 and 60&nbsp;mm according to the sex; they are smaller than the solitary adults.

The [[phase transition]] may be mediated by [[DNA methylation]] in the brain. Expression of the DNA methyltrasferase gene ''Dnmt3'' is high in the brain of the gregarious form, decreases in gregarious locusts when they are isolated, and increases in solitary locusts when they are crowded. Knock-down reduces phase-related locomotor activity.<ref name="Hou2020">{{cite journal |last1= Hou|first1= Li|last2= Wang|first2= Xuesong|last3= Yang|first3= Pengcheng|last4= Li|first4= Beibei|last5= Lin|first5= Zhe|last6= Kang|first6= Le|last7= Wang|first7= Xianhui|title= DNA methyltransferase 3 participates in behavioral phase change in the migratory locust|journal= Insect Biochemistry and Molecular Biology|date= 2020|volume= 121|pages= 103374|doi= 10.1016/j.ibmb.2020.103374|pmid= 32283278|s2cid= 215758648|url= https://www.sciencedirect.com/science/article/pii/S0965174820300631|url-access= subscription}}</ref> Transcriptionally, ''Dnmt3'' is linked with phase-core transcriptional factor, [[hormone receptor]] HR3.<ref name="Hou2020" />

==Neurochemistry==
Increased extracellular [[potassium|K{{sup|+}}]] was found to cause [[membrane depolarization]] in muscle activating nerves by Hoyle 1953. This then in turn reduces the [[nerve potential]], with the final result of reducing the force output of said muscle. He also found ''chronic'' cold temperatures to increase K{{sup|+}} in the [[haemolymph]]. These changes affect ''L. migratoria''{{'}}s nerve states because {{endash}} as with insects and animals in general {{endash}} nerve cells have a high K permeability, which allows K{{sup|+}}'s transmembrane distribution to determine most cellular [[diffusion potential]]. This is shaping and will continue to shape the [[species distribution modelling|distribution of ''L. migratoria''{{'}}s range]] under climate change.<ref name="Overgaard-MacMillan-2017">{{cite journal | last1=Overgaard | first1=Johannes | last2=MacMillan | first2=Heath A. | title=The Integrative Physiology of Insect Chill Tolerance | journal=[[Annual Review of Physiology]] | publisher=[[Annual Reviews (publisher)|Annual Reviews]] | volume=79 | issue=1 | date=2017-02-10 | issn=0066-4278 | doi=10.1146/annurev-physiol-022516-034142 | pages=187–208| pmid=27860831 | doi-access=free }}</ref>

==Relationship with humans==

===Economic impact===
[[File:Die Gartenlaube (1875) b 585.jpg|thumb|left|Adult female (top), adult male (bottom left), fifth instar nymph (bottom right)]]
Locusts are highly mobile, and usually fly with the wind at a speed of about {{convert|15|to|20|km/h}}. Swarms can travel 5 to 130&nbsp;km or more in a day. Locust swarms can vary from less than one square kilometre to several hundred square kilometres with 40 to 80 million individuals per square kilometre. An adult locust can consume its own weight (several grams) in fresh food per day. For every million locusts, one ton of food is eaten.

In Africa, the last serious widespread plague of ''[[Locusta migratoria migratorioides|L. m. migratorioides]]'' occurred from 1928 to 1942. Since then, environmental transformations have made the development of swarms from the African migratory locust unlikely. Nevertheless, potential outbreaks are constantly monitored as plagues can be devastating.
The Malagasy migratory locust (''L. m. capito'') still regularly swarms (roughly twice every ten years). The [[desert locust]], which is very similar to the African migratory locust, remains a major threat too.

Locust survey and control are primarily the responsibility of the Ministry of Agriculture in locust-affected countries and are operations undertaken by national locust units. The [[Food and Agriculture Organization]] (FAO) of the [[United Nations]] provides information on the general locust situation to all interested countries and gives warnings and forecasts to those countries in danger of invasion.

===As food ===
The migratory locust is an [[edible insects|edible insect]].<ref name=Oonincx>{{cite journal |last=Oonincx |first=Dennis G. A. B. |author2=van Itterbeeck, Joost |author3=Heetkamp, Marcel J. W. |author4=van den Brand, Henry |author5=van Loon, Joop J. A. |author6=van Huis, Arnold |author7=Hansen, Immo A. |title=An Exploration on Greenhouse Gas and Ammonia Production by Insect Species Suitable for Animal or Human Consumption |journal=PLOS ONE |date=29 December 2010 |volume=5 |issue=12 |pages=e14445 |doi=10.1371/journal.pone.0014445 |pmid=21206900 |pmc=3012052|bibcode=2010PLoSO...514445O |doi-access=free }}</ref><ref>[http://orbi.ulg.ac.be/bitstream/2268/153905/1/chap15.pdf Barsics, F., 2010. L'alimentation des Populations locales de Madagascar productrices de Vers à Soie. - Univ. de Liège.: 1-84.]</ref> In Europe, the migratory locust is officially approved for the use in food in [[Switzerland]] (since May 2017).<ref>Bundesamt für Lebensmittelsicherheit und Veterinärwesen (2017-04-28): [https://www.blv.admin.ch/blv/de/home/lebensmittel-und-ernaehrung/lebensmittelsicherheit/einzelne-lebensmittel/insekten.html#-399311545 "Insects as food"] (German only)</ref> On 2 July 2021, the [[European Food Safety Agency]] published a scientific opinion stating that the consumption of migratory locust in frozen, dried or ground state is safe for humans.<ref>EFSA (2 July 2021): ''[https://efsa.onlinelibrary.wiley.com/doi/full/10.2903/j.efsa.2021.6667 Safety of frozen and dried formulations from migratory locust (Locusta migratoria) as a Novel food pursuant to Regulation (EU) 2015/2283].'' In: EFSA Journal. Vol. 19, Issue 7. DOI: https://doi.org/10.2903/j.efsa.2021.6667.</ref> On 12 November 2021, the EU member states gave their green light for the EU Commission to authorize the placing on the market of migratory locust as a food. This is one of the final steps in the [[novel food]] authorization procedure. As a next step, the Commission will now adopt a legal act.<ref>European Commission (2 November 2021): ''[https://ec.europa.eu/food/safety/novel-food/authorisations/approval-second-insect-novel-food_de Approval of second insect as a Novel Food]''.</ref>

==Subspecies of ''Locusta migratoria''==
[[File:Locusta m. migratorioides female.jpg|thumb|''L. m. migratorioides'' female (solitary)]]
[[File:Locusta migratoria migratorioides male.jpg|thumb|''L. m. migratorioides'' male (solitary)]]
''L. migratoria'' is found over a vast geographic area, and its range covers many different ecological zones.  Because of this, numerous subspecies have been described; however, not all experts agree on the validity of some of these subspecies.<ref name="Chapuis">{{cite journal|last1=Chapuis|first1=M-P.|last2=Lecoq|first2=M.|last3=Michalakis|first3=Y.|last4=Loiseau|first4=A.|author-link4=Annick Loiseau|last5=Sword|first5=G. A.|last6=Piry|first6=S.|last7=Estoup|first7=A.|date=1 August 2008|title=Do outbreaks affect genetic population structure? A worldwide survey in a pest plagued by microsatellite null alleles|journal=Molecular Ecology|volume=17|issue=16|pages=3640–3653|doi=10.1111/j.1365-294X.2008.03869.x|pmid=18643881|s2cid=4185861}}</ref>

* ''[[Locusta migratoria burmana|L. m. burmana]]'' <small>Ramme, 1951</small>
* ''[[Locusta migratoria capito|L. m. capito]]'' <small>Saussure, 1884</small> (Malagasy migratory locust: Madagascar)
* ''[[Locusta migratoria cinerascens|L. m. cinerascens]]'' <small>Fabricius, 1781</small> (Italy, Spain)
* ''[[Locusta migratoria migratoria|L. m. migratoria]]'' <small>(Linnaeus, 1758) </small> (europe)
* ''[[Locusta migratoria manilensis]]'' <small>(Meyen, 1875)</small>
* ''[[Locusta migratoria migratorioides|L. m. migratorioides]]'' <small>(Fairmaire & L.J. Reiche, 1849)</small> (African migratory locust: Africa and Atlantic islands)
* ''[[Locusta migratoria tibetensis|L. m. tibetensis]]'' <small>Chen, Yonglin, 1963</small>
* ''L. m. danica'' <small>(Linnaeus, 1767)</small> = ''L. m. migratoria'' <small>(Linnaeus, 1758)</small>
* ''L. m. gallica'' <small>Remaudičre, 1947</small> =  ''L. m. migratoria'' <small>(Linnaeus, 1758)</small>
* ''L. m. solitaria'' <small>Carthy, 1955</small> = ''L. m. migratoria'' <small>(Linnaeus, 1758)</small>

== Other species called 'locusts' ==
Other species of Orthoptera that display gregarious and migratory behaviour are called ''locusts''. This includes:

* American locust, ''[[Schistocerca americana]]''
* [[Australian plague locust]], ''Chortoicetes terminifera''
* Bombay locust, ''[[Nomadacris succincta]]''
* [[Brown locust]], ''Locustana pardalina''
* [[Desert locust]], ''Schistocerca gregaria''
* Egyptian locust, ''[[Anacridium aegyptium]]''
* Italian locust, ''[[Calliptamus italicus]]''
* Moroccan locust, ''[[Dociostaurus maroccanus]]''
* [[Red locust]], ''Nomadacris septemfasciata''
* [[Rocky Mountain locust]], ''Melanoplus spretus'' – extinct
* Sahelian tree locusts, ''[[Anacridium]] melanorhodon''
* [[Spur-throated locust]], ''[[Austracris]] guttulosa'' (note: "spur-throated grasshoppers/locusts" may also refer to spp. in other genera)
* Sudan plague locust, ''[[Aiolopus]] simulatrix''

The [[Senegalese grasshopper]] (''Oedaleus senegalensis'') also often displays locust-like behaviour in the Sahel region.

==Photos==
<gallery>
Locusta migratoria L1.jpg|First instar nymph (gregarious)
Locusta migratoria L2 and L4.jpg|Second and fourth instar nymphs (gregarious)
Locusta migratoria L3.jpg|Third instar nymphs (gregarious)
Locusta migratoria L4.jpg|Fourth instar nymph (gregarious)
Locusta migratoria part of hopper band.jpg|Part of a hopper band in Kazakhstan
Locusta migratoria hopper band4.jpg|Hopper band in Kazakhstan
</gallery>

==See also==
* [[2013 Madagascar locust infestation]]
* [[Australian Plague Locust Commission]] (APLC)

==Footnotes==
{{Reflist}}

== References ==
*{{cite book |last=Walker |first=Annette |title=The Reed Handbook of Common New Zealand Insects |year=2000 |publisher=Reed |location=Auckland |isbn=978-0-7900-0718-2 |author2=Heath, Eric}}
*{{cite book |title=Locust Handbook |year=1988 |publisher=Overseas Development Natural Resources Institute |location=London |isbn=978-0-85954-232-6 |edition=2nd |editor=Steedman, Alison}}

== External links ==
{{Commons category|Locusta migratoria}}
* [http://www.fao.org/NEWS/GLOBAL/LOCUSTS/LOCFAQ.htm Food and Agriculture Organization (FAO)] {{Webarchive|url=https://web.archive.org/web/20041030004352/http://www.fao.org/News/GLOBAL/LOCUSTS/LOCFAQ.htm |date=2004-10-30 }}
* [https://web.archive.org/web/20050501042449/http://www.univ-pau.fr/~degreg/site_grasshopper/site_anglais/phases.htm#PP The phenomenon of phases] 
* [https://www.biolib.cz/cz/formsearch/?action=execute&searcharea=1&string=locusta+migratoria Biolib] 
* [https://web.archive.org/web/20070930215432/http://www.faunaeur.org/full_results.php?id=234721 Fauna Europaea] 
* Genus ''Locusta'' at [http://orthoptera.speciesfile.org/Common/basic/Taxa.aspx?TaxonNameID=51512 Orthoptera Species File on Line]
* [http://bio.acousti.ca/taxonomy/term/67 Sound recordings of Migratory Locust at BioAcoustica]

{{Taxonbar|from1=Q1059580|from2=Q15122569}}

[[Category:Oedipodinae]]
[[Category:Orthoptera of Africa]]
[[Category:Orthoptera of Asia]]
[[Category:Orthoptera of Europe]]
[[Category:Orthoptera of Oceania]]
[[Category:Insects of Australia]]
[[Category:Acrididae of New Zealand]]
[[Category:Insects described in 1758]]
[[Category:Edible insects]]
[[Category:Animal migration]]
[[Category:Taxa named by Carl Linnaeus]]
[[Category:Insect pests of millets]]