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These are: solitarious, where they will actively avoid other locusts, and gregarious where they will seek them out. It is in this gregarious state that locusts can form massive and destructive flying swarms or plagues. However, these swarms are usually preceded by the aggregation of juvenile wingless locust nymphs. In this paper we attempt to understand how the distribution of food resources affect the group formation process. We do this by introducing a multi-population partial differential equation model that includes non-local locust interactions, local locust and food interactions, and gregarisation. Our results suggest that, food acts to increase the maximum density of locust groups, lowers the percentage of the population that needs to be gregarious for group formation, and decreases both the required density of locusts and time for group formation around an optimal food width. Finally, by looking at foraging efficiency within the numerical experiments we find that there exists a foraging advantage to being gregarious.<\/jats:p>","DOI":"10.1371\/journal.pcbi.1008353","type":"journal-article","created":{"date-parts":[[2021,7,7]],"date-time":"2021-07-07T14:42:22Z","timestamp":1625668942000},"page":"e1008353","update-policy":"https:\/\/doi.org\/10.1371\/journal.pcbi.corrections_policy","source":"Crossref","is-referenced-by-count":20,"title":["Modelling locust foraging: How and why food affects group formation"],"prefix":"10.1371","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4588-5319","authenticated-orcid":true,"given":"Fillipe","family":"Georgiou","sequence":"first","affiliation":[]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7506-6835","authenticated-orcid":true,"given":"Camille","family":"Buhl","sequence":"additional","affiliation":[]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5061-9563","authenticated-orcid":true,"given":"J. E. F.","family":"Green","sequence":"additional","affiliation":[]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9184-8941","authenticated-orcid":true,"given":"Bishnu","family":"Lamichhane","sequence":"additional","affiliation":[]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9885-3287","authenticated-orcid":true,"given":"Ngamta","family":"Thamwattana","sequence":"additional","affiliation":[]}],"member":"340","published-online":{"date-parts":[[2021,7,7]]},"reference":[{"key":"pcbi.1008353.ref001","volume-title":"Locust handbook","author":"A Steedman","year":"1990","edition":"3"},{"issue":"12","key":"pcbi.1008353.ref002","doi-asserted-by":"crossref","first-page":"e1004522","DOI":"10.1371\/journal.pcbi.1004522","article-title":"Locust Collective Motion and Its Modeling","volume":"11","author":"G Ariel","year":"2015","journal-title":"PLOS Computational Biology"},{"key":"pcbi.1008353.ref003","unstructured":"Food T, of the United Nations (2004) AO. Hunger in their wake: inside the battle against the desert locust;. Available from: http:\/\/www.fao.org\/Newsroom\/en\/focus\/2004\/51040\/index.html."},{"key":"pcbi.1008353.ref004","volume-title":"A handbook for their study and control","author":"of Entomology II","year":"1928"},{"issue":"3","key":"pcbi.1008353.ref005","doi-asserted-by":"crossref","first-page":"370","DOI":"10.1080\/00263206.2014.976624","article-title":"The 1915 Locust Attack in Syria and Palestine and its Role in the Famine During the First World War","volume":"51","author":"ZJ Foster","year":"2015","journal-title":"Middle Eastern Studies"},{"key":"pcbi.1008353.ref006","first-page":"533","volume-title":"Locusts the Forgotten Plague Part II: History of Locust Plagues","author":"CA Spinage","year":"2012"},{"issue":"2","key":"pcbi.1008353.ref007","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1007\/s12665-017-7194-4","article-title":"Climate, disasters, wars and the collapse of the Ming Dynasty","volume":"77","author":"Q Liu","year":"2018","journal-title":"Environmental Earth Sciences"},{"key":"pcbi.1008353.ref008","unstructured":"Kennedy M. Why Are Swarms Of Locusts Wreaking Havoc In East Africa? NPRorg. 2020."},{"key":"pcbi.1008353.ref009","unstructured":"Food T, of the United Nations AO. FAO\u2014News Article: Alarm over Desert Locusts increases as new generation of the destructive pests starts breeding in Horn of Africa. 2020."},{"key":"pcbi.1008353.ref010","first-page":"1","volume-title":"Locust Phase Polyphenism: An Update","author":"MP Pener","year":"2009"},{"issue":"2","key":"pcbi.1008353.ref011","doi-asserted-by":"crossref","first-page":"173","DOI":"10.1016\/0022-1910(94)90089-2","article-title":"Parental effects on the behaviour and colouration of nymphs of the desert locust Schistocerca gregaria","volume":"40","author":"M Saiful Islam","year":"1994","journal-title":"Journal of Insect Physiology"},{"key":"pcbi.1008353.ref012","article-title":"Identification of solitary and gregarious populations of the desert locust, Schistocerca gregaria, by experimental breeding (Caelifera: Acrididae)","author":"GH Schmidt","year":"1999","journal-title":"Entomologia generalis"},{"issue":"4","key":"pcbi.1008353.ref013","doi-asserted-by":"crossref","first-page":"461","DOI":"10.1111\/j.1469-185X.1999.tb00038.x","article-title":"A behavioural analysis of phase change in the desert locust","volume":"74","author":"SJ Simpson","year":"1999","journal-title":"Biological Reviews"},{"issue":"5","key":"pcbi.1008353.ref014","doi-asserted-by":"crossref","first-page":"723","DOI":"10.1086\/284884","article-title":"The Evolution of Gregariousness in Distasteful Insects as a Defense Against Predators","volume":"132","author":"B Sillen-Tullberg","year":"1988","journal-title":"The American Naturalist"},{"issue":"1399","key":"pcbi.1008353.ref015","doi-asserted-by":"crossref","first-page":"889","DOI":"10.1098\/rspb.1998.0374","article-title":"Aposematism and gregariousness: the combined effect of group size and coloration on signal repellence","volume":"265","author":"G Gamberale","year":"1998","journal-title":"Proceedings of the Royal Society of London Series B: Biological Sciences"},{"issue":"2","key":"pcbi.1008353.ref016","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1006\/jtbi.1996.0267","article-title":"Epidemic Diseases and Host Clustering: An Optimum Cluster Size Ensures Maximum Survival","volume":"184","author":"MG Watve","year":"1997","journal-title":"Journal of Theoretical Biology"},{"issue":"2","key":"pcbi.1008353.ref017","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1007\/s00265-010-1041-x","article-title":"Group structure in locust migratory bands","volume":"65","author":"J Buhl","year":"2011","journal-title":"Behavioral Ecology and Sociobiology"},{"issue":"8","key":"pcbi.1008353.ref018","doi-asserted-by":"crossref","first-page":"949","DOI":"10.1016\/j.jinsphys.2010.05.005","article-title":"Phase polyphenism and preventative locust management","volume":"56","author":"GA Sword","year":"2010","journal-title":"Journal of Insect 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Buhl","year":"2012","journal-title":"Interface Focus"},{"issue":"1","key":"pcbi.1008353.ref026","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1140\/epjst\/e2008-00633-y","article-title":"A model for rolling swarms of locusts","volume":"157","author":"CM Topaz","year":"2008","journal-title":"The European Physical Journal Special Topics"},{"issue":"4","key":"pcbi.1008353.ref027","doi-asserted-by":"crossref","first-page":"709","DOI":"10.1137\/130925669","article-title":"Nonlocal Aggregation Models: A Primer of Swarm Equilibria","volume":"55","author":"A Bernoff","year":"2013","journal-title":"SIAM Review"},{"issue":"6","key":"pcbi.1008353.ref028","doi-asserted-by":"crossref","first-page":"534","DOI":"10.1007\/s002850050158","article-title":"A non-local model for a swarm","volume":"38","author":"A Mogilner","year":"1999","journal-title":"Journal of Mathematical 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Codling","year":"2008","journal-title":"Journal of The Royal Society Interface"},{"issue":"3","key":"pcbi.1008353.ref038","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1111\/j.2517-6161.1977.tb01627.x","article-title":"Spatial Contact Models for Ecological and Epidemic Spread","volume":"39","author":"D Mollison","year":"1977","journal-title":"Journal of the Royal Statistical Society Series B (Methodological)"},{"issue":"3","key":"pcbi.1008353.ref039","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1016\/S0022-5193(03)00258-3","article-title":"Modelling the movement of interacting cell populations","volume":"225","author":"KJ Painter","year":"2003","journal-title":"Journal of Theoretical Biology"},{"key":"pcbi.1008353.ref040","volume-title":"Lectures in Mathematics","author":"L Ambrosio","year":"2008","edition":"2"},{"issue":"1","key":"pcbi.1008353.ref041","doi-asserted-by":"crossref","first-page":"397","DOI":"10.1137\/130923786","article-title":"Stationary States and Asymptotic Behavior of Aggregation Models with Nonlinear Local Repulsion","volume":"13","author":"M Burger","year":"2014","journal-title":"SIAM Journal on Applied Dynamical Systems"},{"key":"pcbi.1008353.ref042","doi-asserted-by":"crossref","DOI":"10.1201\/9781420035223","volume-title":"CRC Concise Encyclopedia of Mathematics","author":"EW Weisstein","year":"2002"},{"issue":"1704","key":"pcbi.1008353.ref043","doi-asserted-by":"crossref","first-page":"356","DOI":"10.1098\/rspb.2010.1447","article-title":"Nutritional state and collective motion: from individuals to mass migration","volume":"278","author":"S Bazazi","year":"2011","journal-title":"Proceedings of the Royal Society B: Biological Sciences"},{"issue":"8","key":"pcbi.1008353.ref044","doi-asserted-by":"crossref","first-page":"937","DOI":"10.1016\/j.jinsphys.2010.04.023","article-title":"Behavioural phase change in the Australian plague locust, Chortoicetes terminifera, is triggered by tactile stimulation of the antennae","volume":"56","author":"DA Cullen","year":"2010","journal-title":"Journal of Insect Physiology"},{"key":"pcbi.1008353.ref045","first-page":"167","volume-title":"Chapter Seven\u2014From Molecules to Management: Mechanisms and Consequences of Locust Phase Polyphenism. vol. 53 of Insect Epigenetics","author":"DA Cullen","year":"2017"},{"issue":"28","key":"pcbi.1008353.ref046","doi-asserted-by":"crossref","first-page":"11228","DOI":"10.1073\/pnas.1201739109","article-title":"Role of social interactions in dynamic patterns of resource patches and forager aggregation","volume":"109","author":"N Tania","year":"2012","journal-title":"Proceedings of the National Academy of Sciences"},{"key":"pcbi.1008353.ref047","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1016\/j.jtbi.2012.06.024","article-title":"The effects of facilitation and competition on group foraging in patches","volume":"310","author":"M Lagu\u00eb","year":"2012","journal-title":"Journal of Theoretical Biology"},{"issue":"2","key":"pcbi.1008353.ref048","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1016\/0040-5809(76)90040-X","article-title":"Optimal foraging, the marginal value theorem","volume":"9","author":"EL Charnov","year":"1976","journal-title":"Theoretical population biology"},{"key":"pcbi.1008353.ref049","unstructured":"Ellis PE, Ashall C. Field Studies on diurnal Behaviour, Movement and Aggregation in the Desert Locust (Schistocerca gregaria Forsk\u00e5l). Field Studies on diurnal Behaviour, Movement and Aggregation in the Desert Locust (Schistocerca gregaria Forsk\u00e5l). 1957;(25)."},{"key":"pcbi.1008353.ref050","doi-asserted-by":"crossref","DOI":"10.1093\/oso\/9780198508175.001.0001","volume-title":"Living in Groups","author":"J Krause","year":"2002"},{"issue":"1","key":"pcbi.1008353.ref051","first-page":"20","article-title":"Predator percolation, insect outbreaks, and phase polyphenism","volume":"19","author":"R Am","year":"2008","journal-title":"Current Biology: CB"},{"issue":"10","key":"pcbi.1008353.ref052","doi-asserted-by":"crossref","first-page":"1158","DOI":"10.1111\/j.1461-0248.2012.01840.x","article-title":"Cannibalism can drive the evolution of behavioural phase polyphenism in locusts","volume":"15","author":"V Guttal","year":"2012","journal-title":"Ecology Letters"},{"issue":"1727","key":"pcbi.1008353.ref053","article-title":"Collective foraging in spatially complex nutritional environments","volume":"372","author":"M Lihoreau","year":"2017","journal-title":"Philosophical Transactions of the Royal Society of London Series B, Biological Sciences"},{"issue":"3","key":"pcbi.1008353.ref054","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1007\/s10905-019-09727-8","article-title":"Effects of starvation and Vegetation Distribution on Locust Collective Motion","volume":"32","author":"J Dkhili","year":"2019","journal-title":"Journal of Insect Behavior"},{"issue":"1","key":"pcbi.1008353.ref055","doi-asserted-by":"crossref","first-page":"010602","DOI":"10.1103\/PhysRevLett.102.010602","article-title":"Collective Motion due to Individual Escape and Pursuit Response","volume":"102","author":"P Romanczuk","year":"2009","journal-title":"Physical Review Letters"}],"updated-by":[{"DOI":"10.1371\/journal.pcbi.1009695","type":"correction","label":"Correction","source":"publisher","updated":{"date-parts":[[2021,12,20]],"date-time":"2021-12-20T00:00:00Z","timestamp":1639958400000}},{"DOI":"10.1371\/journal.pcbi.1008353","type":"new_version","label":"New version","source":"publisher","updated":{"date-parts":[[2021,7,19]],"date-time":"2021-07-19T00:00:00Z","timestamp":1626652800000}}],"container-title":["PLOS Computational Biology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pcbi.1008353","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,6,24]],"date-time":"2024-06-24T17:58:58Z","timestamp":1719251938000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pcbi.1008353"}},"subtitle":[],"editor":[{"given":"Iain","family":"Couzin","sequence":"first","affiliation":[]}],"short-title":[],"issued":{"date-parts":[[2021,7,7]]},"references-count":55,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2021,7,7]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pcbi.1008353","relation":{"has-preprint":[{"id-type":"doi","id":"10.1101\/2020.09.21.305896","asserted-by":"object"}]},"ISSN":["1553-7358"],"issn-type":[{"value":"1553-7358","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,7,7]]}}}