{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T04:09:28Z","timestamp":1775016568862,"version":"3.50.1"},"update-to":[{"DOI":"10.1371\/journal.pcbi.1009869","type":"new_version","label":"New version","source":"publisher","updated":{"date-parts":[[2022,3,2]],"date-time":"2022-03-02T00:00:00Z","timestamp":1646179200000}}],"reference-count":61,"publisher":"Public Library of Science (PLoS)","issue":"2","license":[{"start":{"date-parts":[[2022,2,17]],"date-time":"2022-02-17T00:00:00Z","timestamp":1645056000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000001","name":"National Science Foundation","doi-asserted-by":"publisher","award":["1761918"],"award-info":[{"award-number":["1761918"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.ploscompbiol.org"],"crossmark-restriction":false},"short-container-title":["PLoS Comput Biol"],"abstract":"\n Collective living systems regularly achieve cooperative emergent functions that individual organisms could not accomplish alone. The rafts of fire ants (Solenopsis invicta) are often studied in this context for their ability to create aggregated structures comprised entirely of their own bodies, including tether-like protrusions that facilitate exploration of and escape from flooded environments. While similar protrusions are observed in cytoskeletons and cellular aggregates, they are generally dependent on morphogens or external gradients leaving the isolated role of local interactions poorly understood. Here we demonstrate through an ant-inspired, agent-based numerical model how protrusions in ant rafts may emerge spontaneously due to local interactions. The model is comprised of a condensed structural network of agents that represents the monolayer of interconnected worker ants, which floats on the water and gives ant rafts their form. Experimentally, this layer perpetually contracts, which we capture through the pairwise contraction of all neighboring structural agents at a strain rate of\n \n \n \n \n \n \n d<\/mml:mi>\n <\/mml:mrow>\n \u02d9<\/mml:mo>\n <\/mml:mover>\n <\/mml:math>\n <\/jats:alternatives>\n <\/jats:inline-formula>\n . On top of the structural layer, we model a dispersed, on-lattice layer of motile agents that represents free ants, which walk on top of the floating network. Experimentally, these self-propelled free ants walk with some mean persistence length and speed that we capture through an ant-inspired phenomenological model. Local interactions occur between neighboring free ants within some radius of detection,\n R<\/jats:italic>\n , and the persistence length of freely active agents is tuned through a noise parameter,\n \u03b7<\/jats:italic>\n as introduced by the Vicsek model. Both\n R<\/jats:italic>\n and\n \u03b7<\/jats:italic>\n where fixed to match the experimental trajectories of free ants. Treadmilling of the raft occurs as agents transition between the structural and free layers in accordance with experimental observations. Ultimately, we demonstrate how phases of exploratory protrusion growth may be induced by increased ant activity as characterized by a dimensionless parameter,\n \n \n \n \n A<\/mml:mi>\n <\/mml:math>\n <\/jats:alternatives>\n <\/jats:inline-formula>\n . These results provide an example in which functional morphogenesis of a living system may emerge purely from local interactions at the constituent length scale, thereby providing a source of inspiration for the development of decentralized, autonomous active matter and swarm robotics.\n <\/jats:p>","DOI":"10.1371\/journal.pcbi.1009869","type":"journal-article","created":{"date-parts":[[2022,2,17]],"date-time":"2022-02-17T13:49:39Z","timestamp":1645105779000},"page":"e1009869","update-policy":"https:\/\/doi.org\/10.1371\/journal.pcbi.corrections_policy","source":"Crossref","is-referenced-by-count":12,"title":["Computational exploration of treadmilling and protrusion growth observed in fire ant rafts"],"prefix":"10.1371","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9651-5978","authenticated-orcid":true,"given":"Robert J.","family":"Wagner","sequence":"first","affiliation":[]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6138-1431","authenticated-orcid":true,"given":"Franck J.","family":"Vernerey","sequence":"additional","affiliation":[]}],"member":"340","published-online":{"date-parts":[[2022,2,17]]},"reference":[{"key":"pcbi.1009869.ref001","doi-asserted-by":"crossref","first-page":"629","DOI":"10.1140\/epjst\/e2015-50264-4","article-title":"Entangled active matter: From cells to ants.","volume":"225","author":"DL Hu","year":"2016","journal-title":"Eur Phys J Spec Top"},{"key":"pcbi.1009869.ref002","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1016\/j.cis.2018.11.006","article-title":"Biological active matter aggregates: Inspiration for smart colloidal materials","volume":"263","author":"FJ Vernerey","year":"2019","journal-title":"Advances in Colloid and Interface Science"},{"key":"pcbi.1009869.ref003","doi-asserted-by":"crossref","first-page":"1193","DOI":"10.1038\/s41567-018-0262-1","article-title":"Collective mechanical adaptation of honeybee swarms","volume":"14","author":"O Peleg","year":"2018","journal-title":"Nature Phys"},{"key":"pcbi.1009869.ref004","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1016\/j.jtbi.2017.09.017","article-title":"Optimal construction of army ant living bridges","volume":"435","author":"JM Graham","year":"2017","journal-title":"Journal of Theoretical Biology"},{"key":"pcbi.1009869.ref005","doi-asserted-by":"crossref","first-page":"4214","DOI":"10.1039\/C6SM00063K","article-title":"Ant aggregations self-heal to compensate for the Ringelmann effect","volume":"12","author":"S Phonekeo","year":"2016","journal-title":"Soft Matter"},{"key":"pcbi.1009869.ref006","doi-asserted-by":"crossref","first-page":"e95112","DOI":"10.1371\/journal.pone.0095112","article-title":"Physical and Biological Determinants of Collective Behavioural Dynamics in Complex Systems: Pulling Chain Formation in the Nest-Weaving Ant Oecophylla smaragdina.","volume":"9","author":"T Bochynek","year":"2014","journal-title":"PLOS ONE."},{"key":"pcbi.1009869.ref007","doi-asserted-by":"crossref","first-page":"e0156681","DOI":"10.1371\/journal.pone.0156681","article-title":"The Antsy Social Network: Determinants of Nest Structure and Arrangement in Asian Weaver Ants.","volume":"11","author":"K. 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