{{Short description|Species of ant}} {{use dmy dates|date=June 2023}} {{Speciesbox | image = Linepithema Argentine ant.jpg | taxon = Linepithema humile | authority = (Mayr, 1868) }}

The '''Argentine ant''' ('''''Linepithema humile''''', formerly ''Iridomyrmex humilis'') is an ant native to northern Argentina, Uruguay, Paraguay, Bolivia and southern Brazil.<ref>{{Cite book |last1=Hölldobler |first1=B. |title=The Ants |last2=Wilson |first2=E. O. |publisher=Belknap Press |year=1990 |isbn=978-0-674-04075-5 |location=}}</ref> This invasive species was inadvertently introduced by humans on a global scale<ref name=":0" /><ref>{{Cite journal |last1=Vogel |first1=Valérie |last2=Pedersen |first2=Jes S. |last3=Giraud |first3=Tatiana |last4=Krieger |first4=Michael J. B. |last5=Keller |first5=Laurent |date=2010 |title=The worldwide expansion of the Argentine ant |journal=Diversity and Distributions |volume=16 |issue=1 |pages=170–186 |doi=10.1111/j.1472-4642.2009.00630.x |s2cid=41146103 |issn=1366-9516|doi-access=free |bibcode=2010DivDi..16..170V }}</ref><ref>{{Cite journal |last=Wild |first=Alexander L. |date=2004 |title=Taxonomy and distribution of the Argentine ant, ''Linepithema humile'' (Hymenoptera: Formicidae) |journal=Annals of the Entomological Society of America |volume=97 |issue=6 |pages=1204–1215|doi=10.1603/0013-8746(2004)097[1204:TADOTA]2.0.CO;2 |s2cid=11799437 |doi-access=free }}</ref> and has become established in many Mediterranean climate areas,<ref name = Relationships /><ref>{{Cite journal |last1=Roura-Pascual |first1=Núria |last2=Hui |first2=Cang |last3=Ikeda |first3=Takayoshi |last4=Leday |first4=Gwénaël |last5=Richardson |first5=David M. |last6=Carpintero |first6=Soledad |last7=Espadaler |first7=Xavier |last8=Gómez |first8=Crisanto |last9=Guénard |first9=Benoit |date=2011-01-04 |title=Relative roles of climatic suitability and anthropogenic influence in determining the pattern of spread in a global invader |journal=Proceedings of the National Academy of Sciences |language=en |volume=108 |issue=1 |pages=220–225 |bibcode=2011PNAS..108..220R |doi=10.1073/pnas.1011723108 |issn=0027-8424 |pmc=3017164 |pmid=21173219 |doi-access=free}}</ref><ref>{{Cite web |title=''Linepithema humile'' |url=https://www.antweb.org/description.do?genus=linepithema&species=humile&rank=species |access-date=2023-02-27 |website=Antweb.org |language=en}}</ref><ref name=":1">{{Cite journal |last1=Hartley |first1=Stephen |last2=Harris |first2=Richard |last3=Lester |first3=Philip J. |date=2006-09-01 |title=Quantifying uncertainty in the potential distribution of an invasive species: climate and the Argentine ant |journal=Ecology Letters |language=en |volume=9 |issue=9 |pages=1068–1079 |doi=10.1111/j.1461-0248.2006.00954.x |issn=1461-0248 |pmid=16925656|bibcode=2006EcolL...9.1068H }}</ref> including South Africa,<ref>{{Cite journal |last1=Mothapo |first1=Natasha P |last2=Wossler |first2=Theresa C |date=2011 |title=Behavioural and chemical evidence for multiple colonisation of the Argentine ant, ''Linepithema humile'', in the Western Cape, South Africa |journal=BMC Ecology |volume=11 |issue=1 |page=6 |doi=10.1186/1472-6785-11-6 |pmid=21288369 |issn=1472-6785|pmc=3041649 |doi-access=free |bibcode=2011BMCE...11....6M }}</ref> New Zealand,<ref>{{Cite journal |last1=Ward |first1=D. F. |last2=Green |first2=C. |last3=Harris |first3=R. J. |last4=Hartley |first4=S. |last5=Lester |first5=P. J. |last6=Stanley |first6=M. C. |last7=Suckling |first7=D. M. |last8=Toft |first8=R. J. |date=2010 |title=Twenty years of Argentine ants in New Zealand: past research and future priorities for applied management |journal=New Zealand Entomologist |volume=33 |issue=1 |pages=68–78 |doi=10.1080/00779962.2010.9722193 |bibcode=2010NZEnt..33...68W |s2cid=13723013 |issn=0077-9962}}</ref> Japan,<ref>{{Cite journal |last1=Park |first1=Sang-Hyun |last2=Hosoishi |first2=Shingo |last3=Ogata |first3=Kazuo |date=2014-08-28 |title=Long-term impacts of Argentine ant invasion of urban parks in Hiroshima, Japan |journal=Journal of Ecology and Environment |volume=37 |issue=3 |pages=123–129 |doi=10.5141/ecoenv.2014.015 |issn=2287-8327|doi-access=free |bibcode=2014JEcEn..37..123P }}</ref> Easter Island,<ref>{{Cite journal |last1=Varela |first1=Andrea Isabel |last2=Luna |first2=Nicolas |last3=Luna-Jorquera |first3=Guillermo |date=2018-05-02 |title=Assessing potential Argentine Ant recruitment to pipping eggs in the Red-tailed Tropicbird on Rapa Nui (Easter Island) |journal=Emu - Austral Ornithology |volume=118 |issue=4 |pages=381–385 |doi=10.1080/01584197.2018.1464372 |bibcode=2018EmuAO.118..381V |s2cid=89659987 |issn=0158-4197}}</ref> Australia,<ref name=suhr>{{Cite journal |last1=Suhr |first1=Elissa L. |last2=O'Dowd |first2=Dennis J. |last3=McKechnie |first3=Stephen W. |last4=Mackay |first4=Duncan A. |date=2010-12-06 |title=Genetic structure, behaviour and invasion history of the Argentine ant supercolony in Australia |journal=Evolutionary Applications |volume=4 |issue=3 |pages=471–484 |doi=10.1111/j.1752-4571.2010.00161.x |pmid=25567996 |issn=1752-4571|pmc=3352524 }}</ref> the Azores,<ref>{{cite journal | last1=Wetterer | first1=James K. | last2=Espadaler | first2=Xavier | last3=Wetterer | first3=Andrea L. | last4=Cabral | first4=Susana G.M. | title=Native and exotic ants of the Azores (Hymenoptera: Formicidae) | journal=Sociobiology | publisher=California State University, Chico | volume=44 | issue=1 | date=2004-07-26 | issn=0361-6525 | pages=1–20 | url=https://portalrecerca.uab.cat/ca/publications/native-and-exotic-ants-of-the-azores-hymenoptera-formicidae | language=ca | access-date=2024-04-05}}</ref> Europe,<ref>{{Cite journal |last1=Carpintero |first1=S. |last2=Retana |first2=J. |last3=Cerda |first3=X. |last4=Reyes-Lopez |first4=J. |last5=Arias de Reyna |first5=L. |date=2007-10-01 |title=Exploitative Strategies of the Invasive Argentine Ant (''Linepithema humile'') and Native Ant Species in a Southern Spanish Pine Forest |journal=Environmental Entomology |volume=36 |issue=5 |pages=1100–1111 |doi=10.1093/ee/36.5.1100 |pmid=18284734 |issn=0046-225X|doi-access=free }}</ref> Hawaii,<ref>{{Cite book |last1=Reimer |first1=N. |title=Applied Myrmecology |last2=Beardsley |first2=J. W. |last3=John |first3=G. |publisher=CRC Press |year=2019 |pages=40–50 |chapter=Pest ants in the Hawaiian Islands}}</ref> and the continental United States.<ref>{{Cite journal |last=Holway |first=David A. |date=1995 |title=Distribution of the Argentine ant (''Linepithema humile'') in northern California |journal=Conservation Biology |volume=9 |issue=6 |pages=1634–1637|doi=10.1046/j.1523-1739.1995.09061634.x |bibcode=1995ConBi...9.1634H }}</ref> Argentine ants are significant pests within agricultural and urban settings,<ref>{{Cite journal |last1=Silverman |first1=Jules |last2=Brightwell |first2=Robert John |date=2008-01-01 |title=The Argentine Ant: Challenges in Managing an Invasive Unicolonial Pest |journal=Annual Review of Entomology |volume=53 |issue=1 |pages=231–252 |doi=10.1146/annurev.ento.53.103106.093450 |pmid=17877449 |issn=0066-4170}}</ref><ref>{{Cite book |last1=Rust |first1=M. K. |title=Applied Myrmecology |last2=Knight |first2=R. L. |publisher=CRC Press |year=2019 |pages=663–670 |chapter=Controlling Argentine ants in urban situations}}</ref><ref>{{Cite journal |last1=Moreno |first1=D. S. |last2=Haney |first2=P. B. |last3=Luck |first3=R. F. |date=1987-02-01 |title=Chlorpyrifos and Diazinon as Barriers to Argentine Ant (Hymenoptera: Formicidae) Foraging on Citrus Trees |journal=Journal of Economic Entomology |volume=80 |issue=1 |pages=208–214 |doi=10.1093/jee/80.1.208 |issn=1938-291X}}</ref> and are documented to cause substantial harm to communities of native arthropods,<ref>{{Cite journal |last1=Cole |first1=F. Russell |last2=Medeiros |first2=Arthur C. |last3=Loope |first3=Lloyd L. |last4=Zuehlke |first4=William W. |date=1992 |title=Effects of the Argentine Ant on Arthropod Fauna of Hawaiian High-Elevation Shrubland |journal=Ecology |volume=73 |issue=4 |pages=1313–1322 |doi=10.2307/1940678 |jstor=1940678 |bibcode=1992Ecol...73.1313C |issn=0012-9658}}</ref><ref>{{Cite journal |last=Holway |first=David A. |date=1998-08-10 |title=Effect of Argentine ant invasions on ground-dwelling arthropods in northern California riparian woodlands |journal=Oecologia |volume=116 |issue=1–2 |pages=252–258 |doi=10.1007/s004420050586 |pmid=28308533 |bibcode=1998Oecol.116..252H |s2cid=9568183 |issn=0029-8549}}</ref><ref>{{Cite journal |last=Lach |first=Lori |date=2007-08-20 |title=Argentine ants displace floral arthropods in a biodiversity hotspot |journal=Diversity and Distributions |volume=14 |issue=2 |pages=281–290 |doi=10.1111/j.1472-4642.2007.00410.x |s2cid=84782307 |issn=1366-9516}}</ref> vertebrates,<ref>{{Cite journal |last1=Suarez |first1=A. V. |last2=Yeh |first2=P. |last3=Case |first3=T. J. |date=2005 |title=Impacts of Argentine ants on avian nesting success |journal=Insectes Sociaux |volume=52 |issue=4 |pages=378–382 |doi=10.1007/s00040-005-0824-y |s2cid=10817241 |issn=0020-1812}}</ref><ref>{{Cite journal |last1=Suarez |first1=Andrew V. |last2=Richmond |first2=Jon Q. |last3=Case |first3=Ted J. |title=Prey Selection in Horned Lizards Following the Invasion of Argentine Ants in Southern California |date=2000 |journal=Ecological Applications |volume=10 |issue=3 |pages=711–725 |doi=10.1890/1051-0761(2000)010[0711:psihlf]2.0.co;2 |issn=1051-0761}}</ref><ref name=":11" /> and plants<ref>{{Cite journal |last1=Bond |first1=W. |last2=Slingsby |first2=P. |date=1984 |title=Collapse of an Ant-Plant Mutalism: The Argentine Ant (Iridomyrmex Humilis) and Myrmecochorous Proteaceae |journal=Ecology |volume=65 |issue=4 |pages=1031–1037 |doi=10.2307/1938311 |jstor=1938311 |bibcode=1984Ecol...65.1031B |issn=0012-9658}}</ref><ref>{{Cite journal |last1=LeVan |first1=Katherine E. |last2=Hung |first2=Keng-Lou James |last3=McCann |first3=Kyle R. |last4=Ludka |first4=John T. |last5=Holway |first5=David A. |date=2014 |title=Floral visitation by the Argentine ant reduces pollinator visitation and seed set in the coast barrel cactus, ''Ferocactus viridescens'' |url=http://link.springer.com/10.1007/s00442-013-2739-z |journal=Oecologia |language=en |volume=174 |issue=1 |pages=163–171 |doi=10.1007/s00442-013-2739-z |pmid=23892582 |bibcode=2014Oecol.174..163L |s2cid=253978572 |issn=0029-8549|url-access=subscription }}</ref><ref>{{Cite journal |last1=LeVan |first1=Katherine E. |last2=Holway |first2=David A. |date=2015 |title=Ant–aphid interactions increase ant floral visitation and reduce plant reproduction via decreased pollinator visitation |url=http://doi.wiley.com/10.1890/14-0058.1 |journal=Ecology |language=en |volume=96 |issue=6 |pages=1620–1630 |doi=10.1890/14-0058.1 |bibcode=2015Ecol...96.1620L |issn=0012-9658|url-access=subscription }}</ref> within their invaded range.

== Description == ''Linepithema humile'' is a small-bodied (2.2–2.6 mm) ant species, dull light to dark brown in color. Within the invasion zone, ant colonies are large and include many workers and multiple queens.<ref>{{cite web |title=Polygyny |website=AntWiki|url=https://www.antwiki.org/wiki/Polygyny |access-date=27 July 2023 }}</ref>

Argentine ants are opportunistic with regard to nesting preferences. Colony nests have been found in the ground, in cracks in concrete walls, in spaces between boards and timbers, even among belongings in human dwellings. In natural areas, they generally nest shallowly in loose leaf litter or beneath small stones, due to their poor ability to dig deeper nests.<ref name=":10" /> However, if a deeper nesting ant species abandons their nest, Argentine ant colonies will readily take over the space.{{citation needed|date=August 2015}} Because the native habitat for this species is within riparian floodplains, colonies are very sensitive to water infiltration within their nests; if their nests become inundated with water, workers will collect the [https://www.antwiki.org/wiki/Life_in_an_Ant_Colony brood] and the entire colony will move to dry ground.<ref>{{Cite journal |last1=Scholes |first1=D. R. |last2=Suarez |first2=A. V. |date=2009-08-30 |title=Speed-versus-accuracy trade-offs during nest relocation in Argentine ants (''Linepithema humile'') and odorous house ants (''Tapinoma sessile'') |journal=Insectes Sociaux |volume=56 |issue=4 |pages=413–418 |doi=10.1007/s00040-009-0039-8 |s2cid=8207378 |issn=0020-1812}}</ref><ref>{{Cite journal |last=Markin |first=George P. |date=1970-09-15 |title=The Seasonal Life Cycle of the Argentine Ant, ''Iridomyrmex humilis'' (Hymenoptera: Formicidae), in Southern California |journal=Annals of the Entomological Society of America |volume=63 |issue=5 |pages=1238–1242 |doi=10.1093/aesa/63.5.1238 |issn=1938-2901}}</ref>

Austrian entomologist Gustav L. Mayr identified the first specimens of ''Hypoclinea humilis'' in the vicinity of Buenos Aires, Argentina in 1866. This species was shortly transferred to the genus ''Iridomyrmex'', and finally to ''Linepithema'' in the early 1990s. {{multiple image | direction = horizontal | image1 = Argentine Ant (Linepithema Humile).jpeg | alt1 = Illustrating the size of an ant | caption1 = Typical size of worker ants found in Southern California. | image2 = How to identify Argentine Ants (Linepithema Humile).jpeg | alt2 = How to identify Argentine Ants | caption2 = These markers can help identify Argentine ants. }}

== Distribution == The native range of Argentine ants is limited to riparian habitats in the lowland areas of the Paraná River drainage,<ref name = Relationships >These reviews...

{{Cite journal | year = 2002 | issue = 1 | volume = 33 | first5 = Ted | first4 = Neil | first3 = Andrew | first2 = Lori | first1 = David | publisher = Annual Reviews | last5 = Case | last4 = Tsutsui | last3 = Suarez | last2 = Lach | last1 = Holway | journal = Annual Review of Ecology and Systematics | issn = 0066-4162 | pages = 181–233 | title = The Causes and Consequences of Ant Invasions | s2cid = 16691880 | doi = 10.1146/annurev.ecolsys.33.010802.150444 | bibcode = 2002AnRES..33..181H | url = https://www.life.illinois.edu/suarez/publications/Holway_etal2002ARES.pdf | access-date = 28 February 2023 | archive-date = 12 July 2012 | archive-url = https://web.archive.org/web/20120712144921/https://www.life.illinois.edu/suarez/publications/Holway_etal2002ARES.pdf }} <nowiki>https://www.life.illinois.edu/suarez/publications/Holway_etal2002ARES.pdf</nowiki> (dead)

{{Cite journal | year = 2008 | issue = 1 | volume = 17 | publisher = Blackwell Science Ltd. | first2 = Neil | first1 = Andrew | last2 = Tsutsui | last1 = Suarez | journal = Molecular Ecology | issn = 0962-1083 | title = The evolutionary consequences of biological invasions | doi = 10.1111/j.1365-294x.2007.03456.x | pages = 351–360 | pmid = 18173507 | bibcode = 2008MolEc..17..351S | s2cid = 14164860 | url = http://www.life.illinois.edu/suarez/publications/SuarezTsutsui2008MolEcol.pdf | access-date = 28 February 2023 | archive-date = 12 May 2019 | archive-url = https://web.archive.org/web/20190512135244/http://www.life.illinois.edu/suarez/publications/SuarezTsutsui2008MolEcol.pdf }} <nowiki>https://www.life.illinois.edu/suarez/publications/SuarezTsutsui2008MolEcol.pdf</nowiki> (dead)

...cite this study:

{{Cite journal | year = 2001 | publisher = Blackwell Science Ltd. | first4 = Ted | first3 = David | first2 = Andrew | first1 = Neil | last4 = Case | last3 = Holway | last2 = Suarez | last1 = Tsutsui | title = Relationships among native and introduced populations of the Argentine ant (''Linepithema humile'') and the source of introduced populations | journal = Molecular Ecology | volume = 10 | issue = 9 | pages = 2151–2161 | doi = 10.1046/j.0962-1083.2001.01363.x | pmid = 11555258 | bibcode = 2001MolEc..10.2151T | s2cid = 17213219 | url = http://www.life.illinois.edu/suarez/publications/Tsutsui_etal2001MolEcol.pdf | access-date = 8 July 2017 | archive-date = 7 February 2013 | archive-url = https://web.archive.org/web/20130207233358/http://www.life.illinois.edu/suarez/publications/Tsutsui_etal2001MolEcol.pdf }} <nowiki>https://www.life.illinois.edu/suarez/Publications/Tsutsui_etal2001MolEcol.pdf</nowiki> (dead)</ref><ref name=":1" /> which stretches across northern Argentina, Uruguay, Paraguay, and southern Brazil. Within South America, this species has spread into parts of Chile, Colombia, Ecuador, and Peru.<ref>{{cite journal |url=https://archive.org/details/ants_20351 |format=PDF |title=Taxonomy and distribution of the Argentine ant, ''Linepithema humile'' (Hymenoptera: Formicidae) |author=Alexander L. Wild |year=2004 |journal=Annals of the Entomological Society of America |volume=97 |issue=6 |pages=1204–1215 |doi=10.1603/0013-8746(2004)097[1204:TADOTA]2.0.CO;2|doi-access=free }}</ref> ''Linepithema humile'' thrives in Mediterranean climates, and over the past century it has spread to across the globe by human-mediated transport.<ref name = Relationships /> The species has become established to every continent except Antarctica and includes many oceanic islands.<ref name=":0">{{Cite journal |last1=Wetterer |first1=James K |last2=Wild |first2=Alexander L |last3=Suarez |first3=Andrew V |last4=Roura-Pascual |first4=Núria |last5=Espadaler |first5=Xavier |date=2009 |title=Worldwide spread of the Argentine ant, ''Linepithema humile'' (Hymenoptera: Formicidae) |url=https://myrmecologicalnews.org/cms/index.php?option=com_content&view=category&id=377&Itemid=356 |journal=Myrmecological News |volume=12 |pages=187–194}}</ref><ref name=":13" /><ref>{{cite journal |author1=Andrew V. Suarez |author2=David A. Holway |author3=Ted J. Case |year=2001 |title=Patterns of spread in biological invasions dominated by long-distance jump dispersal: Insights from Argentine ants |journal=Proceedings of the National Academy of Sciences |volume=98 |issue=3 |pages=1095–1100 |doi=10.1073/pnas.98.3.1095 |jstor=3054827|bibcode = 2001PNAS...98.1095S |pmid=11158600 |pmc=14714|doi-access=free }}</ref>

=== Global "mega-colony" === The absence of aggression within Argentine ant colonies was first reported in 1913 by Newell & Barber, who noted "…there is no apparent antagonism between separate colonies of its own kind".<ref> {{cite journal |author1=Newell, Wilmon |author2=Barber, T.C. |year=1913 |title=The Argentine ant |journal=USDA Bureau of Entomology Bulletin |volume=122 |pages=1–98 }} </ref> Later studies showed that these "supercolonies" extend across hundreds or thousands of kilometers in different parts of the introduced range, first reported in California in 2000,<ref name=":13"> {{cite journal |author1=Tsutsui, Neil D. |author2=Suarez, Andrew V. |author3=Holway, David A. |author4=Case, Ted J. |year=2000 |title = Reduced genetic variation and the success of an invasive species |journal=Proceedings of the National Academy of Sciences |volume=97 |issue=11 |pages=5948–5953 |doi=10.1073/pnas.100110397 |doi-access=free |pmid=10811892 |pmc=18539 |bibcode=2000PNAS...97.5948T }} </ref> then in Europe in 2002,<ref name=giraud> {{cite journal |author1=Giraud, Tatiana |author2=Pedersen, Jes S. |author3=Keller, Laurent |year=2002 |title=Evolution of supercolonies: The Argentine ants of southern Europe |journal=Proceedings of the National Academy of Sciences |volume=99 |issue=9 |pages=6075–6079 |doi=10.1073/pnas.092694199 |doi-access=free |jstor=3058627 |pmid=11959924 |pmc=122904 |bibcode=2002PNAS...99.6075G }} </ref> Japan in 2009,<ref name=Sunamura-Espadaler-etal-2009> {{cite journal |first1=E. |last1=Sunamura |first2=X. |last2=Espadaler |first3=H. |last3=Sakamoto |first4=S. |last4=Suzuki |first5=M. |last5=Terayama |first6=S. |last6=Tatsuki |date = 2009-03-04 |title = Intercontinental union of Argentine ants: Behavioral relationships among introduced populations in Europe, North America, and Asia |journal = Insectes Sociaux |volume = 56 |issue = 2 |pages = 143–147 |doi = 10.1007/s00040-009-0001-9 |s2cid = 43989276 |issn = 0020-1812 |lang = en }} </ref>{{rp|style=ama|pp= 143–147}} and Australia in 2010.<ref name=suhr/>

Several subsequent studies used genetic, behavioral, and chemical analyses to show that introduced supercolonies on separate continents actually represent a single global supercolony.<ref name=":6"> {{cite journal |author1=van&nbsp;Wilgenburg, Ellen |author2=Torres, Candice W. |author3=Tsutsui, Neil D. |year=2010 |title= The global expansion of a single ant supercolony |journal=Evolutionary Applications |volume=3 |issue=2 |pages=136–143 |doi=10.1111/j.1752-4571.2009.00114.x |pmid=25567914 |pmc=3352483 }} </ref><ref name=Sunamura-Espadaler-etal-2009/>{{rp|style=ama|pp=143–147}}

The researchers stated that the "enormous extent of this population is paralleled only by human society", and had probably been spread and maintained by human travel.<ref name=Sunamura-Espadaler-etal-2009/>{{rp|style=ama|pp=143–147}}

== Behavior == [[File:Linepithema Humile.jpg|thumb|right|Argentine ants on a dead horse-fly]] They have been extraordinarily successful, in part, because different nests of the introduced Argentine ants seldom attack or compete with each other, unlike most other species of ant. In their introduced range, their genetic makeup is so uniform that individuals from one nest can mingle in a neighboring nest without being attacked. Thus, in most of their introduced range, they form supercolonies.<ref name=giraud/> The Very Large Colony, which covers territory from San Diego to beyond San Francisco, may have a population of nearly one trillion individuals.<ref name=Moffett-2010> {{cite book |last=Moffett |first=Mark |date=2010 |title=Adventures Among Ants: A global safari with a cast of trillions |publisher=University of California Press |location=Berkeley and Los Angeles, CA |isbn=978-0-520-26199-0 |pages=203–205 |url=https://archive.org/details/adventuresamonga00moff/page/203 |via=Internet Archive (archive.org) |url-access=registration }} </ref>{{rp|style=ama|p= [https://archive.org/details/adventuresamonga00moff/page/204 204]}}

Conflict does occur between members of different supercolonies. In 1997, UC San Diego researchers observed fighting between different Argentine ants kept in lab, and in 2004 scientists began to map out the boundaries of the different supercolonies that clashed in San Diego. On the border of the Very Large Colony and the Lake Hodges Colony thirty million ants die each year, on a battlefront that covers many miles. While the battles of other ant species generally constitute colony raids lasting a few hours, or skirmishes that occur periodically for a few weeks, Argentine ants clash ceaselessly; the borders of their territory are a site of constant violence and battles can be fought on top of hundreds of dead ants. Fights may be halted by adverse weather such as rain.<ref name=Moffett-2010/>{{rp|style=ama|p= [https://archive.org/details/adventuresamonga00moff/page/203 203–205]}}

In contrast, native populations are genetically more diverse and form colonies that are much smaller than the supercolonies that dominate the introduced range. Colonies living in close proximity are territorial and aggressive toward one another. Argentine ants in their native South America also co-exist with many other species of ants, and do not attain the high population densities that characterize introduced populations.<ref name="tsutsui-2000">[https://biology.ucsd.edu/about/news/article_051500.html ''Success of Introduced Argentine Ants Tied to Reduced Genetic Variation.''] Kim McDonald, University of California, May 2000</ref>

In a series of experiments, ants of the same colony were isolated and fed different diets. The hydrocarbons from the diet were eventually incorporated into the cuticle of the subjects. Those that had the same diet appeared to recognize one another as kin. Those who had at least some overlap in dietary composition also appeared to react non-aggressively to one another. These interactions contrasts drastically with the groups that fed on completely different sources, such as those who lived off flies and those that fed on grasshoppers. The groups appeared to have incorporated hydrocarbons that were not similar to the others and created an unfamiliar identity cue. These groups reacted violently towards each other. This suggests that dietary factors affect the recognition cues for colony members.<ref> {{cite journal |last1=Buczkowski |first1=Grzegorz |last2=Kumar |first2=Ranjit |last3=Suib |first3=Steven L. |last4=Silverman |first4=Jules |date=2005-05-25 |title=Diet-related modification of cuticular hydrocarbon profiles of the Argentine ant, ''Linepithema humile'', diminishes intercolony aggression |journal=Journal of Chemical Ecology |volume=31 |issue=4 |pages=829–843 |citeseerx=10.1.1.549.3594 |s2cid=10808223 |doi=10.1007/s10886-005-3547-7 |pmid=16124254 |bibcode=2005JCEco..31..829B }} </ref><ref name=":8"> {{cite journal |last1=Corin |first1=S.E. |last2=Abbott |first2=K.L. |last3=Ritchie |first3=P.A. |last4=Lester |first4=P.J. |date=2007-06-12 |title=Large scale unicoloniality: The population and colony structure of the invasive Argentine ant (''Linepithema humile'') in New Zealand |journal=Insectes Sociaux |volume=54 |issue=3 |pages=275–282 |doi=10.1007/s00040-007-0942-9 |s2cid=13704966 }} </ref>

== Reproduction and seasonal colony trends == right|300px|Relative biomass (in %) of workers to colony, calculated from a monthly sampling of 1,000&nbsp;random colony inhabitants over one year

Like workers in many other ant species, Argentine ant workers are unable to lay reproductive eggs but can direct the development of eggs in reproductive females; the production of males appears to be controlled by the amount of food available to the larvae.<ref> {{cite journal |author1=Passera, L. |author2=Keller, L. |author3=Suzzoni, J.P. |date=March 1988 |title=Control of brood male production in the Argentine ant ''Iridomyrmex humilis'' (Mayr) |journal=Insectes Sociaux |volume=35 |issue=1 |pages=19–33 |s2cid=45609354 |doi=10.1007/BF02224135 }} </ref> Argentine ant colonies almost invariably have many reproductive queens, as many as one queen for every 125 workers.

The seasonal low occurs in mid-winter, when 90% of a representative colony consists of workers and the remainder of queens, and no reproductive activity and minimal birthing. Eggs are produced in late-winter, nearly all of which hatch into sexual forms by May(*). Mating occurs after the females emerge. Worker production increases steadily from mid-March(*) to October(*), after which their numbers are not replenished; thus, their numbers drop steadily over the winter months.<ref name=":10"> {{cite journal |last=Markin, George P. |year=1969 |title=The seasonal life cycle of the Argentine ant in southern California |journal=Annals of the Entomological Society of America |volume=63 |issue=5 |page=1238 |doi=10.1093/aesa/63.5.1238 }} </ref> ((*) Note that the information regarding the months May, March, and October in this paragraph, as well as the entire Month axis in the graph, are not worldwide correct, in particular in Southern hemisphere, due to the shift of six months in seasons between the two hemispheres.){{Citation needed|date=May 2026}}

Colonies in the Argentine ant's native habitat are kept within a range of ten to one hundred meters by colonies of interspecific and intraspecific rivals. As the colonies expand, they appear to form fluctuating territory borders, which contract and expand on a seasonal and conditional basis. There is an expansive push outward in the summer months, with a retreating motion in the winter. This has to do with soil moisture and temperature conditions.<ref name=Heller-Sanders-Gordon-2006> {{cite journal |last1=Heller |first1=Nicole E. |last2=Sanders |first2=Nathan J. |last3=Gordon |first3=Deborah M. |year=2006 |title=Linking temporal and spatial scales in the study of an Argentine ant invasion |journal=Biological Invasions |volume=8 |issue=3 |pages=501–507 |doi=10.1007/s10530-005-6411-3 |bibcode=2006BiInv...8..501H |citeseerx=10.1.1.307.8013 |s2cid=12278379 }} </ref> At the edges of these borders are either rival ''L.&nbsp;humile'' colonies or other obstacles that prevent further expansion, such as an inhospitable environment for nests.<ref name=Heller-Sanders-Gordon-2006/>

== Impact == The ants are ranked among the world's 100&nbsp;worst invasive animal species.<ref name=":9">{{cite report |last1=Boudjelas |first1=Souyad |year=2000 |title=100 of the world's worst invasive alien species |website=iucn.org |publisher=International Union for Conservation of Nature |url=https://portals.iucn.org/library/sites/library/files/documents/2000-126.pdf |access-date=20 July 2018 }} </ref> In its introduced range, the Argentine ant often displaces most or all native ants and can threaten native invertebrates and even small vertebrates that are not accustomed to defending against the aggressive ants. This can, in turn, imperil other species in the ecosystem, such as native plants that depend on native ants for seed dispersal, or lizards that depend on native ants or invertebrates for food. For example, the recent severe decline in coastal horned lizards in southern California is closely tied to Argentine ants displacing native ant species on which the lizards feed.<ref name=":11"> {{cite press release | title=Proliferation of Argentine ants in California linked to decline in coastal horned lizards | date=March 5, 2002 | website=Science Daily | url=https://www.sciencedaily.com/releases/2002/02/020227071151.htm }} </ref> In South Africa, the Argentine ant has in some cases displaced native ants that disperse the seeds of Fynbos plants like ''Mimetes cucullatus''. The Argentine ants don't take the seeds underground and are left on the surface, resulting in ungerminated plants and the dwindling of Fynbos seed reserves after veld fires.<ref>{{Cite journal |last1=Bond |first1=W. |last2=Slingsby |first2=P. |date=1984-08-01 |title=Collapse of an Ant-Plant Mutalism: The Argentine Ant (Iridomyrmex Humilis) and Myrmecochorous Proteaceae |url=https://esajournals.onlinelibrary.wiley.com/doi/10.2307/1938311 |journal=Ecology |language=en |volume=65 |issue=4 |pages=1031–1037 |doi=10.2307/1938311 |jstor=1938311 |bibcode=1984Ecol...65.1031B |issn=0012-9658|url-access=subscription }}</ref>

Argentine ants sometimes tend aphid, mealybug, and scale insect colonies,<ref name=":3"> {{cite journal |author=Bristow, C.M. |year=1991 |title=Are ant–aphid associations a tritrophic interaction? Oleander aphids and Argentine ants |journal=Oecologia |volume=87 |issue=4 |pages=514–521 |doi=10.1007/BF00320414 |pmid=28313693 |jstor=4219728 |bibcode=1991Oecol..87..514B |s2cid=24475572 }} </ref> sometimes relocating the parasites to unaffected plants, and their protection of these plant pests from predators and parasitoids can cause problems in agricultural areas.<ref> {{cite journal |author1=Grover, Crystal D. |author2=Dayton, Kathleen C. |author3=Menke, Sean B. |author4=Holway, David A. |year=2008 |title=Effects of aphids on foliar foraging by Argentine ants and the resulting effects on other arthropods |journal=Ecological Entomology |volume=33 |issue=1 |pages=101–106 |doi=10.1111/j.1365-2311.2007.00942.x |bibcode=2008EcoEn..33..101G |s2cid=55736630 |url=http://www4.ncsu.edu/~sbmenke/Publications/Grover_et_al%20Ecol%20Ent%202008.pdf |archive-url=https://web.archive.org/web/20110401194814/http://www4.ncsu.edu/~sbmenke/Publications/Grover_et_al%20Ecol%20Ent%202008.pdf |archive-date=2011-04-01 }} </ref> In return for this protection, the ants benefit by feeding off honeydew.

The aggressiveness behavior of ants adds pressure to bumble bees ''Linepithema humile Mayr'' populations when competing for shared resources. <ref>{{Cite journal |last=Miner |first=Michelle Constanza |last2=Wilson Rankin |first2=Erin E |date=2025-11-07 |editor-last=Roeder |editor-first=Karl |title=Bees modulate behavior during nectar foraging in response to direct ant aggression (Hymenoptera: Apidae and Formicidae) |url=https://academic.oup.com/jinsectscience/article/doi/10.1093/jisesa/ieaf076/8317081 |journal=Journal of Insect Science |language=en |volume=25 |issue=6 |doi=10.1093/jisesa/ieaf076 |issn=1536-2442 |pmc=12598628 |pmid=41206706}}</ref> Ant abundance and aggressive biting (not stinging) behaviors more prolonged disrupted bumblebee foraging and resource collection, even though bees have the ability to fight back initially it is energy lost that could be put towards pollination.<ref>{{Cite journal |last=Miner |first=Michelle Constanza |last2=Wilson Rankin |first2=Erin E |date=2025-11-07 |editor-last=Roeder |editor-first=Karl |title=Bees modulate behavior during nectar foraging in response to direct ant aggression (Hymenoptera: Apidae and Formicidae) |url=https://academic.oup.com/jinsectscience/article/doi/10.1093/jisesa/ieaf076/8317081 |journal=Journal of Insect Science |language=en |volume=25 |issue=6 |doi=10.1093/jisesa/ieaf076 |issn=1536-2442 |pmc=12598628 |pmid=41206706}}</ref>

There is also evidence that the presence of Argentine ant may decrease the number of pollinators that visit natural flowering plants via predation on the larvae of the pollinators.<ref name="sahli"> {{cite journal |last1=Sahli |first1=Heather F. |last2=Krushelnycky |first2=Paul D. |last3=Drake |first3=Donald R. |last4=Taylor |first4=Andrew D. |date=Jul 2016 |title=Patterns of floral visitation to native Hawaiian plants in presence and absence of invasive Argentine ants |journal=Pacific Science |volume=70 |issue=3 |pages=309–322 |doi=10.2984/70.3.3 |s2cid=88742821 |issn=0030-8870 }} </ref>

== Pest control == thumb|Argentine ants accessing a commercial bait station commonly available in the United States

Argentine ants are a common household pest, often entering structures in search of food or water (particularly during dry or hot weather), or to escape flooded nests during periods of heavy rainfall. When they invade a kitchen, it is not uncommon to see two or three queens foraging along with the workers.{{Cn|date=December 2024}}

Borate-sucrose water baits are toxic to Argentine ants, when the bait is 25% water, with 0.5–1.0% boric acid or borate salts.<ref>{{cite journal| title=Toxicity and Repellency of Borate-Sucrose Water Baits to Argentine Ants (Hymenoptera: Formicidae)| last1=Klotz| first1=John H.| last2=Greenberg| first2=Les| last3=Amrhein| first3=Christopher| last4=Rust| first4=Michael K.| journal=Journal of Economic Entomology| volume=93| issue=4| pages=1256–8| date=August 2000| access-date=2017-01-15| url=http://www.urban.ucr.edu/docs/Argentine%20Ant/2000%20Klotz%20et%20al.%20Toxicity%20and%20Repellency%20of%20Borate-Sucrose%20.pdf| pmid=10985039| doi=10.1603/0022-0493-93.4.1256| s2cid=17829851| archive-date=24 May 2020| archive-url=https://web.archive.org/web/20200524024631/https://urban.ucr.edu/docs/Argentine%20Ant/2000%20Klotz%20et%20al.%20Toxicity%20and%20Repellency%20of%20Borate-Sucrose%20.pdf}}</ref><ref name=":4">{{cite journal| title=In search of the 'sweet spot'| last1=Klotz| first1=John H.| last2=Rust| first2=Michael K.| last3=Amrhein| first3=Christopher| last4=Krieger| first4=Robert| journal=Pest Control| date=September 2004| access-date=2017-01-15| url=http://urban.ucr.edu/docs/Argentine%20Ant/2004%20Klotz%20et%20al.%20In%20Search%20of%20the%20SweetSpot.pdf| archive-date=24 May 2020| archive-url=https://web.archive.org/web/20200524022239/https://www.urban.ucr.edu/docs/Argentine%20Ant/2004%20Klotz%20et%20al.%20In%20Search%20of%20the%20SweetSpot.pdf}}</ref>

In spring, during a colony's growth phase, protein based baits may be more effective due to much higher demand from the egg-laying queens.<ref>{{Cite journal|last1=Abril|first1=S.|last2=Oliveras|first2=J.|last3=Gómez|first3=C.|date=Oct 2007|title=Foraging activity and dietary spectrum of the Argentine ant (Hymenoptera: Formicidae) in invaded natural areas of the northeast Iberian Peninsula|journal=Environmental Entomology|volume=36|issue=5|pages=1166–1173|doi=10.1603/0046-225X(2007)36[1166:FAADSO]2.0.CO;2|issn=0046-225X|pmid=18284742|doi-access=free}}</ref>

Due to their nesting behavior and presence of numerous queens in each colony, it is generally impractical to spray Argentine ants with pesticides or to use boiling water as with mound building ants. Spraying with pesticides has occasionally stimulated increased egg-laying by the queens, compounding the problem.{{Cn|date=December 2024}} Pest control usually requires exploiting their omnivorous dietary habits, through use of slow-acting poison bait (e.g. fipronil, hydramethylnon, sulfluramid), which will be carried back to the nest by the workers, eventually killing all the individuals, including the queens.

== Research ==

Researchers from the University of California, Irvine, have developed a way to use the scent of Argentine ants against them.<ref>{{cite web |last=Perlman |first=David |url=http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/09/15/BAG75L6BJK1.DTL |title=Ants' own chemical may control them |publisher=SFGate |date=2006-09-15 |access-date=2015-08-25 |archive-date=31 July 2020 |archive-url=https://web.archive.org/web/20200731081122/https://www.sfgate.com/bayarea/article/Ants-own-chemical-may-control-them-2489281.php }}</ref> The exoskeletons of the ants are covered with a hydrocarbon-laced secretion. They made a compound that is different, but similar, to the one that coats the ants. If the chemical is applied to an ant, the other members of the colony will kill it.<ref name=rivenburg>{{Cite news |last=Rivenburg |first=Roy |title=UCI makes ants go ape by giving them B.O.| newspaper=Los Angeles Times |date=September 15, 2006 |url=https://www.latimes.com/archives/la-xpm-2006-sep-15-me-ants15-story.html}}</ref>

Another approach for a large scale control of the Argentine ant has been proposed by researchers from Japan, who showed that it is possible to disrupt its trails with synthetic pheromones.<ref name=":12">{{cite patent | country = US | number = 8278360 | status = patent | title = Behavior-disrupting agent and behavior-disrupting method of Argentine ant | pubdate = 2012-10-02 | fdate = 2004-03-17 | pridate = 2005-09-22 | invent1 = Sadahiro Tatsuki | invent2 = Mamoru Terayama | invent3 = Yasutoshi Tanaka | invent4 = Takehiko Fukumoto | assign1 = Shin-Etsu Chemical Co Ltd}}</ref> This has been confirmed in various later trials by a New Zealand-led team in Hawaii<ref name=":2">{{cite journal |author1=David M Suckling |author2=R. W. Peck |author3=L. M. Manning |author4=L. D. Stringer |author5=J. Cappadonna |author6=A. M. El-Sayed |year=2008 |title= Disruption of Foraging by a Dominant Invasive Species to Decrease Its Competitive Ability |journal=Journal of Chemical Ecology |volume=34 |issue=12 |pages= 1602–9 |doi= 10.1007/s10886-008-9566-4 |pmid= 19034574|s2cid=10882647 }}</ref> and by researchers from Victoria University of Wellington who showed that this approach is beneficial for other local ant species.<ref>{{cite journal |author1=Fabian L. Westermann |author2=David M. Suckling |author3=Philip J. Lester |year=2014 |title= Disruption of Foraging by a Dominant Invasive Species to Decrease Its Competitive Ability |journal=PLOS One |volume=9 |issue=3 |article-number= e90173 |doi= 10.1371/journal.pone.0090173 |pmid=24594633 |pmc=3942413|bibcode = 2014PLoSO...990173W |doi-access=free }}</ref>

A multi-agency study at the environmentally-sensitive California Channel Islands in the mid-2010s eliminated the Argentine ant to sub-detectable levels. The ant was introduced to the islands in the early- to mid-1900s. Due to strict biosecurity measures, the risk of re-invasion was low and allowed for a controlled study. Four (4) km<sup>2</sup>, 2% of the island area, was treated with liquid bait pellets similar to off-the-shelf products, dispersed by helicopter. Cost of treatment ranged from $50000-$200000 USD (2015) per km<sup>2</sup> including the cost of subsequent monitoring, and may serve as an initial guideline for other areas.<ref>{{cite web |url=https://www.californiaislands.net/argentine-ants |title=California Islands Argentine Ant Eradication Program |access-date=20 January 2025}}</ref><ref>{{cite web |last1=Boser, Hanna, Holway, Faulkner, Naughton, Merrill, Randall, Cory, Choe, Morrison |title=Protocols for Argentine ant eradication in conservation areas |url=https://static1.squarespace.com/static/54b5b3e8e4b06e38ad4d2e82/t/593d21e16b8f5b4e85bfc9eb/1497178594753/Boser+et+al+2017+J+Applied+Entomology.pdf |access-date=20 January 2025}}</ref>

== See also == * Linepithema humile virus 1, a virus carried by Argentine ants

== References == {{reflist|22em}}

== External links == {{Commons category|Linepithema humile|''Linepithema humile''}} {{Wikispecies|Linepithema humile|''Linepithema humile''}} * {{cite web |url= http://www.pestworld.org/pest-guide/ants/argentine-ants/ |title=Argentine Ant Fact Sheet |author=National Pest Management Association}} with information on habits, habitat and prevention * {{cite web |url=http://www.cisr.ucr.edu/argentine_ant.html |work=Center for Invasive Species Research |publisher=University of California, Riverside |title=Argentine ant (''Linepithema humile'') |author=Matt Daugherty |access-date=2009-04-20 |archive-url=https://web.archive.org/web/20100623152835/http://cisr.ucr.edu/argentine_ant.html |archive-date=2010-06-23 }} * {{cite web |url=http://myrmecos.net/2008/04/13/how-to-identify-the-argentine-ant-linepithema-humile/ |archive-url=https://web.archive.org/web/20101218142446/http://myrmecos.net/2008/04/13/how-to-identify-the-argentine-ant-linepithema-humile/ |archive-date=2010-12-18 |title=How to identify the Argentine ant, ''Linepithema humile'' |author=Alex Wild |work=Myrmecos|date=2008-04-13 }} * {{cite AV media|url=https://www.youtube.com/watch?v=cqECNYmM23A/|url-status=bot: unknown|archive-url=https://web.archive.org/web/20230917184949/https://www.youtube.com/watch?v=cqECNYmM23A/|archive-date=17 September 2023|title=The Billion Ant Mega Colony and the Biggest War on Earth|author=Kurzgesagt|date=29 September 2019|type=Video, 9'22"|via=YouTube|access-date=29 September 2019}} {{Taxonbar|from=Q645538}} {{Authority control}}

{{DEFAULTSORT:Argentine Ant}} Category:Dolichoderinae Category:Agricultural pest insects Category:Household pest insects Category:Insects described in 1868 Category:Ants of New Zealand Category:Taxa named by Gustav Mayr