Argentine ant

[1] This invasive species was inadvertently introduced by humans on a global scale[2][3][4] and has become established in many Mediterranean climate areas,[5][6][7][8] including South Africa,[9] New Zealand,[10] Japan,[11] Easter Island,[12] Australia,[13] the Azores,[14] Europe,[15] Hawaii,[16] and the continental United States.

[17] Argentine ants are significant pests within agricultural and urban settings,[18][19][20] and are documented to cause substantial harm to communities of native arthropods,[21][22][23] vertebrates,[24][25][26] and plants[27][28][29] within their invaded range.

Linepithema humile is a small-bodied (2.2–2.6 mm) ant species, dull light to dark brown in color.

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.

[32][33] Austrian entomologist Gustav L. Mayr identified the first specimens of Hypoclinea humilis in the vicinity of Buenos Aires, Argentina in 1866.

The native range of Argentine ants is limited to riparian habitats in the lowland areas of the Paraná River drainage,[5][8] which stretches across northern Argentina, Uruguay, Paraguay, and southern Brazil.

[34] Linepithema humile thrives in Mediterranean climates, and over the past century it has spread to across the globe by human-mediated transport.

[37] 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,[35] then in Europe in 2002,[38] Japan in 2009,[39](pp 143–147) and Australia in 2010.

[41](p 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.

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.

[51] 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.

[52][53] 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.

[citation needed] 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.

[56] 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.

[57] This has been confirmed in various later trials by a New Zealand-led team in Hawaii[58] and by researchers from Victoria University of Wellington who showed that this approach is beneficial for other local ant species.

[59] A multi-agency study at the environmentally-sensitive California Channel Islands in the mid-2010s eliminated the Argentine ant to sub-detectable levels.

Argentine ants on a dead horse-fly
Relative biomass (in %) of workers to colony, calculated from a monthly sampling of 1,000 random colony inhabitants over one year
Relative biomass (in %) of workers to colony, calculated from a monthly sampling of 1,000 random colony inhabitants over one year
Argentine ants accessing a commercial bait station commonly available in the United States