Characterized by its diminutive size and highly uniform morphology, this formicid taxon features monomorphic workers measuring between 2.2 and 2.8 mm in length. Their bodies display a shiny, smooth integument with colors varying from light brown to dark brown. Lacking a functional sting, they possess an anal pore that releases noxious chemical compounds when threatened. The head is equipped with 12-segmented antennae lacking a distinct club, and mandibles carrying 5 to 8 teeth. A key diagnostic feature is the single, forward-pointing petiolar node, which easily distinguishes this taxon from other sympatric species. Queens are notably larger, measuring 4 to 6 mm, while winged males reach approximately 3 mm.

Geographical distribution: Native to the wetlands of the Paraná River basin, spanning parts of Argentina, Paraguay, Uruguay, and southern Brazil. However, through human trade and transport, it has successfully colonized vast regions across the globe, becoming one of the most widespread invasive species. It is now thoroughly established in Mediterranean and temperate zones, including southern Europe, coastal California, southwestern Australia, South Africa, Japan, and several archipelagos such as Hawaii, where it forms massive interconnected supercolonies.

Habitat: Thrives predominantly in highly disturbed anthropogenic environments, urban areas, suburbs, and agricultural lands where moisture is readily available. Though ecologically flexible, it exhibits a strong preference for moist, temperate soils. Nests are commonly established under stones, decaying logs, concrete slabs, sidewalks, and leaf litter. It generally avoids dense, undisturbed primary forests and hyper-arid environments unless artificial irrigation is present to modify the local microclimate.

Feeding: Exhibits an opportunistic and highly versatile omnivorous diet. It shows an extreme preference for carbohydrate-rich liquid food sources, particularly the honeydew excreted by hemipteran insects like aphids and scale insects, which it actively protects from predators in a classic mutualistic relationship. To fulfill its protein requirements, this taxon scavenges on dead arthropods, preys upon small invertebrates, and consumes seeds, floral nectar, and domestic organic refuse.

Behavior: Defined by an extraordinary social structure known as unicoloniality, in which geographically separated nests lack intraspecific aggression and instead function as a single, cooperative supercolony. This absence of territorial conflict allows workers to focus entirely on massive foraging efforts and aggressive resource monopolization, which rapidly displaces native ant species. They utilize highly persistent recruitment pheromones to organize dense, continuous foraging trails that can cover extensive distances.

Reproduction: Occurs within a highly polygynous system, where individual nests of Linepithema humile contain multiple fertile queens. Unlike many other ant species, traditional nuptial flights are virtually nonexistent in introduced populations; mating typically takes place inside the nest. Colony propagation and the establishment of new nests are achieved via colony budding or fission, where one or more queens walk away from the parent nest accompanied by a contingent of workers and brood to establish a new satellite colony nearby.

Conservation status: Not evaluated under any threat category of the IUCN Red List due to its status as a highly successful global pest. Instead, it is recognized worldwide as one of the 100 of the world´s worst invasive alien species by the International Union for Conservation of Nature. It poses a severe ecological threat by decimating native insect populations, disrupting mutualistic seed-dispersal networks, harming agricultural systems, and causing significant structural damage in urban areas.