Linepithema fuscum

Linepithema fuscum is native to Argentina, Ecuador, Peru, and Venezuela.^[5] But they have been also found in the Colombian inter-Andean valley.^[6]

Little is known about the biology of L. fuscum. The species has been collected from 200 to nearly 3000 meters in elevation. One sample was collected from a "shrubby pasture" and another sample was collected inside a laboratory building in Madre de Dios in Peru. From the 2 samples, the researchers were able to determine the haploid chromosome number to be N=9 but could not find other differences.^[7]

Little is known about the caste system of L. fuscum. Similar to most ant species, the caste system consists of workers, male, and a queen.

Compared to other species in the Linepithema genus, males of L. fuscum have a smaller, more rounded propodeum with a straight to the convex posterior face. Furthermore, the wing venation pattern of the males is similar to that of the queens and consists of two elongate submarginal cells. This is in contrast to other males in the Linepithema genus which have only one submarginal cell. The volsella, a male reproductive appendage, is strongly extruding in L. fuscum males.^[7]

The leg of the males is relatively short compared to other species (<70 mm). The head, body, and appendages of the male are medium brown in color.^[7]

Smaller in size. Some of the key characteristics useful for diagnosis of L. fuscum workers include sparse to absent metapleural pubescence, variable propodeal shape, 0–9 standing setae, and well-developed pre-sutural clypeal groove. The color of the body is medium brown to dark brown but mandibles, antennae, trochanters, and tarsi are somewhat lighter.^[7]

Moderately sized species (maximum mesosomal length: 1.87–1.91 mm). It is unknown if the queen has wings or not. Some of the key characteristics useful for diagnosis of the queen include mesoscutum with more than 10 standing setae, medium brown body color with lighter colored antennal scapes, legs, and mandibles.^[7]