The Argentine Ant, Linepithema humile, is a small ant that is 1/16" long and light to dark brown in color. Their native range is in South America, specifically Brazil and Argentina. They were likely introduced into United States on coffee ships through the port of New Orleans prior to 1891.
Argentine Ants workers are light brown to brown in color, and about 1/16" long with a one-segmented petiole. The petiole is the body portion between the thorax and the abdomen. One way to identify look alike ants is to crush them, the Argentine Ant will have a musty smell while others will have a sweet smell.
Due to genetic similiarities they are able to form large colonies with sub-colonies that can have millions of ants and many queens. Males are only born occasionally and will die shortly after mating. The ants travel in distinctive trails from the nest to food sites. They eat sweets, oils, nectar and sap from some plants including honey-dew, and fruits/buds on plants.
They do not have stingers but are capable of biting when provoked. The complaint most commonly associated with Argentine Ants is feeding and foraging activities in the home which can be controlled with exterior spraying.
Argentine Ant Worker. Source: Stanford University
<references> group="http://www.clemson.edu/cafls/departments/esps/factsheets/household_structural/argentine_ants_hs42.html""http://www.ipm.ucdavis.edu/TOOLS/ANTKEY/argentine.html"