Practical information to identify and manage non-native, invasive plants and animals
The Quiet Invasion:A Guide to Invasive Species of the Galveston Bay Area
Linepithema humile
| ITIS TSN: | 575041 |
| Presence: | Current Invaders |
| Habitat: | Terrestrial |
| Native Range: | Argentina and Brazil |
Human Health
This species poses no known human health impacts.Prohibited Lists
As of 2010, this species is not prohibited by the TPWD or the USDA.Introduction Pathways
The argentine ant was initially introduced via shipping containers from Argentina in the 1890s. They continue to be dispersed through shipping and freight containers, and natural dispersal (ISSG 2009e).Geographic Distribution
Argentine ants occur worldwide on six continents in both temperate and sub-tropical climates. The Argentine ant is scattered throughout central and eastern Texas and has been identified in the Lower Galveston Bay watershed in Harris County.Specific Primary Habitats
Argentine ants are usually found in open, disturbed sites, but can also invade natural environments. They prefer moderate temperatures and moisture levels, and their range is often limited by one or both of these factors (ISSG 2009e). Argentine ants create shallow, unstable (1-2 inch deep) mounds in soil, under wood, under debris piles, mulch or in tree cavities (UCIPM 2009).Ecological, Economic, or Social Impact
The Argentine ant is a dominant and aggressive invasive that is problematic in both urban and natural settings. In urban or disturbed sites, Argentine ants tend to forage for food inside homes and can be difficult to eradicate from buildings. Outside the urban setting, Argentine ants can severely disrupt both natural and agricultural ecosystems. Due to lack of intraspecific aggression, Argentine ants can form massive colonies which severely impact natural food webs through competition for food and habitat displacement of native ants. Native ants are often responsible for seed dispersal and plant pollination, thus Argentine ant invasions can disrupt these functions, which are important to both natural and agricultural systems (ISSG 2009e).Physical Description
Argentine ants are medium sized ants with a slender, shiny, smooth body. They are light brown to dark brown in color. Worker ants are 2-3 mm long and queens are 4-6 mm long. Their antennae have 12 segments with no defined club (enlarged tip of the antenna) (TAMU 2008a).Reproduction Characteristics
Argentine ant queens can lay up to 60 eggs per day. Eggs take 74 days to develop into adult workers. Alate (winged) queens are present in the colony from April to June although mating occurs without flight, in the nest. New colonies emerge by budding off existing colonies, although workers freely move from nest to nest. A large colony may contain millions of ants. A new colony can be established from as little as one queen and 10 workers (TAMU 2008a).Feeding
The Argentine ant (often referred to as sugar ant) prefers sweet substances to those that are protein-rich. However, the ant has a broad diet including insects, honeydew, nectar and carrion. In homes, the ants will preferentially feed on sweets and animal fat (IFAS 2010).Control
Early detection is key to preventing the spread of this species and regional/local monitoring or surveillance is essential. Argentine ants are attracted to sweet insecticide baits and these have been effective in control of these ants in buildings. Perimeter treatments are often used in places where high densities of ants are found to prevent recruitment of new ants. When using any pesticide to control pests, great care should be exercised to limit exposure of humans and the environment to potentially dangerous chemicals. Contact the Texas AgriLife Extension Service for more information (TAMU 2008a).Lists
This species belongs to the following lists:
Images
To view a larger version of an image, click on the thumbnail. Close up of an Argentine ant (Linepithema humile). Photo courtesy of April Noble, antweb.org |
 Side view of an Argentine ant (Linepithema humile). Photo courtesy of April Noble, antweb.org |
 Argentine ants (Linepithema humile). Photo courtesy of Alvaro Rodriguez Alberich, Wikimedia Commons. |
 Argentine ants (Linepithema humile) accessing a commercial bait station commonly available in the United States. Within two days of this photograph, the ant colony appeared to have been destroyed and had ceased to access the five bait stations which had been placed. Wikimedia Commons. |