Argentine Ants

( Linepithema humile )


Argentine Ant Characteristics


Workers of this species are about one-eighth of an inch in length.


Varies from dark brown to black, and the body is often shiny in appearance.


The colonies of Argentine ants can grow quite large and contain tens of thousands of workers and numerous queens. Each colony will be divided into subcolonies, located in various suitable harborages and connected by established trunk trails.

These subcolonies will number from a few hundred to thousands of individuals. Since members of two separate colonies are not aggressive toward each other, colonies will often combine with one another. This creates huge super-colonies that may extend over several properties.

Argentine ants are very aggressive and will drive out native species of ants, creating an environment where they are the "king" of the anthill, so to speak. Their primary food source during the warm months is the sweet honeydew produced by aphids and mealybugs. The presence of fruit trees, roses and other plants that attract aphids often contributes to Argentine ant infestations.

How Do You Identify Argentine Ants?

While their physical characteristics, such as size and coloring, are the primary method of identifying Argentine ants, habitat and colony formation can also help with identification. As their name implies, Argentine ants originated in Northern Argentina and first made their way to the United States in the late 19th Century, when they were likely unloaded on cargo ships in New Orleans. Today, they are very common in Southern California, but they may also be found in states along the Gulf Coast.

Argentine ants form colonies outdoors, preferring to create shallow nests beneath stones, boards or other items that may lend protection. Subcolonies may be found in piles of lumber, bricks or debris; in landscape mulch or other landscaping features; behind brick and stone veneer; within and under insulation; and in wall voids or in any other suitable void.

Why Are Argentine Ants Bad?

Argentine ants can cause a number of issues. They may enter homes through cracks and voids, and they are able to produce rapidly growing colonies that quickly become large. Typically, when they do enter homes, it is in search of food and water.

Another interesting characteristic of Argentine ants is that they can protect populations of insects, like mealybugs, scales and aphids, that may damage plants. Because Argentine ants feed on the honeydew produced by these insects, they may offer them protection, even relocating them to better habitats where they can thrive, continuing to produce the food the ants need to survive.

Related: What are Those Tiny White Bugs in and Around Your Home?

Are Argentine Ants Dangerous?

Fortunately, Argentine ants do not sting or bite humans, and they are mostly just a nuisance when they are found in homes.

In reality, Argentine ants pose a larger threat to other insects because they are an invasive species. Not only can they drive out other native species of ants, but they can even adversely affect populations of pollinators and vertebrates.

How Do You Kill Argentine Ants?

Argentine ant infestations can quickly get out of control and can be difficult to eliminate. If you live in areas where these ants are common, follow these tips to help safeguard your home and property:

  1. Eliminate piles of lumber, bricks or other debris that may serve as nesting sites
  2. Keep landscape mulch less than two inches thick and at least 12 inches away from foundations
  3. Ensure sprinkler systems do not spray directly onto your home's foundation
  4. Seal as many cracks on the exterior of your homea as possible
  5. Keep tree and shrub branches trimmed to prevent them from touching your home
  6. Consider re-landscaping to avoid plants that are prone to aphids and similar insects, or treat these plants regularly

Argentine ants don't have natural enemies. If you're dealing with an infestation, insecticides are the best method of control. But because insecticides must be handled properly and these ants frequently build colonies underground, it's best to call in the professionals to assess the situation and provide treatment recommendations. Don't let an Argentine ant infestation get out of hand — contact the pest control specialists at Terminix® today.