Argentine Ant

Actual Size: 2.2 to 2.8 mm

Characteristics: Light to very dark brown.

Legs: 6

Antennae: Yes

Wings: The reproductive males and females have wings.

Habitat: Builds nests near water sources. Outdoors, nests are located beneath boards, stones, or at the base of shrubs. Indoors, will build nests in wall voids and insulation.


  • Attracted to wet environments near food sources
  • Very efficient foragers that follow regular trails when searching for food
  • Contaminate food and spread bacteria as they forage for food in pantries and kitchens

Argentine Ants in Puerto Rico

Argentine ants are major household and garden pests common to the San Juan area. When searching for food, they leave pheromone trails everywhere they go, instead of just from nest to food source. This habit ensures they do not waste time visiting the same area twice. Multiple colonies can group together to make a super colony, which is why their infestations can be so dangerous. Worker Argentine ants are not typically aggressive toward each other — instead, they come together and leave behind dense trails as their colony grows. They are ranked among the most stubborn home-infesting pests, contaminating and spreading bacteria wherever they forage.

Argentine Ant Habitats

Argentine ant nests are typically located in moist areas near a food source. This means they usually nest in the ground, concrete wall cracks, and at the base of trees. In more mild weather, the ants can be found next to sidewalks, gardens, plants, or underneath stones or boards. When the weather gets too dry or too wet, these ants invade homes through cracks and crevices and are found near water pipes, sinks, and potted plants. Once inside, they will forage for food, feeding on meat, eggs, oils, fats, and sweet items like fruit.

Argentine Ant Behaviors, Threats or Dangers

Argentine ants are very aggressive and could bite people. They thankfully aren’t venomous. An invasive species, Argentine ants are well organized socially and are particularly aggressive toward other insect populations due to their sheer numbers.  Argentine ants cooperate with each other, causing damage to homes as they build super colonies, and invade nearby homes in large numbers. If you suspect an Argentine ant infestation, it is recommended to contact a  professional ant exterminator.