Facts, Identification & Control
Argentine ants range from light to dark brown and measure about 2.2 to 2.8 mm long. Their antennae have 12 segments.
Behavior, Diet & Habitat
Argentine ants are readily adaptable and can nest in a great variety of places. Colonies are massive and may contain hundreds of queens. Nests are usually located in moist soil, next to or under buildings, along sidewalks or beneath boards. These ants travel in trails.
Argentine ants are omnivorous, meaning that they can eat almost anything, but they prefer sweet foods.
Like other ant species, Argentine ants pass through the development process called complete metamorphosis. Eggs are white, and larvae emerge from them after about 28 days. They reach adult stage in about 74 days.
Argentine ants may live in soil, under wood, logs, debris or mulch. They may also nest in cavities at the base of shrubs and trees. Their nests are often shallow, measuring up to 20 cm (~8 in) in depth in open habitats.
Signs of an Argentine Ant Infestation
The foraging trails of Argentine ants are their most visible sign. The trails can be observed traveling up buildings, trees and into homes. Read more about Argentine Ant infestations.
All Argentine ants are the same size. They travel with well-defined trails between their web of nests and their food sources. Argentine ants feed on sweets, honeydew and oily household foods.
Nests & Colonies
While other ant species have seasonal nuptial swarming flights, Argentine ants do not establish new nests through swarming. They produce reproductives that do not swarm from the nest but instead mate inside the nest. At times, due to temperature or colony pressures, a queen Argentine ant will leave her nest on foot to establish new colonies. New nests are constructed around the original, and remain connected to the queen’s old colony, so workers are sometimes shared between colonies.
Argentine ant queens are different and unusual when compared to queens of other ant species. Some of those dissimilarities and behavioral characteristics are:
- Argentine ant queens are small, about 1/6 – 1/4 inches in length, much smaller than most other species of ant queens
- Winged Argentine ant queens mate once with a winged male, after which they can continuously produce fertile eggs for as long as they live. While other ant species have seasonal swarming flights, these ants do not form new nests through mating swarms. Instead, they mate inside the nest.
- A single Argentine ant colony will have several queens, each of them capable of laying as many as 60 eggs per day.
- Argentine ant queens help workers by feeding their young. Most other ant queens primarily lay eggs and depend on the ant workers to feed and care for the young.
- Argentine ant queens are mobile and may be seen outside the nest along with workers, unlike other ant queens who reside inside the nest for life. Queen mobility enables the rapid movement and establishment of nests to other areas if conditions become inhospitable.
- At times, due to temperature or colony pressures, an Argentine ant queen will leave her nest without taking flight and establish a new nest.
Male Argentine ants hatch from the queen’s unfertilized eggs and are fairly short lived. The single function of a male Argentine ant is to mate with a queen to preserve and proliferate the colony. The males usually die soon after mating.
Argentine ants kill other insects and invade human dwellings. Over time, the network of interconnecting colonies could become a massive infestation. Each colony of Argentine ants can contain millions of insects and multiple queens. These colonies can populate entire city blocks. Argentine ant infestations are best left to a professional pest control operator to identify and treat.