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Everything You Need to Know About Argentine Ants

Aug 3, 2021

Argentine ants in Oregon may be tiny, but they are taking over the state with fewer people realizing what these insects can do. To date, only about half of the existing 14,000 species of ants have gone through thorough research and studies. Most of these ant species inhabit a rigid caste system of social colonies.

Many of the ant species including Argentine ants are tough and can quickly adapt to their environment. No matter how strict the bio-controls in airfreight and shipping may be, they still can’t completely eliminate ants seeking temporary shelters on vegetation, furniture or food. This is why world domination of ants is not impossible. They find ways to attach to food, things, or people without getting noticed. 

Argentine Ants—One of the Most Invasive Species

Argentine ants (Linepithema Humile), originated from Brazil or Argentina before landing in the United States. Today, they are considered a common ant variety in Oregon and have conquered the world, except Antarctica. This is said to be partly caused by the unusual friendliness of the species.

Argentine ants have veered away from the common reproductive strategy being implemented by other species, such as flying ants. The usual reproductive process goes like the drones and fertile princesses coming in hoards to mate. Female ants who have completed the mating process will proceed to set up new colonies.

queen argentine ants

On the other hand, Argentine ant queens tolerate fertile princesses and see them as additional breeders in the same colony—a breeding process referred to as polygenic colony. This way, the army of workers is on standby to help raise the princesses’ broods, leading to the fast rise of the numbers of ants in the same colony. Many other invasive ant species aside from Argentine ants show similar breeding behavior.

Aside from polygenic colonies, many invasive ants also use the budding method to establish new colonies. This is done when a fertile female ant starts a new colony from scratch with the workers she brought along after leaving her original colony on foot.

They prefer the setup rather than going through the nuptial setup of finding a mate, which they find riskier and more complex. Instead, they choose to become a lone parent in the colony they have built.

Unlike most ant species that are fiercely territorial, Argentine ants prefer living harmoniously. They have a peace-loving attitude with their family and neighbors. Despite the enormous ant colonies on the coastlines of western Japan, California, and the Mediterranean, Argentine ants show slight signs of aggression when they are introduced to Argentine ants from other colonies.

Identifying Argentine Ants

These non-native species of ants are small and shiny, with a dark brown color. Unlike sugar ants that have 3 propionate segments, Argentine ants have larger abdomens than their heads.

These ant species are known for the big colonies they create and keep. Their colonies are almost 100x larger than others and their members are 10% bigger compared to other ant species .They become noticeable when foraging for food as they leave wide trails.

Argentine ants like to eat sweets, including garden pests and aphid-produced honeydew. However, they can eat almost anything and are categorized as scavengers. They also like water which is why they are commonly found near water sources, like in the bathrooms.

Argentine ants are the new invasive ant species in Oregon.

Recently, Argentine ants have replaced odorous house ants as the most invasive ant species in Oregon, making them quite common. Although both ants have a rotten coconut-like odor when squished, Argentine ants have a stronger smell.

Aside from Oregon, Argentine ants are now widespread throughout Hawaii and California. According to studies, they entered the continental US in the latter part of the 1800s via the coffee ships from Brazil. They have now conquered the rest of the world even though Argentine ants are native to southern Brazil, Bolivia, Paraguay, Uruguay, and Argentina.

These ants also go through a complete metamorphosis process, a developmental progression that all ants experience. On average, their eggs hatch in less than 30 days (more or less 28 days) and they become adults after about 74 days. However, the development of these ants still varies depending on various factors such as climate and temperature.

argentine ant identification

Quick Description

Name: Argentine ants
Scientific name: Linepithema Humile
Size: 1/8 to 3/16 inch or up to 2.8mm long
Color: Shiny black or dark brown
Shape: Oval, segmented
Number of legs: 6
Antennae: 12 segments
Wings: None (except for some queen ants)

Many people believe that Argentine ants are causing the eradication of sugar ants, but they don’t usually bite humans unless provoked despite being known for their aggressive behavior. They are often aggressive to other native ant species to drive them away from the area. Argentine ants are difficult to control since they attack in droves, making them nuisance species. They love moist places and always want to be near water. Argentine ants could cause food contamination. If they are not controlled earlier, they can spread bacteria on various surfaces of your home or backyard.

Amazing Facts about Argentine Ant Queens

While most Argentine ants do not have wings, some of the reproductive male and queen ants may have wings. The queens grow bigger than the ant workers, with a body length that can reach up to 6mm. Argentine ant queens are quite different when compared to other ant species queens.

queen argentine ant

Here is what you need to know about Argentine ant queens:

  • Winged queens mate once with a winged male inside the nest. After mating, these queens continue to produce fertile eggs throughout their lifespan.
  • Unlike other ant species queens who work just to lay eggs, Argentine queens do not depend on the ant workers to feed their young. They do it themselves.
  • Queens from this species are very mobile and can be seen outside the nest with the workers. This is unlike other ant queens that stay inside the nest for as long as they live.
  • One Argentine ant colony can hold several queens. Each queen can lay up to 60 eggs per day.
  • If there is colony pressure, the Argentine ant can move to establish a new nest.

On the other hand, the primary duty of Argentine ant males is to mate with the queens so as to preserve the colony. However, they are very short lived and die soon after mating. Check out our other article on ant lifespan facts.

Argentine Ant Activity in a Colony

Argentine ants thrive in big colonies with thousands of workers and hundreds of queens in numerous nests. All these ants move freely from one colony to another. Their queens could produce up to 60 eggs every day. The average lifespan of the workers is one year.

Here’s a breakdown of the Argentine ants’ activities depending on the season:

  • Spring – Female and winged male reproductive members mate in the nests.
  • Spring and Summer – Big colonies are split into several smaller colonies. It happens when a queen or several queens leave their original nest along with a number of workers to find a new site to nest.
  • Autumn – Several colonies combine to create super colonies.
  • Winter – The ants enter a dormancy state and only go back to their traditional ways once the temperatures become warmer.

These ants are always on the lookout for a microenvironment suitable for rearing their broods. This is why they move often and favor nests that are unstable and flimsy.

Here are the other interesting facts about Argentine ants:

  • They love to walk on the ceiling.
  • They love spending time in moist areas or near water sources.
  • They can share queens, workers, nests, and colonies.
  • Sugar ants fear them since Argentine ants arrive in hoards.
  • They don’t fight with one another, unlike many ant species.

Other Important Facts about Argentine Ants


Argentine ants love water. Hence, you will most likely find their colonies located near a food source in surroundings that are moist and wet. They invade houses or buildings in hoards when the condition outside is either too dry or too cold.

When indoors, these ants seek areas with moisture such as the bathroom, potted plants, sinks, or water pipes. They usually get inside the house by trailing utility lines or tree branches connected to the building.

When settled outdoors, they prefer building shallow nests in areas with moisture, such as the sidewalks, under the plants, stones, or boards.

Ant Bites

Since these ants do not have stingers, their bites on humans won’t cause severe health risks. They also won’t normally bite people unless provoked.


While the Argentine ants’ bites do not cause serious health risks, they can be carriers of bacteria that can cause diseases, including dysentery. This is because of their habit of walking over dead animals, trash, and sewage as they search for food.

They can become harmful when they enter the house and invade the kitchen. They can spread bacteria all over the ingredients they walk on and can also cause food contamination. There are also instances when Argentine ant workers destroy and attack poultry chicks, which typically happen in places where there is a large number of the ant species.

argentine ants

Argentine ants differ from many ant species in their way of leaving pheromone trails while searching for food. They deposit these trails to and from the source of food. This habit makes them resourceful and practical foragers. When hunting for food, they follow a regular trail. Sometimes, the winged queens may be seen in the tracks along with the workers.

Their technique in leaving pheromone trails helps them to save time. In addition, it allows them to remember which areas they have already visited so they won’t come back to the same place soon.

During spring and summer or the peak of their reproductive period, they load themselves with foods rich in protein. However, on any regular day, Argentine ants love eating anything that has sucrose.

Effects of Invasive Ants on the Ecosystem

While Argentine ants don’t fight one another, their natural instinct is to oust other ants when they arrive in the area where they want to settle. Invasive ants could eliminate up to 90 percent of the native ants thriving in an area. This leads to a massive disturbance of an ecosystem’s balance. For example, after Argentine ants invaded California, most of the native ants were displaced. These ants were the primary food source of Blainville’s horned lizards. Due to the change, the lizards had to change their diet, resulting in a significant decline in their population.

Argentine ants are described as careless invaders. They drew away several ant species in the grassland of South Africa responsible for dispersing elaiosomes seeds after snacking on the rest of the plant. After Argentine ants have taken over the area, the local plant community experiences a significant setback.

Aside from that, Argentine ants also feed on flower nectar. They consume them before the bees, and other native pollinators could feed on the nectar. The biggest loss was felt in Hawaii, where Argentine ants caused silverswords and other rare plants to become endangered.

argentine ants

Hire a Professional to Get Rid of Argentine Ants

Seeing a swarm of ants every now and then may appear normal. However, it becomes a problem when Argentine ants, in particular, begin to invade many areas of your home or backyard. Argentine ants are quite difficult to exterminate because store-bought products usually do not work on them due to too many nest sites. Baiting alone will not also be effective so you need to bring in an ant expert who will usually do a combination of treatments.

organic pest control expert

You shouldn’t wait until the infestation gets out of control before calling a pro. Ant & Garden Organic Pest Control in Beaverton specializes in eliminating Argentine ants and other pests without using chemicals that may harm you and the other dwellers in your home.

What makes us a standout among similar businesses is that we utilize selective pesticides that won’t kill off the beneficial bugs in the area. This is a good thing since 90 percent of the insects in your surroundings are beneficial to the environment where they thrive. Retaining these beneficial insects will boost the health of the ecosystem.

We only use organic pesticides that are more effective than chemically-filled sprays and offer long-term positive results. Organic products are biologically based, making it difficult for the pests to develop resistance as opposed to how they react to the chemicals in other pesticides. Besides, chemical sprays are harmful to human health and can also cause damage to your plants or lawn when repeatedly applied.

Ant & Garden Organic Pest Control will not only get rid of the Argentine ants in your home but we will also keep the pests from coming back. With over 20 years of experience, we know a lot about the area and will explain how you can keep your home pest-free.