Name: Argentine Ant
Latin Name: Linepithema humile (formerly, Iridomyrmex humilis)
Argentine ants are an invasive species introduced to North America and across the world by human dispersal. Argentine ants are native to northern Argentina, Uruguay, Paraguay, Bolivia and southern Brazil. Introduced populations of Argentine ants in North America, Asia and Europe tend to have a more uniform genetic makeup than South American populations, a phenomenon that has resulted in the formation of massive intercontinental supercolonies. What this means is that colonies of Argentine ants in Southern Ontario tend to grow larger than they would in their native ecosystems and may achieve dominance over native ant populations wherever they invade since members of the same supercolony do not compete for food sources or territory. An infestation of Argentine ants on your Ontario property has the potential to become a colony of several hundred thousand ants and should be treated by a licensed professional.
How do you get rid of Argentine ants?
Argentine ant colonies may contain many queens (who may also be seen foraging for food, or a new location for a satellite colony, alongside workers). Insecticidal sprays, killing a single queen, or only focusing on the removal of visible ants, won’t have much effect on correcting your nuisance pest population, but may exacerbate it. Since Argentine ants have a tendency to form supercolonies with many queens and thousands of workers, any ill-executed extermination attempt may cause ‘budding’ or, the rapid establishment of several satellite colonies throughout the property, or structure. A threat to the colony may also instigate increased egg production by the colony’s queens, leading to a population explosion. Argentine ants, unlike most native ants, do not build mound colonies, making their nests challenging and sometimes, seemingly impossible to track.
The best approach to destroying an invading population of Argentine ants is through the use of slow-acting insecticidal baits that exploit the omnivorous diet of the species. When successful,
bait treatments cause insecticide to be brought covertly into the nest by foraging workers, which is then fed to caste members, including the queens, destroying the colony from the root.
How to identify Argentine ants
Appearance/What does Pest Name look like
Light to dark brown in colour, the worker ants are 1.6–2.8 mm (0.06–0.11 in) in length and can easily squeeze through cracks and holes as small as 1 mm (0.04 in). Queens are 4.2–6.4 mm (0.17–0.25 in) long, much smaller than other species of ants.
Life stages & anatomy
Argentine queens are many, about 8 for every 1 000 workers, and typically mate only once. From that single insemination, Argentine ants can lay fertile eggs for up to 10 years. Several queens may live in a single colony, harbouring thousands of insects. Fertile queens will establish connected peripheral colonies when one nest becomes too crowded, leading to the existence of a complex matrix of nests or, a supercolony.
Argentine ants are quite inactive in Southern Ontario’s colder months. Little to no reproductive activity occurs until late in winter when queens produce fertile eggs for spring mating. Workers are typically produced in increasing numbers between March and October for foraging before their winter lull.
Signs of an Argentine Ant Infestation
The presence of Argentine ants in your home indicates a possible infestation. When crushed, they release a stale, musty odour.
Where did they come from / how did I get them?
Argentine ants are adaptive colonists who nest in a variety of shallow and moist conditions: In soil, in concrete walls, in spaces between floor boards and timbers, even among belongings in human habitations and beneath kitchen sinks. Since they possess unicoloniality, separate Argentine ant colonies do not compete. Their genetic makeup is so uniform that individuals from one nest can freely mingle in a neighbouring nest without being attacked, readily leading to the formation of supercolonies. Matrices of Argentine ant colonies are established with trail connections. Polydomous social organization is not only significant to the ecological domination of these ants but can make eradication of an Argentine ant infestation on your property, a frustrating task. Argentine ants will typically enter the home between March and April while foraging for food. The presence of a stable food source, anything from a forgotten jar of honey or spilt beer under the fridge, may lead Argentine ants to establish colonies in your home. A nest found in the home will likely indicate the presence of several nests in, and around, your property.
What do Argentine ants eat?
Although exhibiting a preference for sweet foods like honeydew and plant nectar, Argentine ants have an adaptive omnivorous diet and will almost any plant or animal matter. Like almost any home invading ant, Argentine ants will be drawn to sweet and greasy substances in your home and will happily raid pantries and other food stores that are not contained and concealed.
How Serious are Argentine ants?
Although Argentine ants may bite when provoked, the bite that they deliver is not severe and is unlikely to do much harm. The greatest risk posed by an Argentine ant in your home is the danger of food contamination; since ants crawl over over organic waste, garbage and have a tendency to feed on other insects and animal matter, they may transfer disease bacteria onto your food by mechanical transmission.
How Addison Can Help Eliminate Argentine Ants
Mention Addison’s free quote/consultation service
Home remedies / organic and natural cures – also why these may not work as well as our methods
How Addison can help Prevent Argentine Ant Infestations in the Future
Most active during Southern Ontario’s spring and summer months, Argentine ants will often enter structures in search of food sources when weather conditions are dry and hot, and when escaping flooded nests after rain. Even if the origin of an infestation is rooted out, it is important to be stringent in your implementation of physical controls; fill cracks in building facades, and seal window frames (refit if necessary). Keep outdoor spaces dry and open to sunlight, clear debris that creates humid and moist conditions for ant colony-building, lift firewood off the ground. Establish a perimeter clear of organic matter of at least 1ft around the structure. Shrubs and tree branches should be cut back from your home to limit access points to the structure. Inside, kitchens should be kept clear of spills and crumbs; food should be kept tightly sealed, keep organic waste in the freezer, seal moisture drips and leaks from drains and plumbing, repair cracks and fissures in floors and walls.