Argentine ant (Linepithema humile)
Pest Snapshot - Argentine Ant
- Scientific name: Linepithema humile
- Identification: Mid-Brown. Size: 2.5 – 3.0 mm. Create obvious foraging trails.
- Health threat: Low
- Bite / sting pain: Mild bite, but no sting. (Quite aggressive)
- Difficulty to control: Difficult
- Diet: Ominvore, but mainly protein and honeydew
- Nest locations: Outside in leaf-litter and under objects
- Colony structure: Multi-queen, multi-nest
- Main pest season: Summer / Autumn
- Indoor/Outdoor pest: Outdoors and indoors
Argentine Ant Information
Invasive / native:
Invasive
Distribution:
Argentine ants are found in the cooler and temperate parts of Australia (including Tasmania), but not in Queensland or the Northern Territory. They are found in urban and disturbed areas, and can be a pest in horticulture.
Typical nest location:
Argentine ants will often build their nests in wall cavities but outside will build their shallow nests under leaf litter, rocks, logs and pavers.
Colony size / structure:
Argentine ants are one of the worst invasive species capable of developing super-colonies that can completely dominant an area. They are multi-queen, multi-nest colonies, with up to 1 queen per 100 workers. The nest expands through budding, where males and females will mate within the parent nest and then leave with a small number of workers to create a new nest nearby. These nests are interconnected and the resulting supercolonies can cover thousands of square kilometres over time.
Identification:
Colour: Mid-brown
Size: 2.5 – 3.0 mm (workers are of variable size)
Nodes on petiole: 1
Food preferences:
Argentine ants have a strong preference for sugars, and are big ‘farmers’ of sap feeding insects, from which they harvest honeydew. However, they show a noticeable increase in protein intake during the warmer months in response to the food requirements to support increased production of young.
Distinguishing features / behaviours:
- In areas of significant infestation, massive numbers of ants and brood will be found on the soil surface under leaf litter, sheeting, rocks, pavers, etc
- They can produce extensive foraging trails over many tens of metres, often 10 or more rows of ants wide.
- They have a high level of nest mobility, frequently moving the nest in response to the environmental conditions (heat & moisture)
- They can often invade buildings in large numbers looking for food or when moving nest
Bite / sting:
Argentine ants do not sting but will bite (mild)
Other comments:
Argentine ants maintain the highly productive supercolony by executing the least productive queens each spring. Up to 90% of queens are executed by workers to be replaced by younger more productive queens as the season develops.
Go back to the main ants page for other types of ants.
How to get rid of Argentine Ants:
With the large number of queens in the colony and huge numbers of ants involved, Argentine ant problems are best left to the pest professional. Baits on their own are not a viable option. It is necessary to use a combination of sprays and baits. Where there are large number of ants outside, a general spray treatment should be carried out to all areas of activity. Ideally this will be a non-repellent spray. Once the spray has significantly dented the population the use of baits becomes more viable, especially to areas of activity indoors. With Argentine ants switching between sugar and protein preferences during the year, different bait types may need to be trialled.
As Argentine ants have a multi-queen, multi-nest colony structure and can create super colonies over massive areas, it is never really possible to eliminate an Argentine ant problem. If you have Argentine ants in your area, it will be necessary to have regular treatments to keep them in check and out of the house.
Argentine ant FAQ
Do Argentine ants bite?
Yes, Argentine ants bite but don’t sting. If you happen to encounter Argentine ants, they may swarm over you quickly in large numbers, giving you a number of little nips. However, as there is no sting or venom injected, there is no lasting pain or itchiness.
Are Argentine ants dangerous?
No, Argentine ants are not dangerous to humans. ALthough, if you have an infestation around your house they can certainly be very annoying and can make it difficult to enjoy your outdoor areas and lawn, as they are quite aggressive and do give a mild bite.
However, they are very dangerous to native wildlife. Not only do they attack other ants and invertebrates in the area, but will attack lizards, young birds in their nests and other vertebrates.
Can I get rid of Argentine ants myself?
The scale of an Argentine ant infestation is generally beyond the abilities of a DIYer. With the generally large numbers of ants and combination of products required, homeowners trying to do it themselves will often carry out multiple treatments, spending a significant amount on products, with little succes. Using a pest professional will be cheaper and deliver a better result.
What is an Argentine ant super colony?
Argentine ants have a multi-queens, multi-nest colony structure. They have a high reproductive rate, producing a large number of reproductives (queens) – up to 1 queen per hundred workers. The colony expands with queens moving off with some workers to set up a new nest, all part of the same colony. This growth allows Argentine ants to expand their territory rapidly. In areas when they have invaded from overseas, such as Australia, where they have no natural predators. Over time these colonies rapidly expand and develop in to super colonies covering 10 – 100 square kilometres!
