Tramp ants

​ ​

​​​​​​​​​​​​​​​​​​​​​​​​​​​​ Red imported fire ants crawling over a piece of timber.


Tramp ants​

Exotic to Australia, under eradication or management

Life form: Insect
Origin: Varies, depending on the species
Distribution: Asia, Africa, North America, Central America,
Caribbean, South America, Oceania
Features: Classic ant body shape, under 5 mm, ability to
rapidly disperse, adapts to varied habitats
Pathways: Imported goods, travellers
At risk: Agriculture, environment, social amenity, human health

Tramp ants are a diverse group of aggressive, invasive ant species that can rapidly establish and spread if introduced. Several species of tramp ants are amongst the most serious global invasive pests.

Australia’s environmental, economic, and social wellbeing are threatened by these ants, some of which have already been introduced and established in Australia.

Tramp ants can reduce species diversity and modify habitat structure, and have the potential to severely impact human health and social amenity.

  • Several species of tramp ants have painful stings which can cause anaphylactic shock in some people.
  • Pets, livestock, and native animals may also be severely affected by bites and stings.
  • Ants may eat plants and chew through electrical insulation, and their nest building can damage machinery and buildings.

Tramp ant infestations may also impact on agriculture and forestry. Some species farm sap-sucking scale insects for honeydew. This can lead to larger infestations of pests on host plants, resulting in their death. This also increases the risk of disease being transmitted to plants through these insect vectors.

How to identify Tramp ants

Everyone needs to keep an eye out for tramp ants.

The most likely pathway for tramp ants to be introduced to Australia is with imported cargo and travellers. Ants can be moved in

  • containers
  • soil
  • plants
  • timber
  • machinery
  • even by passengers carrying plant matter or in luggage.

They are found in ships, planes and a range of goods.
Tramp ants are

  • often difficult to distinguish from native ants, as most species are tiny (under 5 millimeters)
  • have a classic ant body shape
  • do not construct obvious nests.

Although the species vary substantially, they all have the ability to rapidly disperse and adapt to varied habitats.

Certain tramp ant species can form super colonies with multiple queens that allow rapid and extensive colonisation.

Some spread by budding, where new colonies radiate out from existing colonies, or by winged ants flying from the colony.

Many species of tramp ant originate from South America, such as:

  • red imported fire ant
  • Argentine ant
  • electric ant.
Red imported fire ants size demonstration Source: DAFWA
Range of sizes of red imported fire ant during its life cycle. The ant varies from 2mm to 5mm in size
Tropical fire ant with 2mm scale Souce: PaDIL

View of the back of the tropical fire ant with red-orange brown body and brown head. They have distinct compound eyes and antennae.

Browsing ant is native to southern Europe.

Yellow crazy ant is thought to originate from Africa but can now be found throughout the Pacific.

Close up view of yellow crazy ants Source: Cairns Post
Close up view of yellow crazy ants with long body and very long legs and antennae. The abdomen is dark brown with yellowish to brown body.

Australia has had a number of incursions of exotic tramp ants.

Summary of tramp ant incursions in Australia

Subject to eradication


African big-headed ant (Pheidole megacephala)



Argentine ant (Linepithema humile)



Browsing ant (Lepisiota frauenfeldi)



Electric ant (Wasmannia auropunctata)



Yellow crazy ant (Anoplolepis gracilipes)


QLD, Christmas Island

Red imported fire ant (Solenopsis invicta)



Tropical fire ant (Solenopsis geminata)

Tiwi Islands



If you work around imported goods you need to look for tramp ants on:

  • crates
  • machinery
  • plant material
  • shipping containers
  • conveyances

Growers and home gardeners

Moving items out of your backyard, including pot plants, can be an easy way for tramp ants to move to new locations. These items should always be checked if you are in an area known to have a tramp ant population. Take action if you see signs of tramp ant infestation.

Keep Tramps ants out of Australia

All Australians and international tourists have a role to keep out exotic pests and diseases.

Australia remains free of many tramp ants, and most of the ones that have been introduced are restricted in distribution and are under eradication or management. We need your help to keep tramp ants out and to control the species that are here.

Check what you can and cannot bring into Australia, whether you are a:

Tramp ants are hitchhikers and stowaways

Hitchhiker pests can arrive in Australia on many pathways such as goods, vessels or personal effects. Tramp ants have spread globally with the movement of travellers and goods in recent decades.

Import restrictions and biosecurity measures

Some items, by law, are subject to certain import conditions to be allowed into Australia. Please check the Biosecurity Import Condition System (BICON).

Be aware of any tramp ant biosecurity measures that may be in place for incoming goods and conveyances. Industry advice notices are reviewed regularly and could change.

Secure any suspect specimens

Containment is critical. If you suspect you’ve seen a tramp ant, take a photo and record the location.

Report detections of exotic pests

Any detections of tramp ants must be reported to authorities.

Import community

If you receive or work around goods imported from overseas, including mail, you need to be vigilant to tramp ants and other exotic pests. If you see an unusual pest, secure the goods to limit the movement of the pest and immediately report it to the Department of Agriculture and Water Resources See.Secure.Report. Hotline 1800 798 636 or by using the online form.

Growers and home gardeners

If you see tramp ants or anything unusual, report it to the Exotic Plant Pest Hotline 1800 084 881. This will put you in touch with the Department of Primary Industries or agriculture in your state or territory.

When reporting your concern, you will be given advice on handling the specimens and what to do next until an officer can investigate.

Additional information