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Yellow crazy ant

Native to Africa, the yellow crazy ant has a long body and very long legs and antennae. Its name comes from its erratic walking style and frantic movements, especially when disturbed. Yellow crazy ants can disrupt natural environments, affect the horticulture industry, and cause skin and eye irritations. They are found throughout the Pacific region and on Christmas Island, and are most commonly transported inside sea cargo.

Yellow crazy ants are regularly detected and eradicated by the Australian Government's Department of Agriculture, Water and the Environment in port areas. They have spread extensively in Queensland since they were first discovered in Cairns in 2001. Despite Biosecurity Queensland's ongoing treatment and surveillance, eradicating yellow crazy ants is no longer considered possible in Queensland. Efforts will now focus on working with councils, industry and landholders to manage yellow crazy ants and their ongoing impacts.

The yellow crazy ant is listed as one of the world's 100 worst invasive alien species by the International Union for Conservation of Nature.

Yellow crazy ant is a restricted tramp ant under the Biosecurity Act 2014.

Scientific name

Anoplolepis gracilipes

Other names

  • Crazy ant


  • Yellow to brownish ant with body about 5mm long.
  • Abdomen is dark brown, sometimes striped.
  • Legs and antennae are very long.
  • Body is long and slender.
  • Walking style is erratic.
  • May spray formic acid when disturbed.


  • Yellow crazy ants typically colonise moist, shady, disturbed habitats such as rainforest margins/gaps and agricultural land, particularly agroforestry.
  • In northern Australia, yellow crazy ants were initially believed to prefer rainforest, but recent research confirms they can thrive in harsh, rocky, dry areas in Arnhem Land, Northern Territory.


  • Infestations have been found at:
    • light industrial properties in Maryborough, Arundel, Rocklea, Slacks Creek, Wacol, Banyo, Tingalpa, Chermside, Woodridge and Eagle Farm
    • suburban Kedron in Brisbane
    • suburban Edmonton and Bentley Park in Cairns
    • industrial estates at Caboolture, Hervey Bay, Pinkenba and Townsville.
  • Previous infestations were in Woree and Portsmith in Cairns but have now been eradicated.

Life cycle

  • Worker ants have a life cycle of 76-84 days. Queens survive for several years. Workers are produced throughout the year, but production fluctuates.
  • Sexual offspring are produced at any time in the year but generally 1-2 months prior to the rainy season.

Affected animals

  • Native animals
  • Crabs



  • Disrupts natural species, including native birds, animals and plants.
  • Is reducing unique red crab population on Christmas Island.
  • Protects sap-sucking insects such as scale and mealy bugs.


  • Can affect horticulture industries.


  • Sprays formic acid, which may cause burning and irritate skin and eyes of animals and potentially humans.


  • Treat infestations by spraying or baiting (foraging ants collect bait and carry it back to colony, sharing it with queens, who are only ants in colony able to reproduce).
  • Landholders can use insecticides that are registered for ant control.
  • Distance® Plus Ant Bait can be effective. However, yellow crazy ants could become resistant to Distance® Plus, so better to combine different insecticides and integrated land management practices.
  • Use insecticides according to label instructions.
  • Further information about insecticides can be found on the Australian Pesticides and Veterinary Medicines Authority website.
  • Landholders may choose to call local pest control operator.

Legal requirements

  • Yellow crazy ant is a restricted tramp ant under the Biosecurity Act 2014.
  • It must not be distributed or disposed of into the environment.
  • The Act requires everyone to take all reasonable and practical steps to minimise the risks associated with tramp ants under their control. This is called a general biosecurity obligation (GBO).

Further information