Yellow crazy ants can out-compete native animals for food and places to live. They can weaken plants by farming sap-sucking insects.

Eradicating pest ants from the Top End

CSIRO researchers are leading the way in understanding the ecology, impacts and control of pest ant species in northern Australia.

• 28 September 2007 | Updated 14 October 2011

• Pest ants in northern Australia
• Why are pest ants a problem?
• CSIRO research
• Communication and capacity-building
• Partnerships
• How to help

Pest ants in northern Australia

Some of the world’s worst invasive species are pest ants. These ants pose significant threats to both biodiversity and agricultural production, and can be major domestic pests.

The four most serious pest ant species occurring in the Northern Territory are:

1. African Big-headed ant (Pheidole megacephala)
   African Big-headed ants have been in Australia for more than 100 years and are well established in all major towns and cities of the NT. The ants are a major threat to native ecosystems, particularly rainforests. As its name suggests, African Big-headed ants originated in Africa. The major (soldier) workers of this species have huge heads, contributing almost half of the body size. African Big-headed ants are slow moving and do not bite or sting
2. Yellow Crazy ant (Anoplolepis gracilipes)
   Yellow Crazy ants were discovered in north-east Arnhem Land in the late 1970s and very recently in Darwin. This species is primarily an environmental threat, and is most famous for its impact on Christmas Island, where it has killed up to 20 million Red Land crabs and caused major changes to the rainforest ecosystem. Yellow Crazy ants get their name from the fast and frenetic behaviour displayed when a nest is disturbed. They spray formic acid, which can cause skin and eye irritations.
3. Tropical Fire ant (Solenopsis geminata)
   Tropical Fire ants are a major pest of horticulture and agriculture around the world, and are a nasty pest of parks and gardens because of their powerful stings. These ants have been in Australia for at least 80 years and are now widespread throughout the Darwin and Katherine regions in the NT, where they are often referred to as Ginger ants. Their nests are very conspicuous, with freshly worked earth heaped into a loose pile, often on lawns. A close relative, the Red Imported Fire ant (Solenopsis invicta) was discovered in Brisbane in Queensland in 2001, and could potentially spread throughout northern Australia if not controlled. Fire ants get their name from their painful stings.
4. Singapore ant (Monomorium destructor)
   Singapore ants are widely distributed throughout Australia. They are mostly a problem with infrastructure, where they are attracted to power points and electrical items. Within Top End Aboriginal communities Singapore ants are estimated to cause more than $1 million damage each year to electrical items. Singapore ants bite and have an irritating sting.

Why are pest ants a problem?

In natural environments, pest ants can eliminate many native animal species and seriously disrupt ecological processes.

Pest ants also cause damage in:

• agricultural and horticultural areas, where crops can be destroyed by direct damage to fruit, or by causing outbreaks of other insect pests
• houses and buildings, particularly electrical items, plastic cabling and pipes.

CSIRO research

Since 1996, CSIRO has been undertaking research into the ecology, impacts and control of invasive ant species in northern Australia. In the early 2000s, CSIRO and Environment Australia conducted a large-scale eradication of African Big-headed ants and Tropical Fire ants from the World Heritage listed Kakadu National Park. The project’s success led to CSIRO’s involvement in a range of pest ant management programmes across the NT including:

1. Yellow Crazy ants in north-east Arnhem Land.
   This project aims to eradicate Yellow crazy ants from the Gove Peninsula and outlying regions where it interacts with people, and to contain the remaining populations in the region to prevent their spread. Project partners include Dhimurru Land Management Aboriginal Corporation, the Department of Environment, Heritage, Water and the Arts, the NT Government, Rio-Tinto Alcan Gove and many local Aboriginal communities. To date, Yellow Crazy ants have been eradicated from at least 20 locations covering over 100 hectares, which is an internationally significant achievement. CSIRO’s research has investigated, the biology and invasive ecology of Yellow crazy ants, its ecological impacts, and improved management options. 
2. African Big-headed ants and Tropical Fire ants on the Tiwi Islands.
   This project appears to have successfully eradicated African Big-headed ants from all four known locations throughout the Tiwi islands, and is also aiming to eradicate Tropical Fire ants from an additional three locations. Project partners include the Tiwi Rangers, the Tiwi Land Council, the Tiwi Island Shire Council and local Tiwi communities. A feature of the project has been the successful incorporation of new understanding of Tropical Fire ant biology into treatment protocols.
3. African Big-headed ants in the Daly region.
   This partnership with  the Malak Malak Rangers successfully eradicated a 5 hectare infestation of African Big-headed ants from the Brown's Creek area on the Daly River in the NT. It was the first ant eradication project to document full ecological recovery of an invaded native system. The project received financial support from the NT Regional Investment Strategy.

Communication and capacity-building

Public awareness and capacity building within communities are essential to the success of pest ant management and eradication.

Effective communication is achieved through:

• face-to-face meetings
• print and radio media
• roadside signs
• posters and information sheets.

Partnerships

The Singapore ant is one of four major pest ant species found in the Northern Territory.

CSIRO is working in partnership  with a wide range of Indigenous, government and community groups including:

In Arnhem Land:

• Dhimurru Land Management Aboriginal Corporation
• Indigenous Land Corporation
• Northern Land Council
• Australian Government Department of the Environment and Water Resources
• Northern Territory Government
• Alcan Gove
• many local Aboriginal communities.

In the Tiwi islands:

• Tiwi rangers
• Tiwi Land Council
• Tiwi Island Local Government
• local Tiwi Island communities.

In the Daly River region:

• Wangamaty Landcare group.

How to help

Pest ants are easily transported by people.

To help people should be extremely vigilant when transporting anything that might contain ants, such as pot-plants and earth-moving machinery.

Eradication of new infestations is relatively easy if acted on early.

Read more about Dr Ben Hoffmann: applied ant ecology in northern Australia.