Red imported fire ant (RIFA)

For more information relating to this invasive species, see Victoria’s invasive ant surveillance program.

About RIFA

Native to South America, RIFA has become globally widespread in the last century as a result of the increasing trade and travel between countries. Since it was found in Queensland in 2001, this species has been under eradication through the National Fire Ant Eradication Program. This is funded via cost-sharing arrangements involving all jurisdictions and the Commonwealth.

RIFA has also invaded part of Northern NSW and has been detected further south in 2 other areas (Murwillumbah and Wardell), which are now under restricted movement controls. Given that ant invasions are associated with trade and travel, the importation of some commodities from controlled RIFA-infested areas in Queensland and NSW could pose a high biosecurity risk for Victoria.

Agriculture Victoria only allows the importation of RIFA host material originating from quarantine or control zones in Queensland and NSW if businesses comply with the current legislation. This legislation allows trade to continue while reducing the risk of RIFA incursions into Victoria.

RIFA biology

RIFA, like other ants, is a social insect that lives in colonies. These can occur in one of 2 structural forms – either established by one newly mated queen (monogyne colony) or by multiple queens (polygyne colony).

Queens live between 2 and 6 years and stay within the nest, where their sole role is to lay eggs (more than 1,400 eggs per day). Colonies generally grow to around 80,000 workers, but can have up to 400,000.

A key feature of RIFA workers is that they are polymorphic, meaning that they can have different forms and sizes (Figure 1). Workers have multiple roles within the colony. They:

• care and tend to the queen and brood
• forage for food
• defend the colony
• build and maintain the nest.

Nests are often visually barely noticeable for the first 6 months after becoming established. After this period, depending on soil and weather conditions, mounds can be easily identified in the field (Figure 2).

Once the colony has between 22,500 and 32,500 workers, the queen may produce up to 4,500 reproductive individuals each year. When they become adults, reproductives will mate and the females will disperse to start new colonies.

Monogyne and polygyne queens have distinct reproductive strategies. Monogyne queens undertake ‘nuptial flights’, where mating occurs. Afterwards, queens will usually travel long distances (up to 5 km) to start a new colony.

Rather than nuptial flights, polygyne queens usually mate in the nest and disperse very short distances from their original nest. They generally take workers with them in a strategy known as ‘budding’.

The longer dispersal distances of monogyne queens make them a greater biosecurity concern. Queensland currently has monogyne and polygyne populations, with the former being predominant.

Like many ant species, RIFA will eat a wide variety of animal and plant material. This trait is responsible for much of the species’ negative impacts on the environment and primary industries.

Why should we protect Victoria from RIFA?

RIFA is an invasive species that is exotic (not native) to Australia. When RIFA establish outside of their native range, they spread quickly and can be a serious threat to urban and natural environments, causing significant negative ecological, economic, health and social impacts.

Ecological impacts

RIFA colonies can invade and disrupt natural habitats. This reduces biodiversity in areas where they become established by displacing or predating on native ant species and other invertebrates. This can indirectly impact ecosystem processes.

Economic impacts

In urban areas, RIFA can be a structural pest. It can cause electrical failure and damage by short-circuiting or occupying connection boxes or electromechanical devices.

Fire ants also cause significant economic losses in agriculture by invading and damaging a wide variety of crops and swarming and stinging livestock. This can lead to reduced production, weight loss and death of farm animals in extreme cases.

Health impacts

RIFA can inflict multiple painful stings. These have a burning sensation and can cause severe allergic reactions in some people.

Social impacts

This species can change the way we go about our day-to-day life. It can limit our capacity to play sports outside, spend time with family and friends at parks and beaches, do gardening and walk our pets safely.

Identifying, collecting and photographing RIFA

• How to identify RIFA
• How to collect and photograph RIFA