Red imported fire ants (RIFA)

Distinguishing red imported fire ants from other ants can be difficult since they look like most ordinary red/brown ants. A sure sign is their very aggressive behaviour when disturbed. If you poke a nest with a stick, they will come pouring out.

Native ants in Victoria are not usually aggressive and tend to run away from disturbances.

Key identifying features of RIFA are (Figures. 1-3):

• reddish-brown with a dark brown abdomen at the rear (Figures. 1 & 2)
• small size - 2 to 6 mm long (Figure. 3)
• a range of sizes can be found within one nest (Figure. 3)
• nest in soil
• aggressive nature

For ants that look similar to fire ants visit RIFA look-a-likes.

Red imported fire ant nests are not always easily identifiable. In warmer and drier months red imported fire ant nests are flat and may look like heaps of loose dirt (Figures. 4 & 5). In winter red imported fire ants build their nest higher above ground to regulate the temperature and retain heat (Figure. 6). Regardless, a characteristic feature is that the nests have no visible entry or exit holes. Native ants typically build nests which have an obvious opening.

Often, the red imported fire ant nest will not be visible, being constructed under objects such as timber, logs, rocks, pavers or bricks. If there is no cover, mounds will be constructed in open areas in full sunlight.

On residential properties they can be found in lawns, around garden beds, along foot path edges, near taps and in and around utility pits. On rural properties looks for them around dams, along edges of cultivated land, unused cropping land, and along fence lines.

RIFA societies can exist as single nests with one queen or super colonies with multiple queens and interconnecting nests (Figure. 7).

For an instructive video on collecting and photographing fire ants visit the Red imported fire ants page.

RIFA pose a serious threat to our environment and has significant environmental, economic, social and health impacts.

Where colonies have been established in the environment, species diversity has declined. The sheer numbers of ants can outcompete local invertebrate fauna. Deaths of lizards, turtles and birds have also been recorded from red imported fire ant attacks.

Red imported fire ant nests built under pavements or foundations can cause structural instability which may lead to collapse. They are attracted to electricity and can damage equipment and infrastructure impacting business, land and property values (Figure. 8).

Red imported fire ants invade a wide variety of crops and have been known to damage agricultural equipment, delay harvesting and ultimately reduce production of some agricultural industries. Animals and livestock can be harmed or even killed by RIFA attacks with the young, weak or sick particularly vulnerable.

Red imported fire ants thrive in disturbed environments within urban areas including backyards, golf courses, parks and recreational areas, schools and roadsides. Their presence will deter outdoor activity which will severely limit Australia's coveted outdoor lifestyle.

The following ants are commonly mistaken for red imported fire ants at first glance. These ants are not required to be reported but if unsure it is better to make a report than not.

Coastal brown ants – Pheidole megacephala (Figure. 9).

Also known as big-headed ants, this globally invasive species originating from Africa. They are distinguished by two very different sizes of workers – minors (2-3 mm long) and majors (3.5-4.5 mm long). The majors have disproportionately large heads and use their powerful jaws for cutting up large pieces of food for ease of transportation.

Meat ants – Iridomyrmex purpureus (Figure. 10).

The meat ant is a native species that is widespread throughout mainland Australia. Measuring 6-8 mm long it is characterised by its iridescent dark blue to purplish body and red head. This ant also displays aggressive behaviour if the nest is disturbed. They can deliver a ‘pinching’ bite, but do not sting. Nests appear as shallow-domed piles of fine gravel.

Sugar ant – Camponotus consobrinus (Figure. 11).

These large native ants (5-15 mm long) are commonly seen in Victorian forests and woodlands although also inhabit urban areas where they are considered a pest. They have orange-brown body and legs with a black head and abdomen. Sugar ants are timid and neither bite nor sting.

Pennant ants – Tetramorium sp. (Figure. 12).

Tetramorium are a large group of ants distributed worldwide with numerous species found in Australia including some undescribed species in Victoria. With their black abdomen and reddish body, they are often mistaken for red imported fire ants.

Mono ants – Chelaner rubriceps. (Figure. 14).

This native species is found on the eastern and south-eastern coast of Australia from Queensland through to South Australia. It often, but not always, has a red coloured body and darker abdomen with lighter coloured patches. Nest locations can be found on the ground, under leaf litter and vegetation or under loose bark on the trunks of eucalypts.

Report

If you think that you have found red imported fire ants you must report them immediately using the Agriculture Victoria Public Online Reporting Form or by calling the Exotic Plant Pest Hotline 1800 084 881.

Red imported fire ants are a notifiable pest in Victoria which means there is a legal obligation to report suspected detections. This obligation applies to everyone, including individuals and organisations

Photograph

Take clear photographs of the ants and nests and upload them with your report. See how to collect and photograph dead red imported fire ants.

Collect

A sample of the ants may be required for diagnostic confirmation. If you are comfortable, you can collect a sample using the instructions below. If you have concerns about your ability to safely collect a sample, please contact us by calling the Exotic Plant Pest Hotline 1800 084 881..

Be aware and alert.

Red imported fire ants bite and sting.

RIFA are aggressive and when disturbed they will sting simultaneously and repeatedly. The stings are painful, producing a burning or itching sensation that can last up to an hour. Victims of multiple stings may feel as if their body is on fire. After several hours small pustules may form at sting sites. These can become itchy and can take up to 10 days to heal (Figure. 14). There is a risk of secondary infection if the pustules break.

In extremely rare cases stings can cause a severe and sometimes fatal allergic reaction (anaphylaxis). Seek medical attention if showing any sign of adverse reaction to stings.

For red imported fire ant fire ants first aid visit the Fire ant first aid | National Fire Ant Eradication Program.

To safely collect and photograph red imported fire ants you should have the following items on hand:

• a pair of latex or washing gloves
• a can of household insect spray
• a long stick
• some tissue
• a zip lock bag

To safely collect a sample, adhere to the following instructions:

1. Put on the gloves and stand well back from the nest
2. Gently prod the edge of the nest with the stick
3. The ants will run up the stick
4. Spray the ants on the stick and move away from the nest
5. Gently wipe the sprayed ants off the stick using the tissue
6. Spray the tissue again if the ants are still moving
7. Photograph the dead ants on the tissue
8. Put the tissue with the dead ants on it in a zip lock bag and keep in the fridge. You will be given instructions on how to submit the sample if this is necessary.
9. Do not spray the rest of the nest with insect spray – it will not kill the whole nest and will cause the ants to move and spread.

For an instructive video on collecting and photographing red imported fire ants visit the Red imported fire ants page.