Fire Ant – Solenopsis

Origin and distribution

The Red and Black Fire Ants originates from South America and has spread to parts of the world such as the USA, Caribbean islands, New Zealand and multiple Asian countries. The Fire Ant is considered a major pest and costs countries millions of dollars in damages and containment programs. 


Fire Ants can spread through numerous methods naturally and artificially. In Australia specifically Queensland, the government has set out rules that an individual or business must abide by when moving hay, soil, earthwork materials, clay, building materials and other mediums within the zones that have been outlined in this zone map.

Artificial spread methods

  • Soil movement via trucks and agricultural machinery
  • Queen ants hitch hiking on vehicles to cover great distances
  • Transportation of Hay
  • Transportation of pot plants 
  • infested cargo ships coming into Australia

Natural spread methods

  • Queen Fire ants flying to new nesting areas to start a new colony.
  • Queens budding off to create a new colony ( This happens when there are multiple queens in one colony and one queen will leave.)
  • Disturbed/flood colonies can move locations, down streams 

What they look like

Fire ants do not have any interesting or unique features about the way they look, they look like regular gardens Ants. They are small and copper/brown in color on the head and the abdomen is generally darker. They come in a variety of sizes ranging from 2mm to 6mm. 

One main distinguishing factor about Fire ants is the variety of sizes they come in. As most ants species generally are the same size.

Life Cycle

The Fire ants life cycle is similar to the other species of ants.  The first stage is the egg,  this stage is closely followed by the larva, the pupae, and finally the adult ant. 

Click here for a more detailed explanation of the Ant life cycle

Diet and habitat

Fire ants are omnivores, which mean they eat both plants and meat. A typical worker diet includes

  • Worms
  • Spiders
  • Dead animals
  • Earth worms
  • Honeydew
  • Ticks
  • Seeds
  • And much more. 

Fire Ants create there nests in moist locations near water sources such as rivers and creeks. usually Fire Ants nests can be tricky to find as they tend to build nests under timbers, logs, pavers, trees, bricks and anything that can provide a cover.

If a Fire Ant colony cannot find cover to build a nest, they will build dome shaped dirt mounds as high as 40cm and can tunnel vertically or horizontally under the ground to manage temperature and humidity. 


Fire ants are aggressive and violent, they will attack in great numbers if they are disturbed. Fire Ants have a history of swarming a target and stinging them with their painful sting that is injected from the abdomen. The toxin is an alkaloid venom called solenopsin, a compound from the class of piperidines. 

Fire Ants are polygmous which means they can have more then one queen in a colony. This queen cooperation means that a colony can become massive within a few months from its first born worker ant. Queens from polygynous nests can ‘bud’ off and travel great distances to form new colonies of Fire Ant.

From a biosecirty viewpoint this expansionist behavior costs millions off dollars to economies. Fire Ants are predatory and disrupt the local land by driving out native species and over a long period of time have a negative impact on the environment. They kill small plants by digging up the soil destroying root systems and consume the seeds. Fire Ants disrupt agricultural irrigation systems and cause disturbances to tourist locations by stinging humans. 

Interesting note about Fire Ants

In the US alone 83 people have died from the Red Fire Ant, not by the sting and bite itself but through secondary allergic reactions and infections. The 2 part attack from a Fire Ant is a bite, mainly to grip and a painful sting loaded with a chemical that causes the release of a chemical in the human body called ‘histemine’. This causes red welts to appear and cause itching, swelling , pain and sometimes a blister will form. The real threat is allergic reactions after the bite and when there are multiple bites coupled with allergic reactions, a trip to the hospital may be required.