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What Are Big-Headed Ants?

Pheidole megacephala, better known as the big-headed ant, is a successful native species threatening the status of other native ants.


Ants have hitched rides with humans for as long as people traveled. In fact, a dig at one of the Roman baths in Britain revealed 2,000-year-old invasive ant species. The big-headed ants’ exact origins remain a mystery, but scientists believe they originated in the Indian Ocean island of Mauritius. Today, they have been distributed throughout Australia and the US. In both countries, they are a formidable pest. The nickname is derived from the disproportionally large heads seen in the species’ worker ants. The head is used to cut up prey and fend off other encroaching ants.


These ants are aggressive towards other insects and territorial, which is why they have such an impact on ecosystems. When disturbed, big-headed ants may bite humans. Like other insects, they leave well-defined trails and are drawn to sweet nectar and other foods. These ants increase rapidly, reproducing to create multiple queens and distribute themselves further across the geography. Furthermore, these ants work as one large team, making them all the more threatening. While many other species are defensive of their turf, even against the same type of ant, these insects create multiple nests that cooperate for food, defense, and reproduction. They thrive in warm climates and enjoy soil that is already disturbed, which is why they are common in fields and gardens. The Pheidole megacephala is highly adaptive. Researchers point out their size is even regulated by the environment; ants in Australia are three times the size of those in Hawaii because of the fierce competition they face.

Ecological Impact

The Pheidole megacephala is rated in the top 100 threatening invasive species in the world. It poses threats to both US and Australian ecosystems and can have enormous impacts on island wildlife. The big-headed ant has been blamed for the destruction of Hawaii’s lowland arthropod and beetle fauna. They also threaten nesting bird and turtle populations (as they can eat hatchlings) and native ant species. This insect is particularly devastating on rainforest ecosystems. Additionally, the ants’ sap-sucking tendencies make them a common agricultural pest. Even electrical items can be damaged from their foraging.

Identifying the Pests

There are several ways to identify African big-headed ants.

The Head

Of course, the easiest way to identify this pest problem is by seeing a major worker ant, or a soldier. The head makes up half of the ant’s body size. Unfortunately, seeing a major worker ant is rare, so unless a homeowner is lucky enough to come across one, he or she may mistakenly assume he’s dealing with a different type. Minor worker ants are more frequently sighted. They have the same body features as the major, but their heads are proportional to their bodies.

Physical Characteristics

Even if you don’t spy a large head, there are other characteristics that can identify the insect you have in custody. Big-headed ants are yellowish or light to dark brown, measuring about 1/16 inch to 1/8 inch. The workers also have two spines on the waist that face almost vertically. The first segment of the antenna is short, and each ant has two nodes, the posterior of which appears swollen. The insects have no smell when crushed and they do not bite or sting like fire ants unless they feel threatened. Members of Pheidole megacephala are also slow-moving and covered in long, sparse hairs.


These ants build mounds practically everywhere, although they prefer shady areas. You may find them underneath shrubs, in gardens or beneath outside stones. The worker ants displace soil as they dig, so it is common to find small piles of soils over nests. The mounds look like craters placed next to each other. The holes are clearly visible. In Florida, the ants will create foraging tubes above ground using plant debris.


Destroying colonies of big-headed ants can be difficult and often takes the knowledge of a professional. Before taking any measures, avoid disturbing the colonies. If homeowners disturb the colonies, it is likely the ants will move their queen to a new location, making successful management difficult. Finally, homeowners must understand that eliminating the ants may not eliminate the problem. A Pest Control operator certified in lawns must treat your yard, otherwise, the ants will return. However, if homeowners act swiftly, they can stop an invasion from becoming a coup d’etat and then seek the help of a professional to keep their yards ant-free.

Clean Up

The first step homeowners should take is to clean up the house. Get rid of any food crumbs, sweep hardwood floors and vacuum. Seal any food waste so the smell will not attract more ants. However, sometimes this step isn’t enough to keep the insects at bay.

Baiting Programs

The Northern Territory Government of Australia recommends baits to use in gardens and around homes. Improperly used bait can injure other animals or get into a runoff, so be sure to follow all directions when attempting this method. Baiting takes several weeks to eliminate the ants completely, and further baits must be placed every two or three months.


Insecticides are another tactic. Use them in areas that are protected from water, such as inside a building, to avoid contaminating runoff. Studies indicate that some insecticides are ineffective against the big-headed ant, so always research before purchasing. Pesticides must be used every 12 weeks until the infestation is gone.

Need Some Weapons of Pest Destruction?

Having big-headed ants crawling about inside your home is no one’s idea of a picnic. Unfortunately, by the time many homeowners realize they have a problem, it’s too late to use the measures above effectively. But we’re here to help. Whether you have a pest-related question or are ready to eliminate your ant problem once and for all, our professionals will create the right plan for you. Submit your information for a free estimate today and prepare to laugh maniacally as we eliminate the ants who were big-headed enough to think they could waltz onto your turf.

Get Started With Reynolds Pest Management, Inc. Today

(844) 326-3100

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