African big-headed ant or Coastal brown ant (Pheidole megacephala)

Pest Snapshot - Coastal brown ant (big-headed ant)

Scientific name: Pheidole megacephala
Identification: Brown / red ant with darker abdoment. Minor workers: 1.5 – 2.5 mm. Major workers up to 4.5 mm. Less common major workers have enlarged head..
Health threat: Low
Bite / sting pain: Does not sting, bite not painful.
Difficulty to control: Moderate – difficult
Diet: Prefers protein and oil
Nest locations: Gardens, wall cavities, roof voids
Colony structure: Mult-nest, multi-queen
Main pest season: Summer / Autumn
Indoor/Outdoor pest: Outdoors and indoors

Coastal brown ant information

Invasive / native:

The big-headed ant / coastal brown ant is one of the worlds worst invasive ants. It is not native to New Zealand.

The big-headed ant is found worldwide in many tropical and sub-tropical areas. New Zealand is therefore borderline suitable for the big-headed ant. However, it has become established in the Auckland area.

Typical nest location:

It prefers moist, disturbed habitats – areas around human population are ideal. Typically, it nests outdoors in soil and under rocks / pavers. Sometimes it will nest indoors in wall cavities and plug sockets.

Colony size / structure:

A multi-queen, multi-nest species. The colonies can develop into massive super-colonies completely dominating an area. They are a highly destructive invasive species and will out-complete most other ant species.

Identification:

Colour: Mid brown / red
Size: 1.5 – 4.5 mm
Nodes on petiole: 2

There are minor and major workers, with the major workers (“soldiers”) having enlarged heads, from which they get their name. The major workers form around 1% of the foraging force, so may not always be visible.

Alates are not often seen as the colony expands through budding, whereby one or more queens with a number of workers move to set up another nest in a new location.

Food preferences:

Although big-headed ants are often seen tending sap feeding insects, they show a strong preference for protein and lipid foods. They will typically feed on live and dead invertebrates, but will eat any dead animal material.

Distinguishing features / behaviours:

The ants will move significant amounts of dirt to make their nests – their activity around pavers becomes particularly obvious.
Workers will travel significant differences between nest sites and to and front food sources.
They sometime build shelter tubes for foraging trails, which can look superficially similar to termite mud tubes.

Bite / sting:

The big-headed ant only has a mild sting which is not painful to humans and its bite is not painful.

Prevention tips:

Regular treatments (at least once a year) will likely be required to keep numbers down
Following good hygiene practices, especially clearing away food and not leaving pet food out, will help minimise any foraging inside buildings.

Other comments:

There are a number of other small brown ants, but the presence of major workers and sheer extent of infestations normally make identification straight forward.

Go back to the main ants page.

How to get rid of coastal brown ants?

You are unauthorized to view this page.

Username or E-mail

Password

*

Remember Me

Forgot Password

Coastal brown ant / Big-headed ant FAQ?

Do coastal brown ants sting?

Coastal brown ants (big-headed ants) both bite (with heir jaws) and sting (from their abdomen). However, both are very mild and neither are particular painful to humans.

Do coastal brown ants eat wood?

No, coastal brown ants do not eat wood. The feed on honeydew from sap sucking insects, prey on other insects and collect seeds.

Are big headed ants agressive?

Big headed ants aren’t aggressive to humans but are territorial, very aggressive to other ant species, and will eat invertebrates, reptiles and birds in their territory. This ecological damage they can do is why they are considered one of the worst invasive ant species globally.