Identification

Types of ants in New Zealand, and how to tell which one you have

The ants in New Zealand homes and gardens by size, colour, smell and trail, which ones bite, why white ants are really termites, and what to do about fire ants.

The short answer

New Zealand has 38 confirmed ant species, 11 of them found only here and 27 brought in, mostly from Australia. Indoors you are almost always looking at one of four: the white-footed house ant, black with pale feet; the light brown Argentine ant; Darwin's ant, which smells strongly when crushed; or the small, shiny black house ant. So-called white ants are termites, not ants. Which one you have decides how ant control is done.

At a glance

New Zealand house and garden ants, by sight

New Zealand house and garden ants, by sight
Ant	Worker size	Colour	Crushed smell	How it moves	Where you find it
White-footed house ant (Technomyrmex jocosus)	3.0–3.4 mm	Black or dark brown, pale legs and feet	Not a useful test	Long trails; lifts its abdomen as it walks	Indoors, wall cavities, under bark; the most common introduced ant
Argentine ant (Linepithema humile)	2–3 mm, all the same size	Uniform light brown	Slight greasy smell or none	Fast, steady, unbroken trails	Gardens, pot plants, under stones and timber; indoors in large numbers
Darwin's ant (Doleromyrma darwiniana)	About 2 mm	Dark brown head, light brown body	Strong, pungent	Long single-file trails	Urban gardens and pot plants; indoors for sweet food
Black house ant (Ochetellus glaber)	2.0–2.5 mm	Shiny black or brown	Not a useful test	Files up tree trunks and fence posts	Gardens; only occasionally indoors
Southern ant (Chelaner antarcticus), native	3–5 mm, mixed sizes	Orange, yellowish brown, dark brown or black	Not a useful test	Wanders loosely, no set trail	Lawns, gardens, under stones; does not forage indoors
Coastal brown ant (Pheidole megacephala)	Minor workers 2 mm, big-headed majors 3.5 mm	Light brown	Not a useful test	Small soil mounds at the nest entrance	Coastal Auckland suburbs, under paving
Pharaoh ant (Monomorium pharaonis)	1.5–2.4 mm	Pale yellow to light yellow-brown	Not a useful test	Trails indoors	Rare; mostly found in hospitals
Native stinging ant (Austroponera castanea)	4.9–6.1 mm	Reddish to dark brown	Not a useful test	Hunts alone, no trails	Under stones and logs in gardens; stings if the nest is disturbed

What are the most common types of ants in New Zealand?

Indoors, the ants Aucklanders find most are the white-footed house ant, which Te Ara describes as the most common introduced ant in the country; the Argentine ant, spreading through northern North Island towns and cities; Darwin's ant; and, less often, the black house ant. Outdoors the most widespread ant of all is the native southern ant, which Landcare Research records right across the country, and which does not come inside.

Nationally the picture is small by world standards. Landcare Research counts 38 confirmed species in New Zealand: 11 endemic, mostly living in forest, and 27 introduced by people, mostly from Australia. The introduced species are the ones in houses, and one of them earns its own page: Argentine ants, and why they are harder than the rest.

How to tell which ant you have

Work through four checks in the order that rules things out fastest: colour and size against the table above; how the ants move, whether in a steady unbroken trail, wandering loosely, or with the abdomen held up; a crushed-smell test, which is useful only for light brown ants; and where you found them. Together they give you a probable answer, which is usually enough to choose a treatment.

The smell test separates the two light brown ants that matter most: a strong smell means Darwin's ant, and little or no smell means an Argentine ant. Be honest about the limits, though. Landcare Research notes that confirming a species needs a microscope at 20 to 40 times magnification, so a field identification is a probability rather than a certainty.

If you want someone else to identify it, what helps most is a sharp phone photo of a single ant next to a ruler, taken from above and from the side, with a note of where the trail was and what the ants were carrying. That tells an identifier far more than a description of the colour alone.

Black ants in the house

In an Auckland house a small black ant is most often the white-footed house ant, so look at the feet: pale legs on a black or dark brown ant about 3 mm long, and an abdomen it tends to lift as it walks. The species actually named the black house ant, Ochetellus glaber, is smaller and shinier, lives mostly in gardens and comes inside only occasionally.

Landcare Research does not regard the black house ant as a major house pest in New Zealand, and records that it does not sting. Are black ants harmful? Not to people: they are a nuisance and they get into food, but they are not a health risk and they do not damage timber. A sudden appearance indoors usually comes down to the season, or to a new source of food or water.

Where you see the trail is a useful clue. Black house ants form conspicuous files up tree trunks, fence posts and flax flower stems in search of honeydew and small insects, and often nest in holes in trees and posts, so a black ant trailing up a post is probably this one, while a black ant trailing along a skirting board is much more likely to be the white-footed house ant.

Brown ants and red ants

A light brown ant in an Auckland house is almost always an Argentine ant or Darwin's ant, and the crushed-smell test separates them. Coastal suburbs also have the coastal brown ant, Pheidole megacephala, whose larger workers have outsized heads, and which leaves small mounds of soil at the nest entrance, often under paving.

Darwin's ant, for its part, spreads mainly by budding and very often nests in pot plants, which is probably how it has moved around the country, and it tends aphids and mealybugs in the garden.

Orange ants in a lawn or garden are usually the native southern ant, Chelaner antarcticus, which varies from orange through brown to black and wanders loosely rather than following a trail. A larger ant, around 5 to 6 mm and reddish to dark brown, found under stones or logs in the garden is likely the native Austroponera castanea, which Landcare Research reports stinging people when its nest is disturbed. The tiny pale yellow Pharaoh ant, Monomorium pharaonis, is rarely collected here and has mostly turned up in hospitals.

White ants in New Zealand are termites

White ants is an old name for termites, and termites are not ants at all: Landcare Research notes that they are sometimes called white ants but are not closely related to them. New Zealand does have native termites, and a find in building timber needs care, because some exotic termites are notifiable and have to be reported to the Ministry for Primary Industries.

No common New Zealand house ant is white. The small white objects ants carry along a trail are their larvae and pupae, being moved to a new nest, which is a sign of a colony on the move rather than a different insect. Pale, soft-bodied insects in damp or damaged timber are the ones to check for termites. What gets rid of white ants depends entirely on what they turn out to be, and if it might be termites, do not spray: our page on telling termites from ants, and when a find has to go to MPI explains what to do.

Which ants bite or sting in New Zealand?

Very few, and none of them seriously: Healthify notes that biting ants are not usually found in New Zealand. The Argentine ant bites but cannot sting, and some people react to its bite. Landcare Research's ant specialists note that the native southern ant can bite, and the native Austroponera ants can sting when a nest is disturbed. The black house ant and Darwin's ant cannot sting.

The red imported fire ant is not established in New Zealand and has been found and destroyed on three occasions; if you think you have found one, photograph it, leave the nest alone and call MPI on 0800 80 99 66.

What to do about an ant bite

Wash it with cool water or hold an ice pack on it, wrapped in a cloth, for up to 10 minutes at a time, and try not to scratch. An insect bite usually shows as a red, itchy bump or a small blister and settles by itself within a few days. A pharmacist can suggest an antihistamine or pain relief if it is uncomfortable.

Call 111 straight away for any sign of a severe allergic reaction: swelling around the lips or eyes, wheezing or shortness of breath, chest or throat tightness, or severe dizziness or fainting. See a doctor if the bite lasts more than two weeks, the red, swollen area keeps getting bigger, there is pus, or the bite is near an eye. For advice at any hour, Healthline is free on 0800 611 116.

There is no way to make an ant bite vanish overnight. Cooling it and not scratching it is what helps it settle, and most are gone within a few days.

Queens, males and workers: the three kinds of ant in a colony

Every ant colony has queens, males and workers. The workers are wingless females, and they are the ants you see on a trail. Queens and males have wings and fly out in swarms to mate, after which the males soon die and the queens drop to the ground, break off their wings and start new nests, as Te Ara describes.

That swarm is the flying ants people notice on a warm day. Two of the ants that matter most in Auckland houses mostly grow without it: Argentine ant queens do not fly, so their colonies spread by budding, and white-footed house ant colonies are kept going by wingless egg-laying females inside the nest. If winged insects are coming out of timber indoors, though, read the termite page before assuming they are ants.

When identification tells you to call someone

Call when white-footed house ants are coming out of the walls, because they need far more bait than a household normally uses; when Argentine ants are on both sides of the fence; or when trails have appeared in several rooms. Anything that might be termites goes to the termite page first, and anything that matches the MPI warning above goes to MPI, not to us.

When you book, a description or a photo of the ant and a note of where the trail runs help us bring the right bait on the first visit. Our page on ant control matched to the species explains how treatment differs from one ant to the next, or you can request a visit.

Questions

Ant identification questions

How many types of ants are there in New Zealand?

Landcare Research counts 38 confirmed species: 11 found only in New Zealand and 27 introduced by people, mostly from Australia. Most of the native species live in forest and are rarely seen around houses, while nearly all the ants that come indoors are introduced. That is a very small ant fauna compared with Australia's, which runs to well over a thousand described species.

Are there carpenter ants in New Zealand?

No. Landcare Research's list of the ant species established in New Zealand includes no carpenter ants, so the timber-damaging ants described on many overseas websites do not apply here. Damage to the timber of a New Zealand house is borer or, much more rarely, termites, not ants.

What does an ant bite look like?

A small red, itchy bump, sometimes with a tiny blister, which usually fades by itself within a few days, according to Healthify. Spreading redness, pus, or a bite that is still there after two weeks is worth showing a doctor, and any swelling of the lips or eyes, or difficulty breathing, means calling 111.

Are black ants harmful?

Not to people. The common black ants in New Zealand houses, the white-footed house ant and the black house ant, are not a health risk and do not damage timber. They are a nuisance that gets into food, and a large colony living in a wall cavity can be persistent, which is when bait placed at enough points, rather than a spray, is the answer.

What is the most common ant in New Zealand?

It depends where you look. Indoors it is the white-footed house ant, which Te Ara describes as the most common introduced ant in the country. Outdoors, and across the country as a whole, it is the native southern ant, which Landcare Research records throughout both main islands and on many offshore islands, although it does not forage indoors.

Sources

If you need someone

Once you know which ant it is

Ants

Ant Control

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