Bug Identifier

Ants

Argentine Ant

Linepithema humile

024
Body length in millimeters. Shaded bar shows the typical adult range.
Scientific nameLinepithema humile
GroupAnts
Size2–3 mm (up to about 0.12 in)
Colors Brown
Legs6 legs
WingsNo (as usually seen)
Where foundKitchen and Garden or plants
Most activeSpring, Summer and Fall
BitesNo
StingsNo
Risk levelNuisance

How to identify it

The Argentine ant is a tiny member of the ants group. Elbowed antennae and a pinched waist with one or two nodes. Check for these three features:

  1. Uniform light-brown body with one flat node
  2. Very wide, steady trails several ants across
  3. Musty, greasy odor when crushed

About this bug

A small, light-to-dark brown ant that forms huge, cooperating supercolonies. Wide, busy trails often stream into kitchens during hot or rainy weather.

You'll usually find Argentine ants in the kitchen and in gardens and on plants. They are most active in spring, summer and fall.

Is it dangerous?

Argentine ants don't sting and rarely bite; they protect aphids and scale insects on garden plants.

Our rating: Nuisance, meaning it is a nuisance pest but not a health threat to most people.

When you'll see Argentine ants

Argentine Ants are most active in spring, summer and fall. In spring, overwintering adults become active and many species lay their first eggs. Summer heat speeds up development, so populations can grow quickly. In fall, many bugs look for shelter, and some move toward or into buildings.

Typical places to check: kitchen and garden or plants.

About ants

The Argentine ant is one of the ants. Ants live in colonies ruled by one or more egg-laying queens. The workers you see are sterile females foraging for the rest of the colony, so killing visible ants rarely solves anything. Winged ants, called swarmers, appear when a mature colony sends out new kings and queens.

Bait works because workers carry it back and share it with the queen and larvae. Repellent sprays can scatter the colony and make the problem harder to fix.

What to do about it

  1. Apply sugar-water baits outdoors along trails
  2. Trim branches and vines that bridge onto the house
  3. Clean trails with soapy water to erase scent paths

Read the full guide: how to get rid of Argentine ants.

Bugs that look similar

Odorous House AntTapinoma sessile2–3 mmNuisance

Color: Argentine Ants are brown; odorous house ants are black and brown.

Red Imported Fire AntSolenopsis invicta2–6 mmHealth risk

Size: Red Imported Fire Ants are larger, reaching 6 mm, while Argentine ants top out around 3 mm.

Longhorn Crazy AntParatrechina longicornis2.3–3 mmNuisance

Color: Argentine Ants are brown; longhorn crazy ants are black and gray.

Frequently asked questions

What does an Argentine ant look like?

Uniform light-brown body with one flat node. Adults measure 2–3 mm (up to about 0.12 in).

Does the Argentine ant bite or sting?

It does not bite. It does not sting. Argentine ants don't sting and rarely bite; they protect aphids and scale insects on garden plants.

Where do Argentine ants live?

Argentine Ants live in the kitchen and in gardens and on plants.

When are Argentine ants most active?

Mostly in spring, summer and fall.