Bug Identifier

Ants

Odorous House Ant

Tapinoma sessile

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Body length in millimeters. Shaded bar shows the typical adult range.
Scientific nameTapinoma sessile
GroupAnts
Size2–3 mm (up to about 0.12 in)
Colors Black and Brown
Legs6 legs
WingsNo (as usually seen)
Where foundKitchen and Bathroom
Most activeSpring and Summer
BitesNo
StingsNo
Risk levelNuisance

How to identify it

The odorous house 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. Small, uniformly dark ant with an uneven thorax
  2. Rotten-coconut odor when crushed
  3. Erratic, fast-moving trails, especially after rain

About this bug

A small, dark brown to black ant that trails along counters and sinks looking for sweets. Crushed workers give off a smell often compared to rotten coconut.

You'll usually find odorous house ants in the kitchen and in the bathroom. They are most active in spring and summer.

Is it dangerous?

Odorous house ants are a nuisance only; they rarely bite and don't sting.

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

When you'll see odorous house ants

Odorous House Ants are most active in spring and summer. In spring, overwintering adults become active and many species lay their first eggs. Summer heat speeds up development, so populations can grow quickly.

Typical places to check: kitchen and bathroom.

About ants

The odorous house 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. Wipe up crumbs and sugary spills and rinse recyclables
  2. Place sweet gel baits along active trails and let ants carry it back
  3. Trim plants touching the house and seal entry cracks

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

Bugs that look similar

Argentine AntLinepithema humile2–3 mmNuisance

Color: Odorous House Ants are black and brown; Argentine ants are brown.

Little Black AntMonomorium minimum1.5–2 mmNuisance

Color: Odorous House Ants are black and brown; little black ants are black.

Pavement AntTetramorium immigrans2.5–4 mmNuisance

Where found: look for odorous house ants in the kitchen and in the bathroom; pavement ants turn up in the kitchen, in basements and garages and in lawns and grass.

Pharaoh AntMonomorium pharaonis1.5–2 mmNuisance

Color: Odorous House Ants are black and brown; Pharaoh ants are yellow and tan.

Frequently asked questions

What does an odorous house ant look like?

Small, uniformly dark ant with an uneven thorax. Adults measure 2–3 mm (up to about 0.12 in).

Does the odorous house ant bite or sting?

It does not bite. It does not sting. Odorous house ants are a nuisance only; they rarely bite and don't sting.

Where do odorous house ants live?

Odorous House Ants live in the kitchen and in the bathroom.

When are odorous house ants most active?

Mostly in spring and summer.