Odorous house ant vs Dark rover ant
These two are easy to mix up. Here's how to tell an odorous house ant from a dark rover ant, and whether either one bites or stings.
Odorous house ant
Tapinoma sessile
Dark rover ant
Brachymyrmex patagonicus
≠The key differences
Slightly larger (about 2.4-3.3 mm) and dark brown to black, with a waist node hidden under the abdomen; it gives off a rotten-coconut smell when crushed, which dark rover ants do not.
⚖︎Side by side
| Odorous house ant | Dark rover ant | |
|---|---|---|
| To humans | Non-toxic | Nuisance ant |
| Size | Workers 2.4-3.3 mm long; queens larger (about 4-5 mm) | 1.3-2.5 mm body length (workers) |
| Colours | Light brown, Dark brown, Black | Dark brown, Brown, Nearly black |
| Family | Formicidae | Formicidae |
| Habitat | Urban and suburban areas, inside buildings (kitchens, wall voids), under stones, wood, mulch and in soil; tolerant of varied habitats | Urban and suburban areas: inside buildings (wall voids, under flooring, behind baseboards), under mulch, beneath stones, in soil, plant pots and irrigation lines. |
| Range | Native to North America and widespread across the United States and southern Canada; found in diverse habitats from forests to cities | Native to South America; introduced and established in the southern United States, Caribbean islands and other warm regions worldwide (often spread by commerce). |
| Active | Active year-round in heated buildings; outdoors mostly spring to fall and during warm parts of the day | Active year-round in warm climates; forages day and night but activity increases in warm, humid conditions. |
| Pest? | Yes | Yes |
🔍How to spot an odorous house ant
- Very small workers (2.4-3.3 mm) with a smooth profile because the petiole is hidden by the gaster
- Colour variable from light brown to dark brown or black
- When crushed, workers give off a distinctive odour often described as rotten coconut, pine, or moldy cheese
- Do not have a distinct antenna club and have 12-segmented antennae
🔍How to spot a dark rover ant
- Very small workers 1.3-2.5 mm long — smaller than pavement ants and about the size of pharaoh ants.
- Uniform dark brown, slightly shiny body without strong sculpturing; a single node in the waist.
- Often travel in slow, diffuse trails near baseboards, irrigation lines, landscaping mulch and potted plants.
- Nests are small and scattered; look under stones, in soil, under bark and inside wall voids near moisture sources.
?Frequently asked questions
What is the difference between an odorous house ant and a dark rover ant?
Slightly larger (about 2.4-3.3 mm) and dark brown to black, with a waist node hidden under the abdomen; it gives off a rotten-coconut smell when crushed, which dark rover ants do not.
Is an odorous house ant or a dark rover ant more dangerous?
Odorous house ant: Non-toxic. Dark rover ant: Nuisance ant. Odorous house ants do not have a sting. Dark rover ants do not have a harmful sting and are not known to transmit serious diseases.
Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.