Japanese Pavement Ant (Tetramorium tsushimae) — identification, habitat & look-alikes

The Japanese pavement ant is a small, ant found on disturbed, open ground in parts of the United States. Its small, dark workers can gather in large numbers near food.

Appearance

Appearance: Workers are tiny, about 0.10–0.11 in (2.5–2.8 mm), and usually dark brown to nearly black. Fine ridges cross the middle of the body, two small spines project from the back of that middle section, and the waist has two boxy segments.

Look-alikes

immigrant pavement antTetramorium immigrans

Immigrant pavement ant workers are usually slightly larger and have shorter spines at the back of the middle section. The two species are difficult to separate in ordinary photos, so close views or expert examination may be needed.

Why they get mixed upBoth are small, dark pavement ants with ridges on the middle of the body and a two-part waist.

Where it lives

Typical habitats: disturbed open ground
suburban yards and play areas
Range: In the United States, this non-native ant has been documented around St. Louis, Missouri, and in nearby parts of Illinois and Kansas. Its full U.S. range is still being tracked.
Preferred conditions: Around St. Louis, it occupies disturbed, open ground in towns and suburbs.

Behavior

Diet: In Missouri, it eats a wide range of organic food, including small animals and plant material.
Activity: Workers gather quickly around food on the ground.
Social life: Introduced U.S. populations form with multiple . This can help them become locally dominant.

Name and classification

About the name: Older sources grouped it with Tetramorium caespitum.

Conservation

IUCN Red List: NENot EvaluatedNot yet assessed
Threats: Where it overlaps with the immigrant pavement ant (Tetramorium immigrans), it may outcompete that species and become locally invasive. Its broader ecological effects in the United States are still being studied.

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