Pavement Ant

Tetramorium immigrans

Size2.5–4 mm

Colony Size3,000–10,000

Active Season:Active March through October. Swarmers emerge June-July.

Small brown ants that nest under sidewalks, driveways, and foundations. One of Canada's most common household ant pests.

Anatomy

Anatomical Details

Loading anatomy...

Identification

ColourDark brown to black with lighter legs and antennae

Size2.5–4 mm

Distinguishing Features

Parallel grooves on head and thorax (visible with magnification)
Two nodes (segments) between thorax and abdomen
Small stinger present but rarely used
12-segmented antennae with 3-segmented club

Similar Species

Carpenter ants are 3-6x larger with only one waist node.
Pharaoh ants are smaller (2mm), yellow-brown, and nest only indoors.

Biology

Lifecycle

Complete metamorphosis. Colonies mature in 3-5 years with 3,000-10,000 workers.

Diet

Omnivorous: grease, sweets, seeds, insects, honeydew. Will tend aphids.

Nesting

Under pavement, stones, and foundations. Soil mounds at crack edges are diagnostic.

Signs of Infestation

Volcano-shaped mounds

Distinctive small mounds of fine soil or sand pushed up through cracks in concrete, resembling mini volcanoes. The most reliable indicator of pavement ant activity.

Trailing ants on floors and counters

Workers follow pheromone trails between nest and food, especially at night.

Ants in pet food

Pavement ants are strongly attracted to protein-rich pet foods.

Swarmers indoors (June-July)

Winged reproductives emerging inside suggest a nest under or against the foundation.

Where They Nest

Under driveways, sidewalks, and patios
Along foundation walls and basement slabs
Under heated floors (remain active in winter)
In wall voids near heat sources
Under stones and landscape edging

Common Nesting Sites

Nesting Site Details

Loading diagram...

Distribution in Canada

Found in all provinces. Most abundant in urban and suburban areas.

Loading map...

Active Season

Active March through October. Swarmers emerge June-July.

House Types at Risk

This pest is commonly found in these home types

Bungalow / Ranch

High Risk

Large foundation footprint with extensive concrete-soil interface. Heated basement slabs attract colonies year-round.

View house details →

Bi-Level

High Risk

Lower level slab on grade provides direct nesting access. Cracks in concrete allow interior foraging.

View house details →

Split-Level

Moderate Risk

Multiple foundation levels with expansion joints between sections create entry points.

View house details →

Townhouse

Moderate Risk

Shared foundation walls and common driveways mean colonies can affect multiple units.

View house details →

Prevention

Seal cracks in foundation and basement slab
Caulk gaps around pipes and wires entering building
Remove food sources: store pantry items in sealed containers
Fix moisture issues attracting colonies
Keep vegetation and mulch away from foundation

Professional Treatment

Exterior perimeter treatments and targeted baiting eliminate colonies at the source. Interior sprays alone are ineffective—the nest must be addressed.

Get Ant Control Service

Frequently Asked Questions

What does a Pavement Ant eat?

Omnivorous: grease, sweets, seeds, insects, honeydew. Will tend aphids.

Where does a Pavement Ant nest?

Under pavement, stones, and foundations. Soil mounds at crack edges are diagnostic.

When is a Pavement Ant most active?

Active March through October. Swarmers emerge June-July.

What are the signs of a Pavement Ant infestation?

Volcano-shaped mounds: Distinctive small mounds of fine soil or sand pushed up through cracks in concrete, resembling mini volcanoes. The most reliable indicator of pavement ant activity. Trailing ants on floors and counters: Workers follow pheromone trails between nest and food, especially at night. Ants in pet food: Pavement ants are strongly attracted to protein-rich pet foods. Swarmers indoors (June-July): Winged reproductives emerging inside suggest a nest under or against the foundation.

How can I prevent a Pavement Ant infestation?

Seal cracks in foundation and basement slab. Caulk gaps around pipes and wires entering building. Remove food sources: store pantry items in sealed containers. Fix moisture issues attracting colonies. Keep vegetation and mulch away from foundation.

How is a Pavement Ant treated?

Exterior perimeter treatments and targeted baiting eliminate colonies at the source. Interior sprays alone are ineffective—the nest must be addressed.

Scientific Classification