Pavement Ant
Tetramorium caespitum
Pavement ants are a persistent nuisance in commercial properties, particularly those with ground-level access, concrete aprons, or loading areas.
They enter through expansion joints, foundation cracks, and under door thresholds, and are frequently found in food service and food storage environments.
Habitat
Commonly nest under concrete slabs, loading docks, and along building foundations. May establish indoor nests under equipment, inside wall voids, and beneath raised flooring.
Food preparation and storage areas near ground-level entry points are particularly vulnerable.
Active Areas
Windsor
Extremely common in urban areas with extensive paved surfaces
Tecumseh
LaSalle
Amherstburg
Lakeshore
Essex
Kingsville
Leamington
Chatham-Kent
High prevalence. Pavement ants are extremely common throughout Chatham-Kent, nesting in walkway and driveway cracks and trailing into homes.
St. Thomas
High prevalence. One of the most common ant pests in St. Thomas. Pavement invasions and kitchen trailing are very frequent complaints.
Seasonality
Persistent year-round presence in heated buildings. Swarming events in spring (April–June) indicate high colony density near or under the building. Summer brings the greatest foraging pressure and highest risk of food contamination incidents.
Spring
Summer
Autumn
Winter
Appearance
Small (2.5-4mm), uniformly dark brown to black ants. Workers are monomorphic (all one size). Winged reproductives are slightly larger and may be found emerging from floor expansion joints or under equipment in spring.
- Parallel grooves (striations) on the head and thorax
- Two-node petiole
- Pair of small spines at the back of the thorax
- Uniform dark brown to black colouration
- Trails often seen in lines along pavement edges and foundation cracks
Behaviour
Trail along baseboards, under equipment, and through wall penetrations to reach food sources. Can contaminate food products and surfaces.
Territorial battles between colonies create characteristic mating swarms on pavement in spring — a visible warning sign of large outdoor populations near the building.
Lifecycle
Egg
Eggs laid in protected nest chambers under concrete, equipment bases, or floor voids. Confirm infestation via trailing workers rather than egg inspection.
Larva
Larvae confined to protected nest chambers. Their presence is inferred from worker activity rather than direct observation.
Pupa
Pupal stage occurs in underground chambers. Worker activity levels remain constant during this stage as new adults are being produced.
Adult
Workers trail in large numbers to food sources and are the primary pest concern. Swarming reproductives in spring are a highly visible sign that large colonies exist in or under the building’s hardscape.
Signs You May Have a Problem
- Ant trails entering through expansion joints, foundation cracks, or under exterior door thresholds
- Sandy soil debris pushed up through floor cracks in production areas, storage rooms, or loading docks
- Workers foraging in food storage areas, around drains, or near grease-prone equipment
- Spring swarming events on exterior paved areas adjacent to the building — a sign of high colony density
- Ants emerging from under equipment bases or from behind wall-floor junctions
- Trail activity at multiple simultaneous points suggesting large colonies under the building's slab
- Winged reproductives found inside near windows or light fixtures in spring
Risks & Concerns
Food contamination risk in food service, hospitality, and food storage environments. Presence during health inspections may result in violations.
Large outdoor colonies near the building perimeter can produce continuous re-infestation if only interior treatments are applied.
Prevention
- Seal all expansion joints, pipe penetrations, and foundation cracks on the exterior
- Maintain rigorous sanitation in food preparation and storage areas
- Inspect deliveries and storage areas regularly for early signs of activity
- Ensure all exterior doors at ground level have functioning door sweeps
- Include pavement ant control in routine IPM monitoring visits
DIY Control
- Place tamper-resistant bait stations along foraging trails and near entry points
- Apply residual insecticide granules around the building perimeter, particularly at concrete edges and expansion joints
- Document all activity and treatment applications for IPM records
Professional Control
- Comprehensive site inspection of all paved areas, loading docks, and ground-level entry points
- Exterior perimeter and sub-slab treatment using professional-grade products
- Interior baiting in all affected areas, including under equipment and in wall voids
- Exclusion work and follow-up inspections included in IPM contract