Pavement Ants

What Are Pavement Ants?

Pavement ants (Tetramorium caespitum) are a common species of ant found throughout North America, particularly in urban and suburban environments. As their name suggests, these ants typically make their nests under or near pavement, including sidewalks, driveways, building foundations, and patios. They are especially prevalent in areas with concrete slabs or asphalt surfaces, where they exploit cracks and expansion joints to establish colonies.

Are Pavement Ants Harmful?

While pavement ants (Tetramorium caespitum) are not inherently dangerous in the way that venomous or more aggressive pests might be, they can still be considered harmful:

Food Contamination

• Pavement ants readily forage indoors, especially in kitchens, pantries, break rooms, and food storage areas. They are omnivorous and will consume a wide range of food, including sweets, grease and fats, proteins (meats, cheese, pet food), bread and grains
• Risks: Ants crawling through unsanitary areas like garbage bins, drains, or bathrooms can carry bacteria such as Salmonella or E. coli and transfer them to food or food prep surfaces. Infested food must be discarded, leading to waste and potential health code violations in commercial settings.

Structural Nuisance and Minor Damage

Although not wood-destroying like carpenter ants or termites, pavement ants can still be destructive in subtle ways:

• They excavate soil from beneath concrete slabs, sidewalks, driveways, and foundations, creating small piles of displaced dirt (often mistaken for termite activity).
• Their tunneling can slowly lead to soil erosion under foundations, potentially contributing to cracks or settling in slabs over time—especially when colonies are large or established near moisture-prone areas.

Pavement Ant Appearance

Pavement ants (Tetramorium caespitum) have a distinct and identifiable appearance, making them relatively easy to distinguish from other common household ants. Below is a detailed description of their physical characteristics:

• Size: Workers are small, typically 1/8 inch (2.5–4 mm) long. Queens are larger, around 3/8 inch (8–10 mm) in length.
• Color: Most pavement ants are dark brown to nearly black, though they can also have lighter brown legs and antennae. Their bodies have a slightly glossy or shiny sheen, which helps in identifying them in proper lighting.
• Body Segmentation: Like all ants, their bodies are divided into three main sections: head, thorax, and abdomen, with a narrow "waist" in between.
• Head and Thorax: Both have distinct parallel grooves or fine striations—a key identifying trait.
• Antennae: Composed of 12 segments, ending in a 3-segmented club. The club helps differentiate them from other ants with unsegmented or differently segmented antennae.
• Waist: They have a 2-node petiole (a pair of small segments between the thorax and abdomen), which distinguishes them from ants with only one node, such as Argentine ants.
• Spines: Small but noticeable pair of spines project from the rear of the thorax.
• Abdomen: The gaster (rear section) is generally smooth, oval-shaped, and may appear slightly larger than the thorax.
• Hair: Sparse but visible fine hairs on the body and legs, often visible under magnification.

Winged Reproductives (Alates)

During mating season (typically spring to early summer), winged males and females emerge:

• They resemble workers but are larger.
• They have two pairs of wings, with the front pair longer than the hind pair.
• Wings are typically pale or translucent with visible veins.

Pavement Ant Habitat

Pavement ants nest in various outdoor locations, particularly in urban and suburban environments. They have a preference for nesting in or around human-made structures. Here are some of the common places where pavement ants can be found nesting:

• Under Pavement: As their name suggests, pavement ants often build nests underneath sidewalks, driveways, and the cracks and crevices of concrete and asphalt surfaces. These locations provide them with protection and insulation from the elements.
• In Walls: Pavement ants may nest within the walls of buildings, especially if they find access through cracks, gaps, or openings. They can nest in wall voids, insulation, and other concealed spaces.
• Beneath Rocks: In natural environments or garden areas, pavement ants may establish nests beneath rocks, stones, or landscape features. These areas provide shelter and protection.
• Within Logs or Woodpiles: In outdoor settings, pavement ants may nest within decaying logs or woodpiles. The rotting wood provides a suitable environment for their colonies.
• Under Debris: Pavement ants can create nests under debris, fallen leaves, mulch, or organic matter on the ground. These materials help regulate temperature and humidity within their nests.
• Near Moisture Sources: Pavement ants are attracted to moisture, so they often nest near water sources like leaky pipes, drains, or areas with high humidity. This is especially common when they invade indoor spaces.
• In Soil: Occasionally, pavement ants may dig their nests directly into the soil in gardens or yards, particularly if the soil is loose and easy to excavate.

Pavement ants are adaptable and opportunistic in their choice of nesting sites. They select locations that offer protection, moisture, and proximity to food sources. Their nesting behavior can vary depending on local conditions and environmental factors.

Pavement Ant Diet

Pavement ants are opportunistic omnivores, which means they have a diverse diet and can consume a variety of foods. Their dietary preferences can vary depending on the availability of food sources in their environment. Here are the primary types of food that pavement ants typically eat:

• Sugars: Pavement ants have a sweet tooth and are attracted to sugary substances. They feed on nectar from flowers, honeydew produced by aphids and other sap-feeding insects, and sweet food scraps. This attraction to sugars often leads them to invade kitchens and pantries in search of sweets and spilled sugary items.
• Proteins: These ants also require proteins for their diet. They consume small insects, such as flies, spiders, and dead arthropods, as well as protein-rich food scraps like meat, fish, and pet food. Pavement ants actively forage for protein sources to nourish their colony and develop their brood.
• Fats and Grease: Pavement ants may seek out fatty or greasy food items, such as oily crumbs or discarded fast food. These substances can provide a source of energy and nutrition for the colony.
• Human Food: In urban and suburban areas, pavement ants are known to scavenge for human food scraps. They can infiltrate homes and picnic areas, searching for crumbs, leftovers, and spilled beverages.
• Seeds and Grains: Although less common, pavement ants may occasionally consume seeds, grains, and other plant matter. They are not strict herbivores, but they may opportunistically feed on these items if found in their foraging territory.
• Liquid Foods: Pavement ants are attracted to liquids, including water, sugary drinks, and syrups. They may forage for and consume liquid food sources.

Pavement ants are highly adaptable, and their food preferences can change with seasonal variations and the needs of their colony. Their ability to exploit various food sources contributes to their success in urban environments. To control pavement ant infestations, it's crucial to eliminate access to food and moisture sources that attract them into homes and structures.

Pavement Ant Life Cycle

The life cycle of pavement ants, like many other ant species, consists of four main stages: egg, larva, pupa, and adult. Let's explore each stage of their life cycle in more detail:

• Egg Stage: The life cycle begins when the pavement ant queen lays eggs. These eggs are typically small, white, and oval-shaped. The number of eggs laid depends on various factors, including the age and health of the queen. The queen's primary role is to reproduce and produce eggs for the colony.
• Larva Stage: Once the eggs hatch, they give rise to ant larvae. Ant larvae are legless, soft, and worm-like in appearance. During this stage, the larvae are entirely dependent on worker ants for their care. Worker ants feed the larvae by regurgitating liquid food, consisting of a mixture of saliva and pre-digested food, which provides essential nutrients for their growth.
• Pupa Stage: As the larvae grow and develop, they enter the pupal stage. In this stage, the ant larvae undergo metamorphosis, transforming into adult ants. The pupae are typically encased in a cocoon-like structure. This stage is a critical period of development when the ant's body undergoes significant changes to develop into an adult.
• Adult Stage: Once the metamorphosis is complete, the pavement ant emerges from the pupal stage as an adult ant. Adult pavement ants have a fully developed exoskeleton, six legs, antennae, and segmented bodies. They are now capable of performing various roles within the colony, such as foraging for food, caring for the young, and defending the nest. Within a pavement ant colony, there are typically three main castes of adult ants: queens, workers, and males.
• Queen: The queen is the largest ant in the colony and is responsible for egg-laying. Her primary role is to reproduce and establish new colonies. Queens can live for several years, continually laying eggs.
• Worker Ants: Worker ants are smaller than the queen and perform various tasks to support the colony. They forage for food, care for the young, construct and maintain the nest, and defend the colony against threats.
• Male Ants: Male ants are typically produced during certain times of the year for mating purposes. They have wings and are often larger than worker ants. Males leave the colony to mate with young queens, and they do not play a significant role in the ongoing activities of the colony.

The length of time it takes for pavement ants to complete their life cycle from egg to adult can vary depending on environmental factors such as temperature and food availability. In optimal conditions, it generally takes several weeks to a few months for an egg to develop into a mature adult ant.