Pavement Ants

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Pavement ants, Tetramorium caespitum (L.), are among the most common ant species in our area. The common name “pavement ants” is actually derived from the ant’s unique nesting habits in pavement seams.

During summer, these ants will occupy a wide range of pavements and become a nuisance, especially when they find their way into a structure. Although pavement ants do not create any health-related risks, they may forage in unsanitary areas and leave debris or contaminated food items behind. Therefore, management of these ants is critical, particularly early in the spring before they produce a large number of ants and become a problem. 

HOW DO I KNOW IF I HAVE PAVEMENT ANTS?

  • Pavement ants build small, crater-like piles of excavated materials near cracks in the sidewalk and pavement, especially if located close to a lawn.
  • Occasionally they can be found in basements, near cracks in the floor or near a source of heat.
  • If you have a serious problem with pavement ants you will begin to see them in your home, especially in your kitchen.
  • The ants that you see are most likely worker pavement ants foraging for food.

WHAT DO PAVEMENT ANTS LOOK LIKE?

  • Pavement ants are a small species of ant, with the workers reaching about 1/8” in length.
  • Pavement ants are dark brown to black with lighter colored legs and antennae.
  • Pavement ants have a petiole (the segment between the abdomen and thorax) with two nodes.
  • The thorax is uneven with one pair of spines.
  • There are grooves on head and thorax of pavement ants.
  • Pavement ants have 12-segmented antennae with 3-segmented clubs

ARE PAVEMENT ANTS DANGEROUS?

  • No, pavement ants are considered nuisance pests.
  • Pavement ants are not aggressive and will avoid confrontation rather than trying to defend themselves.
  • Pavement ants do not sting but will pinch if handled.

CAN MY HOUSE BE DAMAGED BY PAVEMENT ANTS?

  • No. Generally, pavement ants do not cause structural damage to your home.
  • A large nest under a slab or window bay could possibly excavate enough dirt to cause concern.

WHY ARE PAVEMENT ANTS IN MY HOUSE/YARD?

  • If you see pavement ants inside your home they most likely found their way in while looking for food.
  • Pavement ants normally nest outdoors in the soil near or under driveways, slabs, sidewalks, and patios.
  • Pavement ants also nest in lawns in areas with vegetation cover >40% bare ground or under stones, wood, or boards near water.
  • Indoors, they nest under the foundation and within hollow block foundation walls, under floors or in insulation.

WHAT DO PAVEMENT ANTS EAT?

  • Pavement ants are omnivorous, meaning they eat both plant and animal items, but they prefer fatty or greasy food.
  • Their normal diet consists of dead arthropods, including insects and carcasses of small vertebrates, such as birds, mice, frogs, but they will feed on sweets and the honeydew from aphids as well.
  • Often they will also feed on young plants in your prized flower garden!

WHAT IS THE LIFECYCLE OF PAVEMENT ANTS?

  • Usually there is one functional queen per colony. Winged reproductive ants undergo mating flights in the spring to form new colonies. (In heated buildings, a swarm may occur at any time of the year.)
  • Males die soon after mating, while fertilized females (queens) dig in the soil, shed their wings and begin laying eggs in two to three days.
  • Each queen may deposit from 5-20 eggs per day.
  • Eggs hatch in 8-12 days and go through three larval developmental instars (stages) in about 25 days.
  • Pupae emerge as workers in 12-18 days.
  • The entire life cycle from egg to adult takes from 43-63 days.

2 INTERESTING FACTS ABOUT PAVEMENT ANTS:

  • Pavement ants are known to be very territorial.
  • Workers will aggressively fight ants from adjacent colonies belonging to the same or other ant species.