Tetramorium caespitum (Linnaeus)
This ant gets its name from commonly locating its nest in or under cracks in pavement. Pavement ants were introduced from Europe by the early colonists. They are found in most of the eastern half of the United States and in California and Washington.
Workers monomorphic, about 1/16-1/8" (2.5-4 mm) long; queens about 3/8" (8 mm) long. Body light brown to black with paler legs and antennae. Head and thorax furrowedlgrooved with parallel lines. Antenna 12-segmented, with 3-segmented club. Thorax with pair of small spines on upper back part, profile unevenly rounded. Pedicel 2-segmentect. Stinger present.
Swarmers can be distinguished from other ant swarmers by the presence of fine furrows/grooves on their head and thorax, similar to those of the workers.
- Similar Groups
- Harvester ants (Pogonomyrmex spp.) have underside of head with a brush of long bristles (coarse hairs/setae).
- Acrobat ants (Crematogaster spp.) with pedicel attached to upper surface of abdomen (gaster), gaster heart-shaped.
- Other small dark ants with only 1 node/segment in pedicel or if with 2 nodes, then thorax lacks spines on upper surface.
- Damage and Signs of Infestation
Often the only exterior indication of damage is the accumulation of debris expelled by these ants, especially if the debris is styrofoam insulation. They prefer wood softened by decay fungi or styrofoam insulation, but may enlarge cavities in wood made by other insects. They will occasionally strip the insulation from electrical or telephone wires which can cause short circuits.
Very little work has been done on this ant. Colonies are moderately large to large. Developmental time varies from 36 to 63 days. Winged reproductives appear outside primarily in June and July, but may emerge anytime inside including during the winter months. Workers have been shown to be an intermediate host of the poultry tapeworms Raillietina tetragona (Molin) and R. echinobothrida (Mednin).
Inside, pavement ants will occasionally nest in walls, in insulation, and under floors. The most likely place is in ground-level masonry walls of the foundation and especially near some heat source in the winter. They often follow pipes which come through slabs for access to upper floors of buildings.
Outside, these ants typically nest under stones, in cracks in pavement, and next to buildings. They enter buildings through cracks in the slab and walls, slab expansion joints, and the natural openings of buildings. Although not aggressive, workers can bite and sting. These ants feed on almost anything including insects, honeydew, seeds, plant sap, and household foods such as meats, nuts, cheese, honey, and bread, but show a preference for meats and grease. They forage in trails, and for distances of up to 30 feet (9 m)