Tetramorium caespitum
pavement ant

Tetramorium caespitum are native to Europe and were introduced to North America in the 1700's. Pavement ants are now found in most of the eastern and southern United States. (Holldobler and Wilson, 1990; National Pest Management Association inc., 2001; Wheeler, 1910)

Tetramorium caespitum tend to nest under sidewalks, stones, pavement, and in the crevices of housing structures (Day 1998).

Pavement ants prefer a temperature range of 10-40 degrees Celsius (Holldobler 1990). (Day, 1998; Holldobler and Wilson, 1990)

Tetramorium caespitum have dark brown bodies with pale legs. Both queen and male ants are larger than workers. Both queens and males have wings, which fall off shortly after mating. A typical worker (which is an unfertilized, sterile female) is about 3.25mm while the queen is about 8mm long. Pavement ants have 12-segmented antennae with a three -segmented club. On females, the thorax has a pair of small spines on the upper part while males do not have spines on their back. A stinger is present, and the pedicel has two segmented parts. Worker pavement ants have distinguishing characteristics. They have two clearly visible humps, and grooves or ridges running from anterior to the posterior part of their bodies (National Pest Management Assoc., 2001).

A colony can sustain about 10,000 workers who weigh about 6.5g in the aggregate (Wilson 1971). (National Pest Management Association inc., 2001; Wilson, 1971)

Tetramorium caespitum hatch from the egg as grub-like larvae, and pass through three larval instars (growth stages) before they undergo complete metamorphosis into adult physiology. T. caespitum queens (there may be more than one) lay all of the eggs in the colony, which are cared for by workers throughout the development process. (Brian, 1965; Holldobler and Wilson, 1990; Werner and Olson, 1994)

Individual workers live approximately 5 years, and queens may live much longer than that. Tetramorium caespitum are very adaptable to changes in their environment. (Holldobler and Wilson, 1990)

Tetramorium caespitum is known for its aggressive behavior toward nest intruders, as well as other ant species. T. caespitum can often be found battling other ant individuals or even entire colonies, and will fight until either death or injury occurs. (Holldobler and Wilson, 1990)

Pavement ants use chemical signals in order to communicate with one another. When foraging for food, Tetramorium caespitum workers will leave a chemical trail by wiping their gasters on the ground as they walk. In this way, workers may follow trails to food, and also find their way back to the nest without getting lost. T. caespitum have been observed to not travel more than 30 meters from their nest, and therefore generally stay closer to home than many ant species. In addition to chemical signals (called pheromones), pavement ants use polarized light to navigate and guide their paths. (Holldobler and Wilson, 1990)

Tetramorm caespitum are scavengers and will eat almost anything left within their territory. T. caespitum tend to be drawn toward sugary food. The pavement ant also stores seeds and grains in its nest for later use. T. caespitum has a mutualistic relationship with several species of lycaenid caterpillar. Pavement ants drink nectar produced by the caterpillars, and in return ants provide shelter and protect the caterpillers from predators. (Holldobler and Wilson, 1994; Wheeler, 1910)

T. caespitum has a foul taste when eaten due to a toxin produced by the species. Pavement ants also possess a stinger, and give off a smell of banana oil that aids in deterring potential predators. (Werner and Olson, 1994)

Tetramorium caespitum is the host for many parasitic ant species. The most common is Teleutomyrmex schneideri. The T. schneideri queen lives with the T. caespitum queen, often sitting on the pavement ant queen's back in order remain within the nest. Other parasitic ants include Anergates atratlus and species of Strongylognathus.

Pavement ants may host the caterpillars of lycaenid butterflies, including Lycaeides melissa. The caterpillars secret sugary compounds that the ants consume, and the ants allow the caterpillars to spend the winter in their nest.

These ants also aerate soil as they dig their nests. (Wilson, 1971)

Pavement ants excavate large amounts of sand and soil from under roads, walkways and shallow building foundations. Over time this activity can cause these items to sink and settle causing structural damage. The most common complaint about pavement ants however, is of ants foraging for food in peoples houses. These ants can also sting. (Holldobler and Wilson, 1990)

Pavement ants provide no direct economic benefit to humans.

There is no threat to this species.

Tetramorium caespitum workers are an intermediate host of the poultry tapeworms Raillietina tetragona and Raillietina chinobothrida. (National Pest Management Association inc., 2001)