The pavement ant, Tetramorium caespitum is an ant native to Europe, but also occurs as an introduced pest in North America. Its common name comes from the fact that colonies in North America usually make their homes in pavement. It is distinguished by one pair of spines on the back, two nodes on the petiole, and grooves on the head and thorax. During early spring, colonies attempt to conquer new areas and often attack nearby enemy colonies. These result in huge sidewalk battles, sometimes leaving thousands of ants dead. Because of their aggressive nature, they often invade and colonize seemingly impenetrable areas outside their native range. In summer, the ants dig out the sand in between the pavements to vent the nests.
Diagram of the pavement ant. (a = Female; b = female after loss of wings; c = male, d = worker, e = larva; g = pupa; f = head of larva more highly magnified)
The pavement ant is dark brown to blackish, and 2.5–4 mm long. Like other ants there are the workers, and a queen. new queen ants and drones, have wings, and are twice as large as the workers. The drone’s only job is to mate with the queen, and reproduction is at its highest in spring and summer. Tetramorium, like many other ants have nuptial flights where drones fly high up in the air and mate with new queens. The queen finds a suitable nesting location and digs a founding chamber. As the eggs hatch and the ants develop they will spend that time, about two to three months, tending to the queen of their colony. They will continue helping in the colony until they are a month old. Older workers hunt and defend the colony. They will eat almost anything, including insects, seeds, honeydew, honey, bread, meats, nuts, ice cream and cheese.
Carpenter ant species reside both outdoors and indoors in moist, decaying, or hollow wood. They cut “galleries” into the wood grain to provide passageways for movement from section to section of the nest. Certain parts of a house, such as around and under windows, roof eaves, decks and porches, are more likely to be infested by carpenter ants because these areas are most vulnerable to moisture.Carpenter ants have been known to construct extensive underground tunneling systems. These systems often lead to and end at some food source – often aphid colonies, where the ants extract and feed on honeydew. These tunneling systems also often exist in trees. The colonies typically include a central “parent” colony surrounded and supplemented by smaller satellite colonies.
A major worker of Camponotus sp. Carpenter ants are foragers that typically eat parts of other dead insects or substances derived from other insects. Common foods for them include insect parts, “honey dew” produced by aphids, or some secretions from plants. Carpenter ants can increase the survivability of aphids when they attend to them. They attend to any aphid species, but can also express preference for specific ones.[Most species of carpenter ants forage at night. When foraging, they usually collect and consume dead insects. Some species less commonly collect live insects. When they discover a dead insect, workers surround it and extract its bodily fluids to be carried back to the nest. The remaining chitin-based shell is left behind. Occasionally, the ants bring the chitinous head of the insect back to the nest, where they also extract its inner tissue The ants can forage individually or in small or large groups, though they often opt to do so individually. Different colonies in close proximity may have overlapping foraging regions, though they typically do not assist each other in foraging. Their main food sources normally include proteins and carbohydrates
When workers find food sources, they communicate this information to the rest of the nest. They use biochemical pheromones to mark the shortest path that can be taken from the nest to the source. When a sizable number of workers follows this trail, the strength of the cue increases and a foraging trail is established. This ends when the food source is depleted. Foraging trails can either be under or above ground.
Although carpenter ants do not tend to be extremely aggressive, they have developed mechanisms to maximize their provision from a food source when that same food source is visited by a competing organism. This is accomplished in different ways. Sometimes they colonize an area near a relatively static food supply. More often, they develop a systemic way to visit the food source with alternating trips by different individual ants or groups. This allows them to decrease the gains of intruders because the intruders tend to visit in a scattered, random, and unorganized manner. The ants, however, visit the sources systematically such that they lower the mean standing crop. They tend to visit more resource-dense food areas in an attempt to minimize resource availability for others. That is, the more systematic the foraging behavior of the ants, the more random that of its competitors. Contrary to popular belief, carpenter ants do not actually eat wood because they are unable to digest. They only create tunnels and nests within it.
Carpenter ants work to build the nests that house eggs in environments with roughly 12-15% humidity due to their sensitivity to environmental humidity. These nests are called primary nests. Satellite nests are constructed once the primary nest is established and has begun to mature. Residents of satellite nests include older larvae, pupae, and some winged individuals. Only eggs, the newly hatched larvae, workers, and the queen reside in the primary nests. Since satellite nests do not have environmentally sensitive eggs, the ants can construct them in rather diverse locations that can actually be relatively dry.
When conditions are warm and humid, winged males and females participate in a nuptial flight. They emerge from their satellite nests and females mate with a number of males while in flight. The males die after mating. These newly fertilized queens discard their wings and search for new areas to establish primary nests. The queens build new nests and deposit around 20 eggs, nurturing them as they grow until worker ants emerge. The worker ants eventually assist her in caring for the brood as she lays more eggs. Again, satellite nests will be established and the process will repeat itself