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Ants are one of the most successful insects on earth. They are social insects and live in colonies. These colonies have specific castes that perform separate tasks within the colony. These castes are one or more reproductives, workers, eggs, larvae, and pupae. The worker ants are responsible for the maintenance of the nests, from the actual structure of the nest, to the care of the reproductives and the larvae, and to the collection of food for the nest. Some species live in the ground while some live within wood such as logs, fence posts, and hollow trees or even within structures.
The ants' bodies are composed of three distinct body parts, the head, the thorax, and the abdomen. The head contains antennae, which, in ants, is elbowed or bent. Some insect, such as the termite, has straight antennae. The presence of mandibles, or jaws, is also a general characteristic of the ant. The first one or two segments of the abdomen, where it attaches to the thorax, are much smaller than those that make up the rest of this body region. This gives the ants a thin waist appearance. This is properly called the abdominal pedicel. The number of segments in the pedicel will help in identifying the species of ants. Sometimes, the ants will do what is called swarming. This is when fertile adult ants leave the nest to form new colonies. These swarmers will have wings, usually four wings, two large front ones and two smaller rear ones.
Ants use a chemical secretion called pheromones to communicate to other members of the nest. These are especially important when foraging for food. They will leave a "pheromone trail" for the ants within a nest to find their way to and from food sources and the nest. They will also use pheromones for sex, alarms, and for other important signals.
Most structure-infesting ants do not have the ability to sting. However, when a wood-infesting ant such as a carpenter ant bites, they do have the ability to inject a mild acid, used to help break up wood, and this can cause a mild sting. Ants from more tropical regions have been introduced into parts of the southern United States. Some of these ants do have the ability to sting by injecting venom with their bites. This venom can cause rapid, intense pain and may cause serious allergic reactions in some people.
Termites are often confused with ants. There are four specific differences between ants and termites.
1. Swarmers (winged insects) - Ants have the front pair of wings noticeably larger than the rear wings. Termites have all four wings the same size.
2. Swarmers - Termite wings are not clear, but have a milky, translucent appearance. Most ant wings will appear clear.
3. Ants usually have a thin waist, because of the pedicel segments of the abdomen. Termites have a broad-waisted appearance because of the lack of the pedicel segments.
4. Ant antennae are elbowed. Termite antennae are straight.
Once the insect has been determined to be an ant, then the correct species of ants should be determined. There are two general categories of ants, ones that can nest inside the structure and ones that do not nest inside the structure. I will separate these two categories for identification purposes. As for ant management purposes, I will group those ants that nest outdoors into one group, because the management practices for this category of ants is fundamentally the same.


Some ant species are known to nest inside the structure. The following ants are some of those ants:
Carpenter Ant

Carpenter ants are the largest ants in North America. They are also found throughout the U. S., but most especially in the Northeast, Midwest, and Pacific Northwest. Workers can vary in size, from 1/4 inch to 3/4 inches long. Many species are black, but they can be red or a combination of red and black. Therefore, size and color are not necessarily identifying characteristics (however, large black ants are very likely to be carpenter ants).
There are three identifying characteristics to identify carpenter ants. First, the presence of one pedical between the thorax and the abdomen. Second, the back of the thorax in a carpenter ant is rounded. Third, the presence of a small amount of hairs at the bottom end of the abdomen.
Sometimes, the presence of frass will be the first sign of an infestation. Frass is sawdust-type material that the carpenter ant leaves behind when making their nests. This sawdust-type material will be mixed with small pieces of ants and other insects. This will also help in locating the nest.

Pharaoh ants are 1/15 to 1/12 inch in size. Their color is light yellow to reddish-brown. They are found in localized regions throughout the United States and Canada. They can be easily distinguished from the thief ant by the presence of three segments on the antennal club.

Odorous house ants are found nearly throughout the United States. Workers are 1/12 to 1/8 inch in size. Their color is brownish-black. This ant is darker in color than the Argentine ant (see below) and the front of its abdomen overhangs the pedical, giving the appearance of no pedical. When crushed, this ant gives off an unpleasant odor, hence its name.

This ant is found sporadically throughout the United States. Workers are 1/10 inch long. Their color is dark brown. Their legs and antennae are much longer than normal for other ants.


All other ant species generally nest outdoors. Occasionally, foraging workers will enter the structure looking for food or water. This is when they become a pest inside structures.

The workers are about 1/15 inch in size. Their color is jet-black. They are found in all states.

Workers are 1/8 to 1/6 inch in size. Their color is dark-brown, with paler legs and antennae. The abdomen is all black. On the head and thorax are parallel lines or ridges. There is a pair of small spines on the back of the thorax and the body has small hairs all over it.

This tropical ant can be found in Florida and California. It is about 1/15 inch long. The color is reddish. Their movement is slow. Their sting is very painful.

Harvester ants are found in the drier climates of the western and southern states. The worker are 1/4 to 1/2 inch in size. Their color is reddish brown to dark-brown. Long hairs form a bush under their heads.

These ants hold their abdomen over their head and thorax when excited. They are yellowish-brown or black in color. They have a heart shaped abdomen, which is flattened on the upper side and curved below.

These ants are mainly found mainly in the southern United States and California. Workers are 1/12 to 1/8 inch in size and their color is light to dark brown.

These ants are found primarily the foothills and mountains of southern California. Their glistening, velvety-black abdomen, red thorax, and brownish-black head easily identify them.

These ants are common in the southern United States and in California. They vary in color from dark brown to brown with a reddish tint. The workers are 1/15 to 1/12 inch in size. Workers have a distinct single bump on their thorax, which causes the thorax to form a pyramid shape.

Workers are 1/8 to 1/4 inch in size. Their color may be brown, black, reddish, or have a combination of these colors. They are found throughout the United States infesting fields, lawns, and gardens. Nests are commonly built as earthen mounds along fences, sidewalks flower beds, and in lawns.

These ants have another caste of worker ants called soldier ants. These soldier ants are used to defend the nests from attacks. These soldiers have distinctly large heads in relation to their body size. The workers do not have such large heads but can be distinguished from other ants by the fact that their heads narrow abruptly behind the eyes. They are found in warmer and drier areas of the United States.

These ants are found in from New England to the Midwest. Workers are 1/5 inch in size and are reddish brown in color. When this ant is crushed, it gives off a distinct citronella-like odor, hence these ants are commonly called CITRONELLA ANTS.

This ant is found throughout the United States. Workers are 1/8 to 1/6 inch in size. Their color is light to dark brown and they tend to be shiny.

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