Ants are among the most abundant insects infesting the home and yard. Ants are distinguished from other insects by having the abdomen narrowly joined to the thorax, the first one or two segments of the abdomen reduced into a knobbed pedicel or node and their antenna elbowed. The forewings of ants are larger than the hind wings. By contrast, termites have a broad waist and an antenna like a string of beads. The four wings of a termite are equal in size. Ants vary in size from one twenty-fifth to one inch in length.

Ants are social insects. The colony is established when the newly mated female selects a nesting site and lays eggs for her first brood. After hatching, this brood assumes the worker responsibilities. The queen's sole function then becomes egg production. Worker ants feed the queen, care for the brood, expand the nest and defend the colony.
Ants can be detrimental to human health; their presence under certain situations can pose a serious human health risk. In hospitals, health care facilities, food processing plants, food packaging plants and food preparation areas of various structures, the presence of ants should not be tolerated because of potential for disease transmission.

Ants frequently are annoying and sometimes dangerous because of their bites and or stings. Not all ants sting. In many ants, the sting has practically disappeared, but venom may be injected into a wound made from a bite. Many ants produce a toxin secreted by glands in the head which is deposited in the bite. The substance is called formic acid and is the source of the scientific name of the ants, Formicidae.

Ants commonly attack livestock. Workers of harvester and fire ants have been reported attacking and killing young pigs. There are also reports of fire ants attacking and killing chicks and newborn calves. Some species of the big-head ant are intermediate hosts of various poultry tapeworms.

Ants can damage crops and ornamental plants. The red imported fire ant is known to remove seeds from seed beds and feed on the seeds of corn, peanuts and beans. Workers of the red imported fire ant will chew on the roots, stems and leaves of plants. In some cases, seedlings are girdled and die.

Ants can spoil range land for grazing by building mounds and clearing sites for their nests. Harvester ants clear large areas of all vegetation about their nest structure. These ants have a potent sting which may further discourage grazing about their nests, Fire ants pose a special problem to harvest operations in hayfields as their large, hardened mounds are known to break harvesting equipment.

Carpenter Ant

Carpenter Ants are one-eighth to one-half inch long, black or red, thorax is round when viewed from the side, 12 antennal segments and one node. There is a circlet of hairs at the anal opening. These ants will nest in voids or excavated wood, but do not feed on wood. Feed on proteins and sweets and will tend honeydew producing insects like aphids. Are most active at night.

Pavement Ants

These ants are one-eighth to three-sixteenths inch long, with a brown to black body and lighter covered legs. There are two nodes on the pedicel. The narrow, parallel furrows on the head and thorax most easily identify pavement ants. These ants nest in soil beneath stones, pavements or slabs. Occasionally the nest is located in walls, under floors or in insulation. Pavement ant colonies produce swarms from out-of-door nests in the spring, but continuously within a structure. They prefer meat or grease, but also feed on dead insects, seeds and sweets.

Little Black Ant

This ant is jet black and the workers are one-sixteenth inch in length. The petiole has two nodes. The antennas end in a three-segmented club. The nest may be located in soil, rotten wood, woodwork or masonry of houses. The colony produces swarms from late spring to early fall. These ants feed on dead insects, honeydew sweets, meats, bread, grease, oils, vegetables and fruits.

Large Yellow Ant

These ants are relatively large, ranging from one-fourth to three-sixteenth inches in length. They are pale yellow to yellow-red and have a single node on their petiole. Large yellow ants are sometimes called "citronella ants" because they have lemony smell when crushed. The nests may be in soil under cover, in rotting wood or foundation walls. The nests are usually underground, and the ants only come to the surface at swarming time. These ants swarm in early spring. When a colony is under a heated slab, winter swarms may occur. They may push soil out of basement cracks giving the homeowner a "termite scare". Yellow ants prefer sweets and tend aphids for honeydew.

Odorous House Ant

The worker ants are brown to black and one-eighth inch long. The petiole has only one segment with a small node hidden by the abdomen. The best identifying mark is the "rancid butter" smell of crushed ants. These are native ants that often nest out-of-doors under stones or logs. They also nest indoors in walls or floor voids, especially around heat sources. Theses odorous house ants usually mate in May to mid July and seldom swarm. The females mate in the colony, and produce new colonies by budding off the original colony. Each nest will have several egg-laying females. These ants prefer sweets but will feed on honeydew and almost any household food. They may invade houses during rainy weather in search of food.

Pharaoh Ant

These ants are very small; the one-sixteenth inch long workers are yellow to light brown to red. The petiole has two nodes. The nest site is usually in a hard to reach location. Common nesting sites include warm wall voids, subfloor areas, wall sockets, attics, cracks, crevices, behind baseboards and in furniture. These ants do not swarm. Females mate in the nest, and new colonies are formed by budding. This means part of the original colony moves new masses with a young queen to a new nesting site. Mating may occur in the nest at any time during the year. Pharaoh ants seem to prefer meat or grease but will eat almost anything, including insects, sugar syrups, fruit juices, jellies and cakes.