Infesting Pests: Ants

Introduction to ants

Ants are pests around the home because they feed on and contaminate human foods, infest structures, and build unsightly mounds in lawns. In some cases, ants are able to inflict painful bites or stings. Ants do not attack or eat fabrics, leather or wood in houses. However, some species can establish nests in decaying wood in structures.

Several species of ants are found in or around houses. In general, the most common ants can be grouped as house-infesting ants, yard-infesting ants, and carpenter ants. The most commonly encountered pest ants are Pharaoh, ghost, carpenter, native fire, imported fire, little fire, crazy, thief, bigheaded, and acrobat ants.

Ant Identification

Ants can be recognized from other insects because they have a narrow waist (pedicel) with one or two joints (nodes) between the thorax and abdomen. Also, ants have elbowed antennae. Winged reproductives have four wings, with the first pair being much larger in size than the hind pair.

Ants are frequently confused with termites. However, termites have a broad waist between the thorax and the abdomen. Also, termite reproductives have four wings of equal size.

Ant Biology

Ants are social insects. Three castes (workers, queens, and males) can be found in most colonies. Worker ants, which are sterile females, are seldom winged. They often are extremely variable in size and appearance within a given species (monomorphic - one form; dimorphic - two forms; polymorphic - many forms). The function of the worker is to construct, repair, and defend the nest. They also feed the immature and adult ants of the colony, including the queen, and care for the brood.

Queens normally have wings, but lose them after mating. The primary function of the queen is reproduction. However, in some of the more highly specialized ant species the queen cares for and feeds the first brood of workers on her salivary secretions. The queen may live for many years and is usually replaced by a daughter queen. Depending on the species, ants can have one (monogyne) or more (polygyne) queens.

The male is usually winged and retains its wings until death. The sole function of the male is to mate with an unfertilized female reproductive. After mating occurs, the male dies. Males are produced in old or very large colonies where there is an abundance of food. After reaching maturity, the male usually does not remain in the colony very long.

Ants have an egg, larva, pupa, and adult stage. Eggs are almost microscopic in size and hatch into soft legless larvae. Larvae are fed by workers on predigested, regurgitated food. Most larvae are fed liquids, although some older larvae are able to chew and swallow solids. The pupa resembles the adult except that it is soft, uncolored and immobile. In many ant species the pupa is in a cocoon spun by the larva. Six weeks to two months are required for development from egg to adult in some species.

Ants establish new colonies by two main methods: flights of winged reproductives and budding. The most common method is for male and female reproductives to leave the nest on mating flights. The mated queen constructs a cavity or cell and rears a brood unaided by workers. The small first brood workers then forage for food. The colony grows in size and numbers as more young are produced.

Budding occurs when one or more queens leave the nest accompanied by workers who aid in establishing and caring for the new colony. Some of the most difficult ant species to control spread colonies by budding. Pharaoh ants, some species of fire ants, ghost ants, and Argentine ants spread colonies by budding.

Ant Food Preferences

Most ants eat a wide variety of foods, although some have specialized tastes. Fire ants feed on honeydew, sugars, proteins, oils, seeds, plants and insects. Pharaoh ants feed on sugars, proteins, oils and insects. Crazy ants like sugars, protein, and insects. Carpenter ants prefer sugars and insects.

Ants locate food by random searching. When a scouting ant finds promising food, she carries it or a piece of it back to the nest. Any workers she meets on the way become excited and rush toward the nest. The means of communication is unknown, but some ants leave scent trails that others can follow to the food source. Ants require water and will travel some distance for it if necessary. Workers are able to bring water to the colony in their stomachs.

Ant Control

The best approach to control in the home is cleanliness. Any type of food or food particles can attract and provide food for ants. Store food in tight containers. Remove plants that can attract ants or control aphids, whiteflies and other insects that produce honeydew. Reduce moisture sources, including condensation and leaks.

Location of the nest is the key to control because ants are social insects. Large numbers of individual ants can be killed without ever solving the problem. Determine the kind of ant species. Most species of ants never enter buildings, while others build their nests near buildings and forage indoors. Others usually nest indoors.

Chemical control of ants can be applied as barrier, drench, nest and bait treatments. Insecticides, sprays, dusts, granules and baits are useful in ant management.