Pharaoh Ants

Appearance

Pharaoh workers are very small (about 1/16-inch long, or 2.0 milimeters), light yellow to reddish brown in color with the abdomen (hind portion of body) somewhat darker. There is no stinger. The petiole (narrow waist between the thorax and abdomen) has two nodes and the thorax has no spines. Eyes are poor and possess on average 32 ommatidia. The antennal segments end in a distinct club with three progressively longer segments.

Habit

Relies on artificial heating in buildings to survive. Infestations commonly occur in food service areas. Will nest in any well-protected and hidden areas throughout a structure. Can also nest outdoors in lawns or gardens.

Pharaoh ants engage in a behavior pattern known as "satelliting," "fractionating," or, more commonly, "budding". Part of the colony migrates to a new location, which contrasts with the more common mechanism of colony reproduction where single females disperse and independently found colonies after a reproductive swarm. A queen together with a few workers carrying immatures (eggs, larvae and pupae) leave the nest and set up a new colony elsewhere. Budding is a major factor in the rapid spread of infestations.

Nests can be very small for example, located between sheets of paper, in clothing or laundry, furniture, foods, etc. Nests usually occur in walloids, under floors, behind baseboards, in trash containers, under stones, in cement or stone wall voids, in linens, light fixtures, etc. They prefer dark, warm areas near hot water pipes and heating tapes, in bathrooms, kitchens, intensive care units, operating rooms, etc. They are "trail-making" ants and often are found foraging in drains, toilets, washbasins, bedpans and other unsanitary sites as well as in sealed packs of sterile dressing, intravenous drip systems, on surgical wounds, food and medical equipment.

Diet

Food of all types, but especially sweets. Will also eat other insects.

Reproduction

A single seed colony can populate a large office block, almost to the exclusion of all other insect pests, in less than six months. Elimination and control are made difficult because multiple colonies can also contract into smaller colonies and 'weather the storm' of a baiting programme only to rebound when baiting is withdrawn. Pharaoh ants are a major hazard in hospitals, where their small size means they can access wounds, driplines, and instrumentation, causing spread of infection and electrical interference.

Grows from egg to adult in about 45 days. Females live as long as 39 weeks and can lay about 400 eggs. Workers only live up to 10 weeks.

One of the most persistent and difficult ants to control. Very large colonies with up to several million workers and thousands of queens.