Pharaoh Ant

The pharaoh ant (Monomorium pharaonis) is a small (2 mm) yellow or light brown, almost transparent ant notorious for being a major indoor nuisance pest, especially in hospitals. The origin of this "tramp" ant is uncertain, although favoured alternatives include West Africa and Indonesia. The Pharaoh ant has been introduced to virtually every area of the world including Europe, the Americas, Australasia and Southeast Asia. Pharaoh ants are a tropical species but they thrive in buildings anywhere, even in temperate regions provided central heating is present.

Unlike most ants the Pharaoh ant is polygynous, meaning its colonies contain many queens (from 2 to over 200). An individual colony normally contains 1000–2500 workers but a high density of nests gives the impression of massive colonies. Colonies also lack nestmate recognition so there is no hostility between neighbouring colonies. Pharaoh ants lack the normal cycle of reproduction observed in most ants; they are able to produce sexual reproductive individuals as required. Laboratory colonies exhibit weak reproductive cycles but this cannot be assumed to be the natural condition. Colonies reproduce by "budding", where a subset of the colony including queens, workers and brood (eggs, larvae and pupae) leave the main colony for an alternative nest site. Budding is the major factor underlying the invasiveness of Pharaoh ants. 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can also contract into smaller colonies and "weather the storm" of a baiting programme only to rebound when baiting is withdrawn.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.

Pharaoh ants have become a serious nuisance pest in hospitals, rest homes, apartment dwellings, hotels, grocery stores, food establishments and other buildings. They feed on a wide variety of foods including jellies, honey, shortening, peanut butter, corn syrup, fruit juices, baked goods, soft drinks, greases, dead insects and even shoe polish. Also, these ants gnaw holes in silk, rayon and rubber goods. In hospitals, foraging ants have been found in surgical wounds, I.V. glucose solutions, sealed packs of sterile dressing, soft drinks, water in flower displays and water pitchers. These ants are capable of mechanically transmitting diseases and contaminating sterile materials.


Carpenter Ant

Carpenter ants are large (¼–1 in) ants indigenous to many parts of the world. They prefer dead, damp wood in which to build nests. Sometimes carpenter ants will hollow out sections of trees. The most likely species to be infesting a house in the United States is the Black carpenter ant, Camponotus pennsylvanicus. However, there are over a thousand other species in the genus Camponotus.

Carpenter ants can damage wood used in the construction of buildings. They can leave a sawdust like material behind that provides clues to nesting location.

In at least nine Southeast Asian species of the Cylindricus complex, such as Camponotus saundersi, workers feature greatly enlarged mandibular glands. They can release their contents suicidally by rupturing the intersegmental membrane of the gaster, resulting in a spray of toxic substance from the head, which gave these species the common name "exploding ants".

Its defensive behaviors include self-destruction by autothysis. Two oversized, poison-filled mandibular glands run the entire length of the ant's body. When combat takes a turn for the worse, the ant violently contracts its abdominal muscles to rupture its body and spray poison or glue in all directions. The ant has an enormously enlarged mandibular (abdomen) gland, many times the size of a normal ant, which produces the glue. The glue bursts out and entangles and immobilizes all nearby victims. The termite, Globitermes sulphureus has a similar defensive mechanism.


Fire Ant

Fire ants are a variety of stinging ants with over 280 species worldwide. They have several common names including ginger ants and tropical fire ants (English), aka-kami-ari (Japanese), fourmis de feu (French), Feuerameisen (German), and Langgam (Filipino).

A typical fire ant colony produces large mounds in open areas, and feeds mostly on young plants, seeds, and sometimes crickets. Fire ants often attack small animals and can kill them. Unlike many other ants, which bite and then spray acid on the wound, fire ants only bite to get a grip and then sting (from the abdomen) and inject a toxic alkaloid venom called Solenopsin, a compound from the class of piperidines. For humans, this is a painful sting, it hurts, a sensation similar to what one feels when burned by fire—hence the name fire ant—and the aftereffects of the sting can be deadly to sensitive individuals. The venom is both insecticidal and antibiotic. Researchers have proposed that nurse workers will spray their brood to protect them from microorganisms.

Fire ants nest in the soil, often near moist areas, such as river banks, pond edges, watered lawns and highway edges. Usually the nest will not be visible as it will be built under objects such as timber, logs, rocks, pavers, bricks, etc. If there is no cover for nesting, dome-shaped mounds will be constructed, but this is usually only found in open spaces such as fields, parks and lawns. These mounds can reach heights of 40 cm (15.7 in).

Colonies are founded by small groups of queens or single queens. Even if only one queen survives, within a month or so the colony can expand to thousands of individuals. Some colonies may be polygynous (having multiple queens per nest).