Compared to carpenter ants, Pharaoh ants are significantly smaller: they measure only about 1/16 inch, with some workers reaching 1/12-inch in length. The color of their body is pale yellow to reddish, with black shading on the top and rear of their abdomen. Their antennae have 12 segments with each segment growing larger toward the apex of the club. They have relatively small eyes and poor eyesight, with approximately 32 ommatidia (photoreceptor cells). Workers are wingless; winged males will make their appearance periodically to mate with the queens (also winged). Although a stinger is present, it is rarely used for something else than to generate pheromones.
Pharaoh ants are often confused with another Canada resident, the thief ant, which has the same color and shape, but is even smaller in size. The best way to differentiate between the two is to look at the antennae: the Pharaoh has 12 segments and 3-segmented antennal clubs, while the thief ant has only 10 segments in total and only 2 in the club-like structure at the end of their antennae.
Probably due to their tropic origins, Pharaoh ants prefer nesting in heated structures with temperatures between 80 and 86 degrees Fahrenheit. They are often found in kitchens, pantries, and bathrooms, where they obtain food and water. Pharaoh ants are not picky – they feed on a variety of food items, including breads, butter, sugar, jelly, syrups, cake, honey, but also meat, grease, and fat. They may feed on other insects (alive or dead) and even household items such as shoe polish, silk, rayon, and rubber goods.
Their preferred nesting sites are not necessarily near food – they are mostly associated with high temperature and moisture, as well as light. Workers will travel long distances – up to 100 feet – to search for food and water. Colonies consist of up to 300,000 workers and multiple queens and are usually mobile. Workers, along with pupae, larvae, and a couple of queens (usually, 1 queen, 5 workers, and 10 preadults are sufficient to form a new colony) will search for a new nesting location when the current nest becomes too large or is disturbed. The lifespan of workers is 9-10 weeks, while queens can live to be 4-12 months; males die after 3-5 weeks following mating.
In some parts of the world, especially those with warmer climates, the ant has become a common pest of residential and commercial properties, food factories, plants, office buildings, apartment complexes, and hospitals. Although there are no specific diseases associated with this ant species, they can pose serious health risks to hospital patients, especially burn victims and newborns, as they have been observed seeking moisture from babies’ mouths and food from victims’ wounds. They can also penetrate sealed containers of food and spread pathogens picked up from garbage and waste, such as Salmonella, Staphylococcus, and Streptococcus spp.
Although very small in size, pharaoh ants are not so difficult to detect. Here are some of the telltale signs of infestation:
Due to their tiny size and preference to nest in inaccessible areas, Pharaoh ants are some of the most difficult to treat residential pests. In order to effectively treat an infestation, adequate treatment must be applied at all their nesting areas, as well as foraging sites. This means starting with cracks and crevices in walls, looking inside hollow doors and windows, behind baseboards and in floor voids, and thoroughly checking the house, including linen, stored clothing, foodstuffs, and appliances.
Pesticide applications are not only completely ineffective (killing only the sprayed ants), but they can make matters worse by causing the ants to split into several colonies (process called budding) and avoid the treated areas completely. Chemical liquid pesticides are also unsafe and dangerous to humans and pets.
The preferred approach to getting rid of Pharaoh ants is ant baits, set up and managed by pest control specialists. However, if baits are placed at random, without examining first the trails and preferred foraging locations of ants, the baiting strategy will most likely fail. Applying non-repellent baits (such as those based on boric acid, hydramethylnon, and sulfonamide) in corners of walls, along the edges of baseboards, on windowsills, underneath carpet edges, and in several other areas where scout ants leave pheromone trails will guarantee their successful annihilation.
Boric acid and insect growth regulators such as methoprene are typically mixed with egg yolk, peanut butter, mint jelly, or some other combination of carbohydrate and protein foods, which will be sampled by workers and spread into their colonies over a period of 4 to 6 weeks. Insect growth regulators will not kill adult workers, but they will prevent larvae from reaching adulthood and sterilize the queen, so the nest will die naturally; the only downside is that it usually takes 30-50 days to achieve control.
The best way to prevent a Pharaoh ant infestation is to not allow them inside your house. To make your property unwelcoming for these pesky creatures, make sure to: