- Of the approximately 100 species of ants found in Canada, the pharaoh ant is the second most common, after the carpenter ant.
- The pharaoh ant gets its name from 18th century biologist Carl Linnaeus, who believed the ants were one of the biblical plagues of Ancient Egypt, but was later proven wrong.
- They are most likely tropical in origin but have currently been introduced to every area of the world, including Europe, Australia, Asia, and the Americas.
- Pharaoh ants love hospitals – they are known to invade sick rooms and feed on surgical wounds, IV solutions, blood plasma, and wound dressings (either sealed or used).
- Mature colonies can reach up to 300,000 members and hold up to 200 queens.
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.
Diet, Behavior & Habits
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.
Commonly infested areas:
- Wall and cabinet voids
- Inside hollow curtain rods
- Behind refrigerator insulation
- Under houseplants
- Between books
- In appliances
- Behind baseboards
- In sheets, clothes, and paper
- Crevices in foundation, service ducting
- Boxes and sealed containers of food
- Boiler rooms
- Around central heating pipework
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.
Signs of Infestation
Although very small in size, pharaoh ants are not so difficult to detect. Here are some of the telltale signs of infestation:
- Trailing ant patterns on the walls of a building – the most obvious sign of an infestation – that often resemble moving veins. Following the trail will lead to their nests and food sources.
- Pet food dishes and bathroom faucets are usually used by ants as a source of food and water.
- Look inside cupboards for opened boxes of cereal, grain, and rice packets – ants love carbohydrates, as well as jams, jellies, and honey, and they can easily make their way through jar lids if they aren’t properly sealed.
- Garbage bins are always a point of attraction for the omnivorous ants who love meat and protein-rich foods.
- Aside from places where food is stored, don’t forget to check out humid areas in your home – they need moisture to breed, so they will likely be found nesting near central heating systems and heated indoor areas.
Management & Control
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:
- Store food items in properly sealed containers (ants are very small and they can infiltrate even the tiniest of cracks and crevices).
- Practice cleanliness and housekeeping routines.
- Don’t leave pet food out the entire day.
- Make sure to clean spills and food scrapes immediately.
- Don’t leave dirty dishes in the sink overnight.
- Use garbage bins with tight-fitting lids and empty them regularly.
- Seal holes in windows and doors.
- Refrain from using bug and ant sprays. Instead of killing all the ants inside, it will only cause the nests to split and multiply.