Ants in the Walls
Depending upon distribution and cold weather conditions, ants may be as likely to nest outdoors as indoors, especially in many parts of the warmer, more southerly portions of their distribution. Also, the preferred indoors locations and food preferences of the ants listed below may vary to some degree since there is a lot of species-specific variability among ants.
Why Ants Live in Walls
Ants become dwellers inside walls and other voids simply as the result of finding a more preferred site for food, moisture and protection than what is available to them outdoors. Another important situation that favors ant activity in walls and other voids is the opportunity to gain entrance inside the home or other structures through cracks, gaps and openings that lead directly inside.
Without a doubt a structure that has none or minimal access inside will result in a structure that is hard for foraging or migrating ants to penetrate.
So, what does an effective ant integrated pest management (IPM) program look like? The first component of such a program is identification and understanding of the foraging for food, moisture and characteristics of shelter that favors particular ants.
Once that information is known, your pest management professional (PMP) can target his inspection to locate food sources, water leaks or pooling that provides sources of moisture and likely entry points and places where the pest ants are located.
While the above non-insecticidal approaches to ant management are critically important to the ant IPM program inside voids, most of the time some treatment using an insecticide may be needed to obtain the expected level of control.
For many situations, the use of insecticide baits specifically formulated for ants, plus dusts, aerosols, foams (formulations that look much like aerosol shaving creams) and liquids are applied to voids to reduce the void ant nester population.
At this point in our discussion, it is important once again stress that you pest management professional should be consulted to address the what, how, where and when ant control products can be used in a void ant IPM program.
Common Ant Species That Will Live in Walls
Some of the common species of ants occupying interior walls and voids include:
Acrobat ants: nest in door and window frames, particularly those damaged by termites, other insects and moisture; feed on sweets and proteins.
Argentine ants: nests found in wall voids, bath traps and insulation; feed on sugars, carbohydrates and greases.
Carpenter ants: excavate their nests in wood that is sound or decayed by moisture or damaged by other insects. May have both a primary nest and secondary (satellite) nests located near each other. Found in attic rafters, bay window voids, wall voids, hollow doors, insulation in attics and crawlspaces, ceiling voids next to skylights, homes with flat roofs, dormers and hollow porch columns, holes or cracks where utility lines enter the home. Feed on sweets, carbohydrates and other insects.
Crazy ants: wall voids, under carpets, and in potted plants; prefer feeding on sweets and fats, oils and grease.
Ghost ants: nest inside in potted plants, behind baseboards and voids between cabinets, in firewood that is brought indoors; typically forage in the kitchen to search for sweets and grease.
Citronella ants: winged ants swarm indoors from cracks and gaps in floors or walls and from the basement and foundation; feed on honeydew from aphids and mealybugs that live underground.
Little black ants: indoors they may nest in wall voids, cabinet voids, in brick or stone veneer.
Odorous ants: nest in areas that are moist in wall voids near pipes, bath traps and termite-damaged wood, feed on sweets and carbohydrates.
Pharaoh ants: nest in places with moisture such as kitchens and bathrooms near water sources, interior wall voids, under floors, behind baseboards or window sills; feed on proteins and sweets.