Many kinds of ants can become a nuisance in homes and other buildings. Most indoor ant problems originate from outdoor locations. Once they enter a building they may establish colonies in wall voids, behind baseboards, and even in hollow doors. Often however, ants are living outdoors and only entering buildings to forage for food. The key to controlling ants is understanding how they live, how they behave, and what they need to survive.
Ants are social insects. They live in colonies in which one or more queens produce eggs. The eggs hatch after a few days into small larvae that are cared for by workers. After a few weeks the larvae spin a cocoon to pupate. The pupal stage is when the ants change from their larval form to an adult. When they emerge from the cocoon, most will be workers. Normally after a colony is several years old, some of the new adults will have wings. These flying ants are called swarmers. Swarmers fly away from their home colony, mate, and find a suitable location to begin new colonies. Ant swarmers can be found throughout the year when temperatures are mild, but usually they are observed in the spring and summer. Unfortunately, ant swarmers are sometimes confused with termites. Winged termites are also often referred to as swarmers. Swarmer ants and termites can be easily told apart by looking for a few obvious characteristics pointed out in the diagram.
Ants enter buildings in their search for food. Most ants fed on the same foods that humans do. Some types of ants are attracted to greasy foods, while others prefer sweets. Whichever type they are, when one worker locates the food their colony likes, they will lay down a chemical signal as a trail for other workers to follow to the source of the food. This is why large numbers of ants can be observed in the same spot.
Effective ant control requires a multi-faceted approach that includes a combination of habitat alteration and toxic baits or sprays.
Habitat alteration means changing the environment so that it is less appealing to the worker ants. This can include simple changes like keeping food in sealed containers, keeping fruit in the refrigerator, and keeping dirty dishes and counter tops clean. Other changes may take more effort like caulking around windows and doors, having adequate screening, and reducing outdoor sites where ants can have colonies.
Toxic baits and sprays are good tools to use for ant control. Ants sprays applied to cracks and crevices will help control ants for a short time. Entire floors, walls, counter tops, inside drawers, or cabinets should never be sprayed. The most effective control will be achieved with the use of toxic baits designed for ants. Worker ants will feed on the bait and take it back to share with the rest of their colony. Because the baits are slow-acting, the workers have enough time to return to the colony to feed others before they die. Ant baits are available in small stations and can be purchased from most discount and grocery stores. Place ant bait stations where you see ants, but away from children and pets. Bait stations should not be sprayed or moved when ants are feeding.
Originally published 08/98