Ants are one of the most successful animals on Earth. They thrive due to their social organization, which allows them to defend themselves, exploit resources, and modify their behavior. Unfortunately, they can wreak havoc on home environments.
To understand how to get rid of ants, it is important to understand how they live and how they sustain themselves.
Ants are social insects in the Formicidae family and are most closely related to bees and wasps. They live in colonies, although the size of the colony varies greatly depending on the species. Some species have colonies of only a few dozen individuals, while others form colonies with many millions of ants over a large area. Most of the ants in a large colony are sterile females that belong to the worker or soldier castes. Other castes include the royalty caste, or queens, which are the only fertile females in an ant colony. Drones are fertile males, whose sole function is to fertilize the queen. Scientists often refer to ant colonies as super organisms, since the individual ants function as single entity to support the colony.
Ohio State University reports that over 14,000 species of ants have been classified of the estimated 22,000 species that exist. Virtually all land masses on Earth have native ant species, except for Antarctica and a few large islands like Greenland, Iceland, and the Hawaiian Islands. They occupy many ecological niches, although most species are general omnivores. However, some species are more specialized feeders, including carnivores and herbivores. Ants comprise 15 to 25% of the biomass of terrestrial animals, according to Proceedings of the National Academy of Sciences.
Ants have six legs and an exoskeleton, like all other insects. The exoskeleton provides the body with structural strength, as an internal skeleton does with vertebrates. It also serves as an attachment point for muscles and allows the passage of gases such as oxygen and carbon dioxide into the body through small valves known as spiracles.
An ant’s distinctive body shape is characterized by its three primary body segments, which consists of its head, mesosoma and metasoma. The mesosoma is the fusion of the thorax and first abdominal segment. The metasoma is composed of a narrow waist, or petiole, and the remaining abdominal segments, which are known as the gaster. All six of an ant’s legs are attached to the thorax. The queens and drones of most ant species also have wings that they shed after their nuptial flight.
Types of Ants
All ants may look alike to you, but there are some distinctive differences characteristic to each type of ant. And while there are far too many ant species to address in a single article, here’s a run-down of the most common household pests.
Argentine ant – these are small ants, about 1/16 to 1/4 of an inch, and their color ranges from a deep brown to black. They are a common household pest, sometimes called sugar ants, and they sometimes give off an odor when crushed.
Odorous house ant – one of the most common household pests, the odorous household ant gives off a sweet/musty odor when crushed. They tend to be small, about 1/16 to ⅛ of an inch, and tend to be brown or black.
Carpenter ants – Carpenter ants are perhaps the most destructive type of ant. They do not feed directly on wood, but they do burrow into it, and this can cause problems when the wood they invade is of structural importance. They’re relatively large and tend to be black.
Black ants – When you see a large black ant, it’s probably a carpenter ant. A small black ant may be an odorous house ant, or it may be a little black ant, a species native to North America. These ants are tiny, usually not much longer than 1/16 of an inch, and while they may launch an ant invasion to forage in your home, a little black ant usually lives in an ant mound out of doors.
Sugar ant – this type of ant comes last, because while there is one species of ant which is properly called a “sugar ant,” people use the name for several different types of ants—including carpenter ants, odorous household ants, and Argentine ants—whose only common characteristic is that they’re household pests attracted by sugar or sweet substances in the home.
Do You Have an Ant Infestation?
A long trail of ants is one of the strongest signs that a building has an ant infestation, according to InterNACHI. Straggler ants that aren’t part of the mainline are likely to be scouts in search of new sources of food and water. A trail often forms on a pipe or wire that allows the ants to easily travel in and out of a building. You may be able to trace a line of ants back to its entry point, which is usually a gap in the baseboard or around a water pipe. A trail may contain hundreds, or even thousands, of ants.
Most ant species build complex nests, although a few nomadic species do not build any permanent structures. Depending on the particular species, they build nests of soil and plant matter underground, inside logs, on in trees. Ants usually select a nest site very carefully to avoid diseases and predators. One species will even avoid building a nest in an area with dead ants.
For pest control purposes, the most easily recognizable ant nest has a pile of material (primarily composed of dirt) above its entrance. Workers dig tunnels and chambers in the ground and deposit the excavated earth outside. Most species form a simple pile with this material, although a few sculpt it into a specific shape.
Ants in the Kitchen
The presence of food makes kitchens a common infestation site for small species like Argentine ants, odorous house ants, pavement ants, pharaoh ants, and thief ants. They are primarily attracted to sources of simple sugar, such as table sugar, syrup, honey, and fruit juice. They may also be attracted to protein sources such as meat and pet food.
Ants will typically continue invading the kitchen unless they’re treated, especially if there is enough food and water to support additional colonies. Multiple colonies will make the ants much more difficult to eradicate, since each colony will have at least one queen. A kitchen with abundant food and water may also cause the ants to build nests inside the house.
Other Sites for Ant Infestations
Locating the nest is highly helpful for dealing with a severe indoor infestation, since it will indicate the best methods for treating the infestation and for pest management going forward. Keep in mind that this nest may be inside or outside. Even if an ant nest is outdoors, ants may enter from the outside to forage or seek shelter from bad weather. Since some species live outside exclusively and only come indoors for those reasons, it helps to be able to identify the species before starting on an ant removal plan.
A line of ants entering a house through a crack in a door or window is a strong indication that the nest is outside. But a line that goes into a cabinet or wall indicates that the nest is more likely to be indoors. A potted house plant is also a common location for an indoor ant nest.
Finding a carpenter ant infestation can be made especially difficult by their practice of nesting in wooden structures: hollow doors, for example, are a favorite hiding place for a carpenter ant colony. In contrast to other species, carpenter ant damage to woodwork and framing material can pose a structural (and financial) risk. As you look for the site of a carpenter ant nest, look for a type of fine sawdust known as frass. Tap on a piece of woodwork that you suspect of being infested to see if any frass falls away from it. The ants in a large nest may also produce a perceptible rustling noise similar to that of crinkling cellophane.
Bait and Spray: Treating Ant Infestations
Treatments for ant infestations include baiting and chemical and natural methods. The best choice for pest control often depends on the species, since this determines preferences for food and nest sites. The most effective methods of ant removal generally involve killing the queens, as they are a colony’s only reproducing females.
The most common active ingredient for ant bait is borax, which is effective for several reasons. Borax is inexpensive because it occurs naturally in seasonal lake beds at high levels of purity. It’s also highly lethal to ants, but only mildly toxic to humans. Furthermore, ants eagerly seek out borax because it has a sweet taste.
Ant bait works very slowly, allowing the workers to make multiple trips to the bait source. The workers lay down pheromone trails, which attract more workers. This habit means that ant baits will initially cause more ants to be visible as they form lines to the bait source. Do not disturb these lines once you have set the ant bait. Let them retrieve the bait and carry it back to the nest. This bait will eventually kill the individual workers that consume it, but its primary purpose is to kill the queen.
Chemical Ant Control
Chemical forms of ant control are rated for indoor or outdoor use, so it’s important to ensure that you use an ant killer that’s appropriate for the location. Indoor insecticides are generally much less toxic because they will be used in closer proximity to humans. These products may be in spray or powder form, with deltamethrin and permethrin being the most common active ingredients.
Eradicating an ant nest in the house often involves more than just applying spray: a pest control company may have to drill small holes in the wall near the floor. Insecticidal dust may then be applied through the holes with a special applicator or plastic bottle with a nozzle, a procedure that’s especially necessary for carpenter ant control. It’s important not to apply too much dust, as this could cause the ants to avoid it or abandon the nest entirely.
Ant pesticides for outdoor use typically use one of the following active ingredients:
Acephate is used for liquid pesticides and spray, while bifenthrin and cyfluthrin are the active ingredients in solid pesticides. Carbaryl and permethrin used in both liquid and solid pesticides. Liquid pesticides should generally be allowed to soak into the nest, while solid pesticides are placed outside the nest so they appear to be a food source. Both types of pesticides often require multiple applications to kill the queen, especially if the nest is large—and killing the queen is essential in ant removal.
f you’re interested in trying some do-it-yourself ant control, there are some household substances that can, to an extent, act as a natural ant repellent, and some naturally-occurring chemicals that even work as bait.
Essential oils – Essential oils are what their name implies—concentrated oils taken from various plants, such as cinnamon oil, lemon oil, and peppermint oil. They’re effective at disrupting the chemical trails that ants use to lead other ants to food sources. Put a small amount in a spray bottle with water and spray this on the trail and the areas around it, and ants may lose interest in the food source that has them invading your home. You can also put essential oils on a cotton swab and apply them directly to the trail.
Natural ant repellents – There are a few natural products that act as barriers to ants by damaging their exoskeletons. Chalk is sometimes effective in this role, as is granulated salt. The most widely recognized barrier is diatomaceous earth—a naturally-occurring substance created by the build up of tiny marine plants called diatoms. The bits and parts of the diatoms’ skeletons fall apart into jagged microscopic pieces of silica that damage ants’ exoskeletons and eventually cause them to dehydrate. Ants naturally avoid diatomaceous earth, and so sprinkling it across ant pathways acts as a repellent. If you choose to use diatomaceous earth, avoid the type that’s used as a purification agent for swimming pools, which can harm people if inhaled. Instead, use food-grade diatomaceous earth, which is used as a dietary supplement and is less harmful.
Herbal approaches – some common cooking ingredients can also be used to get rid of ants. Cayenne pepper can disrupt trails in the same fashion as diatomaceous earth, as can ground-up bay leaf. Vinegar (used in a 50% solution with water and applied with a spray bottle) works in much the same way as essential olls: spray it on ant trails and the areas around them.
Natural ant bait traps – You can make ant baits that are comparable in effectiveness to commercial ant traps by heating borax (a common cleaning agent) and sugar together in water, letting that solution cool, and leaving it in shallow containers (jar lids are effective) in the ants’ path, just like a standard bait station. In powder form, boric acid, which is refined from borax, can be laid across ant paths in a manner similar to diatomaceous earth. Both methods achieve the same result: the ants carry the boric acid back to the nest and ingest it, eventually killing off the colony.
Stopping an ant problem before it starts is typically much easier than controlling them once they’ve become established. Prevention methods may be classified into the following categories:
- Food storage
Remove pheromones around the house’s entry points, thus preventing other ants from following a trail. Scrub these areas with a mild solution of soap and water. Clean up spilled food in the kitchen to avoid attracting ants.
Keep food in sealed containers, especially those containing sugar. Dispose of unused pet food instead of allowing it to remain in a dish. Taking out the garbage regularly keeps the smell from attracting ants.
Minimize the amount of water around your house by fixing leaky pipes. Ensure that your gutters drain water away from your house. You may also want to remove excess moisture from the air with a dehumidifier if you live in a humid area.
Seal any entrance points for ants in your house—primarily cracks in your foundations, walls and windows. Caulk is the most common sealant for this purpose, although the best choice may depend on the specific material that you’re sealing.
Top Tips for Ant Control
Baiting is one of the most effective methods of controlling ant infestations, especially when you can’t locate the nest or easily access it. Remember that this method will require several days to kill the queen. The number of visible ants will also increase during this time as they carry the bait back to the nest.
Contact pesticides, including commonly-sold sprays are the best way to kill visible ants, especially if they don’t have a well-established nest. These pesticides work quickly and have residual effects that last for weeks. Contact pesticides are typically used in specific areas that aren’t used to prepare food.
Granules are the most effective type of pesticide for preventing ants from entering your home. They are effective as a general perimeter defense because you can apply it around the outside of your house. However, granules are much more effective against a known nest. In this case, you will create a circle of granules around the nest.
When to Call a Professional
A professional exterminator may be necessary if there are multiple nests, or even a single large nest, invading your house.
Be aware that wood-cutting species such as carpenter ants often cause property damage that require a contractor to repair. These ants can bore long tunnels, or galleries, in wood, and these tunnels can greatly weaken load-bearing structures in your house.
Professional pest controllers typically handle a range of insects, but may also specialize in a particular species. They are likely to be highly experienced with the particular ant species that live in your area, as well as pesticides and treatment methods that are safe for children and pets. These professionals frequently provide free estimates, allowing you to determine the severity of the infestation before making a financial commitment.