Outsmarting Structure-Infesting Ants

Just how smart is an ant? Ants give the appearance of intelligence when one is trying desperately to keep them out of someone’s home or business. How many times have you had to go back to the same place again and again trying to control an ant problem?

The truth is that an ant has no capacity for rational or conscious thought, thus no real intelligence. Each ant’s nervous system is comprised of a few large ganglia (nerve fibers) that join together at the ends in the head to form a modicum of a brain. The ant operates on its genetic programming — doing whatever comes "natural."

The "intelligence" we think ants exhibit comes from the collective "brain" of the colony. Remember, the overriding mission of an ant colony is to grow large enough to produce reproductives to disperse and thus continue the survival of the colony’s genetic makeup. Everything that a colony does is geared toward growth and survival. Accomplishing this goal amidst the perils of the world requires adaptability — something of which the most pestiferous ant species have plenty.

Think about what must go through the ant colony’s "mind" when a treatment is applied to an exterior foundation of a home. The service professional with his three-pound brain made the application under the reasonable-sounding theory that an insecticidal "barrier" will keep the ants outside from foraging inside. What happens after the professional leaves to go to his next customer? Hmmmm...

The ants foraging on the foundation at the time of the application certainly will die since they were directly contacted with the treatment. Confusion reigns among those trailing up to the foundation. "What’s this?" "What are these strange odors?" "The trail tastes funny." "Guess we better check out a better route."

The ants already inside are experiencing the same problem.

A few hours later the treatment has thoroughly dried. Will the ants cross the treated surface? If they do, they’ll likely begin acting "sick" and ultimately die. But what if the surface is still repellent, as we find with many pyrethroid insecticides? Might the ants continue to skirt the edge of the "barrier" looking for a gap? Days, maybe even weeks, might pass before the repellency drops enough for the ants outside to venture around again. Maybe they discover a gap even sooner.

What about the ants inside that are now trapped, unable to reconnect to their parent colony? Are they experiencing what we might recognize as panic? It certainly seems so if you have dealt with Argentine ants in California after applying a barrier treatment with a pyrethroid wettable powder. The ants begin behaving strangely, foraging across ceilings, nesting in places one would never expect to see Argentine ants — maybe Pharaoh ants, but not Argentine ants. The ants are adapting, trying to find a suitable environment to survive in until they can reconnect with the parent colony, or they might just start a whole new colony from whatever queens or brood they might have had with them when they were "cut off."

A similar scenario can be discerned from the situation where ant baits are failing to control a particular infestation. Why are the baits failing? Hey, they’ve always seemed to work before on this species of ant. What’s different? The answer is simple enough — this specific colony is not interested in the bait. They either don’t find it tasty enough or they fed on it and discovered it to be something bad. Do they know it’s a poison? No, but their survival instincts are protecting them. Place another type of bait in front of the same ants and amazingly, they can’t seem to get enough.

SMART EXAMPLES. How do you outsmart structure-infesting ants? The answer is knowledge and persistence with a healthy dash of experience thrown in. The process, in theory, is quite simple. First, identify the type of ant involved (see related story, page 42), then find the colony or colonies and treat them directly. Experience shows us, however, that in practice, considerable effort may be required. Let’s take a look at several situations where knowledge, persistence and/or experience paid off in solving ant infestations.

A colleague in my office building called me and complained about the ants in his second floor office. I asked him if he had brought in any potted plants recently. Amazed, he replied, "How did you know that?" I told him I was a "genius" but it was simply experience. Ants found in offices far above the ground often are found nesting in the soil of potted plants. In this case, the ants were big-headed ants. In a similar case involving another coworker, fire ants were carried inside in a potted plant.

Some cases take a lot more work. A former coworker had left work to take care of her newborn twins. She called one day very concerned about the ants showing up in her nursery, especially the ones she found in one of her baby’s cribs. Upon investigation, the offending ants were odorous house ants that were present in large numbers under the edge of the carpet on an exterior wall in the nursery. The same ants had also shown up in the kitchen. Odorous house ant infestations nearly always originate outdoors, but in this situation, I could not find a single odorous house ant outside, even on subsequent evening inspections, when these ants would be more active. I did find, however, several fire ant nests next to the foundation living beneath the new sod (this was a new house). These were treated by drenching the colonies.

Since the odorous house ants were obviously nesting inside or behind the brick veneer, there was little that could be done to treat the colony directly indoors. Granular ant bait was applied under the edge of the carpeting where the ants were trailing and Terro II ant bait was placed on pieces of card in the corner. The ants readily took to the Terro bait and continually took the bait for several weeks with fresh bait being offered every two or three days. To keep the ants out of the cribs, the beds were moved away from the wall and the bottom of the legs were coated with a thin layer of petroleum jelly.

During the time the baiting process was being enacted indoors, ants showed up in the living room. These ants proved to be fire ants that presented a considerable health threat since the babies were often laid upon blankets on the floor. The ants were found around a doorway leading to a small porch out back. On either side of the porch were two small fire ant mounds I either missed on my first inspection or had moved into the area since then. After drenching these colonies and completing the baiting program indoors, the ants have not reappeared.

ODOROUS HOUSE ANTS. In another case involving odorous house ants in an apartment complex, the service professional was making daily calls to respond to tenant complaints about ants in several buildings. He diligently would treat or apply baits indoors. The problem, however, was that he failed to think about the real source of the ant infestation. Treating where the ants are is not going to "outsmart" the ants. Upon investigation, the ant colonies were entirely outdoors, foraging in huge trails around the foundation of the building and then trailing up the walls into the apartments above.

By pulling the grass away from the foundation, we discovered the large horizontal trunk trail nearly encircling the building. By following this trail, we found that it branched off into the grass at one point. Looking in that direction, we could see several river birch trees. Beneath the loose bark of these trees were tens of thousands of ants which were also nesting in the soil at the base of the trees. These colonies were drenched, the tree trunks thoroughly treated and the trails on the building treated. Inside, baits and dust treatments beneath the edges of carpets in infested units relieved the problem. The process was repeated at the other buildings in the complex where ants were invading. The complex was then put on a regular schedule of exterior service to look for and treat ants and other pests.

Early in my career, I sold a carpenter ant service to a woman in Indianapolis. Completing a thorough inspection inside and outside, I could not discover the location of even one colony. However, based on questioning the customer, I found that the ants were seen in one bedroom of the house, even on cool rainy days during the spring. On warmer days, they might be seen in other parts of the home. I took a guess that the nest was located somewhere in one of the two exterior walls in the bedroom. By drilling each of these walls and treating with a residual aerosol, the problem was solved for several months. The customer then called reporting piles of sawdust beneath a closet door in another room. Sure enough, carpenter ants had set up a colony inside the door and were detectable with a stethoscope. I removed the door from its hinges and then drilled through the bottom and treated the void in which the ants were living.

Each of these cases did not require any significant "genius" or superior intelligence. My goal is always to see if I can find the colony or colonies involved. The source of ant infestations is almost always outdoors or, at the very least, a strong exterior component is involved with the infestation. Except for Pharaoh ants, baits are usually a last resort with me, used only in conjunction with other treatments or when the ant colony just cannot be found. Ants are not difficult to outsmart, but there sure are a lot of them — that is why they can be difficult to control. Keep after them and learn from each failure and each success.