In tropical climates, ants have surpassed cockroaches, mice and rats as the number one pest. The southern regions have hundreds of species that commonly enter structures causing home and business owners grief.
Rather than list common ant species and detail their biology and habits, I will explain in general the common sense approach to eliminating ants from your structure.
It is a widely held misconception that by spraying or baiting the foraging ants indoors, they can be controlled or eliminated. Most ants live outside! Any kid that received an ant farm for a birthday or Christmas present knows that ants (for the most part*) dwell in the ground. It is for this reason that any treatment strategy should focus on the exterior of the structure. Many times I'm called to a home or office where they have placed ants bait stations from one end of their house to the other or have the standard spray can sitting on the window sill by the sink. It's no surprise that these treatments fail when we look at how the common ant forages for food.
Ants are social insects not much different than bees. Every member of the colony is charged with a job. Some care for the queen, some protect the colony, some are reproductives and some are worker/foragers.
The foraging scouts are sent out to find food for the colony. Once a source is found, it is their job to “pave the road” for the convoy that will soon follow. They do this by leaving a chemical message like road signs along the path back to the nest. Other workers will then follow those pheromone road signs back to the food source all the while pronouncing the trail by leaving more pheromone's as they go. If you can imagine that I-95 probably started as a foot path for Native Americans, then when horses were introduced to the America's the path became a horse trail. After a century, the trail became a road where carriages could pass. With the advent of the horseless carriage, the road became a street and so on until we have a super highway today. The ant's trail will become more and more pronounced the more they travel it. It stands to reason, that by placing baits (food with a poison) inside, the trial will soon become a super highway. Even if the bait makes it's way through the supply chain to the nest, new colonies will follow those same paths, trails, roads, and super highways into the structure.
Some ant species have multiple queens. These colonies often split into several colonies to further the success of the species. This nest budding also occurs when the colonies is stressed or threatened. The commercially available sprays today are mostly repellent insecticides. The companies that manufacture these sprays design these products to satisfy the customer. Most people want to spray a surface and see no activity afterward. This is a temporary fix as these “pyrethroids” do not last very long and does nothing to address the tens of thousands of ants in the ground outside. What could end up happening, is that you cut the foragers off from the colony like flooding a bridge on a major highway. If this happened on I-95, you would take a detour. The same is true with ants. Often it is reported to me that when a customer sprayed one area they popped up in another.
So here we are. Sprays and baits don't do the job. What now? Ants feed on many different food source found in nature. Some feed on dead insect parts as a source of protein and some feed on honey dew (a sweet excretion from aphids and scales) for carbohydrates. Knowing what ants eat and where they find these things in nature is important.
Solution: Ants live and prefer to feed outside. Ants are extremely efficient insects and will locate their nests as close to an abundant food source as possible. This is normally around broadleaf shrubs and trees where aphids and other organisms live. Ants also look for suitable nesting sites with sufficient protection from the elements. Often you will find ants using roots, sidewalks, or landscaping timbers for support and shelter of the nest.
Baiting - Some of the commercially available baits have a high percentage of active ingredient that actually can kill the forager on her way back the nest (especially in species where the ant is very small). It is imperative to apply baits close to the nesting area. Test the bait by applying a small amount to the visible trails and then watch. Follow the workers carrying the food back the nesting site. Once you've found the suspected colony, apply bait more liberally. This should be done on a day when rain is not threatening, allowing for at least 4-5 hours of feeding. Various ant baits are available at your local hardware store including liquid and granular baits. I suggest a smorgasbord as some species of ants change their preferred food depending on the needs of the colony.
Spraying – In most cases, spraying is not recommended as it will encouraging “budding” and split colonies into several nests. Although you may want to spray the masses foraging, understand that while you may kills hundreds or even thousands, there are tens of thousands of their sisters in the ground that will take their place a few days later. There are several non-repellant insecticides that are designed specifically for ants and termites. These products depend on ants moving through the treated soil and contacting the insecticide where it will be passed on through interaction with the rest of the colony. These insecticides can be extremely effective but should only be applied by a pest professional.
Inside – What to do about the ants inside on my kitchen counter? Now that you know that these are the scouts trying to find new food sources, remove the source. Cleaning counter tops, garbage receptacle, and floors will not only remove possible food sources but effectively erase the pheromone trail that has been established by the foragers. Wiping trails with ammonia cleaners will erase the trails and confuse the following foragers. This should be enough to allow your exterior treatments a chance to work on the source... the nest.
Enjoy your summer cook-outs without the extra guests.... :)
* This article covers most ants however, Carpenter ants and Pharaoh’s ants are very different in their habits. Contact me for specific information.