It's the rainy season in Missouri so of course we have increased incidence of ants in the home. But this year, for the first time, I am finding these small black ants in my ice-making machine. The machine is located at a wet bar in the family room and is not near to any source of stored or spilled food. It's been there and in operation for 10 years and this is the first time I am finding ants there. I can't figure what draws the ants to the ice machine bay. They seem just to go there, freeze to death and force me to clean out the ice bay every day. Any ideas why they are there and what I can do to keep them out?
St. Louis, Missouri
That is an interesting question. It's hard to say for sure, but they might be going after water, or they just might be attracted to the electricity (we don't really understand why some ants go to areas near electric currents, but it's a pretty well-documented behavior in some species--see especially the Rasberry Crazy ant). To keep them out, you need to isolate your ice machine from the ant nest. If it has legs, and wires connecting it to the floor, you can either make it too slippery for the ants to get up with insect-a-slip , or too sticky for the ants to get up with tangle-foot.
Many ants use invisible trails made of tiny droplets of chemicals, which are pheromones that essentially say, "follow me!" If you see ants moving steadily in a line, wiping the surface across which they are traveling with rubbing alcohol and/or detergent will remove this message, and perhaps discourage them from finding it again.
In general, the best way to keep ants away from a particular area in your home is to remove anything that might tempt them. This is of course much more straight-forward if the attractant is food--you just have to keep the area clean. But if the attractant is water or electricity, it may be more realistic to use physical barriers like those mentioned above, which can last for a month or more. Killing the ants with a spray will not help very much, because the ants you see that are out gathering food or other resources often represent only 5% of the total colony. It may be possible to poison the entire colony with commercially available ant baits, but not all ants will eat all baits, and not all poisons will be 100% effective.
Some of my friends in remote areas were trying to keep ants from biting them at night, and they found that putting the legs of their beds in cans of water worked really well, as did wrapping the legs of their beds with rags soaked in diesel. (Needless to say, the commercially available products would be much safer for indoor use on an electrical appliance.) I even knew a family who built their house on cement stilts, and around the base of each stilt, made a small moat about the width of a finger-tip they could fill with water to keep the ants out permanently. However, the ants still got in by walking along the wires leading into their house! You really have to think of everything to keep the ants away.
Jesse Czekanski-Moir & the AntAsk Team