Carpenter Ants

Here, There, and Everywhere Carpenter Ants

Question:

A customer is having problems with black and red ant swarmers (together) inside her house - we can't find any ants outside whatsoever. It has been going on for two weeks now, and we can't figure out where they're coming from. They are in every room, including the attic, but they don't appear to be entering from the attic. Neighbors tell her that this happens to this house every year, just like clockwork!

BRIAN, AZ

Answer:

My first question is are these some ants that are red and some ants that are black, or are the ants just a combination red and black colored. This could make a difference, as having swarmers of two distinctly different colors would suggest two different species. What seems more likely, and I'll run with it, is that you have swarmers that are bicolored, and being inside the home like this I would guess at carpenter ants. Whenever you get large numbers inside the home, and not just onesy twosy showing up, it suggests the probability that you are dealing with a colony of the ants within the structure, and carpenter ants are famous for this. Swarming is a typical annual event, usually triggered by some environmental circumstance that "tells" the colony that condition are appropriate for the swarmers to get out, mate successfully, and begin new colonies. Since Arizona typically has late July monsoon rains it could be that the moisture available now was the trigger, and this house must have been enjoying their colony of carpenter ants for quite awhile for the whole neighborhood to know about it.

Once the swarmers emerge they instinctively head toward light in their effor to make it to the outside. It would be unusual for carpenter ants to have this colony inside the home without also having the parent colony outside in the soil somewhere. The moist soil is a far more conducive environment for the queen and her eggs, and satellite colonies in structures often are created for late stage larvae and pupae, which are not so dependent on moisture. This doesn't rule out the possibility of a colony isolated within the structure, particularly if there is moisture available for them there, so this could be one thing to search for in the home......moisture. It could be a damp crawl space, or it could be a moisture problem within the walls, around the tub, etc., and the moisture not only draws many kinds of insects but also could lead to decay fungus.

I would think that if the attic were the place the swarmers were exiting to you would find a lot of the ants in the light fixtures, and of course in the attic itself. Since they are in the various rooms it tells you they are coming out somewhere in the living areas, and this begins your challenge, to discover exactly where this nest is. Carpenter ants normally are nocturnal insects, and having the homeowners carefully inspect each room after dark may help. An inspection of the exterior after darkness also may reveal trails of the ants outside, often using well established trails as they forage for food or make their way to and from a soil-based parent colony. Since they have to eat, and honeydew and other insects comprise much of their food, they likely are going outside every night, and thus exposing themselves to some control measures you could put there. This may be granular insect baits, which carpenter ants seem to accept very well, or a residual product like Termidor, which could allow the exposed ants to take back on their bodies and spread around within the colony.

Sometimes you can discover the location of a nest in the home by listening carefully, especially with a stethoscope or some similar listening device placed against walls. The activity of the large ants creates a rustling sound you may pick up on. Have the homeowners noticed any odd sprinklings of sawdust anywhere on counters, floors, or window sills? This is strong evidence of an ant nest above that point. Is there a crawlspace you can inspect, for moisture, ants, sawdust (frass), etc. If so, is there insulation against the subflooring that the ants could be nesting above? I'd suggest that early evening inspection inside and outside, listening into the walls for sounds of ant activity, and the use of baits and Termidor outside in the hope they'll pick these up as they go outside to forage.