This ant obviously gets its name from the fact that they are found in the Pacific NW in locations with high moisture content. It is also known as the cornfield ant because it is closely associated with the corn root aphid. We like to refer to them as moisture ants because when we find them they have been in advanced damp rotting wood. It just makes far more sense to us in our business.
Not only do these ants start infesting in advanced damp rotting wood, but they also bring in more moisture themselves. One location they are known to be in because of the notorious moisture problems is in bathrooms behind bathtub wall, tiles or in the bath trap. Tile looks great, but you can't see behind the tile to know if you have a moisture problem. A serious moisture meter is able to detect if you have a problem. The obvious way to know is when you have tiles coming loose and falling off your wall. Another area is underneath the toilet when the wax ring fails and moisture seeps into the subfloor.
Inside they feed on sweets and meats, including insects. Outside they tend honeydew producing insects, feeding on dead or live insects and gather nectar.
This type of ant has only one queen in their colony and they mate in the nest before swarming, which can happen July through September. Queens lay eggs the following spring.