Some ant pest species only establish nests within the natural environment, while many others are capable of establishing both indoor and outdoor nests. The ant pest species that nest solely outdoors may still enter homes to seek out human food sources or shelter from extreme climatic conditions. Outdoor nesting ants can damage lawn grass by creating unsightly dirt mounds that provide an exit and an entrance into underground nests and foraging galleries. Ant pests that establish nests within homes must first locate an enclosed indoor area that is moist enough to nourish a colony. These indoor areas include wall voids and sub floors located near bathtubs, sinks, toilets and gutters. No matter where an ant colony resides, ant pets tend to invade homes in large numbers during and after heavy bouts of rainfall.
Since ants create nests and complicated networks of foraging tunnels within soil, heavy rainfall can become a serious crisis for the insects. Surprisingly, worker ants expertly build subterranean tunnel networks in a manner that allows rainwater to be diverted into a reservoir, similar to storm drains on city streets. Workers of some ant species plug the holes on their anthills in order to prevent rainwater from flooding into their subterranean nests and foraging galleries. Due to these protective measures, ants generally seek refuge within subterranean nests during moderate bouts of rainfall, but heavy bouts of rainfall prompt ants to seek shelter within homes and other structures.
During heavy bouts of rainfall, some ant species, like Pharaoh ants, relocate en masse to other nesting sites located on higher ground. When rainfall is significant enough to cause flash floods, ants will make a mad dash into homes where they may establish a new satellite nest or simply wait out the storm before returning outdoors. Due to the small size of ants, one would think that they could not possibly relocate to a dry area quickly enough once a storm begins. However, ants possess many sensory organs that allow them to discern subtle changes in the atmosphere. This allows ants to sense oncoming storms in enough time to secure adequate shelter. This is why they tend to appear suddenly within homes at the start of a rainstorm. Even in cases when ant colonies cannot anticipate storms in enough time to seek shelter, their ability to survive a week or more submerged in water makes them largely storm-proof.
Have you ever found ants in your home shortly before a heavy bout of rainfall?