[Insect Control] Takins Swarms by Storm

If you’ve ever found yourself in a sudden swarm of insects, you might have been alarmed and wondered what was happening. This phenomenon called "swarming" is a natural and normal occurrence in the insect world.

From time to time swarming happens when large numbers of social insects leave their nest and move to other locations. The insects most commonly associated with this swarming behavior are termites, ants and honeybees.

Other insects may appear to swarm, but that occurrence is most likely a large number of adults emerging from the pupal stage to the adult stage all at once, or a large number of adults simply taking flight at the same time. Common examples of a mass adult emergence would be midges and black flies.

True swarms are usually associated with a portion of an insect colony leaving to start its own smaller group, or adults taking flight all at once for mating purposes. Swarms are triggered by environmental factors (i.e., temperature, humidity or sunlight), pheromone production, population pressure and the innate, natural urge that all living creatures have to reproduce so their species survives. (Pheromones are chemical secretions insects produce to communicate between one another.)

While swarming is an act of nature, service technicians can keep pests outside of customers’ home or facility. Here are some common questions and answers when it comes to insect swarming.

Q: Can swarming be stopped? a: Physically excluding insects can stop a swarm from appearing indoors. Using sealants like a joint or caulking compound in cracks where ants enter may stop the swarm from appearing inside. Chemical sprays applied in these cracks and on surfaces where ants could land after swarming will kill these individual insects, but will not stop the swarming activity from taking place. Sealing these swarming avenues will stop the swarm from appearing or will force the swarm to appear elsewhere — hopefully outside.

By practicing population elimination or reduction, swarms may be delayed or eliminated, but the most effective method of social insect population reduction involves using insect baits. By using baits that typically work slowly, the foraging workers are allowed to bring the toxicant back into the nest and reduce or knock out the colony.

Q: What can be done after swarming insects fly inside?

a: When adults fly inside after a swarm, flying insect aerosols can be used to knock swarming insects down. Care needs to be used and the area should be evacuated before spraying anything into the air. (Follow label instructions at all times to make sure pesticides are used properly.) A vacuum can be used to pick insects out of the air. Illuminated light traps can sometimes be helpful in removing large numbers of swarms of some species.

Q: How do insect swarms occur?

a: Your customers may wonder why they’re experiencing insect swarming now when they have never experienced this problem in the past. This is because populations sometimes have to build up to a critical mass in order to initiate the swarming behavior. This can take years to occur in some species and is difficult to predict.

Environmental conditions also change from time to time and conditions may not have been optimal to trigger swarming in previous years. In addition, structures age over time, and cracks and gaps may develop and allow a swarm to invade and area that previously was excluded.

The author is technical director, Waltham Services, Waltham, Mass. He can be reached at rberman@giemedia.com.