Paper wasps swarm in the fall

Wasps can be irritating when they swarm and build nests under porch overhangs or inside thick shrubbery, but they are beneficial - wasps eat other insects, including pest caterpillars, flies and beetle larvae. They are usually gone after the first frost.

Last week, a gentleman who works at Fort Gordon called to tell me about a big swarm of wasps around a water tower. He said he had never seen so many in one place. I told him it was fairly common.


We are all familiar with wasps, specifically the paper wasp. Most of us are scared of them and don’t want to get stung, but they are actually beneficial insects in their natural habitat and are critically important in natural pest control.

Adult paper wasps feed on other insects, including caterpillars, flies and beetle larvae. They are considered beneficial by gardeners because they are predators of pest caterpillars.

Though these insects can produce a painful sting, they are not really aggressive. They generally attack only when their nest is being threatened, so it’s best to avoid their nesting sites.

Problem is, we don’t know always know where the nest is until it is too late.

They will usually build underneath something such as a porch ceiling or window sill. Many times I have had them start a nest underneath the top rail of my deck.

Many years ago, I was walking behind somebody and we came upon a fairly large bell. He rang it and out came a swarm of wasps. Fortunately, I was faster than some of the other people!

You also have to be careful during late summer and fall when pruning thick shrubbery as they love to build nests in there, too.

The paper wasp gets its name from the appearance of its nest, which is composed of wood fibers held together by saliva.

Wasps have a life cycle of complete metamorphosis, which means what hatches from the egg looks nothing like the full-grown wasp. A mature nest can house anywhere from 20 to 30 adults at once.

In the nest, the queen lays a single egg inside each cell. The egg hatches in about two weeks, producing a legless, grublike larvae. The workers feed the larvae chewed up caterpillars and nectar. The sex of a wasp is determined by whether or not the egg is fertilized. Adult males are produced from unfertilized eggs, and the queens and sterile females come from fertilized eggs.

The entire life cycle from egg to adult takes about two months.

Going back to the question from Fort Gordon, paper wasps show swarming behavior during the fall. This behavior is connected to mating. Male wasps look for the best places to hang out and attract females. On warm days during the fall, the future queens become active and fly about. Dozens or hundreds might be seen around towers or upper stories of buildings or any tall structure.

Males locate a good perch on which to sit and become somewhat protective of this spot as they release odors (pheromones) to attract a female wasp for mating. It is not totally understood why tall structures are attractive to the wasps or why they choose certain structures over others. Structures might substitute for tall trees or rock formations, especially in relatively flat land.

It is common for a house that stands taller than others in the neighborhood to have wasps swarming about while there are none at any of the neighbors’ homes.

Last week, I got an e-mail from a lady in the Summerville area of Augusta asking what to do about “hornets” swarming around her chimney. I’ll bet she had the tallest house on her street.

Communication tower climbers, grain bin workers, fair employees and others with jobs that take them atop tall structures might be uncomfortable with all the wasps swarming around them, but there is a very low threat of being stung. The wasps are too busy mating to pay attention to a human.

Sometime after mating, the males die and the females seek shelter for the winter.

Fertilized queens overwinter in cracks and crevices of structures or under tree bark. They select a site and begin to build a nest in the spring to start the life cycle over again.

You don’t have to worry about wasps too much longer, as they will be gone after we have a frost or two. The queen will have found her overwintering site and the remainder of the colony does not survive.