Every year around Labor Day, swarms of flying ants begin appearing all over west Michigan in huge droves. For the next couple days, they’re flying around everywhere. You might even remember the infamous “flying ant day” of 2017, when the swarms descended on Detroit. Then, as mysteriously as the ants appear, they seem to vanish without a trace.

What are these winged ants, exactly? Where did they come from? Where do they go after they’re done darting around all over the place? Most importantly, are they going to try to infest your home this fall? Here’s everything you should know about the enigmatic winged ants you’re seeing this September.

What are they?

The flying ants that you’re seeing right now are the reproductive swarmer (or alate) variety of yard ants. Yard ants are related to carpenter ants, but they nest in the ground instead of chewing through wood. Swarmers are around ¼ to ⅜” long, look reddish brown, and have a hump between their heads and thoraxes. They look like normal ants in every way, except that they have wings. Swarmer wings are clear and translucent. They fold behind the ants’ backs when the ants aren’t flying.

There are more than 50 different species of common yard ant native to Michigan. The ant swarms you’re seeing represent many different types of species that all become active this time of year. Different swarms come out at different times, which is why it seems like the swarming doesn’t stop for days. You’ll often notice swarms seem to gather or even collide in midair and then begin moving as a group.

why do flying ants show up in Michigan every fall around Labor day?

Why are they here?

Flying ants exist for one reason: to reproduce. Alates spend most of spring and summer inside their ant colonies, where they’re fed by workers. In late summer and under the right conditions, they fly out of the nest to seek mates. The ants require high temperatures and humidity and clear, sunny weather without much wind to begin swarming. They’re particularly prone to begin their swarming on the first clear day after several days of rain.

Most yard ant species reproduce around late summer because that’s when their ideal swarming conditions happen. Ants also tend to begin reproducing in late summer to prepare for winter. When conditions are just right, many different species’ will begin the mating process all at once. Although late summer reproduction is most common in Michigan, other ant species may swarm at other times of year. Some flying ants swarm in spring, fall, or even mid-summer.

What are they doing?

Flying ant swarms are either actively mating or in the process of seeking out mates. Flying ants mate in midair in a process called “nuptial flight.” On “flying ant day,” unfertilized flying queen ants (sometimes called “princesses”) leave their colonies and begin secreting attraction pheromones. Male and female alates purposely fly away from their nests to help ensure outbreeding. The pheromones secreted by princesses attract nearby male reproductives (sometimes called “drones”).

Princesses actually often fly away from males, forcing them to pursue her in order to mate. The swarms you see are groups of male drones pursuing one of these princesses. Mating itself occurs very quickly and in midair. Male drones die very soon after mating. The fertilized female will fly to the ground and begin making a new nest. Soon after, she will lose her wings and begin laying eggs. The first of these eggs will hatch into workers, who will lay the foundations for a new colony.

are flying ants dangerous?

Are they dangerous?

No. Swarms only have mating on their mind. They won’t bite, sting, or attack you. Swarming ants aren’t aggressive, territorial, or defensive in any way. Even if swarms appear to be flying right at you, it’s only because they’re pursuing a princess. Swarms are more-or-less totally uninterested in people, though they may congregate on human structures. Swarmers may also accidentally flutter into buildings through openings like cracks and crevices.

Yard ants can’t make their nests indoors. To form a nest, a fertilized queen must dig into soil. Queens may build their nests near your home, however. Often, ants build their colony sites near human structures because of the natural cover they provide. Queens are particularly vulnerable when they start building nests, so they may seek cover and darkness near your home. When yard ants establish colonies near you, you may encounter their foraging workers inside your home. These workers aren’t dangerous, either, but they could be annoying.

Despite how frightening it can seem, swarming season is nothing to worry about. Flying ants aren’t dangerous, and they’ll die off and disappear very soon. If you’re very bothered by ant swarms this year, we recommend staying inside whenever possible while swarms are active. Luckily, you won’t have to wait long until they pass.

Swarms may be more-or-less unavoidable, but that doesn’t mean ant infestations must be. If you have an ant problem in your home, give Griffin a call any time. We’ll find out why you have ants, where they’re coming from, and how to stop them.

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