Despite the British summertime proving to be something of a washout this year, it doesn’t mean that we get to escape another equally unpleasant aspect of the season: flying ants.
Each summer, there comes a point when flying ants descend without warning – crawling on the ground, flying through the air and generally proving to be a nuisance for those keen to keep the critters at arms’ length.
While the peak of this period tends to be known colloquially as “flying ant day”, it’s actually something of a misnomer, as the appearance of the creatures tends to occur over several days. The peak can also vary depending on where you are in the country.
Regardless of when and where they appear, this decidedly irksome occurrence is an annual event in the UK. Here’s everything you need to know.
When is flying ant day?
As stated above, the term flying ant “day” is not accurate, as the swarming insects tend to appear and peak over a series of days, rather than a single day.
The Royal Society of Biology (RSB) says: “Flying ants often seem to appear on the same day in different locations in the UK – flying ant day. Most ant colonies start with a flying ant – when young queens leave the nest to found their own colony.
“However, our citizen science project, the Flying Ant Survey, has found that there is not actually one day where these ants all appear all at once, but that, depending on weather conditions, the ants can start emerging and flying at almost any point during the summer months, and won’t all necessarily appear only on one day either.
“Really, it depends on the conditions, and ants emerge when wind speeds are less than 6.3 metres per second and temperatures are above 13°C, which can happen several times in the summer.”
But the most likely time for flying ants to emerge is in July or August when there is often hot and humid weather.
Professor Adam Hart from the University of Gloucestershire ran the three-year study from 2012 in partnership with the RSB.
The RSB adds: “One of the primary findings from the survey was that there is certainly not only one flying ant day; the frequency in which the flying ants appear changes each year and is dependent on the weather.
“Colonies also don’t exhibit any significant geographical co-ordination when it comes to taking to the skies; one garden may see flying ants on one day, with neighbours seeing them weeks or even months later.
“During the course of the study, every day in the UK summer that had a mean temperature above 25°C had ants flying somewhere.”
Is there no way to tell?
According to the experts, the weather can be an indicator of their impending arrival.
The RSB study found that swarming is triggered by the weather. It claims that ants only flew on days when it was warm, not windy and conditions had improved compared to the previous day.
There is also anecdotal evidence that flying ant days often occur after some summer rain.
And in July 2023, a swarm of flying ants a mile long was caught on a weather radar on the south coast.
The swarms appeared on the radars and looked similar to rainfall, but the Met Office can check their weather gauges to confirm if it is rain or flying ants.
Simon Partridge, a forecaster for the Met Office, said: “Every year around this time we do pick them up on the rain radar. At the moment it’s harder to tell because we’ve got so many showers and the ants look like showers.
“When we do get the rain, they don’t fly as much.
“It’s generally the southern parts of the UK where we tend to notice it most.
“They can be seen several miles across – they look like very heavy showers. On Friday, it was about a mile.
“They’re an interesting phenomenon and it’s always this time of year and usually over about a week or so.”
Meanwhile, pest controllers Merlin Environmental analysed search data to look at when people are Googling for information on flying ants.
“Flying ants, usually of the species Lasius Niger (commonly known as a black ant), can come out to fly on pretty much any warm, calm day,” they state.
“They only come out when wind speeds are less than 6.3 meters per second and temperatures are above 13 degrees Celsius. These weather conditions are non-negotiable for flying ants.”
According to their research, they conclude that “the vast majority of flying ant activity is generally concentrated over a short time span each July”.
They add: “In July 2023, the UK had three major spikes in flying ant activity. Over the past seven years, all spikes in flying ant activity occurred in the month of July, but the specific date varied from year to year.
“With British summers being quite unpredictable and diverse weather-wise, it’s not always possible to predict when exactly Flying Ant Day will be.
“But using historic data we can determine that July is almost always ‘flying ant month’ across the vast majority of Britain. This is because July always has the highest amount of flying ant activity, as well as major spikes in flying ant swarming.”
Why does flying ant day happen?
The ants leave their underground nests to mate and begin new colonies.
Ant colonies start with a female flying ant that will have left their previous colony to begin a new one.
Mating takes place during flight, and the males will die shortly after.
The fertilised female then lands, chews off her wings, then goes about creating a new colony and producing offspring.
Flying ants are not harmful, so if some emerge in your garden it’s best to leave them alone, and they will disappear after a few hours.
How to deal with flying ants
There are several methods of combat when it comes to coping with the onslaught of flying ants.
The most obvious approach is to keep windows and doors closed or consider investing in fly screens for this time of year.
When it comes to discouraging them from entering your home, it’s also important to keep your space clean and tidy. Like all pests, ants are attracted to sweet and sticky foods, so consider a deep clean and ensure all food is stored properly and securely.
Using natural deterrents is another way to repel flying ants. Orange and lemon peel and essential oils, such as peppermint and citrus, are unpleasant for ants. Consider investing in some essential oil, diluting it with water and spraying it around potential entry points, such as doors or windows.
If you still find that ants are gaining access to your home, it’s worth assessing your property to identify cracks or holes through which they may enter. Seal any potential entry points and review these on a regular basis. This is particularly pertinent if you have an old or wooden-framed home.
If you’re still struggling with infestations of flying ants, it’s worth calling in the professionals to deal with the problem.
Before doing so, it’s important to remember that as unpleasant as these critters are, they have a vital role in nature.
Their tunnelling activities improve soil quality, they provide an important food resource for many birds and they are especially important to the survival of the silver-studded blue butterfly, with whom they have developed a mutually beneficial relationship.