If you've been in London or the South of England over the past few days, you've probably found yourself accidentally breathing in — and then coughing up — an increasing number of flying ants as the region has been plagued by swarms of the small insect.

"GUYS I just walked through an entire colony of flying ants. They're out!! Remain in your houses, I repeat, REMAIN IN YOUR HOUSES!!" warned one Twitter user.

Every year, the queen ants of colonies all over the region fly the nest to look for a male to mate with and begin a new colony. The end result is vast swarms of flying ants blanketing the region.

It has become known as "Flying Ant Day."

But why do all the ants decide to do this on the same day?

Technically, flying ant day isn't just one day, it can be several days throughout the summer. According to The Independent, there were four flying ant days last year, and it's mostly related to the warm summer temperatures.

Like humans, balmy temperatures put ants in the mood. There needs to be no chance of rain, no predators in the area, and of course, plenty of fertile ants. Global warming, however, has seen ant days arrive earlier and earlier in the year.

This was the state of the turf at Wimbledon, where players have been fending off the small insects. Gareth Fuller/PA Wire/PA Images

To make matters worse, ants don't keep their mating process to a confined space. The males and females all leave the nest at once their wings have developed. The female then separates from the males in order to avoid

The female then separates from the males in order to avoid cross-breeding, and releases her pheromones into the air in order to attract new male suitors. Once a male has paid attention to her, she plays hard to get by flying away, leaving the male ant to chase her down — and us humans to avoid swarms of frisky, flirting ants.

Not surprisingly, people in the south of England aren't taking too kindly to the infestations — and tennis players at Wimbledon were fighting them off on Wednesday afternoon.