Billions of bugs to burst from the ground for first time in 221 years

Billions of insects are set to emerge from the ground this year.

You may be familiar with cicadas and their habit of suddenly emerging from underground in huge numbers every few years.

Well, this year is set to be a little bit different for the cicadas of the world.

Even under normal circumstances the insects emerge in masses, but this year could see billions of them appearing.

So why are there likely to be so many cicadas this year in particular?

Well, it's because in a regular year you would only have one brood of cicadas emerging, but this year there will be two - Broods XII and XIX - for the first time in the US in 221 years.

Why such a specific time? Because cicadas have a propensity for prime numbers, normally emerging once every 13 years or 17 years.

This means that predators can find it difficult to keep track of them, and they are less likely to synchronise.

In fact, the 13 and 17-year cycles last linked up 221 years ago.

Creative Touch Imaging Ltd./NurPhoto via Getty Images

Mathematician Professor Hannah Fry said in a TikTok video: “Thirteen years and 17 years are special because they’re both prime numbers, which means it’s really hard for a predator to have a cycle that syncs up with them.

“Also, they almost never synchronise with each other - 13 and 17, kind of missing each other - apart from every 221 years.”

So rather than just one brood of cicadas coming out we will have two enormous groups, meaning seemingly apocalyptic levels of cicadas.

The cicadas will emerge from the ground, shed their exoskeletons, and take to the skies to mate - but a mind-altering fungus could crash the party for some of the insects.

Matt Kasson, an associate professor of forest pathology and mycology at West Virginia University, told NPR that the fungus Massospora cicadina causes cicadas 'to be hypersexual and to have prolonged stamina and just mate like crazy'.

The nasty Last of Us style parasite spreads through attempted mating, and causes the cicadas to keep trying to mate even after their genitals have fallen off. Yikes.

It only affects 13 and 17 year cycle cicadas, so poor Broods XII and XIX might be in for a pretty grim time.

mikroman6 / Getty

The last time 13 and 17-year broods of cicadas both emerged in one year was 1803, less than 30 years after the signing of the Declaration of Independence.

1803 was a historic year for the US, as it was the year of the Louisiana Purchase when the States bought 530 million acres of land from France for $15 million.

This massively expanded US territory westward, though many states including Texas and California were still not in the union.

When the cicadas last came out like this, Thomas Jefferson was the US president and the Napoleonic Wars were about to kick off in Europe.