Facts About Cicadas Before Brood X Emerges Around the U.S.

Trillions of cicadas are set to emerge from below ground in more than a dozen U.S. states in May and June, in a rare and remarkable natural phenomenon that promises to be both visually spectacular as well as an assault on the ears.

Where do cicadas live?

Brood X contains three species: Magicicada septendecim, Magicicada cassini and Magicicada septendecula.

They are collectively known as periodical cicadas, because they spend almost the entirety of their lives underground, only emerging after either 13 or 17 years, and they're only found in North America.

From around mid-May to late June, the insects will pop up in Georgia, Kentucky, North Carolina, Virginia, and Tennessee in the south east and south, and Illinois, Indiana, Michigan and Ohio in the Midwest.

The northeastern and eastern states of New Jersey, New York, Pennsylvania, and West Virginia will also see the bugs, as well as Delaware and Washington, D.C., in the mid-Atlantic region.

Once above ground, these cicadas only live for up to four weeks, the majority of which they'll spend in trees, trying to attract a mate.

After mating, the females deposit their eggs on branches.

The adults then die off in their trillions, and when the eggs hatch the baby cicadas make their way into the soil, where they will spend the next 13 or 17 years of their life.

What do cicadas eat?

Cicadas do not have mouthparts for biting. Instead, they have a beak, and feed by sucking a fluid called xylem out of the roots and branches of plants and trees.

Xylem transports water from a plant's roots to its upper parts, but it also contains amino acids and minerals.

Young cicadas tend to feed on the roots of small plants, such as grasses, while nymphs can move onto more robust tree roots.

Only as adults do cicadas emerge from below the ground to feed on branches and twigs.

How long do cicadas live?

Periodical cicadas live for either 13 or 17 years, depending on the specific species.

That's an extremely long life cycle for an insect. Some other species of cicada only live for between 2 and 4 years.

It hasn't yet become clear why periodical cicadas stay underground for such a long time, but the fact that 13 and 17 are prime numbers has fascinated researchers.

One common theory is that both their long lifecycle and living underground have made it difficult for predators to evolve to target periodical cicadas specifically.

However, after emerging from ground, these cicadas typically only live for up to a month.

Why and how do cicadas make noise?

Cicadas are well-known for the loud and unusual noise they emit when they're above ground, which can hit 100 decibels.

It's commonly compared to buzzing, rattling or clicking, and it's typically associated with adult males trying to attract a mate, however, it can also be used to communicate distress and establish territory.

They make the sound by flexing a set of organs in their abdomen called tymbals.

Cicadas can also make sounds by flicking their wings, but this is very different to the buzzing.

Cicadas covering a tree's leaves
Trillions of cicadas are set to emerge from the ground for the first time in up to 17 years across the U.S. in May and June, in one of nature's most unusual phenomena. iStock