So where do all these insect-eyed beasts come from? How do they know how to arrive at the same time? And should we be afraid? KidsPost asked Matt Kasson, a scientist who studies cicada diseases at the University of West Virginia.
The first thing you need to know about cicadas is that they are harmless.
“They don’t really have any tusks,” Kasson says. “Their only defense is their numbers.”
Kasson said that while there will certainly be billions of cicadas buzzing shortly, the real number could be “in the hundreds of billions, maybe even growing into the trillions.” But having a lot of cicadas is probably also the reason why they never developed the ability to bite or sting.
“They fill virtually every predator on the planet when they emerge, so that every bird, snake and fish within range gorges on cicadas, and yet there will still be plenty left to linger,” he says.
This group of cicadas is officially known as Brood X (X is the Roman numeral for 10). You might think they’re newborns, but these bugs are older than you. This is because they have been hiding underground for almost 17 years.
Kasson explains that cicadas undergo a metamorphosis (change), much like a butterfly, but they do not have a larval or caterpillar stage. Cicada eggs hatch into nymphs, which spend more than a decade underground sucking the juice from tree roots. Then they come out of the ground, climb a tree trunk and turn into adults with wings. (When emergence occurs, you will be able to collect tons of cicada exoskeletons, or seashells, which remain from the transformation. If you are brave enough, you can hold the adults as well. Be gentle.)
Adults live four to six weeks. During this time, they will mate, and the females will lay eggs in tree branches. By July, the adults will be gone and the nymphs will begin to fall to the ground to burrow into the ground.
There are two reasons why so many cicadas appear at the same time. First, nymphs can count, and they keep mental notes of how many years have passed by the starting and stopping of the tree sap that occurs each winter. They are also temperature sensitive and will wait until the ground reaches a comfortable 64 degrees before going outside to mate and lay eggs.
While some people don’t like the look of cicadas, Kasson says it should be cause for celebration. Periodic cicadas, which we call the varieties of cicadas that emerge in huge batches every 13 or 17 years, only occur in the United States.
“So I would say I’m just amazed that you are witnessing something that no one else in any other part of the world can see,” Kasson says. “And it’s right in your garden.”