Wicadas spend most of their lives – more than 90% – underground. But this spring, two broods of more than a billion cicadas will make their above-ground debut in the Midwest and Southeast, in an event that hasn’t happened in more than two centuries.
“When these emerge, it really is a natural and unique phenomenon,” says PJ Liesch, director of the Insect Diagnostic Laboratory at the University of Wisconsin-Madison, who compares the emergence of the insects to Monday’s total solar eclipse. “If you think about your entire life, you may only have a few opportunities to see an eclipse. And for these periodic cicadas it’s very similar.”
Cicadas have already begun to emerge in some southern states, including North Carolina and Georgia. The insects, which have been living underground for more than a decade, begin burrowing upward when the soil temperature reaches about 64 degrees Fahrenheit or higher.
“When this happens, you often get a decent amount of rain, which can be a trigger to cause this emergence. So that’s what we’re starting to see in some parts of the US. For us in northern Illinois and southern Wisconsin, it will probably be another month, month and a half before we see most of our activity in more northern parts of the cicada range.
Here’s what you should know about cicadas.
What are the two broods of emerging cicadas?
There are two adjacent broods of cicadas that will emerge at the same time. Brood XIX resides in Alabama, Arkansas, Georgia, Kentucky, Louisiana, Missouri, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee and Virginia. Brood XIII can be seen in Iowa, Wisconsin and possibly even Michigan.
What do cicadas do?
Cicadas have a long lifespan of 13 or 17 years, depending on the litter. There are three species of 17-year cicadas and four species of 13-year cicadas. The insects live almost their entire lives in a soil depth of 8 inches or more, according to Liesch. During the time they are buried underground, they typically tunnel and feed on the sap of tree roots as a food source.
Once they emerge, male cicadas begin buzzing using tymbals attached to the sides of their abdomens. The noise works as a way to attract a mate and reproduce. Cicadas are some of the loudest insects in the world, according to the Centers for Disease Control and Prevention. Other than the high-pitched buzzing sound, however, the insect is harmless to humans.
“After mating, females have a structure called an ovipositor, and what it allows the female to do is go to the branches or branches and make a small crack where she will insert a batch of eggs. There could be around 10 or 20 eggs, and she will repeat this process”, says Liesch. “It’s analogous to if you took a pocket knife and started making little slits in the branches.” Liesch adds that damage to the trees is minimal and doesn’t really affect the long-term health of the tree.
How do cicadas impact the environment?
Experts say cicadas are beneficial to the ecosystem.
“When they emerge from the ground, they are tunneling and if we are in a cicada hotspot, there will be dozens, if not hundreds of holes in the ground in a relatively small area,” says Liesch. “This is very similar to if you have your lawn aerated by a lawn care company and this can allow oxygen to penetrate the soil better. Maybe it can alleviate soil compaction to some extent and allow water to flow better into the soil.”
Cicadas also make a great meal for other wildlife in the area. Turtles, fish, birds, skunks and raccoons like to feast on the insect. Dogs can also eat cicadas, although most veterinarians suggest they only eat a few. Humans can eat them too.
“Also, when all these millions of cicadas die, they will fall to the ground in these areas, decompose, and the nutrients will be returned to the ecosystem,” adds Liesch. “So it’s essentially free lawn fertilizer in those areas when you think about it.”
This story originally appeared on Time.com read the full story
