TODAY | April 11, 2013
>>> cicada invasion. if you live here on the east coast , get ready because after a 17-year hiatus, billions of cicadas are about to invade.
>> they're going to come crawling out when the ground temperature reaches 64 degrees and when they do, watch out. here's nbc's chief environmental correspondent anne thompson .
>> reporter: periodical cicadas coming back after a 17-year absence. a ritual, buzzing loudly with their siren songs of love .
>> who is making all this noise?
>> only the males make the noise.
>> reporter: university of connecticut researcher says it's the male cicada's mating call .
>> females don't make that sound.
>> reporter: they respond to the racket with a wing flip that sounds like this. even more annoying than the noise of the males are the numbers of both genders.
>> the usual figure we like to quote is several million per acre.
>> per acre?
>> per acre.
>> so we're talking billions and billions ?
>> yes, billions and billions . it's a lot of cicadas.
>> reporter: they will infest the east coast from north carolina all the way up to new york and connecticut. for 17 years, the cicadas have fed under ground near the bases of trees. small holes in the dirt are the first sign of an invasion.
>> what should they be looking for?
>> they'll start to see something that looks a little bit like swiss cheese if they have cicadas. there'll be hundreds of holes like this.
>> in about a four-week span, they'll emerge, shed their skins, become adults and mate.
>> they're going to sing, fly to the tree tops.
>> reporter: the females will lay eggs and both sexes die, but not before driving some people crazy.
>> how loud do these get?
>> these cicadas, a chorus might get to about 90 or 100 decibels and that's comparable to a rock concert .
>> trim the tree branches at your home so they don't get in your windows.
>> in your house? oh, even worse .
>> the last time, people were making soup and jewelry out of them.
>> that's even better.
>> lemonade out of lemons.