After a long silence, one of the largest broods of Cicadas in Virginia is coming back. Brood 2 has been
slowly growing under ground for the past seventeen years and for people who are anywhere near them, it might get loud. Robbie Harris has more.
Like any brood of seventeen year olds finally out on one of those first spring days, the Cicadas raise quite a ruckus. Eric Day, manager of the Insect ID lab at Virginia Tech, says, “The ones that are making the noise are the males so it’s the boys calling for the girls. When you get a area with a big emergence of cicadas you can get densities up to a million per acre so figure half are males you can see how the noise gets to be virtually deafening when you get these large numbers of them. On the side of their body they have this drum like structure called a tymbal and they vibrate the tymbal at a very fast frequency to make the noise.”
Cicadas are found nowhere else but the eastern half of the United States. They are surely some of the best timekeepers of the insect world, somehow counting the warming and cooling cycles each year until they get to their magic number; a number that is different for each brood. But even after waiting all that time, they won’t come out until the temperature of the surface soil reaches 64 degrees.
Eric Day: “Initially they’re pale. So they’re white with red eyes, very striking, and then later on as the skin begins to thicken and harden it turns essentially black so you have these black insects with red eyes -and orange wings and orange legs, very distinctive, not much you would not confuse it with.”
This year, one of the largest broods will be back, showing up in much of Central Virginia.
Eric Day: “Brood 2 covers probably the biggest geographical areas, but it tends to be areas with low human population density, so not as many people interact with it. On comparison with that is brood 10 which most recently came out in 2004 and that hits northern Virginia and other places that are high population density like Baltimore, Philadelphia, New York. So brood 10 tends to really get in the news because it tends to impact a lot people."
Any large number of insects can pose problems. They don’t bite people, but Cicadas lay their by burrowing into small twigs which can damage trees. For the birds, their arrival is like an invitation to an all you can eat buffet. To Eric Day, Cicadas are kind of a celebrity species of the insect world.
Eric Day: “I think they’re an amazing insect but you have to temper that because it is a pest for fruit growers and they have to deal with it damaging their trees, but I think overall this insect is a pretty neat one because it has a lot of interest to non entomologists. It’s a gateway where people develop an interest in insects and coupled with their unusual life cycle and these huge emergences it overall becomes a pretty neat insect.”
Maybe it’s their serenade which punctuates the spring air as it takes you back to where you were the LAST time the critters came out, but you just have to admire any species that could show up on time for a date after seventeen years.