ROCHESTER, N.Y. — While certain breeds of cicadas emerge every year, this spring and summer is the year that Brood X will emerge from the soil across the United States.
This bug is called a periodical cicada that shows up every 17 years (the other periodical cicada is every 11 and 13 years)
We spoke with Cornell Entomologist Jody L. Gangloff-Kaufmann about what cicadas are and what to expect from this year’s emergence. She is a part of Integrated Pest Management.
WHAT IS A CICADA?
A cicada is different from a locust. A locust would be a grasshopper and a cicada is a type of homoctura, related to an aphids and stinkbugs. They are more tropical in the world. There are a lot of different species in the tropics, but we have a few different species here in North America. People are likely to see them every year because there’s a different species that is annual.
What we’re going to see here in the Northeast and the north-central region is this emergence of a 17-year cicada which is what we call Brood X. It’s phenomenal because this group will only emerge every 17 years. There are other groups that emerge on 11 year cycles and on 13 year cycles. What those numbers have in common is that they are prime numbers, so they cannot easily be replicated by other organisms that might, for example prey on them.
IS THAT AN EVOLUTIONARY OCCURRENCE?
Yes, they didn’t pick those dates so much as they developed it as a response to predation. Cicadas don’t have a lot of defenses, so they are among the most favored foods of many animals, birds, and mammals, and other insects. If they can, they do what’s called masting in plant terms. All the oak trees in one area will produce such a huge crop of acorns and that’s called masting. Insects do it to an extent as well. If you flood the area with your progeny, some will survive.
It’s a phenomenon because it’s so distinct and on this strange cycle and there are different groups that are in different geographic areas, different every year, there are something like 15 different Broods with roman numerals for their identity. They emerge in different times and space, so they’re essentially reproductively separated so they’re different.
ARE THERE DIFFERENT BROODS FOR DIFFERENT YEARS?
Every 17 years we will see Brood X, but in 2013 New York State saw Brood II, and that was in Westchester County. We have photographs on our FlikR website where there are hundreds of them in a landscape and dozens on a branch. So Brood II was pretty phenomenal for New York, and Brood X does not look like it will be phenomenal for New York. It’ll be great in Indiana and Pennsylvania and Maryland. We have only a few locations in the north northeast.
Long Island has a small area where they have been spotted, but the last time they were spotted and it was recorded was 1987.
SO IF YOU WANTED TO SEE THEM, YOU’D HAVE TO GO SOUTH TO PENNSYLVANIA?
Yes, and the people who live there will start complaining of the noise and the abundance of these big bumbling insects around. But they are harmless. I need to stress that they are truly harmless. They’re noisy, but they last only a short amount of time.
According to cicadamania.com, the states that will see this Brood are Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, North Carolina, New Jersey, New York (extinct or nearly so), Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and Washington D.C.
It’s probably a good month to a month and a half. Call it four to six weeks. That’s because they will emerge over a weeks time depending on temperatures. By the time you have a peak, it can be extremely loud.
DO THEY DO DAMAGE TO PLANTS?
What they do is they emerge, they don’t feed, but they do find mates and the females will lay their eggs in the tips of branches on trees, so what you end up seeing in a high population is flagging, as if the branch was broken and turns brown on the tip. Maybe the end piece. Does that harm trees? Not really. It’s a sort of pruning in a sense.
When that branch falls down, the nymphs will hatch out of those eggs and go right into the ground. And for that 17 years they’ll feed on the roots of those trees and other woody trees around, but that doesn’t do much damage either. Because their life cycle is so long, they feed and grow very slowly.
WHEN DO THEY EMERGE?
In the southernmost region where they will be emerging which is southern Indiana and below that, they’ll probably start seeing them possibly March, but it really depends on how warm a spring we have. Here where I am I never really see cicadas until about May or June.
Along with cicadas, you’ll get a number of cicada killer wasps which are another phenomenon of their own. They’re among the biggest wasps we have in the Northeast, but I’d like to stress to people that they’re also harmless, and they’re just taking advantage of the large bodied insects that they can feed to their young.
IS BROOD X ONE OF THE BIGGER BROODS THAT YOU SEE?
It is because it has a really wide range in the north central regions, across Indiana and maybe up into Michigan. There’s another population in Pennsylvania and up into West Virginia. Those are really widespread areas so they do see a lot of them there. There are other Broods that are impressive as well.
Image above from Dan Mozgai at cicadamania.com