By Tracy Leskey
Want to see people’s eyebrows raise? Tell them you are en entomologist, aka someone who studies bugs, in the summer of the “cicada invasion.”
According to the Peterson’s A Field Guide to the Insects, “Entomologists fall into two categories: those who find insects endlessly fascinating and those who would get rid of them.” To put the Peterson mantra another way, there are those who say “cool” when they hear about my job and those who try to hold back their “ewww” reaction.
Despite my passion for bugs, I, too, spend a great deal of time battling serious pests. In my case, the invasive stink bug dominates my research. If you’ve ever had them in your office, house or orchard, you understand exactly why we need to spend more time studying them and learning how to deal with them.
When the discussion of the “2013 cicada invasion” began, I thought back to my first encounter with cicadas as a teenager in 1982. (As a refresher, that year watching Saturday morning cartoons like The Smurfs and the movie ET were totally cool ways to spend your time.)
For me, however, the most memorable alien encounter of 1982 was with cicadas, likely belonging to Brood V (how’s that for a movie title?). Cicadas that emerge in the same region during the same year belong to a certain “brood”. To give you a feel for the variety of periodical cicadas, there are at least 12 different 17-year broods and four different 13-year broods in the United States. Any budding scientists reading this can try to identify the brood and report a citing in their area on this great website: magiciada.org.
What struck me back in the summer of 1982 was that these cicadas were actually older than I was at the time. They were born during the summer of 1965, while I came along three years later in 1968.
Based on their sudden and spectacular appearance that summer, it seemed like these bug-eyed “sleeping beauties” had been awakened from some sort of magical spell. Coincidentally, the scientific genus to which our periodical cicadas belong is Magicicada. However, there was no magic (Harry Potter-esque or otherwise) involved, and they were not sleeping all those years.
During their time underground, cicadas literally grow up. They feed as nymphs – the juvenile stage – using a straw-like mouth to suck sap from plant roots. After their nearly 17-year subterranean stint, mature nymphs begin to dig their way to the surface to wait. What were they waiting for? The soil temperature to reach about 64F (17.8C) – much like waiting for the water in a pool or the ocean to be warm enough to swim in during the summer. After they receive their signal to finally take the plunge, cicada nymphs burrow to the surface, often under cover of darkness, to emerge from their underground world.
After crawling up tree trunk or a fence post, they molt one last time, and that’s when many of us start to really notice them. Their old exoskeleton splits open to be left behind, while the young adult emerges. I can tell you from experience that collecting the abandoned brown, crunchy exoskeletons and placing them inside the sleeping bags of friends can be a very fun endeavor. Some of my less-entomologically inclined friends beg to differ, although they had plenty of years to get over it before the cicadas came back.
If you or your children actually take some time to look at cicadas, you will start to notice some “cool” features. Most cicadas have very conspicuous red eyes. However, a few have bright blue, white, yellow, or even multi-colored eyes. In 2004 during the great Brood X emergence in the eastern US, I spied a blue-eyed male on a young apple tree and quickly plucked it from a branch to show to my staff. The male, of course, was none too pleased with his imprisonment in my hand and made some serious noise, so I immediately let him go.
Later that month, I heard a rumor that a boy was able to sell a blue-eyed cicada for $10,000 on eBay and more recently, tales have persisted regarding scientists paying rewards for these unusual specimens. As far as I know, these are only rumors. So, if you have the good luck to come across one of these unique individuals, admire the genetic variation, but don’t expect to make a small fortune.
Males do make a lot of noise. They literally have a pair of built-in drums called tymbals at the base of their abdomens. The sounds they produce are made by tiny ribbed membranes powered by muscle contractions and amplified by the males’ hollow abdomen. Although it may sound like a cacophany to us, it is sweet music to female cicadas. These reverberating beats are actually songs used by males to attract females for mating. After mating, females begin depositing eggs in punctures they make in the tips of twigs of woody plants and trees. These eggs hatch and eventually those small nymphs drop to the soil where they will remain for almost 17 years.
The adults, however, serve as super summer all-you-can eat buffet for everything from birds, fish, snakes, and even predaceous insects like cicada killers wasps.
My advice is take the time to admire these spectacular “senior citizens” of the insect world. It’s going to be a very long time before the magic of Magicicada return again to your neighborhood.
Tracy Leskey is an entomologist at the United States Department of Agriculture’s Agricultural Research Service. She is an editor for Environmental Entomology, and in 2001 she won the Entomological Society of America’s John Henry Comstock Award. Dr. Leskey is an expert on the brown marmorated stink bug, an invasive insect pest of fruits and vegetables. You can see more of her in these videos on the BMSB. Follow her on Twitter at @BMSBresearch.