- Education and Science
Hey, Eastern U.S. Here Comes 2013's Edition of The 17-Year Cicadas
This Year They Promise To Outnumber People 600 to 1
When I was a kid we called them heat bugs, because it seemed like you only heard them on hot summer days. I loved the sound then, and still do. It’s a summertime sound.
But in researching this column, I learned that I’m probably the only person on the planet who likes the loud buzz of (drum roll, please) The Cicada.
Actually, it’s the periodical cicada, also known as Magicicada, which has a life span of 13 or 17 years, depending upon the species, and is found only in the eastern part of the United States. Four species of periodic cicadas have the 13 year lifespan while there are 3 that have a 17 year lifespan.
In each case, all but a few weeks of those years are spent in total darkness, underground, sucking juice from the roots of trees and shrubs. Oh, and they also molt four times during that period, growing from the size of a small ant to almost adult size. Other than that, it’s a pretty dull life.
But then, after their 13 or 17 years underground, they get their time in the sun. Actually, their initial time is usually in the moon since they normally emerge after sunset.
The time of emergence is thought to be a function of soil temperature, and 64 seems to be the magic number.
Those cicadas in the southern portion of the territory start emerging in April, while in the north they emerge in May and June.
In a pretty much synchronized mass emergence, they crawl out of the ground as wingless nymphs, ascend into the trees, and molt one last time.
Their exoskeletons split along the back; and red-eyed, winged cicadas crawl out of their old skin right before your very eyes.
They’re sort of white at this stage, but get dark quickly as their new exoskeletons harden, a process that takes from 4 to 6 days to complete.
They'll only live for a few weeks above ground, and during that time they’ll feed on the twigs of trees and bushes. And they'll mate. That, after all, is what all the buzzing is about.
The males will "sing" their courtship song to arouse the females, and it works very well.
When enough of the cicadas feed on the same plant, they can cause damage. Damage is also caused when the females cut multiple series’ of Y-shaped slices into the twigs. Each forms a nest in which they deposit around 20 of the 600 or so eggs they’ll lay.
The mouth parts that enable them to eat woody plants can also deliver a pretty good bite, but they only bite if you try to handle them.
They’ll usually fly away when approached and the males, in an attempt at intimidation, will sometimes emit their loud buzz, which is normally reserved for getting the females of the species all hot and bothered.
After completing their reproductive duties, the adults will die. You’ll sometimes see huge numbers of bodies littering the ground beneath trees.
It takes from six to ten weeks for the eggs to hatch. What hatches is the life form entomologists refer to as the first-instar nymph. These little guys, about the size of a small ant, drop to the ground and burrow in.
They find a nice, juicy root that will support them for the next 13 or 17 years and hunker down for an exciting life of metamorphosing, molting and sucking root juice in the dark.
Not all cicadas are periodical cicadas. There are annual species as well, which is most likely what I was hearing while growing up in the suburbs outside of Boston.
Except for 1957, when Massachusetts saw Brood XIV emerge. I was 11. The last time we saw Brood XIV was in 2008, so we’re not due again until 2025.
The periodical species are divided into numbered broods. The 2013 crop of 17-year periodical cicadas, known as Brood II, will emerge for the most part from Virginia north to Connecticut.
When these guys went underground as first-instar nymphs, Bill Clinton was in the White House. We won’t see their offspring until 2030. Any bets on who will be occupying 1600 Pennsylvania Avenue then?
The next crop of 13-year periodical cicadas won’t be seen until 2014. That will be Brood XXII emerging in Louisiana and Mississippi. Also in 2014, the 17-year Brood III will emerge in Iowa, Illinois and Missouri.
There are a couple of extinct broods, too. Brood XI last appeared in Connecticut in 1954, while XXI last appeared in 1870 in Florida. Brood II has replaced XI in CT, but FL remains Magicicada-less.
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Some Pretty Impressive Numbers
Why 13 or 17 year cycles? Contemporary wisdom suggests that it’s so predators can’t anticipate the cicada's emergence and adapt their own reproductive cycles to take advantage of the incredibly dense banquet, which scientists estimate could be as high as 1.5 million cicadas per acre.
They figure Brood II could contain anywhere from 30 billion to one trillion insects, outnumbering people 600 to 1.
This density also enables what is known as predator satiation; a phenomenon where predators apparently can eat their fill without decimating the population.
Cicadas are preyed upon by natural predators such as birds, snakes, spiders, raccoons and coyotes, and also by opportunists like cats and dogs.
A lot of folks refer to Magicicada as 13 year or 17 year locusts, but that’s not accurate. Locusts are members of the grasshopper family.
Anyway, I’ll just have to be content with enjoying the buzz of the occasional annual cicada I'll hear each summer until 2025, when Brood XIV emerges. I’ll be 78. I just hope I’m on this side of the grass when it happens.
FIND OUT WHEN YOUR BROOD IS EMERGING
If you'd like to know when you can expect your region's brood to emerge, the web site, Cicada Mania features a detailed brood chart. It shows what states make up each brood's region and what year those broods will emerge. You'll discover a lot of additional and interesting information and features to enjoy. Here's the link:
- Are Periodical Cicadas Coming to Your Town - Magicicada Broods and Brood Maps
How to determine if Magicicadas (Periodical, 'Locusts') will emerge and when they will emerge in your area, including Brood Maps