No Wonder They Make Such A Racket!

The sound is pervading, it’s unrelenting . . . surreal. Heard from a distance, one imagines some kind of industrial equipment humming along; or maybe a mass cheer from a far off football stadium—a cheer that doesn’t end. Up close, it sounds  like thousands of rattlesnakes in the trees.  It’s been thirteen years in the making and now one month of noise-making. We’ve been invaded by the Thirteen Year Cicada.

The love calls begin at daybreak and end at dark . . . until the next daybreak when it starts all over again. Unless you happen to hear an individual cicada (a.k.a. “locust”) zip by or on a branch just above you, what you hear is the mass of cicadas—all doing their thing at once without a break.

Julie and I recently took a jaunt down to our creek to look at some wildflowers. We began to notice the classic empty “shells” of locusts on tree trunks and plant leaves.  But it wasn’t the occasional ones that you see every summer in the Ozarks. They were everywhere! And a couple of days later the noise started. It is so constant that the mind unconsciously ignores it—selecting it out as unimportant background--until someone points it out to you. And then you hear it and you are amazed. And it doesn’t go away.

Finally, I saw a live one on our picnic table. The most striking feature is the almost glowing brick-red eyes. I didn’t remember our regular locusts with those eyes. A quick internet search told me that this was not the regular Dog Day Locust that we have each year (so called because they emerge during the hot, dog-days of July and August). This was the first week of May. I determined by its markings that we had Magicicada tredecula. There are basically three species of periodical or cyclical cicadas in the U.S. All three species have a 13-year and a 17-year version of the same insect.

Weirder than those eyes is the fact that these little guys and gals have been waiting since 1998 for this big moment. One month of non-stop flirting and mating. (They do stop at night, apparently, but non-stop in the sense that apparently the adult stage doesn’t even bother to eat) They’re here for one thing only. The noise is from the massive congregation of males calling to the females, trying to attract a mate--like thugs catcalling and talkin’ trash at the girls walking down the street. Check out a wonderful video short  from the BBC with David Attenborough of Planet Earth fame.

The males have two little flaps on their segmented bellies covering a hollow chamber. Stretched across the Inside of the chamber is a thin membrane like the skin of a drum, with muscles that it can use to vibrate the drum to make its sound. The female, on the other hand, has no such structure; she only makes a clicking sound with her wings to indicate that she is hot to trot and likes what she hears from her bug-eyed Romeo. After they mate, she uses a saw-like appendage on the end of her belly to cut a couple of slits into a nearby tree stem. She then lays her eggs in a neat row in each slit.

Dime-size emergence holes under our water oak tree.

The eggs will hatch after a few days, and tiny larval versions crawl out of the slit and drop to the ground. They burrow about one foot deep into the earth and start sucking sap from tree roots for the next thirteen summers, buried in the dark, not hearing a sound. God only knows (I mean that literally) how each cicada knows when the thirteen years are up and it’s time for everyone to emerge again.

Geographic range of Brood XIX

It turns out there are different groups or “broods” of these bugs around the country. Each brood might be dispersed over many states in the Upper South and Midwest. Another brood may only be in a couple of states on the Atlantic Seaboard. All of the individual cicadas of a certain brood emerge at the same time: every thirteen or seventeen years, depending on which brood. Ours is Brood Nineteen (XIX) which stretches from the Gulf Coast to Indiana and from Oklahoma to Virginia. [map from Cicadia Mania] The last emergence was in 1998; the next will be in 2024—clean as clockwork. There is a brood of 17-yr cicadas in New England which were first noted by European colonists in the early 1600’s. Four hundred years later the same brood is still emerging every 17 years. They’ve been doing that, no doubt, since the last glaciers retreated from New England ten thousand years ago or so.

Thirteen summers … thirteen winters … thirteen springs and falls … that’s a long time to wait for . . . well, you know. No wonder they make such a racket!

[all photos by Bob Holland; first video by Julie Holland]