For the Birds Radio Program: Cicadas
I was just in Chicago visiting my family on the same weekend that Garrison Keiller did his show from Ravinia, and public musical performance was apparently the order of the day wherever you were. During daylight hours, everywhere I went outdoors, and anytime I was indoors and opened a door or window, what to my wondering eyes, and ears, would appear but a miniature orchestra of tiny but deafening players. This orchestra performs in Chicago every 17 years, and within a few days of the final encores, the performers are all dead. They all play the same instrument, one that is strong on dynamics but lousy on melody. I think this new musical fad is one of the coolest things ever, but night now it’s driving a lot of people crazy. I’m of course talking about 17-year cicadas.
The reason I find these cicadas so charming may well be because I’ve never really experienced them in my day-to-day life. They appeared in 1956, the summer when I was four years old, but we were living in the city then, in a neighborhood densely packed with two-flats and alleys and hardly any trees. The next time they appeared was 1973, when I was 21 and married and living in Michigan. When they appeared in 1990, we were living in Duluth and had children, and didn’t have a chance to visit. So this is the first time I’ve experienced this magnificent event. Of course, I didn’t have to deal with them flying into my house or car, and was there only for a couple of days so had only a few crawling under my clothing and didn’t accidentally sit on one or anything. In a very real way, these guys are like noisy, flying army worms, and so I guess I can understand why people are going bonkers, but really, they don’t seem to cause any harm to anyone or anything during this brief period when they emerge from the soil to sing and mate. According to National Geographic:
“The business of finding a mate and reproducing is the sole purpose of the cicadas’ short existence above the ground. It begins with the males flying to a sunny tree and, with thousands of their buddies, beating out a tune on their undersides.
“…[They] orient themselves to maximize sun exposure, which maximizes body temperature, which allows them to sing more vigorously and louder…
“When a male successfully attracts the attention of a nearby female, she will flick her wings as he finishes his song. A courtship dance ensues, with the male continuing to sing up until the physical act of copulation.
“Shortly after mating, the male usually keels over and dies. The female buzzes off to excavate nests in a young twig for her 600 or so eggs. Once her egg supply is exhausted, the female dies. Six to eight weeks later, the eggs hatch and the 17-year cycle begins anew.”
The 17-year cycle is a lovely melding of mathematics and nature—if any predatory insects became cyclical to capitalize on the huge feast, they’d have to match that 17 years precisely. Had the cycle been, say, every 10 years, insects that had either a 2- or a 5- year cycle would always be present during the cicada emergence. Weren’t they clever to adopt a prime number?
When the new babies, called nymphs, hatch and crawl out of their twigs, they fall to the ground, where they start burrowing, first grubbing on grass roots and then tunneling about 12 inches deeper to where they feed on small tree roots for the next 17 years. Then they tunnel back up for their chance for romance and reproduction before they die. It’s not much of an existence, or is it? They’re once of the longest lived of all insects, and if they spend the vast majority of their existence underground, munching on juicy roots, they do get to emerge in time for a huge celebration of music and mating before they give up the ghost. Army worms should have it so good.