17-Year Cicadas

17-year cicadas

The Sound

The noise is shocking. The intense background hum of thousands – millions? – of 17-year cicadas humming their love song.  As I move away from the parking lot at Highbanks Metro Park in Ohio, the sound fades.  I’m used to the rising drone of the annual cicadas culminating in a pulsing alarm-like rhythm.  The sound of this single insect is the sound of summer in Illinois.  However, there are no discernible individual songs for these periodical cicadas, just an unreal cacophony of white noise. (Turn your sound up for the video).

 

A wide rolling path leads me through a mixed hardwood forest, past shale-lined creeks, to the Olentangy River overlook high above the bank. The sound of cicadas has completely faded away deep in the woods.  However, I can tell when I’m approaching a clearing as the din of the insects ramps back up again.

The Lifecycle

The 17-year Brood X cicadas (Magicicada) started emerging in this area last week.  Once the ground temperature warms to 64 degrees, the nymphs begin to emerge from their subterranean homes. They bore up through the soil at night, seeking the nearest vertical object where they will transform.

https://youtu.be/YyvL7W1vP0I
All of those dark circles are exit holes from the nymphs. Their carcasses are piled at the base of this big oak.

Their back splits down the middle like the Incredible Hulk bursting out of containment. The soft, vulnerable white insect peels out of its seventeen-year shell. Its body hardens in the air turning matte black.  Their folded, dark, mangled wings unfurl to purely translucent flight.

17-year cicadas
Newly emerging adult

Their hard shell is made of the same stuff (chitin) as shrimp, lobsters, and crab shells, prompting the caution that those with shellfish allergies not eat them. Also, like fish, they are high in mercury, so don’t overindulge. As if I needed a reason!

17-year cicadas
Empty shell

Only the males sing. The females are silent. After mating, the Magicicada lays two to four dozen eggs in the split bark of a tree.  The 17-year cicadas have to make the most of their few weeks above ground, so they will mate many times with females laying upwards of 600 eggs.  Two months later, after all of the adult cicadas have perished, the eggs quietly hatch out small, white shrimp-like juveniles who fall to earth and immediately burrow down.

Having the longest known lifecycle of any insect, they will spend the next seventeen years feeding on tree roots (drinking the xylem) and maturing before they emerge at the end of their lives. 

17-year Cicadas
Courtesy Scientific American Magazine

 

In Perspective

The last time this happened, seventeen years ago in 2004, Facebook was in its infancy exclusively at Harvard, the last episode of Friends aired, and it was still three years before the first iPhone was released.

The usual Midwest forest characters are all here; the spiders in their shimmering webs, the mushrooms decomposing fallen wood, the lilting chatter of songbirds flitting through the canopy, and squirrels and chipmunks scurrying about always with a cautious eye on the trail.

I’m stopped in my tracks by a novel sight.  Pinecones? Mushrooms? A Midwest pineapple? It’s American cancer-root a fully parasitic plant that grows on the roots of oak trees that is native to the eastern US.  Nature always has something new to teach me.

The cicada emergence is a buffet for all of the forest denizen. Everyone here eats cicadas. Their millions of numbers emerging at once is their survival strategy. They can’t all be eaten.

squirrel
Belly full of cicadas

Back at the parking area, the intensity of the buzzing grows. I follow my ears across the road to the picnic area, where the smell of death is staggering. A few big oaks here are surrounded by exit holes in the soil and piled with nymph carcasses. Adult cicadas crawl on the trunk and on me.

It’s overwhelming – the smell, the sight, the insects in the air and squashed on the jogging path.

 

They said there would be billions, but it’s hard to wrap my head around a number that big.  It’s a spectacle that was awe-inspiring to visit. Nevertheless, like many things, I wouldn’t be excited to have them in my backyard.

Subscribe here to receive an email whenever a new blog posts.

2 Replies to “17-Year Cicadas”

  1. I had forgotten about those little holes in the ground near the tree trunk where they emerge, but yes they do look familiar. You have now refreshed my old memories but also nicely explained the cycle of their lives which I must admit IS a bit unique. Do you know when we might expect them to emerge around here? I keep hoping that it won’t happen or at least won’t be that bad. I think 17 years ago here, based on previous 17 year cycles back when our area was farms and fields we didn’t have as many as I remember in some towns nearby that I drove thru to and from work where the sound was unbelievable even in my car, and it lasted for many weeks!

    1. Our 17-year cicadas will be back in 2024. If there weren’t mature trees around you in 2007 then you shouldn’t have too many. In Ohio they were dense in the woods but not many in the subdivisions.

Leave a Reply

Your email address will not be published.