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Excerpts from Jim Conrad's
Naturalist Newsletter
from the June 10, 2001 Newsletter, issued from the woods just south of Natchez, Mississippi, USA
PERIODICAL CICADAS
This last week the periodical cicadas fell from the trees.
About a month ago their nymphs began emerging from the ground. They left black holes leading straight down in the dirt of my footpaths. The nymphs, about the size of the end length of my thumb and looking like oversized dog fleas, climbed onto bushes, tree trunks and even pots and pans in my outside kitchen, planted their feet firmly on whatever was beneath them, and then the skin along their backs began splitting. Before long red-eyed, two-inch-long adult cicadas emerged and after drying a bit the adults flew away leaving brown husks. Thousands of these brown husks still cling to things all around my camp.
I planned to photograph an adult emerging from the nymphal skin, but in moving the metamorphosing creature so I could keep an eye on it as I worked, to catch it at the right moment, I accidentally dropped it. This small knock caused the metamorphosis process to stop and the animal died with just part of the insect's back emerging from the husk. This must be a very delicate process, despite the enormous scale of its occurrence around me. I did scan a dead adult and its skin, however, and it's shown at the right.
Periodical cicadas are members of the genus Magicicada (Homoptera: Cicadidae), but I don't know which species we have now. There are several species, each with its own cycle. A scanned picture of the head of the above cicada appears at the left.
One interesting thing is that of all insects on Earth the immature stages of the periodical cicada may last for the longest time. In our area the nymph stays underground eating tree roots for 13 years, but species in the Northeast remain below for 17 years.
For a couple of weeks our cicadas roared so mightily that sometimes the sound was both awe-inspiring and oppressive. If you listened long, it almost overwhelmed you, like standing next to a very large waterfall. You know you're safe, but the simple enormity just weighs upon you.
But then this week the millions and millions of them began dropping from the trees and each day their roar diminished. Now there is just an occasional whir.
The main day of the cicadas' demise came last Tuesday, June 5. That's when the tropical depression called Alison suddenly formed in the Gulf and moved into eastern Texas. Since then, each day Alison has sent at least some rain our way, a bit over 6 inches so far, rain that we desperately need. Last Tuesday was the day of the first rain and also it cooled down then. The rain and cool weather was hard on the cicadas.
But I think the cicadas may have died even without Alison. Some are dying now, though it's dryer and warmer today than usual. They fall onto the trailer's top as I work and I hear them lying on their back, seemingly unhurt in any way, yet they can only flutter. And in an hour or two they are dead. It's as if they have simply run out of energy. Their death on such a grand scale is nearly as majestic as their calling was the week before.