17-Year Cicadas Appear, A Few Years Off Cycle

Each year, the distinctive buzz of "annual" or "dog day" cicadas signals August in Chicago Wilderness. But in June, residents of many Chicago suburbs observed a species they don't see nearly so often. A substantial brood of Magicicada septendecim, the 17-year "periodical" cicada, emerged from yards and preserves en masse, surprising some suburbanites who didn't expect the insect for another few years. These out-of-sync cicadas once belonged to the region's main brood of 17-year bugs, but were thrown off-cycle in 1969 when their ancestors crawled out of the soil four years before the rest of the brood, which is expected to emerge in 2007.

On the morning of June 8, just as nature photographer Dennis Manning and his wife Caren were leaving their Downers Grove home to attend a banquet, they noticed that their yard was full of 17-year cicada nymphs.

Cicadas normally emerge in the cool of dawn to crawl onto a vertical surface, shed their nymph shell, and become an adult. This morning was rainy and unusually cool, so the insects were transforming later in the day than usual. "I don't care if we're late for the banquet," Caren told her husband. "This is a once-in-a-lifetime opportunity."

As the Mannings describe it, the process of transformation is a dramatic and beautiful one. At about 8 a.m., the cicada (pictured) had already fastened itself to a tree. Soon, says Dennis, who accompanied the insect through the entire two-hour rite of passage, he could see a clear fluid pulsing under the nymph's shell.

Without much warning, the top of the thorax, "at the nape of the neck," split a little, and for half an hour, the adult cicada slowly thrust its body, pure white with orange-red eyes, from the shell. "The outside of its body just glistened," Dennis says. Like a freeze-frame of a spirit rising from a body, the cicada rested for another half hour before dragging itself completely out of its shell. Its "jelly-like, ripply, milky white" wings, by Caren's description, took another hour to harden into dry membranes. All the while, the cicada's body shifted from white to black and doubled in length as fluids pumped through it.

Yet another instance of the natural cycles that make up Chicago Wilderness, the cicada would later fly up to lay eggs for the next generation in a branch of that tree. And the Mannings would go to their banquet, with a fine story to tell.

—Don Parker