A convergence of emergence

OK, yes, it feels a bit melodramatic to get so worked up over a benign bug that doesn’t sting, bite or carry disease.

But imagine the rare concert looming in Illinois this year with the concurrent emergence of a brood of cicadas that appears only once every 13 years with one that appears only once every 17 years. This convergence of emergence occurs only once every two and a quarter centuries. It hasn’t happened since Thomas Jefferson was president and the U.S. Army was establishing Fort Dearborn on the site that would become Chicago. It won’t happen again until 2245.

For us in the suburbs, the music — if you can use that term for six weeks of constant screeching by billions of insects crying out for mates, and we do — may not be quite so raucous as in portions of central and southern Illinois. Here, we’ll just get the usual 17-year cacophony of Brood XIII. To the south, some portions of the state will experience the rarest of duets from both Brood XIII and Brood XIX, a family of cicadas that, contrary to the implications of its Roman nomenclature, crawls out of the ground every 13 years to climb onto bushes and trees and belt out its mating song.

“This is an exciting and rare experience that should draw the attention of both bug enthusiasts as well as everyday outdoor visitors,” Matt Mulligan, an ecologist with the Forest Preserve District of DuPage County, told our Mick Zawislak for a Page 1 story last Sunday on the topic.

The forest preserve districts in DuPage, Lake, Cook and other collar counties plan a variety of programs to build on this unusual educational opportunity, and we encourage folks to get out and take advantage. Even for those of us whose contact with the phenomenon will be limited to the roar outside our car windows as we sit at stop lights near forest preserves or large stands of trees, it is remarkable to consider that we are part of a cycle that hasn’t occurred for generations and won’t be experienced again for generations more.

It is, we suppose, the entomological equivalent of a rare comet’s passing - but with a lot more noise.

And perhaps some other physical manifestations. Most of us are accustomed to seeing the papery shells of common cicadas that shed their skins on tree trunks, streets and sidewalks every summer, and the prospect of hordes of additional periodical visitors has the potential for greater abundance of the insects’ leavings.

But scientists caution not to worry. The cicadas don’t hurt our plants and trees, and trying to eradicate them with chemicals won’t have much effect because of the huge size of the multitude. Moreover, such applications may do more damage to our plants and bushes, not to mention other beneficial insects, than they will to the cicada population.

Our plan? To enjoy the rare sounds on walks in our neighborhoods, parks and forest preserves. To take opportunities to learn more about this fascinating phenomenon. And to reflect on marvelous oddities of our natural environment that add something pleasant to the uniqueness of life in our generation’s own space and time.