|Everybody has their own treasured experience of insects -- a nighttime lit by fireflies, the sight of monarchs clustered for the winter, listening to katydids singing in the evening, watching dragonflies hunting around a pond edge, a glimpse of a rare species. But relatively few of us witness what residents and visitors in the Atlantic coast region, from Connecticut to Virginia (and maybe southward toward Georgia), are about to experience, the mass appearance of 17-year periodical cicadas. |
Seemingly from nowhere, cicadas emerge in astonishing numbers -- maybe as many as a million insects per acre! -- covering trees and bushes. During their nymphal stage, periodical cicadas live underground, feeding on the roots of trees for seventeen years. During the weeks before emergence they dig a tunnel to the surface, sometimes marking the exit with a turret, in preparation for their final appearance.
Seventeen-year periodical cicadas occur in the eastern United States in a region bounded by Connecticut and Georgia in the east and Texas, Nebraska, and Wisconsin in the west. The cidadas that appear in one year are called a brood, and these have been well-enough studied to predict where and when they will emerge. Seventeen-year periodical cicadas don't appear every year; there are only twelve known broods.
Probably more memorable than the sight of so many insects is the startling cacophony. Cicadas emerge to breed, and to attract a mate amid so many competitors, the males "sing" -- loudly. Male cicadas have a pair of tymbals (ridged membranes) on the sides of their abdomen that they vibrate to produce a buzzing call, which is amplified greatly by a large air chamber. Individual cicadas sing for a few seconds and then rest, but when there are so many singing at once it creates a never-ending chorus.
The good thing is that these cicadas don't sing at night. At least there is a good chance you will get some sleep during the few weeks they are in your neighborhood.