Image Credit: the United States Department of Agriculture
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Image Credit: Taffy M. from Little Rock, AR
Image Credit: G. from Virginia Beach, VA
The 17-year Periodical Cicada is both seen and heard when huge population explosions occur.
The Periodical Cicada is generally more well known in the Midwest as the Seventeen-Year Cicada due to their periodical emergence every thirteen or seventeen years. Cicadas during this time can appear in the hundreds, if not thousands, as mating season commences. These collections - called 'broods' - leave behind many molted, brown, crunchy body exoskeleton shells on window screens, fence posts, tree trunks, plant stems and anywhere else they can stand. The long periods of high-pitched screeching calls are produced by the males in search of female partners. Different species of Cicada produce their own distinct sound. Their life spans as adults is somewhat short, so reproduction is the focus of all their energy once they mature into adults.
Periodical Cicadas are large, chunky insects with bulging eyes on the sides of their heads. They are slow fliers and easy to catch by birds and other flying insects (i.e. wasps). Their abundance in the years their population explodes means an easy feast for their predators. They have no real defense against predators except large numbers - the neighboring cicada may be more appetizing.
Though Cicadas are generally found in forested areas and grasslands, the species can become a common sight (and sound) in neighborhoods during the summer. Folks from the Mississippi River basin to the eastern United States and Canada are pretty familiar with the Periodical Cicada. While they are completely harmless, large numbers of them can become a nuisance to some people, covering cars and driveways, making it 'uncomfortable' to walk outside or drive on the unwitting insects (brings to mind the buggy cave scene in "Indiana Jones: Temple of Doom").
Females will insert eggs into a tree branch or bark and the hatched nymphs eventually make their way down the tree into the ground. They burrow down by the tree's root system. Total maturity time of the nymph is about 13 to 17 years (hence 'periodical'). They eventually resurface after almost 2 decades underground and begin molting its early exoskeleton. There are always a few that develop a year or two before or after the masses, meaning you are likely to see at least a handful in 'off' years.
Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed above as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.