Periodical Cicadas

Distribution Map

Periodical cicadas emerge in specific locations once every 17 years in the northern part of their range, and once every 13 years in the southern part. Different groups called "broods" emerge somewhere in the eastern United States almost every spring.

In Ohio, we have four broods that regularly appear. The map below illustrates the approximate range of each of these broods and the years that they should appear.

Because of the long time taken by these insects to complete their life cycles, many things can happen that modify local populations. Wood lots are often destroyed and new developments where trees that are 14 to 15 years old have been established after the last brood's emergence. If new developments are adjacent to wooded areas that have supported a brood, the adults will commonly fly to the younger trees to lay their eggs. This helps expand their territory and maintain their populations for the next 17 years!

It is a regular occurrence of broods to have individuals (occasionally significant numbers) that emerge a year early or a year later than what would be expected.

In Ohio, all our broods contain the three species of 17-year cicadas! It is difficult to separate the species unless you hear their songs!

 

For more information on the distribution of periodical cicadas in North America, we recommend that you visit the University of Michigan Periodical Cicada Site. The Great Lakes Cicada page also has great maps of all the broods (but watch out for the pop-ups!).

In 1987, Dr. Gene Kritsky (Department of Biology, College of Mount St. Joseph) performed a survey of OSU extension agents in counties of Ohio to determine the presence of Brood X. The results of this survey were published in 1988 (Ohio J. Sci. 88: 27-28) and the activity map is redrawn to the right. Because this was a letter survey, counties that had previous records may not have had 1987 records simply because no one reported the cicadas. However, this map is useful in showing the potential range (all dots), where populations were actually observed (orange and red dots) and where extensive populations were observed (red dots). The orange and red dot areas can likely expect similar results in 2004, but counties with green dots may experience localized, small emergences.

(note: click on the map to view a larger version)