If a person was driving down the street in Perryville and heard a loud buzzing noise or even just outside trying to enjoy a nice summer evening. Their leisure time could be interrupted.
Periodical cicadas are emerged from the soil in northern Illinois for the first time in 17 years to spend three to four weeks as adult insects. These cicadas are harmless to humans and pets—they cannot sting, bite, or pinch—but there will be many millions of them. Particularly in areas with lots of mature trees, their mating calls will be very loud and they may be annoying.
Periodical cicadas are an amazing natural phenomenon, so amazing that scientists call them Magicicada.
The presence of cicadas will last only about four to six weeks. An individual cicada dies after three to four weeks, but there are always stragglers. The two cicada broods were projected to emerge in a combined 17 states across the South and Midwest. They emerge once the soil eight inches underground reaches 64 degrees, beginning in many states in April and May and lasting through late June. t turns out that it is extremely hard to estimate the population sizes of periodical cicadas, for any number of reasons. The oft-quoted figure of densities that can exceed a million per acre comes from a census taken during the 1956 emergence of Brood XIII in Raccoon Grove, IL (Dybas and Davis 1962). Ironically, Brood XIII appears to have gone extinct or nearly extinct in Raccoon Grove in the years since 1956 (Cooley et al. 2016; Karban 2014), so it is clear that periodical cicadas are variable across space and time!
If we accept a rough estimate of one million cicadas per acre… should that be surprising? How many ants are there per acre? How many mayflies? How many fruit flies? Insects often come in large numbers. What’s special about Magicicada is not the large numbers per se, but the periodicity– the predictable, synchronous emergence of large numbers of adults and their near-total absence in the years between (see the “straggler” page for more information).
The state of Delaware is roughly 1.5 million acres in size. If we accept an estimate of a million cicadas per acre and if the total combined area of a periodical cicada emergence is roughly the size of Delaware, then more than a trillion cicadas will be involved. For 2024, since cicadas will emerge from Maryland to Oklahoma, Illinois to Alabama, clearly, trillions of adult cicadas will be present– but not all in the same place at the same time.
They are native insects that have an ancient relationship with our native American trees. This web page offers information and lore about these remarkable insects as well as answers for common questions concerning the emergence and how to co-exist with the cicadas.
Cicadas emerge every year somewhere in the eastern United States, at either 13-year or 17-year intervals.
This year is remarkable because two broods are emerging simultaneously for the first time in 221 years. That does not mean that the Chicago area will see more cicadas than usual: The two broods occupy different geographic ranges, so most places, including the Chicago area, will experience only a normal cicada emergence. The two-brood emergence mainly means that a wider area than usual will see periodical cicadas this year.
Cicadas and trees have a long-term relationship, so the biggest crowds of cicadas will emerge in neighborhoods with many old, mature trees or in wooded natural areas. There will be few cicadas in new developments with no old trees, in dense urban neighborhoods with more paving than trees, or in places where the soil has been disturbed by construction. Cicadas evolved with native trees, such as oaks and maples, but nonnative trees can also host them.
Scientists estimate that in a forested area, there can be up to 1.5 million cicadas per acre. The density of cicadas in your neighborhood will depend mainly on how many mature trees there are. It will also depend on whether there has been development or construction since the last emergence in 2007. Cicadas spend most of their lives underground as nymphs, so construction that disturbs the soil destroys the cicada nymphs and their habitat.
