Many periodical cicadas emerged four years early in the Chicago area in 2020. These cicadas belong to the Brood XIII (13) which is set to emerge in 2024, and last emerged in 2007. Periodical cicadas often emerge in years proceeding or following the year their brood is expected to emerge. This phenomenon is called straggling. Most of the time these “stragglers” emerge in small numbers and are quickly eaten by predators, and do not go on to sing, chorus (synchronized singing for the purpose of attracting females), mate, and lay eggs. Sometimes they emerge in numbers large enough to survive, chorus and reproduce — this seems to have happened in the Chicago area in 2020. It is thought this this is how new broods formed over the millennia — cicadas emerge 4 or 1 year early in significant numbers and form a new brood. When enough stragglers emerge to successfully reproduce it is called an acceleration.
So, is a new brood forming around Chicago? Is this due to climate change or localized “heat islands”? Will the progeny of these stragglers emerge in 13, 17 or 21 years? Lots of questions — but we’ll need to wait quite some time to answer them.
There is a precedence for Brood XIII cicadas straggling in the Chicago area:
In 1969 massive numbers of periodical cicadas emerged in the Chicago suburbs 1 (Williams, K.S. & Simon, C. 1995).
In 1986, another 4-year acceleration was observed in the Chicago area by Monte Lloyd 1.
In 2003, many people left observations on our forums. Observations were made in Glenview, Flossmoor, Riverside, Downers Grove, Homewood, Westmont, Oak Park, and Hinsdale. Here are some examples:
Magicicada emerging this evening
Date: Wednesday, Jun/4/2003
Message: As I went for a walk this evening I noticed quite a few periodic cicadas emerging in the grass, crawling on the sidewalks and on the trunks of trees. This is not our year for the 17-year brood. We should not have them until 2007. Has anyone else in the Chicago area seen these cicadas? — Sue, Flossmoor, IL
Date: Monday, Jun/9/2003
Message: I heard the cicadas singing for the first time this morning after my walk. Now that I have my doors open I can hear them on and off. — Sue, Flossmoor, IL
In 2020 many people left comments on the Brood XIII page, emailed us (thanks Neil) and left sightings via the Cicada Safari app.
The Brood Chart features the names of the broods (Roman numerals), their life cycle length, when they will emerge next, which states they’ll emerge in, links to Maps, the species that will emerge, and other information. Click the maps for larger, detailed maps.
Species: M. tredecim, M. neotredecim, M. tredecassini, M. tredecula.
States: AR, IL, IN, KY, LA, MO, MS, TN
When will they emerge?
📅 🌡️ Generally speaking, these cicadas will begin to emerge when the soil 8″ beneath the ground reaches 64 degrees Fahrenheit (Heath, 1968). A nice, warm rain will often trigger an emergence. They typically emerge in May but have been known to emerge in late April or early June. It all depends on the weather.
What should you look for before they emerge?
Chimneys / Turrets
Look for cicada chimneys a.k.a. turrets. These are structures cicadas build out of the soil, positioned above the hole where they will emerge.
Look for holes the diameter of an adult’s finger near the root system of a tree. These are sure signs that cicadas will emerge in the area.
Cicadas Under Stones & Slates
You might discover some cicada nymphs while turning over stones or when performing landscaping chores.
This is a recently emerged nymph crawling up a tree. Note that its eyes are red.
Once cicadas nymphs have emerged from the ground, they will try to find a tree (or similar vertical surface), and then begin the process of shedding their old nymph skins (ecdysis), expanding their wings, and changing to their adult coloring. Watch this amazing transformation.
How to tell the difference between the seven Magicicada species:
The first way is based on the Brood. Take a look at the Brood chart above, and see which species appear with the Brood.
There are 3 basic types of Magicicada: “‘Decims”, “‘Cassini” and “‘Deculas”.
Ask someone who lived there 17 (or 13) years before.
Old timers (hint: old timers usually call them locusts).
Check your local Library for old newspaper articles.
Check with a local college: contact the entomology, forestry, or agriculture-related departments.
Your local national, state, county and town parks department (parks and rec). Some county parks departments plan events around cicada emergences.
When will they emerge?
They will emerge sometime in the Spring, for sure.
They typically emerge once the soil 8 inches (20 cm) below the surface gets to 64 degrees Fahrenheit (18 degrees Celcius). At that temperature, they will start digging their tunnels to the surface. After a couple of days with above-ground temperatures near the 80’s F, and after a good rain, they will definitely emerge. Read this paper for more info: Thermal Synchronization of Emergence in Periodical “17-year” Cicadas (Homoptera, Cicadidae, Magicicada) by James Edward Heath, American Midland Naturalist, Vol. 80, No. 2. (Oct., 1968), pp. 440-448.
Cicadas in sunny areas of your yard will emerge before cicadas in shady areas.
Cicadas in the southern-most states will emerge before cicadas in northern states.
Question: Why do I have cicadas in my neighborhood, but your chart indicates that I shouldn’t?
Answer: Some possibilities: 1) they are stragglers, periodical cicadas that emerge too soon or late, 2) they are not periodical cicadas, but are a different North American species, 3) you live on a continent other than North America, in which case, try one of these pages, or 4) SURPRISE! The U.S. is a big place and some cicada populations have yet to be documented.
Question: Why don’t I have periodical cicadas in my area, but the information on your website indicates that I should?
Answer:Stragglers can emerge 1 or 4 years early or 1 or 4 years late. Don’t be surprised if you see some periodical cicadas emerge earlier than planned this year. 17-year brood members are most likely to straggle 4 years early, and 13-year brood members are most likely to straggle 4 years late. Straggler probability chart.
Question: Why are there no Brood XI, XII, XV, XVI… ?
Answer: Perhaps you’ve noticed there are no Broods XI (11), XII (12), XV (15), XVI (16), XVII (17), XVIII (18), XX (20), XXI (21), XXIV (24), etc. Don’t worry about that. They never existed or are extinct (XI, XXI).
More Magicicada websites:
For much more information about 17-year cicadas visit Magicicada.org. The maps on this page link to that site.
The Cicada Safari App is available for Android and Apple devices 📱. Use it to see where people are finding cicadas, and to report your own sightings.
In 2020, the main periodical cicada brood expected to emerge in the U.S. is Brood IX (9). Brood IX will emerge in southern West Virginia, western Virginia, and a small portion of north-western North Carolina. This we know for sure.
If you want to see where cicadas are being reported, try the Cicada Safari App is available for Android and Apple devices 📱.
OK, here’s the point of this article:
Cicadas from other broods will also emerge this year in small numbers. When cicadas emerge early or late, they’re called stragglers. Don’t get hung up on the meaning of the word. If it makes you happy, call the ones that emerge early “precursors”, “pioneers”, or “heralds”.
Members of Brood XIX (19) are emerging in parts of North Carolina and Georgia, where Brood XIX is know to exist. There’s some discussion of this over on the Cicada Discussion, Science and Study Group on Facebook. You might see them in Alabama, Arkansas, Georgia, Illinois, Indiana, Kansas, Kentucky, Lousiana, Missouri, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, and Virginia.
Members of Brood XIII (13) are likely to emerge 4 years early in Iowa, Wisconsin, Illinois, Indiana, and possibly Michigan.
The rest of Brood XIII emerge in 2024 (a big year for periodical cicadas). Here’s a map.
Some members of Brood X (10) should emerge 1 year early in Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and Washington D.C.
The rest of Brood X will emerge next year in 2021. Here’s a map.
Here’s a screen shot from the Cicada Safari app:
Within the app, you can zoom in to see where the cicadas are appearing. Here’s a “Live Map” of the sightings from the app.Pinch and zoom to get details.
We expect some periodical cicadas to emerge earlier and later than expected this year:
Members of Brood IV, the Kansan Brood, should emerge in IA, KS, MO, NE, OK & TX. Brood IV last emerged 4 years ago.
Members of Brood XXIII, the Mississippi Valley Brood, should emerge in AR, IL, IN, KY, LA, MO, MS, & TN. XIX last emerged 4 years ago.
Members of Brood X are emerging, so far in the Virginia area, but they have the potential to emerge anywhere in DE, GA, IL, IN, KY, MD, MI, NC, NJ, NY, OH, PA, TN, VA, and WV. 2-year early emergences are rare, but it happens. Brood X is expected to emerge in 2 years.
We’re getting a lot of reports from the Anacostia area of Washington D.C. and Maryland.
Here’s an example of someone Tweeting about a Brood X “straggler” on Twitter.
Periodical cicadas are cicadas insects that emerge periodically, and not annually. In North America, there are 7 species of periodical cicadas, 3 of which have a 17-year lifecycle, and 4 have a 13-year lifecycle, and all 7 belong to the genus Magicicada. Here is a chart that shows where they are expected to emerge next. Magicicada regularly straggle — some emerge before or after they’re expected to.
Typically 17-year cicada stragglers emerge 4 years early, and 13-year cicada stragglers emerge 4 years late, but 1, 2 and even 8 year deviations are possible — see the probability chart.
At this point, most people question the use of the term “straggler” to define something that emerged early rather than late. If you’re uncomfortable using the term “straggler”, you can use the term “precursor” for cicadas than emerge earlier than expected. You might make up your own slang for them, like “deviant”, “pioneer” or “laggard” too.
“The periodical cicada four-year acceleration hypothesis revisited and the polyphyletic nature of Brood V, including an updated crowd-source enhanced map (Hemiptera: Cicadidae: Magicicada)”
Authors: John R. Cooley, Nidia Arguedas, Elias Bonaros, Gerry Bunker, Stephen M. Chiswell, Annette DeGiovine, Marten Edwards, Diane Hassanieh, Diler Haji, John Knox, Gene Kritsky, Carolyn Mills, Dan Mozgai, Roy Troutman, John Zyla, Hiroki Hasegawa, Teiji Sota, Jin Yoshimura, and Chris Simon.
The periodical cicadas of North America (Magicicada spp.) are well-known for their long life cycles of 13 and 17 years and their mass synchronized emergences. Although periodical cicada life cycles are relatively strict, the biogeographic patterns of periodical cicada broods, or year-classes, indicate that they must undergo some degree of life cycle switching. We present a new map of periodical cicada Brood V, which emerged in 2016, and demonstrate that it consists of at least four distinct parts that span an area in the United States stretching from Ohio to Long Island. We discuss mtDNA haplotype variation in this brood in relation to other periodical cicada broods, noting that different parts of this brood appear to have different origins. We use this information to refine a hypothesis for the formation of periodical cicada broods by 1- and 4-year life cycle jumps.
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Gene Kritsky, author of Periodical Cicadas. The Plague and the Puzzle, let us know that many of what are likely Brood X cicada stragglers have emerged around the Mount St. Joseph University campus, in Cincinnati, Ohio. It’s likely that cicadas are emerging elsewhere in the Cincinnati area.
This is significant because Brood X cicadas should not emerge until 2021.
This is a photo of a Magicicada periodical cicada emerging on the MSJ campus, courtesy of Gene:
Gene Kritsky is a periodical cicada expert and Dean of the School of Behavioral and Natural Sciences and Professor and of Biology at Mount St. Joseph University. Read more.
Brood X is a massive brood of Magicicada (the genus) periodical (the lifecycle type) cicadas that are set to emerge in 2021 in 15 states.
A straggler is a periodical cicada that emerges off-schedule, often a few years before or after the rest of its Brood.
So, what’s a straggler? A straggler is a periodical cicada that emerges sooner or later than it is expected to emerge. In this case, a cicada with a 13-year lifecycle emerged in 16 years — 3 years off.