Category: Life Cycle

Cicadas have three types of life cycles: annual, periodical, proto-periodical.

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FAQs Life Cycle Magicicada Periodical

Why do Magicicada stay underground for 13 or 17 years?

People ask: why do periodical cicadas stay underground for 17 or 13 years?

There are three parts to this puzzle that people are interested in:

  1. How cicadas count the years as they go by.
  2. Why prime numbers? 13 and 17 are prime.
  3. Why is their life cycle so long? They are one of the longest living insects.

Cicadas likely don’t count like people do (“1,2,3,4…”) and you won’t find scratch marks inside the cell (where they live underground) of a Magicicada, marking off the years as they go by. However, there is a kind of counting going on, and a good paper to read on that topic is How 17-year cicadas keep track of time by Richard Karban, Carrie A. Black, and Steven A. Weinbaum. (Ecology Letters, (2000) Q : 253-256). By altering the seasonal cycles of trees they were able to make Magicicada emerge early, proving that cicadas “count” seasonal cycles, perhaps by monitoring the flow and quality of xylem sap, and not the passage of real time.

Why prime numbers, and why is the life cycle so long? This topic fascinates people. The general consensus is that the long, prime-numbered life-cycle makes it difficult for an above-ground animal predator to evolve to specifically predate them. Read Emergence of Prime Numbers as the Result of Evolutionary Strategy by Paulo R. A. Campos, Viviane M. de Oliveira, Ronaldo Giro, and Douglas S. Galva ̃o (PhysRevLett.93.098107) for more on this topic. An argument against that theory is that a fungus, Massospora cicadina, has evolved to attack periodical cicadas regardless of their life cycle. Of course, a fungus is not an animal. Maths are easy for fungi.

There are also questions about why there are 13 and 17 year life cycles, why a 4 year acceleration of a brood might occur1 and why Magicicada straggle.

1 This is a good place to start: Genetic Evidence For Assortative Mating Between 13-Year Cicadas And Sympatric”17-Year Cicadas With 13-Year Life Cycles” Provides Support For Allochronic Speciation by Chris Simon, et al, Evolution, 54(4), 2000, pp. 1326—1336.

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Eggs FAQs Life Cycle

30 Things Cicadas Do

One of the most frequently asked questions we receive is: “what do cicadas do“? This question is similar to the question “what is the purpose of cicadas” — the answers to both questions help people understand why these fascinating, unusual creatures exist at all.

The simplest reduction of their life cycle is:
1) They hatch from an egg.
2) They burrow underground where they will drink from plant roots for most of their lives.
3) They leave the underground and become adults.
4) The males make sounds that attract females.
5) Males & females court & mate.
6) Females lay fertilized eggs in the branches of plants, and the cycle continues.
7) They die.

The specifics of a cicada’s life cycle varies from species to species, but here is a more detailed view of what cicadas do:

From egg to 1st instar nymph:
1) Cicada nymphs hatch from eggs.

Marlatt 1907 Egg Nest Detail

2) Nymphs feed on plant fluids which they access thanks to the egg-nest groove made by their mothers.

3) They leave the groove, and drift to the ground. Their descent to the ground doesn’t hurt them because they weigh so little.

4) Once on the ground, they dig into the soil until they find small rootlets, from which they will feed.

Once Underground:
5) Underground, they will tunnel/dig…

6) and establish a cell…

7) from where they’ll comfortably feed. Cicadas feed on the xylem sap of plants. With the help of bacteria they transform the water, minerals and amino acids found in tree fluids to the tissues of their own bodies.

8) They pee, in fact they seem to use excess plant fluid to moisten soil to help mold the walls of their cells.

9) Throughout their life underground they will move from root to root… as plant root systems change with the seasons, when roots die off, or perhaps to avoid predators.

10) Underground, a cicada may (depending on the species) go through four instars, molting three times (see an image of the four instars).

Preparing to emerge:
11) Cicadas will build a tunnel to the surface of the ground, in preparation for their emergence.

12) Cicadas often take that a step further an build a chimney/turret above ground. This often happens in shady areas or when the ground is muddy.

Once above ground:

13) They emerge from their tunnels…

14) Cicadas run as fast as they can…

15) And find a surface perpendicular to the ground, hold tight, and begin to molt…

16) During the molting process (ecdysis), cicadas perform many acrobatic moves to separate themselves from their nymphal skin, including pulling their old trachea from their bodies.

17) Once outside their nymphal skin, they will inflate their wings…

18) … and expand various parts of their bodies, like their heads.

19) They will change color.

20) Once their bodies are hard enough (sclerotization counts as a thing they do)…

21) They will either seek shelter, perhaps by crawling up higher along a tree trunk…

22) or if your are a Magicicada, you might stick around in the hopes that a predator will eat you.

Mating and Reproduction:

23a) If you are a Male cicada, you are going to sing… unless you belong to a species that cannot sing, in which case, you’ll move your wings in a way that will produce a sounds.
There are many types of songs: a) distress calls, b) calls to establish territory, c) calls to attract females, d) including choruses of many cicadas and e) courting calls

23b) Female cicadas, and some male cicadas, move their wings to make sounds, also in an effort to attract and engage a mate.

24) Most cicadas (aside from Magicicada during the early days of their adult lives) will try to avoid being eaten by predators.

25) They’ll fly, of course.

26) Cicadas, like Magicicada, will establish chorusing centers, which are places where the male cicadas sing together and females come to meet them.

27) Male and female cicadas will court…

28) and mate…

29) the female cicada will lay her eggs in grooves (ovipositing) she etches into a suitable plant stem, and we’re back to step 1.

30) The last thing cicadas do, of course, is die, and return the nutrients found in their bodies to the soil, where they will be broken down and absorbed by the plants they fed upon.

Some things cicada do not do:

Here are some things cicadas do not do:

1) They don’t seek shelter during the fall months (i.e. they don’t try to live inside your house), unlike Ladybugs or Stinkbugs.
2) They don’t sting or otherwise pass venom onto people.
3) They don’t chew plant leaves, like caterpillars or grasshoppers.
4) They don’t dump garbage in the ocean.

Categories
C.L. Marlatt FAQs Magicicada Periodical

What are Broods?

It is important to note that when we talk about cicada broods, we are talking about the 17 & 13-year periodical Magicicada cicadas. We are not talking about Tibicen or other species.

All Broods

There are 12 groups of Magicicadas with 17-year life cycles and 3 groups of Magicicadas with 13-year life cycles. Each of these groups emerge in a specific series of years, rarely overlapping (17 & 13-year groups co-emerge every 221 years, for example). Each of these groups emerge in the same geographic area their parents emerged. These groups, each assigned a specific Roman numeral, are called broods.

Gene Kritsky’s book, Periodical Cicadas: The Plague and the Puzzle, documents the history of the recognition and naming of the broods. The first person to document that different groups of periodical cicadas emerged in different years was Nathaniel Potter in 1839. Benjamin D. Walsh and Charles V. Riley devised the system for numbering the different broods in 1868, and then C. L. Marlatt sorted the 17 year broods out from the 13-year broods, giving us the system we have today.

Visit our Broods page which features a grid of the Brood names, their lifespan, when & where they’ll emerge next and links to maps.


Categories
FAQs Magicicada Periodical

How Long Does a Periodical Cicada Emergence Last?

People often ask: “how long do cicadas last”, “how long will the cicadas be here”, or “how long do cicadas live above ground”?

People probably ask these questions, sadly, because they are tired of listening to the love songs of these cicadas. Like the saying “it is darkest before the dawn”, however, silence is typically a few weeks away.

The length of a local emergence:

The typical periodical cicada emergence will last between 6 to 8 weeks in a single location, with significant chorusing (singing) lasting about 3 to 4. Cool weather or rain can prolong an emergence.

The research paper Emergence of 13-Yr Periodical Cicadas (Cicadidae: Magicicada): Phenology, Mortality, and Predator Satiation by Kathy S. Williams, Kimberly G. Smith, and Frederick M. Stephen1 contains a wonderful study of the arc of a periodical cicada emergence. The entire emergence event takes place within 8 weeks, from the first emerged cicada to the last dead cicada (see Fig 4 in that document 1). The number of live adults reached its peak within two weeks and then began to die off in significant numbers two weeks after that, due mostly to natural causes. After that, the population of cicadas gradually dwindles due to natural deaths and predation.

Length of the chorusing:

Male cicadas will not begin chorusing at the start of an emergence, for a couple of reasons: 1) the first cicadas to emerge, which are primarily males (Fig 3 in 1), are mostly lost to consumption by predators (Fig 6 in 1), 2) Males can’t sing until their adult bodies are fully sclerotized, and 3) they need a significant number of males present before they will chorus. That said, chorusing typically begins within two weeks 2. Males will continue to chorus until enough cicadas die to no longer sustain the chorus, which is why the chorus lasts less than a month.

Length of the emergence of an entire brood:

An emergence spanning multiple states could last between 8 to 10 weeks from when the first cicadas emerge in the South to when the last cicada dies in the North. For example, Brood XXIII began appearing the second to last week of April in Mississippi, and there were likely some left in southern Illinois up until the last week of June.

References:

1 Kathy S. Williams, Kimberly G. Smith, and Frederick M. Stephen, Emergence of 13-Yr Periodical Cicadas (Cicadidae: Magicicada): Phenology, Mortality, and Predator Satiation, (1993), Ecology, Volume 74, Issue 4 (Jun., 1993), 1143-1152
2 Kathy S. Williams and Chris Simon, The Ecology, Behavior, and Evolution of Periodical Cicadas, (1995), Annu.Rev. Entomol. 40:269-95

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FAQs Magicicada Periodical

What is Predator Satiation?

Why are there so many Magicicada periodical cicadas, and what does it have to do with the survival of their species? One of the answers is: Predator Satiation.

A predator is any animal that would eat a periodical cicada, i.e., birds, raccoons, squirrels, dogs, snakes, etc. Satiation, in the case of cicadas, means to supply predators with enough cicadas to eat until they are wary of eating and thus avoid them completely.

Predator satiation works like this:
1) Periodical cicadas emerge in tremendous numbers.
2) Adult cicadas are often timid, even after having sclerotized.
3) The first cicadas that emerge are eagerly consumed by predators.
4) The predators are so overwhelmed by the bounty of easily eaten cicadas, that they fill themselves to the point of disgust and exhaustion.
5) This gives the remaining cicadas a chance to escape the predators.

The first periodical cicadas are literally “fodder”, in the battle between predators and periodical cicadas, to use a war/video game analogy.

Look at this periodical cicada: it is thinking “hopefully this creature will eat me, so my siblings will live on!”

Magicicada on my finger by Dan from Cicada Mania on Vimeo.

The research paper Emergence of 13-Yr Periodical Cicadas (Cicadidae: Magicicada): Phenology, Mortality, and Predator Satiation by Kathy S. Williams, Kimberly G. Smith, and Frederick M. Stephen (Ecology, Volume 74, Issue 4 (Jun., 1993), 1143-1152) is worth reading if you are interested in this topic. They found that predation of cicadas peaks during the first few days of the emergence, and doesn’t resume in significant numbers until three weeks later (see figure 6, if you read the paper).

Unfortunately, this strategy could be detrimental to periodical cicadas in areas with dwindling populations, where there isn’t enough of them to satiate the predators completely.

This strategy might also be used by other types of periodical cicadas like the Chremistica ribhoi of India, or cicadas that emerge in large numbers like Callogaeana festiva of south-east Asia.

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Accelerations FAQs Periodical Periodical Stragglers

What are stragglers?

Periodical cicadas often emerge in years before or after they are expected to emerge. When periodical cicadas don’t emerge on schedule we call them stragglers, regardless of whether they show up early or late. Typically cicadas with a 17-year lifecycle will emerge 4 years early, and cicadas with a 13-year cycle will emerge 4 years late.

Probability of Straggling chart from Chris Simon
This image indicates the probability of Magicicada straggler emergences. Courtesy of cicada researcher Chris Simon.

People hear the word straggler and assume it means something that lags behind, but that is a laggard. A straggler can mean something that has deviated from an expected date/time or moved away from others of its kind. That said, periodical cicadas that emerge early can also be called precursors, but in the scientific literature, they are called stragglers.

Visit Brood Chart to see when stragglers will be most likely.

Extremely likely stragglers in the next few years:

2025: Brood X 4 years late.

Accelerations

An acceleration occurs when periodical cicadas straggle in numbers significant enough to sustain future generations. In other words, a large population of a 17-year brood emerge in just 13 years, they avoid being eaten by predators, they mate and reproduce, and then 17 years later their offspring emerge in large enough numbers to reproduce and sustain their population. This is one reason why two different broods might exist in the same area. 1

It is thought that Brood X was formed when a group of Brood XIV accelerated 4 years (they emerged in 13 years, rather than 17). Then Brood VI came from Brood X, and Brood II came from Brood VI. Brood XIV -> X -> VI -> II is called the “main sequence”1.

Accelerations may have been more prevalent and successful (successful in terms of sustaining future generations) in the past when much of eastern North America was forests, and there was no human intervention or destruction of habitat to interfere.

References

1 Monte Lloyd & Jo Ann White. Sympatry of Periodical Cicada Broods and the Hypothetical Four-Year Acceleration. Evolution, Vol. 30, No. 4. (Dec., 1976), p. 795.

Here’s a paper that discusses 13-year Magicicada emerging 4 years early: David C. Marshall, Kathy B. R. Hill, and John R. Cooley “Multimodal Life-Cycle Variation in 13- and 17-Year Periodical Cicadas (Hemiptera: Cicadidae: Magicicada),” Journal of the Kansas Entomological Society 90(3), 211-226, (1 July 2017). https://doi.org/10.2317/0022-8567-90.3.211

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Brood V Brood VIII Magicicada Matt Berger Periodical Periodical Stragglers

Look and listen for Magicicada stragglers in 2015

Another straggler sighting, this time in Cleveland which should make it a Brood V one year straggler:

Matt Berger Brood V Stragger 2
A Brood V straggler found by Matt Berger in West Virginia. See more photos of this cicada.

The emergence of Brood XXIII is well underway in the states along the Mississippi, and Brood IV should kick off in the west as soon as it stops raining every day. These aren’t the only Magicicada periodical cicadas emerging in the U.S. this year — some stragglers will emerge as well.

A straggler is a periodical cicada that emerges before or after the rest of its brood. Typically a straggler belonging to a 17 year brood will emerge 4 years early, but they might also emerge a year early, or a year late, or even 4 years late. This probability chart, details the probability of a straggler emergence.

In 2015 you might find the following stragglers:

Tyla MacAllister found a Brood XIX Magicicada straggler (emerged 4 years late) in Alabama!

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Brood IV Magicicada Periodical

Brood IV, the Kansan brood, will emerge in 2015

Brood IV will next emerge in the year 2032.

This page was last updated in 2015.

The most popular question is “how long will the cicadas last“. They’ll last as long as it takes for them to mate and run our of energy. They translates to about 4 weeks of singing. Good weather — dry, calm, and in the 80s — helps them finish their business quicker.

Here is a video that will show you how to identify the various species:

2015 Brood IV

Brood IV, the Kansan brood, will emerge in Texas, Oklahoma, Missouri, Kansas, Nebraska, and Iowa, in the spring of 2015.

The cicada species that will emerge are Magicicada cassinii (Fisher, 1852), Magicicada septendecim (Linnaeus, 1758), and Magicicada septendecula Alexander and Moore, 1962. These periodical cicadas have a 17-year life cycle. The last time they emerged was 1998.

Counties:

Here is a list of the Counties where Brood IV periodical cicadas have appeared in the past. The data came from the Cicada Central Magicicada Database(RIP). The bolded counties are the ones Cicada Central has specimens for, indicating that they’re more of a sure thing.

Iowa: Adair, Adams, Cass, Dallas, Fremont, Johnson, Mills, Montgomery, Page, Pottawattamie, Ringgold, and Taylor

Kansas: Allen, Anderson, Atchison, Bourbon, Butler, Chase, Cherokee, Coffey, Crawford, Doniphan, Douglas, Geary, Greenwood, Johnson, Labette, Linn, Lyon, Marion, Montgomery, Neosho, Osage, Pottawatomie, Riley, Saline, Sumner, Wilson, Woodson, and Wyandotte

Missouri: Atchison, Barton, Buchanan, Caldwell, Clay, Clinton, Daviess, Dekalb, Gentry, Grundy, Harrison, Holt, Jackson, Johnson, Lafayette, Livingston, Mercer, Nodaway, Pettis, Ray, Saline, Vern, and Worth

Nebraska: Cass, Douglas, Johnson, Nemaha, and Sarpy

Oklahoma: Bryan, Carter, Choctaw, Comanche, Cotton, Craig, Garvin, Grady, Lawton, Mayes, McCurtain, Muskogee, Noble, Osage, Ottawa, Pawnee, Rogers, Stephens, Tulsa, and Washington

Texas: Cooke, Denton, Fannin, Grayson, Kaufman, Lamar, Montague, Wise

Learn more about Brood IV:


1907 Map from Marlatt, C.L.. 1907. The periodical cicada. Washington, D.C. : U.S. Dept. of Agriculture, Bureau of Entomology.

Marlatt 1907 04 Brood IV

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Brood XXIII Magicicada Periodical

Brood XXIII, the Lower Mississippi Valley brood, will emerge in 2028

Brood XXIII, the Lower Mississippi Valley brood, will emerge in Louisiana, Mississippi, Arkansas, Tennessee, Missouri, Kentucky, Illinois, and Indiana, in the spring of 2028.
Brood XXIII stragglers are emerging in 2024!
Brood XXIII last emerged in 2015.

About Brood XXIII:

Species:

The cicada species that will emerge are Magicicada tredecim (Walsh and Riley, 1868); Magicicada neotredecim Marshall and Cooley, 2000; Magicicada tredecassini Alexander and Moore, 1962; and Magicicada tredecula Alexander and Moore, 1962. These periodical cicadas have a 13-year life cycle.

All the counties/parishes:

Here is a list of the Counties where Brood IV periodical cicadas have appeared in the past. The data cames from the Cicada Central Magicicada Database(RIP).

  • Arkansas counties: Bradley, Calhoun, Carroll, Chicot, Clark, Cleburne, Cleveland, Columbia, Conway, Craighead, Crawford, Crittenden, Cross, Dallas, Drew, Faulkner, Franklin, Fulton, Garland, Howard, Independence, Izard, Jackson, Jefferson, Lafayette, Marion, Mississippi, Monroe, Montgomery, Newton, Perry, Poinsett, Prairie, Randolph, Saline, Sebastian, St Francis, Stone, Union, Van Buren, Washington, White, Woodruff, Yell
  • Arkansas cities: Bayou Deview Wildlife Management Area, Poinsett County, Devalls Bluff, Harrisburg, Holland Bottoms, Jacksonville, Jonesboro, Knox Co., Lake Hogue, Lake Poinsett State Park, Little Rock, and Wynne.
  • Illinois counties: Alexander, Champaign, Clark, Crawford, DeWitt, Edwards, Jackson, Lawrence, Logan, Macon, McLean, Perry, Piatt, Pulaski, Randolph, Richland, St Clair, Union, Vermilion, Wabash, Williamson
  • Illinois cities: Anna, Carbondale, Carterville, Chester, Clinton Lake, Giant City State Park, Marissa and Robinson.
  • Indiana counties: Bartholomew, Clay, Daviess, Franklin, Gibson, Greene, Harrison, Jackson, Jefferson, Knox, Lawrence, Parke, Perry, Pike, Posey, Putnam, Ripley, Spencer, Sullivan, Vanderburgh, Warrick
  • Indiana cities: Harmonie State Park, Hymera, Leanne, Richland, Sullivan And Posey Counties.
  • Kentucky counties: Ballard, Barren, Calloway, Carlisle, Christian, Clinton, Crittenden, Daviess, Fulton, Grant, Graves, Hardin, Hickman, Hopkins, Lee, Logan, Lyon, Marshall, McCracken, Metcalfe, Muhlenberg, Ohio, Simpson, Todd, Trigg, Warren, Webster
  • Kentucky cities: Benton, Calvert City, Gilbertsville, Henry County, Murray, and Paducah.
  • Louisiana counties: Bienville, Caddo, Caldwell, Catahoula, East Feliciana, Jackson, Livingston, Madison, Morehouse, Ouachita, Pointe Coupee, Richland, Tangipahoa, Tensas, Washington, Webster, West Carroll
  • Louisiana cities: Bastrop, Choudrant, Grayson and West Monroe.
  • Mississippi counties: Adams, Alcorn, Amite, Attala, Benton, Calhoun, Carroll, Choctaw, Claiborne, Clarke, Clay, Coahoma, Copiah, Covington, DeSoto, Franklin, Grenada, Hinds, Holmes, Issaquena, Itawamba, Jasper, Jefferson, Kemper, Lafayette, Lamar, Lauderdale, Lawrence, Lee, Leflore, Lincoln, Lowndes, Madison, Marion, Marshall, Montgomery, Neshoba, Newton, Noxubee, Oktibbeha, Panola, Pike, Pontotoc, Prentiss, Quitman, Rankin, Scott, Sharkey, Simpson, Sunflower, Tallahatchie, Tate, Tishomingo, Warren, Washington, Yalobusha, Yazoo
  • Mississippi cities: Alva, Arlington, Booneville, Brandon, Clinton, Corinth, Desoto County, Florence, French Camp, Hernando, Holcomb, Houlka, Jackson, New Albany, Oxford, Potts Camp, Silver Creek, Tishomingo, and Water Valley.
  • Tennessee counties: Carroll, Cheatham, Chester, Decatur, Dyer, Fayette, Gibson, Hardeman, Hardin, Haywood, Henderson, Henry, Humphreys, Lake, Lauderdale, Madison, Maury, McNairy, Montgomery, Obion, Rutherford, Shelby, Stewart, Tipton, Wayne, Weakley, Williamson
  • Tennessee: Atoka, Benton, Cordova, Henry County, Huntingdon, Jackson, Lavinia, Leach, Lexington, McNeary County, Memphis, Paris, Savannah, and Speedwell.

More location tips:

Here are the locations where folks reported the cicadas to Cicada Mania in 2002:

Brood XXIII reports from 2002

Brood XIII Map from Marlatt, C.L.. 1907. The periodical cicada. Washington, D.C. : U.S. Dept. of Agriculture, Bureau of Entomology:

Marlatt 1907 23 Brood XXIII

The Latest (from 2015):

The most popular question in the comments: “how long will they last”. The typical answer is about 4 weeks of singing or less. They sing to meet a mate, and once they mate a few times, they run out of energy and die. Four weeks is the typical time, although this varies depending on the weather. The cicadas will complete their mission faster if there are drier, calm days in with temps in the 80s.

My gallery of photos from Brood XXIII.

The Giant City State Park area of Illinois was loaded with cicadas. This area has all four species. It isn’t easy to tell the difference between M. neotredecim and M. tredecim, but you might notice a difference in the coloration of their abdomens (tredecim is almost all orange, while neotredecim is orange and black). There is also a difference in the pitch of their calls when they are in close proximity, so you might hear an odd dissonance in their calls. M. tredecim pitches lower. I will post photos, videos and sounds later in the week.

There are plenty of cicadas in the Land Between the Lakes area of Kentucky & Tennessee. The best place so far was Kenlake State Resort Park where M. tredecassini, M. tredecula, and M. tredecim are chorusing. The tredecula and tredecim were up in the trees out of reach, but I was able to find a few tredecim (the bigger ones with very-orange abdomens) in the weeds at ground level.

Cold and rain (and road weariness) has prevented me from locating cicadas in Texas, Louisiana and Arkansas — I know they’re there but if I can’t hear them, I can’t investigate. I’m headed north to Tennessee, Kentucky, and Illinois. Sun and temps in the 80s should make for good cicada observation. If you’re wondering why cicadas have suddenly become quiet, it’s typically because of cold temps and rain. Generally, these cicadas like it to be about 77F before they’ll fly and sing. Colder than that, and they’ll chill.

I arrived in the Jackson Mississippi area on May 19th around 3 pm. M. tredecassini were chorusing along route 20 west of Roosevelt State Park, and I found an M. tredecim (below) at a gas station. There were plenty of M. tredecassini and M. tredecula chorusing and courting in the woods behind the Mississippi Museum of Natural History. Neocicada hieroglyphica (a non-periodical cicada) was also calling in the woods.

Gas Station Cicada

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Magicicada Periodical U.S.A. Video

Time to start looking for signs of periodical cicadas

Depending on where you live, it might be warm enough for periodical cicadas to start moving around underground, or start digging tunnels to the surface and building cicada “chimneys” above their holes.

What to look for:

1) Animals can hear the cicadas stirring underground, and will try to dig them up and eat them. Look for holes (about the size of a walnut or larger) made by animals digging for cicadas.

Brood II; Cicada Holes

2) Look for cicadas under stones and slates. Some cicadas will burrow their way to the surface, but they hit a large stone or slate and can go no further.

If you find them in this situation, gently put the stone or slate back. They will usually find their way around the obstruction once the time is right.

One clue that a Magicicada nymph is not ready to emerge is its eyes are still white. Their eyes turn red/orange before emerging (a few retain a white/blue color).

3) Cicada holes are about the size of a dime. Cicadas preemptively dig holes to the surface and wait until the weather is nice enough for them to emerge. Sometimes you can see them down in the holes.

Magicicada holes
Magicicada holes

4) Cicadas form chimneys above their holes when the soil is moist or muddy. These chimneys might look like a simple golf ball-sized dome or a structure over six inches tall.


Photo by Roy Troutman.

Brood II 2013 - Dan Mozgai - Cicada Chimneys

Periodical cicadas typically won’t emerge until their body temperature reaches approximately 65 degrees Fahrenheit (17-19.5 Celsius1). Their bodies are warmed by surrounding soil or warm water from rain. A good rule of thumb is, if the soil 8 inches(20 cm) deep is 65°F, the conditions are good that they might emerge.

And here’s how to tell if a nymph is ready to molt:

A diagram that shows when a nymph is ready to molt.

1Heath, J.E. 1968. Thermal synchronization of emergence in periodical “17-year” cicadas (Homoptera. Cicadidae, Magicicada). American Midland Naturalist 80:440—448.