Brood VI (6) 17-year cicadas (“locusts”) will emerge in the spring of 2017, in South Carolina, North Carolina and Georgia… and very possibly other locations as well.
About Brood VI:
The cicada species that will emerge are Magicicada septendecim (Linnaeus, 1758)1, Magicicada septendecula Alexander and Moore, 19621, and possibly Magicicada cassini (Fisher, 1851) 2. These periodical cicadas have a 17-year life cycle. The last time they emerged was 2000.
When: Generally speaking, these cicadas will begin to emerge when the soil 8″ beneath the ground reaches 64 degrees Fahrenheit 3. A nice, warm rain will often trigger a emergence. So, definitely May, but something might happen in April if we have a particularly hot spring.
Locations where they are likely to emerge:
This data comes from the Cicada Central Magicicada Database and other sources.
Counties: Buncombe, Burke, Caldwell, Henderson, McDowell, Polk, Wilkes.
Counties: Oconee, Pickens.
Various counties in Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, Wisconsin, and West Virginia. More about that here.
Learn more about Brood VI:
- Brood VI on Magicicada.org. Includes the best map.
- Learn more about Periodical Cicadas, including what to look for before they emerge and how to figure out if they’ll emerge in your town.
- Cicada Frequently Asked Questions
Here’s some more stuff to get you excited about the emergence:
Watch a cicada emerge from its skin:
A whole lot of cicada nymphs:
Other than Georgia, North Carolina, and South Carolina
Warning: this ramble might be boring for folks not in GA, NC, and SC. You might want to skip it.
The most interesting aspect of Brood VI for cicada researchers is its widespread distribution according to literature from the past. Take a look at the Brood VI map on Magicicada.org to see what I mean. See all those blue triangles? Those represent locations from the 1923 version of C.L. Marlatt’s The Periodical Cicada (United States Department of Agriculture, Bureau of Entomology Bulletin 71). Notice that they’re all over the United States, east of the Mississippi, and not just concentrated in Georgia, North Carolina and South Carolina, like the recent, verified sightings which are marked with Gold & Brown symbols.
The question is: was C.L. Marlatt mistaken? Is Brood VI really as widespread as his bulletin suggests, or do these sightings represent:
- Stragglers from other Broods like X or V.
- Members of Brood XIX that just happened to emerge the same year as Brood VI.
- A combination of two or more of these.
Or… perhaps they are (or were) totally legitimate, actual populations of Brood VI.
If you look at the data from the Cicada Central Magicicada Database and compare the County/State locations where the Literature says Brood VI is, with other broods that emerge in these County/State locations, you’ll find an argument for the possibilities mentioned above.
Brood X really stands out.
Stragglers from other 17-year Broods
Quoting David Marshall’s paper Periodical Cicada (Homoptera: Cicadidae) Life-Cycle Variations, the Historical Emergence Record, and the Geographic Stability of Brood Distributions: “Many of the questionable brood VI records fall within the ranges of 17-yr broods II, V, and – separated from brood VI by 1 or 4 yr.”4
It’s very likely that Brood X stragglers, arriving a very-probable four years early, might be mistaken for Brood VI. About 41% of the Brood VI records overlap with Brood X. Reports of Brood X stragglers, year after year, could add up to significant numbers, and appear to be populations of Brood VI.
Not as likely, but still possible are Brood V stragglers emerging a year late. That would account for about 20% of the overlaps.
Probability of Magicicada straggling in order most likely first: 1) 4 years early, 2) 4 years late, 3) 1 year early, 4) 1 year late. Read more about stragglers.
Co-Emergence with Brood XIX
Brood XIX cicadas have a 13-year life cycle, and Brood XIX and VI will emerge in the same year every 221 years 13 x 17 = 221).
About 9% of the Brood VI records show an overlap with Brood XIX. The last co-emergence of these broods happened in 1881. There’s a good chance in that in 1898 Brood XIX +4 year stragglers emerged along with Brood VI too.
Legitimate groups of Brood VI not in GA, NC or SC
About 20% of the Brood VI records share no overlap with other Broods (at least according to the database). These are the interesting ones (to me at least). These seem to be the most likely candidates for something unique, and not a straggler or descendant of another Brood. There seem to be about seven counties in Wisconsin that share no overlap with another Brood. Notice on the Magicicada.org Brood VI page this: “Isolated populations in WI were not confirmed in 2000, but the search was not exhaustive.” Hmmm… I have to ask.
It is possible that groups of Brood VI existed during Marlatt’s time, but they have gone extinct since the 1920s. We lost Brood XI in 1954 — extinction is highly possible.
The Jim Thorp Pennsyvalnia periodical cicadas that emerged in-sync with Brood V in 2016 are an example of a group of periodical cicadas that share the same cycle as a major brood, but differ in location, and probably lineage. There might be a few examples like this as well.
Gene Kritsky’s must-own book Periodical Cicadas the Plague and the Puzzle (2004, Indiana Academy of Science, page 97) notes that in 2000 there were several large emergences of periodical cicadas outside of GA, NC & SC. They emerged in Maryland, Virginia, Washington D.C., Ohio, Kentucky, and Indiana. Note that Brood X also emerges in these areas. Has part of Brood X been accelerating to fall into the same cycle as Brood VI? Maybe.
Last, it is important to mention that there will be plenty of legitimate Brood X stragglers emerging next year (Brood X map). These might get confused with Brood VI.
1 Teiji Sota, Satoshi Yamamoto, John R. Cooley, Kathy B.R. Hill, Chris Simon, and Jin Yoshimu. Independent divergence of 13- and 17-y life cycles among three lineages of periodical cicada lineages. Proceedings of the National Academy of Sciences of the USA.
2 Gene Kritsky Periodical Cicadas the Plague and the Puzzle (2004, Indiana Academy of Science, page 97)
3 James Edward Heath, Thermal Synchronization of Emergence in Periodical “17-year” Cicadas (Homoptera, Cicadidae, Magicicada) American Midland Naturalist, Vol. 80, No. 2. (Oct., 1968), pp. 440-448.
4 David C Marshall Periodical Cicada (Homoptera: Cicadidae) Life-Cycle Variations, the Historical Emergence Record, and the Geographic Stability of Brood Distributions. Ann. Entomol. Soc. Am. 94(3): 386Ð399 (2001). Link to website where you can get this document.
* The map is based on this map from the Wikimedia Commons by Lokal_Profil. The data for the map come’s from Magicicada.org.