Mark Sturtevant Loc: Grand Blanc, MI

The 17 year cicada (Magicicada septendecim) is one of the periodical species of cicadas. This species lives for 17 years (!) as nymphs, where they stay underground and feed on tree sap from their roots. Then, in a rather tightly synchronized mass emergence, they emerge as winged adults, mate, lay eggs, and die over a period of a couple weeks. The eggs soon hatch and the nymphs burrow into the ground until it is their turn to emerge 17 years later. It is an incredible site to see high thousands of adults in great concentrations, sitting on tree limbs, houses, and singing loudly. I have never experienced this natural wonder, although my parents endured a very dense mass emergence at my old home while I was away to college. I missed it.

There are several different "broods", and a very large one, called brood ten (brood X) is due to appear over many areas of the eastern U.S. sometime in mid-May - early June, the exact timing depending on temperatures. So if you live in this part of the country, you might want to get ready!

Here are links.
>> Maps of the different broods of 17-year cicadas, with their year of peak emergence: https://www.fs.fed.us/foresthealth/docs/CicadaBroodStaticMap.pdf

>> A very detailed and zoomable map for brood X, due to emerge early this summer: https://cicadas.uconn.edu/m_septendecim/.

>> General information about this cicada: https://www.cicadamania.com/cicadas/periodical-cicada-brood-x-10-will-emerge-in-15-states-in-2021/ This includes an example of an emergence schedule, and one can see that the timing depends on soil temperature and rainfall. An emergence has different stages. So to see the peek of action I suppose it would be handy to look for freaked out anchors on your local news.

>> Of course only Sir David Attenborough will do to show what it can be like: https://www.youtube.com/watch?v=EWr8fzUz-Yw.

Quixdraw Loc: x

Been through it many years ago - a couple of boxes of chromes somewhere. Absolutely bizarre, kinda creepy event. You will not be able to resist taking photos.

Mark Sturtevant Loc: Grand Blanc, MI

Oh I fully intend to take photos!

Quixdraw Loc: x

Back then my photo genres included neither Nature nor close ups, but it got me fired up anyway.

naturepics43 Loc: Hocking Co. Ohio - USA

If your anything like me you'll probably take way too many photos. (But I really don't think you can take too many). My photos are from brood V in 2016 in Ohio. Have fun!

Mr. B Loc: eastern Connecticut

Thanks for all the information. The photo ops (and fly-fishing) should be wild.

relbugman Loc: MD/FL/CA/SC

Experienced an emergence in MD in 1952, I think, or near there - BC (before camera), I was just around 10, a budding entomologist. Got my first Brownie at 13, loved it except for the flashbulbs. Moved around, missing all broods since (64 yrs in CA- no Periodicals there). Hoping they show up now in my back yard in NW SC - chancy, but will be somewhere nearby. On the primary number brood cycle, check out Mark's URLs and excellent info! For something that outsmarts the primes, check out: https://www.pbs.org/video/gross-science-why-dont-these-cicadas-have-butts/. 'Gross' kidwise fun. Figured SOMETHING would 'outsmart' them, a LONG facultative life cycle!

Mark Sturtevant Loc: Grand Blanc, MI

Gross! But now I will look for butt-less cicadas. Thanks!
There is this other idea about periodical cicadas using prime #s in their cycle which is that if two broods ever have a coinciding emergence in the same area (and I suppose that could be a bad thing for them), then the coincidence won't happen again.

sippyjug104 Loc: Missouri

Thanks for the links, Mark. We are in the 13-year brood and my area is one of them that is classified as being multiple broods. Our big emergence is predicted to be in 2024 although I do see several individuals each summer just not in swarms.

relbugman Loc: MD/FL/CA/SC

Mark.
Somewhere (I think in your refs) I saw that when two broods overlap and one is 13 the other 17 yr cycles, it would be 221 yrs (I don't remember the exact number they said, but this makes sense) before they could interact again -- 17 and 13 cycles resp., since there is no smaller common denominator. This would be the most dangerous recombination since similar genes would control the time difference.

It would depend on a few things, though. The genes would have to act in the same manner in the mixed genomes (half from each species parent) to work. One could be dominant over the other, and only that gene would function. The species must be inter-fertile, sometimes but not often true between different species. The species must be open to mating with each other, overcoming inevitable song and courtship differences. The genes could? blend in the effect (15 yr??), and this new brood would always depend on heterozygotes (have both 13 and 15 yr genes every time) in following generations and would be a much smaller population – only half of the offspring in each generation: this reduces probability of new brood success in the future. Homozygotes (2x13 and 2x17) would be even smaller offspring pops (¼ each) and even less successful in future generations. Too, small populations could succumb to ‘glut predation’, they are so obvious and easily caught they might be quickly wiped out.

Another problem is that each species has a species-specific and unique song; this gets in the way of successful inter-species courtship. However, in such dense populations, chance meetings would happen, and one look into those riveting red eyes and a horny cicada might overcome all prejudices.

The multiple broods each of 17 and 13 year species do have ‘mistakes’, usually 1 or 2 years earlier or later, or, strangely, 4 years, but these are so uncommon that they would hardly ever initiate new broods, succumbing to ‘glut predation’ or not finding any mates, yet they might have been the initiators of the existing broods by rare chance circumstances long ago, perhaps triggered by changes in a period’s weather. Each brood usually includes 2 or 3 species of the same cycle, but they normally avoid intermating because their songs are more different than some 13/17 mixes.

relbugman Loc: MD/FL/CA/SC

Sippy; there are over 30,000 species of Cicadas world-wide, probably over 100 in the US; they range from pygmies less than 15mm body length to giants over 5cm in the US, some larger in the tropics. Many of these species are annual or biennial, the latter usually having two broods alternating years and sometimes individuals skipping one and intermixing maintaining the single species. Some species have 3-5 year cycles.
Only three species are 17 year, and four 13 year, and each of three pairs of one 13 and one 17 are more closely related than to the others, the cycles perhaps determined by regional temperature regimes and genetics. (Things are always updating, so there may be more than seven species now?) So the ones you see/hear each year are not the same species as the Periodical Cicadas coming up now or in ‘24 or other brood years. Broods are named for the aggregate abundance and the cycle history, not for the various species they contain, and may characteristically have 1, 2, 3 or 4 species present, or even more if 13 and 17 overlap (but then, both a 13 and a 17 brood are listed).

relbugman Loc: MD/FL/CA/SC

Correction, to Bugman "Somewhere (I think in your refs)"
Actually, I missed -- there are more commonly 4 year mistakes than 2 or 3, don't know why. If they were to mix with another brood, they might gain protection from the recurring brood, and might mate with their species in the co-current brood, reinforcing their species over multiple broods.