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June 3, 2017

Look & listen for Brood X Stragglers

Filed under: Accelerations,Brood X,Magicicada,Periodical Stragglers — Dan @ 1:01 am

Surprise!

Update #12 Last week I traveled west to look for stragglers in Ohio and Indiana. I found exuvia (cicada skins) north west of Indianapolis, Indiana; exuvia in Cedar Springs, Indiana; active, mating periodical cicadas in several small towns north-west of Columbus, Ohio; and exuvia & a few adults in Princeton, NJ. See a map of my sightings.

Periodical cicadas have been spotted in the Hudson Valley of New York state.

Don’t forget to report cicadas to Magicicada.org.
Feel free to add YouTube or IG links to the comments.
In the Ohio area, send your cicada photos of Mount St. Joseph University.

Other updates can be found in the comments.

What’s the deal with these amazing insects?

This year “precursors” to Brood X are emerging or will emerge in small to large numbers in D.C., Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, Missouri, New Jersey, New York (Long Island), North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Virginia, and West Virginia. Magicicada.org has the most up-to-date map from Brood X.

Note: because of the significant number of cicadas emerging ahead of time, this might be an acceleration event. Periodical cicada accelerations occur when a significant group of an established brood emerge in years ahead of the main brood, and sometimes the accelerated group are able to reproduce and create what is essentially a new brood. Brood VI was likely part of Brood X at one point of time1. We’ll have to see if the Brood X stragglers are able to survive predation, and reproduce in significant numbers to sustain future populations. They are certainly trying.

Some more info to impress your friends with:

These are the species you might hear/see:

  1. Magicicada septendecim
  2. Magicicada cassini
  3. Magicicada septendecula

Don’t panic! Less that one percent of a Brood straggles. If you had 10,000 cicadas in your yard back in 2004, you can expect a less-frightening or more manageable dozens or hundreds (okay, maybe 1,000s). :)

Here's Johnny

Brood VI is also emerged this year?

Brood VI also emerged this year in North Carolina, South Carolina and Georgia. These cicadas emerged on schedule, and are not stragglers. It is believed that Brood VI descended from Brood X through acceleration (mentioned above).

Brood VI compared to Brood X:
Brood X vs VI
The data comes from Magicicada.org.

What are stragglers, and why do they straggle

Stragglers are periodical cicadas that emerge in years before or after the brood they belong to is expected to emerge. Typically 17-year periodical cicadas emerge 4 years early (see the probability chart). While stragglers might not produce enough offspring to produce future generations, straggling is something periodical cicadas do — it is hard-wired into their DNA. The 4-year interval is also typical.

Stragglers are not a new phenomenon. William T. Davis documented accelerations of cicada populations back in the 1800s, which was reported by C.L. Marlatt in the 1898 document The Periodical Cicada. An Account Of Cicada Septendecim, Its Natural Enemies And The Means Of Preventing Its Injury.

Mr. W. T. Davis records the occurrence of scattering individuals on Staten Island in both 1890 and 1892, neither of which is a Cicada year. These may have been of accelerated or retarded individuals, but possibly represent either remnants of broods or insignificant broods not hitherto recorded.

In the case of W. T. Davis’s observations, Brood II would have emerged in 1894 in Staten Island, so 1890 would have been a 4-year straggler/processor/acceleration, and 1892 a rare 2-year acceleration.

The term “straggler” throws people off, because most people are familiar with the definition of straggler that means “something that falls behind the main group”. These cicadas are clearly ahead of the main group, not falling behind. Straggle can also mean “to wander from the direct course or way” (Merriam-Webster), “to trail off from others of its kind” (Merriam-Webster). In terms of cicadas, scientists and naturalists have been using the term “straggler” for over a century, so it has stuck around. For now, don’t worry about the term, just know that it means periodical cicadas that are not emerging on schedule.

More information on stragglers and accelerations.

Climate and Stragglers

Dr. Gene Kritsky, in this recent article, is quoted as saying “[c]limate changes are behind the premature debut”. Visit Gene’s website.

It makes sense that climate variations would trigger periodical cicadas to emerge ahead of time. Periodical cicadas take cues from the seasonal cycles of their host trees. An unusual climate event, like a hot fall or winter, might cause trees to signal cicadas that additional years have passed, and cause them to shift to emerge early. In the paper, How 17-year cicadas keep track of time, Richard Karban was able to show that you can speed up the time it takes for a periodical cicada to emerge by artificially altering the seasonal cycles of their host trees2. It’s likely that the Brood X stragglers emerging now were set on their path to emerging 4 years early not this year or the last, but many years ago.

Metropolitan areas like Washington D.C., called “HEAT ISLANDS” (read this article), can often be much hotter than surrounding rural areas due to human activity. The effects of living within a heat island may have disrupted the seasonal cycles of the cicadas’s host trees, and therefor the cicadas themselves. Localized climate change will be considered as a contributing factor to their early emergence. If we find considerably less stragglers in rural areas than city areas, then we could draw a conclusion that local climates are contributing to straggling.

Other than climate (in the long term), weather (in the short term), and a natural propensity to straggle or accelerate, population density is another reason why cicadas will straggle. If there is a high density of them underground, vying for limited resources, some might emerge a year or so before or after the main Brood.

References:

1 Monte Lloyd &J o Ann White. Sympatry of Periodical Cicada Broods and the Hypothetical Four-Year Acceleration. Evolution, Vol. 30, No. 4. (Dec., 1976), pp. 786-801.

2 Richard Karban, Carrie A. Black and Steven A. Weinbaum. How 17-year cicadas keep track of time. Ecology Letters, (2000) 3: 253-256.

May 12, 2016

Cicada Straggler Alert 2016

Filed under: Magicicada,Periodical Stragglers — Dan @ 9:29 pm

Straggler Alert

The point of this article is that you should be on the alert for Magicicada periodical cicadas, no matter what year it is, and if you see or hear them, report them.

Stragglers, in terms of cicadas, are periodical cicadas that emerge in years prior to (precursors) or after their brood is expected to emerge. Most often, 17 year cicada stragglers emerge four years prior to their expected emergence date — but it is possible for periodical cicadas to emerge between 8 years earlier and 4 years later than expected. Read more about cicada stragglers.

This year (2016) Brood IX stragglers should emerge in southern West Virginia, western Virginia and the north-middle part of North Carolina that connects with western Virginia. See a map here.

Looking at the live map on Magicicada.org, it is obvious that most reports come from Brood V and stragglers appear to be emerging in the Brood IX & VI areas as expected — however, there are a fair number of reports in the Brood II and X areas, which is odd.

Map

  • Red: Brood V
  • Orange: Brood IX, 4 years early (most probable)
  • Yellow: Brood VI, 1 year early (probable)
  • Green: Brood II, 3 years late (rare, but possible)
  • Dark Green: Brood X, 5 years early (rare, but possible)

As stated before, it is common for periodical cicadas to emerge 4 years early, but 5 years early is rare. So why Brood X be stragglers this year? That requires a little more thought.

Now we enter the realm of conjecture…

Rick Karban in the paper How 17-year cicadas keep track of time1 demonstrated how you can get cicadas to emerge earlier than expected if you alter the seasonal cycles of their host trees. Make the tree experience two cycles in one year, the cicadas will read this as “two years have passed” and they’ll emerge a year earlier. So, in the case of Brood X stragglers, it could be that their host trees experienced weather fluctuations that caused them to do something that signaled the cicadas that 2 years had passed. Add the 4 years they would likely straggle + 1 year caused by fluctuations from the host tree, and that makes for a 5 year straggler.

The other day wethertrends360 posted this on their facebook page:

Growing Degree Days tell us why the Northeast had such an early surge in plant growth but then slowed. From late February to early April temperatures were near record warm in the Northeast with the 2nd most Growing Degree Days (GDD) in 25 years (chart/map left). This allowed plants to emerge way too early and then the freezes came!

Perhaps this early surge in plant growth, then a freeze, then growth again seemed like two years had passed to some cicadas. Perhaps.

1 How 17-year cicadas keep track of time, Richard Karban, Carrie A. Black1 and Steven A. Weinbaum, Ecology Letters (2000) 3 : 253-256.

October 11, 2015

Look/Listen for Brood IX Cicada Stragglers in 2016

Filed under: Brood IX,Magicicada,Periodical Stragglers — Dan @ 11:11 am

There is a high probability that Brood IX (17 Year Magicicada) stragglers will emerge in 2016. Look for them in southern West Virginia, western Virginia and north-west North Carolina:

Brood IX

M. septendecim, M. cassini, and M. septendecula are all part of this brood.

Learn more about periodical cicada stragglers.

Visit Magicicada.org’s Brood IX page for detailed information.

June 27, 2015

What are stragglers?

Filed under: Accelerations,FAQs,Periodical,Periodical Stragglers — Dan @ 1:02 pm

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. 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. Image courtesy of 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 scientific literature, they are called stragglers.

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

Extremely likely stragglers in the next 10 years (or so):

2017: Brood X 4 years early.
2018: Brood XXII 4 years late.
2019: Brood XXIII 4 years late.
2020: Brood XIII 4 years early.
2021: Brood XIV 4 years early.
2025: Brood I 4 years early.

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 off-spring 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.

June 11, 2015

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:

  • Brood XIII 17 year cicadas emerging 4 years early in OH, PA, WVA.
  • Brood V 17 year cicadas emerging 1 year early in NY, OH, PA, VA, WVA.
  • Brood XIX 13 year periodical cicadas emerging 4 years late in AL, AR, GA, IL, IN, KS, KY, LA, MO, MS, NC, OK, SC, TN, VA
  • Brood XXII 13 year cicadas emerging a year late in LA, MS, OH, KY

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

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