US braces for cicadas by the trillion as two broods of periodic insects coincide | Hacker News Reader

US braces for cicadas by the trillion as two broods of periodic insects coincide

theguardian.com

58 pointsvinni246 comments

Fun math in action here: these two broods emerge every 13 and 17 years, respectively. Those two numbers are coprime, so their least common multiple, the next time a multiple of one will coincide with a multiple of the other, is 13 * 17 = 221, which subtracted from 2024 is 1803, when Thomas Jefferson was president and the previous time the broods emerged in the same year.

Thats from the article

The simultaneous appearance of the two cicada broods – known as Brood XIX and Brood XII – is a rare event, not having occurred since 1803, a year when Thomas Jefferson was US president

Right but the article didn’t explain the calculation

Also to the point: the reason that the breeding cycles of these species are prime numbers of years is that it makes it less likely for a successful predator to evolve. To be a successful specialized predator of these species, your feeding cycle has to be a multiple of their breeding cycle which in practical terms means, since the cycles are so long, it has to be a exact match.

The 13s also get 17-1 breeding iterations without shared food competition from the 17s, etc, during the breeding days. The coprime periods effect strong attraction to the involved prime periods.

True but that’s less of a factor because the two species don’t have a lot of geographic overlap.

Here's a map to support your observation.

https://stateimpact.npr.org/pennsylvania/2019/05/20/everythi...

Crypto mating will eventually be a human endeavour

I want my broods named like my superbowls and final fantasy games.

Legend has it that these strange-looking numbers date to even older than the NFL and Squre Enix! :O

https://en.m.wikipedia.org/wiki/Roman_numerals

I'm really curious how the broods 'know' when to pop out.

Tiny clocks.

https://www.scientificamerican.com/article/how-do-periodical...

Some how they keep track of the growing cycle of the trees they feed on.

When I schedule periodic tasks I always use prime numbers for the loop time. That way it's less likely that tasks will be run at the same time.

It's not really that important, but I do it as a form of tribute to the cicadas.

Of course, you still need the worst case when they overlap to meet performance requirements, and you just made testing that that much harder.

With enough tasks and/or small enough timing precision, that worst case may only occur once every thousand years or more.

Haruki Murakami, is that you?

Is the US really "bracing" for this event? Girding their loins to brace in anticipation of this event? Bracing their bodies or their minds? Will the Walmart people make runs on toilet paper? If I want to properly brace, what do the experts say?

Brace, brace, brace. Brace for bugs.

I'm in Illinois not far from where the broods overlap. I'm looking forward to it.

The last big brood was a bust where I live (About 30 miles west of Chicago downtown.)

Are you properly-braced for this event?

yeah - no.

If the person in charge doesn't properly "brace" then the opposing party will "slam" them

Or "rip" or "sound off" on them even. After all, they've been issued a FINAL WARNING.

Earplugs at least.

Man, walking outside to a concert volume roar was nuts. And then them flying around and pelting you.

Then opening your car door quick and shutting it because they like to fly at you right as you get in in.

Was driving and noticed one walking on my neck. I certainly was braced in that moment.

> The two broods may only overlap slightly in a small area of central Illinois, meaning there mostly won’t be a larger-than-normal boom in numbers in any one place

It's too bad that for all the headlines making this sound like a biblical plague the reality will be that this summer won't be much different from normal unless you actually care to get to so up close and personal with these bugs that you'll notice differences in species.

I'm hoping that they'll at least sound different enough that I can appreciate the variety since I almost never see them crawling or flying.

Take notice if you're a motorcycle rider. If you see a swarm, pull over and drive at minimum speed because crushed bugs en masse can absolutely de-bike you.

I remember last time the 17 year brood emerged I was living in Illinois. I remember riding my bike to school and it was impossible to not run over a bunch of cicadas. Also a nearby zoo was paying people to bring in buckets of them which they would use to feed animals there.

Yeah I remember this, it was pretty gross in a fascinating way. You'd walk outside and every step was crunchy.

What is the going rate for a bucket of cicadas?

The logistics of transportation sound tricky. Am I scooping up dead cicadas? If live, transporting the bulk intact is going to be fun. I am imagining broke teenagers balancing squirming buckets on a bike handlebars.

Yep, it was basically something for us kids and teens to do to make some cash, and iirc there were a decent amount of people who did it that lived nearby the zoo

So time to invest in Sesame futures?

In case anyone needs the reference: https://www.youtube.com/watch?v=KUxMY77i0q4

On-topic: I don't know why, but the videos of masses of cicadas always seemed so overwhelming to me, I mean I just cannot imagine walking through an effected area. Nature can truly produce incredible phenomena.

I'd include locusts as well, I cannot fathom the experience of being in the path of a insects swarm extending for hundreds to thousands of kilometres.

But then the locusts would be eating anything green in their path as they were swarming. Cicadas are a walk in the park, comparatively.

In the real world, by the time this reaches the news it's already priced in.

I upvoted you, but would say - Only if you assume markets are perfectly efficient. It seems there is often some money to be made.

Peter Gregory is pleased

Time to load up on sesame seed futures.

Cicada broods only come out infrequently, but people freaking out about cicadas is closer to an annual tradition. https://www.washingtonpost.com/food/2021/05/11/cicadas-resta...

Isn't it Brood XIII, not XII?

Yes.

(source: > In 2024, 13-year Brood XIX, which is the largest of all periodical cicada broods, will co-emerge with 17-year Brood XIII; these two broods are adjacent (but not significantly overlapping) in north-central Illinois.

- https://cicadas.uconn.edu/)

Are they edible? We should eat them, protein powder.

My family and I just arrived in Dallas to see the eclipse since it’s on the same day as my son’s 5th birthday.

Where should we travel to see the cicadas?

You have a chance to see them in northwestern Lousiana or western Arkansas:

https://en.wikipedia.org/wiki/Periodical_cicadas#Map_of_broo...

You might want to double-check with a local. The ones closest to you in Dallas would be Brood XIX, the light blue ones on the map.

Times nicely with the Armageddon of 2024.

I see no signs of being braced.

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