The Cicada's Love Affair with Prime Numbers (2013) | Hacker News Reader

The Cicada's Love Affair with Prime Numbers (2013)

newyorker.com

62 pointsoptimalsolver13 comments

The title immediately made me think of this article on using prime numbers in CSS to grow natural-looking variations.

https://www.sitepoint.com/the-cicada-principle-and-why-it-ma...

I’m excited to see the badass Deluxe Edition coloration of Brood X when they emerge in my area. I dunno what I was doing in 2004, but I clearly was not spending enough time outside.

I've read about a system that used prime numbers in scheduling timers and timeouts to reduce the chances of event synchronization. If you've got to pick a mostly-arbitrary number, why not make it prime? :)

I read an article a month or so ago but I can't find it now. I was expecting it to talk about the cycles being prime numbers but instead it described the cicada's cycle in terms of 1 year + 3 or 4 cycles of 4 years. Same phenomenon but just a different way of thinking about it.

The article does a great job explaining why lifecycle periodicity is prime. But its very curious that 13 and 17 year cicadas are common, but not 7 or 11. Do such cicadas exists as well? Why do we not see cycles beyond 17 years?

The article briefly touches on why not 7 or (almost) 11:

"If we discount those cicadas with life cycles of ten years or fewer (as being too close to predator life cycles), we find that the most successful emergence rates for cyber cicadas are thirteen and seventeen years—precisely what we find in the wild."

Why not beyond 17? The article does not say. The next prime would be 19 (only two years longer). Perhaps 17 provides a sufficiently large local optimum that there is little pressure to lengthen the cycle to 19 or beyond.

The upper bound could be because it’s a long time to live as a glorified grub.

It’s also interesting that the different periodical broods have pretty distinct boundaries: https://en.m.wikipedia.org/wiki/Periodical_cicadas#Map_of_br...

Perhaps the same selective pressures that separated the broods geographically also filtered out shorter cycles due to predation?

Also, is it known how they manage to count to 17? Are a noticeable fraction of them off by one?

> Sometimes periodical cicadas emerge “off-schedule” by one or more years. This phenomenon is often referred to by the general term “straggling,” although straggling cicadas can emerge either later or earlier than expected.

https://cicadas.uconn.edu/broods/

https://cicadas.uconn.edu/stragglers/

Thanks. "Straggling emergences in which only a few cicadas are present are common, but larger unexpected emergences of thousands of individuals have also been reported."

There's a suggestion that climate change may be causing more stragglers, but nothing else on how they count or time it.

Not just minimizing contact with predators, also minimizes resource competition with other species of cicadas.

I wonder if this has anything to do with Cicada 3301? Their puzzles involve prime numbers quite a bit.

Anyone got the non paywall link?

https://archive.vn/oRlwW

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