5 ms·
The Cicada's Love Affair with Prime Numbers (2013)
- the__prestige 5y agoThe 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?
- pwg 5y agoThe 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.
- filoeleven 5y agoThe 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_brood_locations 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?
- abecedarius 5y agoAlso, is it known how they manage to count to 17? Are a noticeable fraction of them off by one?
- js2 5y ago> 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/broods/ https://cicadas.uconn.edu/stragglers/ https://cicadas.uconn.edu/stragglers/
- abecedarius 5y agoThanks. "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.
- filoeleven 5y agoThe 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-matters-to-web-designers/ 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.
- cpeterso 5y agoI'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? :)
- deepdmistry 5y agoAnyone got the non paywall link?
- greenyoda 5y agohttps://archive.vn/oRlwW https://archive.vn/oRlwW
- cracker_jacks 5y agoNot just minimizing contact with predators, also minimizes resource competition with other species of cicadas.
- Alekhine 5y agoI wonder if this has anything to do with Cicada 3301? Their puzzles involve prime numbers quite a bit.
- jccalhoun 5y agoI 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.