[HN Gopher] The Cicada's Love Affair with Prime Numbers (2013)
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       The Cicada's Love Affair with Prime Numbers (2013)
        
       Author : optimalsolver
       Score  : 31 points
       Date   : 2021-05-21 18:52 UTC (4 hours ago)
        
 (HTM) web link (www.newyorker.com)
 (TXT) w3m dump (www.newyorker.com)
        
       | deepdmistry wrote:
       | Anyone got the non paywall link?
        
         | greenyoda wrote:
         | https://archive.vn/oRlwW
        
       | the__prestige wrote:
       | 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?
        
         | filoeleven wrote:
         | 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?
        
         | pwg wrote:
         | 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.
        
       | cracker_jacks wrote:
       | Not just minimizing contact with predators, also minimizes
       | resource competition with other species of cicadas.
        
       | filoeleven wrote:
       | 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.
        
         | cpeterso wrote:
         | 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? :)
        
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       (page generated 2021-05-21 23:00 UTC)