3 ms·

Found a good PBS video on YouTube https://www.youtube.com/watch?v=W_fy2vCcIiE https://www.youtube.com/watch?v=W_fy2vCcIiE So they spend 17 years underground, t

• dspillett 5y ago
  For some groups it is 13 years. It is thought that the co-prime-ness of 17 & 13 (all primes are co-prime, as are many combinations of non-primes, so these two numbers are not especially special in that sense) helps reduce competition for resources between those with the different periods. Nature doing its clever but simple solutions thing.
  • benstrumental 5y ago
    What resources would they be competing for? I would expect more overlapping years would be beneficial since their primary survival strategy is predator satiation.
  • valarauko 5y ago
    The ranges of the 17 & 13 year Periodic Cicadas don't really overlap, so the strategy isn't to avoid competition with other cicadas. It's believed that the prime number periodicity is to avoid the life cycle periodicity of predators. Besides, in areas where different cicadas overlap, they spend something like 99.9% of their time underground consuming the same food resource, alongside the non periodic annual cicadas. Competition between cicadas doesn't seem a major issue.