
Periodical Cicadas - unkulunkulu
https://en.wikipedia.org/wiki/Periodical_cicadas
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unkulunkulu
> The nymphs emerge in large numbers about the same time, sometimes more than
> 1.5 million individuals per acre (>370/m²).[14] Their mass emergence is a
> survival trait called predator satiation: for the first week after
> emergence, the periodical cicadas are an easy prey for reptiles, birds,
> squirrels, cats, and other small and large mammals.[5][15] Early ideas
> maintained that the cicadas' overall survival mechanism was simply to
> overwhelm predators by their sheer numbers, ensuring the survival of most of
> the individuals. The emergence period of large prime numbers (13 and 17
> years) was hypothesized to be a predator avoidance strategy adopted to
> eliminate the possibility of potential predators receiving periodic
> population boosts by synchronizing their own generations to divisors of the
> cicada emergence period.[16] Another viewpoint holds that the prime-numbered
> developmental times represent an adaptation to prevent hybridization between
> broods with different cycles during a period of heavy selection pressure
> brought on by isolated and lowered populations during Pleistocene glacial
> stadia, and that predator satiation is a short-term maintenance
> strategy.[17] This hypothesis was subsequently supported through a series of
> mathematical models, and stands as the most widely accepted explanation of
> the unusually lengthy and mathematically precise immature period of these
> insects.[18] The length of the cycle was hypothesized to be controlled by a
> single gene locus, with the 13-year cycle dominant to the 17-year one,[19]
> but this interpretation remains controversial and unexplored at the DNA
> level.

