So what do prime numbers have to do with music?

Read here to find out about cicadean rhythms. Many composers use prime numbers, for the same reason that insects do!!! To avoid predators!

http://www.theatlantic.com/business/archive/2013/05/why-do-cicadas-breed-in-prime-year-intervals-economics-explains/276284/

The 17-Year Itch: Why Cicadas Love Prime Numbers

The invisible hand at work — in bug shells and Gap storefronts

(c) Reuters

The mystery of cicada reproduction is two-fold. Such strange timing and such large portions.
What would the bugs gain by having sex in large prime-number intervals — 13 or 17 years — and all at the same time, Stephen Jay Gould asks in his famous essay “Of Bamboos, Cicadas, and the Economy of Adam Smith.” He had a theory. It’s called predator satiation.