Cicada swarmaggedon

Most of the life cycle of the Magicicada Septendecim is spent underground.  Then at 17 year intervals, these cicadas emerge from the ground, climb deciduous trees, molt into adults, mate, lay eggs, and die.

Why does the 17 year interval help this species survive?

In this activity students learn about the length of a life cycle and why a large prime number makes an excellent survival technique.