Why carry out cicadas have such a peculiar life cycle?

.NATURE IS TREATING Americans to all kinds of spectacles. On April 8th millions experienced a complete solar energy eclipse. Many will certainly be much less magnetized when, in the coming days, trillions of cicadas seem in the country’s Midwest and south-east.

The throng will certainly be actually unusually large because 2 forms of the insect– Brood XIII and Brood XIX– are actually developing all at once. The last time they seemed all at once resided in 1803, when Thomas Jefferson was actually head of state. Why carry out the cicadas possess such an unique life cycle?