Why carry out cicadas have such an unusual life cycle?

.TYPE IS Attending To Americans to all type of spectacles. On April 8th millions saw a total solar eclipse. Numerous will definitely be less charmed when, in the coming days, mountains of cicadas seem in the country’s Midwest and south-east.

The throng will be actually unusually large considering that pair of kinds of the pest– Family XIII and Brood XIX– are emerging at the same time. The last time they seemed all at once remained in 1803, when Thomas Jefferson was president. Why carry out the cicadas have such an unusual life cycle?