Billions of cicadas will emerge in these states after 221 years
Newsy
It is a statistical rarity for cicadas who reach adulthood at 13 years old and cicadas who reach adulthood at 17 years old to emerge simultaneously.
It’s a phenomenon that hasn’t happened in 221 years: Two cicada broods will emerge simultaneously this year. The double emergence of these broods hasn’t happened since 1803.
Cicadas have a periodical life cycle. These insects spend most of their lives without being seen or heard by humans. However, these nymphs thrive below the surface, living on tree sap and awaiting adulthood.
Some cicadas wait 13 years to become adults, while others wait 17 years. Once they become adults, they emerge from the ground and mate. This explains all the racket that cicadas make during the summer. To us, it’s noise, but to female cicadas, it is a courting call.
It is a statistical rarity for cicadas who reach adulthood at 13 years old and cicadas who reach adulthood at 17 years old to emerge simultaneously. This event will not happen again until 2245.
Scientists hypothesize that periodical life cycles are an evolutionary response. Periodical cicadas might emerge at distinct periods as a means of both avoiding predators’ life cycles as well as protecting against brood hybridization.
