Listening practice: The insects that wait seventeen years

Imagine spending almost your whole life in the dark, beneath a tree, and then appearing with millions of neighbors on almost the same evening. That is the strange rhythm of periodical cicadas in eastern North America. The University of Connecticut explains that the genus Magicicada contains seven species. Four follow a thirteen-year cycle, and three follow a seventeen-year cycle. These numbers describe the years spent underground, not the short life of the flying adult. Today we will follow a cicada from a tiny nymph in the soil to a noisy adult in the trees, and we will ask a question scientists still cannot answer completely: how does it keep track of the seasons for so long?