Transcript:

The chittering of cicadas is a familiar sound during the hot days of summer. Some cicadas join together by the
thousands to sing, and if you listen closely, you'll hear that it's a three-part chorus, that changes throughout the
day. I'm Jim Metzner and this is the Pulse of the Planet, presented by DuPont. When they reach adulthood, male
cicadas begin singing and gradually, other males join in. The goal is to make as much noise as possible, to
attract more female cicadas to mate with. Cicadas make this sound by vibrating drum-like organs on their
abdomen. And among the periodical cicadas, their symphony is very well-orchestrated.

"At first, it sounds like anarchy. You know, everybody making noise. But if you listen rather carefully, throughout
the day, you find that there are discrete times of day at which the cicadas sing."

Gilbert Waldbauer is the author of "Millions of Monarchs, Bunches of Beetles: How Bugs Find Strength in
Numbers." "Each one of these emergences of cicadas consists of three different species that look quite a bit
alike, but are actually distinguishable if you look at them closely. And one species sings in the morning, another
sings in the middle of the day and another sings in the afternoon."

Here's the species of cicada that starts singing in the morning.
(Cicada sound)


And here's the species that joins in the chorus around midday.
(Cicada sound)


This third type of cicada does most of its singing in the early afternoon.
(Cicada sound)


And for a time during the middle of the day, the three types of cicadas are all singing at once.
(Cicada sound)


Pulse of the Planet is presented by DuPont, bringing you the miracles of science, with additional support
provided by the National Science Foundation. I'm Jim Metzner.