Discuss “How Things Work: Fireflies”

During the summer, a bird’s-eye view of your house might show little dancing lights around it. Up close, these lights are fireflies.

These “lightning bugs,” though, aren’t actually flies at all. They’re beetles, with one pair of wings. (To spot similar fakers in the future, when the name of an insect contains the word “fly,” it probably isn’t a true fly.)

There are more than 170 species of fireflies in the United States and more than 1900 known species worldwide. Fireflies are found on every continent except Antarctica.

Fireflies glow with “fire” or “light” from within their bodies in a process called bioluminescence. Bioluminescence can be seen when light-producing chemical reactions occur in specialized cells in the...