July 7, 2000

     Lightning Bugs

After the sun goes down and it becomes dark, the flashing of lightning bugs or fireflies can be seen if one is in or near their habitat.  From May into mid-summer we usually see their tiny lights over meadows and grassy ditches not far from woodlands.

The flashing is a recognition signal enabling the sexes to find each other.  Each firefly species has a characteristic flashing rhythm, and an expert observer can identify species by the length of the flashes and the interval between flashes.

Lightning bugs are soft-bodied beetles that have segments near the ends of their abdomens that enable them to produce light.  The light is unique in that it is cool, and nearly 100 percent of the energy given off appears as light.  It is produced by the oxidation of a substance called luciferin that is manufactured in the cells of the light-producing organ.

Because they can take in air through tiny openings in their abdomens, the fireflies control their blinking yellow lights by controlling the air supply.  When the air is admitted, the luciferin in the presence of an enzyme called luciferinase is almost instantly oxidized, releasing the energy as light.