These evenings our granddaughters beg to stay up late. It isn’t a TV show or to play with their computer; they want to go out and catch some fireflies. I can still remember when as a youngster I would take a mason jar and try to catch enough fireflies to make a temporary night light.
The tail abdominal segments of the male firefly are luminous with greenish-yellow light. This light alternately brightens and dims as the firefly’s wings slowly move back and forth in the earliest hours of darkness.
Fireflies are also known as “lightning bugs.”
The light from these insects is due to a chemical reaction in which a cell product called luciferin is burned in the presence of an enzyme, luciferase. The female has the light only in one segment. This flashing light serves in these nocturnally active insects to bring the opposite sexes together for mating.
In one common species in Pennsylvania it serves to bring the male to a carnivorous female who after mating will devour the male. Most of the females are short-winged and flightless.
The aquatic or nearly aquatic larvae feed on snails and slugs. Because of the help in controlling slugs that often destroy early garden crops they are a welcome sight in the dusk of a farmyard.
Often, in our area, the fireflies’ flashing is rhythmic as they flash in single or double flashes, according to species. It has been noticed that they flash more frequently the warmer the night air is.
In the tropics, they are a real sight. In Panama, I once saw a cloud of them flashing brightly in unison.
Not a great deal is known of their complete life cycle including how they spend time off-season.
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