All The Facts About Fireflies

One of my fondest memory growing up was receiving a letter from Ranger Rick (yes I am dating myself) explaining why Fireflies, or Lightning Bugs, light up. It had always been fun to chase them around the yard at night with my friends. Turns out, I never asked Ranger Rick about Fireflies. My grandfather wanted to know the answer and wrote the question in my name! Nevertheless, the answer was fascinating.

A Little About Fireflies

Fireflies are neither flies or bugs (there really is an insect family called bugs!). They are actually soft winged beetles.

For the common eastern firefly, eggs are laid in moist soil and hatch about a month later. All immature fireflies (or larvae) are called glowworms. They emit light, too, though it is a low intensity glow used to warn predators that they taste bad. The larvae of our eastern firefly develop over two summers, overwintering twice, before pupating and emerging as adults this time of the year. Larvae are predacious on other ground-dwelling critters, including other insect larvae, slugs, and snails. While eastern firefly adults do not feed, other species are predacious on scale crawlers, aphids, and other small, soft-bodied insects.

Fireflies are considered beneficial insects because their larvae feed on animals that can harm our garden plants.

Why Do Fireflies Light Up

Sex! The males flash their light in order to attract females to mate with.  Males of the common eastern firefly (Photinus pyralis) flash every six seconds. Females watch the light “show” from below. If a display from a specific male is particularly attractive, she will flash a response. The male will then go to the female to mate.

The light emitted by a firefly is actually a chemical reaction in the beetle’s abdomen. The light organ or lantern has special cells that contain a chemical called luciferin. An enzyme called luciferase combines oxygen with luciferin in these cells to create light. Scientists actually do not know how fireflies regulate their lights to turn them on and off.

So the next time you are outside enjoying the summer light show, you will know all the facts behind the fireflies.


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