Tom Turpin
Professor of
Purdue University







Fireflies: Torchbearers Of The Insect World

Fireflies are members of the insect family of beetles known as Lampyridae. The name is a wonderful choice for this group of insects that have the ability to produce light. Translated literally, Lampyridae means “torchbearer.”

The torches of these insects have been used by humans for some practical purposes. For instance, the medical doctor William Gorgas once was operating on a wounded soldier in Cuba during the Spanish-American War when the lights went out. Dr. Gorgas was able to finish the operation using the light of fireflies, called cucuyos in Spanish. Dr. Gorgas later turned the tables on insects, for he is credited with helping wipe out mosquitoes that were transmitting yellow fever and hindering the construction of the Panama Canal.

How the firefly torch works has always fascinated scientists. The first understanding of the production of light by living things was generated by Frenchman Raphael DuBois, who showed that the light was produced by the interaction of two chemicals. He named the two chemicals, a substrate and an enzyme, luciferin and luciferase after Lucifer, the light bearer who brings the dawn. Lucifer also is known as the fallen angel of light, or the devil.

Luciferin and luciferase need oxygen for the reaction to work, much as a fire needs oxygen to burn. The insect controls the blinking by literally feeding the fire. When a firefly is smashed, the glow is continuous and goes out when either the luciferin or luciferase is depleted. For this reason, when a firefly crashes into the windshield of an auto, the light glows brightly for a moment before going out. The oxygen in the air rushing over the windshield is fanning the flames of a firefly fire.

One of the outstanding characteristics of Lampyridae, that they produce light, has not been lost on the entomologists who have given scientific names to some of the roughly 2,000 species in this insect family. The idea of photo is included in the names of the genera Photuris and Photinus. Microphotus is another genus of fireflies that uses photo. However, from the name it is not clear if the insects of that genus are little insects or insects with a little light.

One species of Photinus is called pyralis, a word based on the same root as the word pyromaniac. Pyro also shows up in the genus Pyractonema, two species of which are lucifer and borealis. Since borealis means northern, do you suppose the person who named the latter insect had the northern lights in mind at the time? Lucifer, that devilish character, shows up again in the genus Lucidota.

Even the scientific names of the fireflies can be used to shed a little light on the subject.


Writer: Tom Turpin
Editor: Andrea McCann