Fireflies

Written By:  Andrew Eide

My topic today is Fireflies. Before I launch into my article please be advised that fireflies are not flies at all…they are beetles.

The scientific name for these beetles we call fireflies is Lampyridae of the beetle order Coleoptera. They are winged beetles which are commonly called fireflies or lightning bugs. This is due to their conspicuous use of bioluminescence to attract mates or prey. Fireflies produce what is called a “cold light” with no infrared or ultraviolet frequencies. This light is chemically-produced from the lower abdomen and the light may be yellow, green, or pale-red, with wavelengths from 510 to 670 nanometers.

There are about 2,000 species of fireflies found in temperate and tropical environments. Many are found in marshes or wet wooded areas. The larvae of the firefly also emit light and are often called “glowworms.”

The light production of fireflies is due to a type of chemical reaction called bioluminescence. This process occurs in specialized light-emitting organs usually on a firefly’s lower abdomen. The enzyme luciferase acts on the luciferin, in the presence of magnesium ions, ATP, and oxygen to produce light.

The production of light in the larvae, or glowworms, serves a different function than it does in adult fireflies. It appears to be a warning signal to predators since many firefly larvae contain chemicals that are distasteful or toxic.

It was originally thought that the light produced by adult fireflies was also used as a warning signal but the primary purpose is now thought to be in selecting a mate. They have various ways of communicating with their light during courtship including: steady glows, flashing, and the use of chemical signals unrelated to the photic systems.

The female of the Photuris fireflies are known to mimic the mating flashes of other fireflies for the sole purpose of predation. Target males are attracted to what they believe is a suitable mate only to be eaten. This has caused the Photuris firefly to be referred to as femme fatale fireflies.

I grew up in Oakland, California in the San Francisco Bay Area and I don’t remember seeing fireflies in the Bay Area. I believe I saw a few here and there when we camped in the mountains but they are not common in this area. When I lived on the East Coast, both in the States of Virginia and Connecticut, I remember those nights when I could sit outside and watch the fireflies flit around and flash their lights. It was a truly calming and relaxing experience.