I remember chasing fireflies around the back yard on warm summer evenings when I was a kid. The fireflies would come out just after dusk and float in the humid late-summer air, dipping in and out of the oak and maple trees and landing occasionally on clumps overgrown grass. I used to follow a single firefly as it floated through the air and position myself so it was at about eye level. I would then gently lift my palm up from underneath the flying insect and it would land on my hand and start crawling around, its belly still flashing on and off. After a few moments it would again take flight and drift off into the growing darkness.

I don't recall when I started calling them fireflies, I knew them first as lightning bugs. Their larvae, which are also capable of luminescing, are called glow worms. All these common names are used rather loosely to refer to members of the Family Lampyridae, a group of insects that in turn belongs to the Order Coleoptera, the beetles.

The Order Coleoptera is not the only order of insects to boast glowing members. The orders Collembola, Hemiptera, and Diptera too have representative species that exhibit bioluminescense.

Simply put, bioluminescence is the ability of an organism to emit light. This light production is the result of a chemical reaction (and as a result the term chemiluminescence is also used to describe this light production). In the case of fireflies, this reaction involves luciferin, luciferase, and oxygen. In the case of bioluminuescent marine organisms, the reaction often involves other substances such as coelenterazine or vargulin.

Find out more: Why do Fireflies Glow?

Photo © Gomez Photography / iStockphoto.