Fireflies, also known as lightning bugs, glow to lure prey, discourage predators, and most importantly to attract mates. The characteristic green-yellow glow produced by a firefly is the result of a chemical reaction that takes place in the insect's abdomen. This chemical reaction involves three ingredients: luciferin (a heat-resistant substrate and serves as the source of the light), luciferase (an enzyme that triggers the light-producing chemical reaction), and oxygen (provides the fuel for the reaction to proceed).
The rate and wavelength at which female fireflies produce flashes is the key to attracting a mate. To understand why this is so crucial, it helps to note that the common name 'fireflies' does not refer to a single species of insect. Instead, there are numerous species of fireflies, many of which are glowing in the night sky at just about the same time in just about the same places.
So each species needs a way of distinguishing itself from the others if males and females of each species are to locate appropriate mates. Thus, the flashing rate and wavelength provide a suitable way for different species to send out different signals. By emitting light at different intervals and glowing at different wavelengths, the various species are able to distinguish among one another.
Firefly larvae are capable of bioluminescence like the adults. For this reason the larvae are sometimes referred to as glow worms. The various species of fireflies belong to the Family Lampyridae, a group of insects that in turn belongs to the Order Coleoptera, the beetles. There are over 2000 species of fireflies, worldwide. These insects are found in woodlands and moist grasslands.
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.
- Babu, G. and M. Kannan. 2002. 'Lighnting Bugs'. Resonance, Sept:49-52.
- Fireflies (Wikipedia)
- Book of Insect Records (University of Florida)