Fireflies, also known as lightning bugs, have fascinated ancient cultures and still remain a mysterious insect.
Contrary to their name, fireflies are not actually flies; they are beetles. They are members of the lampyridae family in the beetle order of coleoptera. The Pyralis firefly or lightning bug is the most common species found in North America. In fact, there are at least 136 species of fireflies in the world.
Why Fireflies Glow
In nature, everything has a function. For fireflies, it is part of their mating ritual. In some species, the male when seeking a female, will flash a signal in order to catch the attention of a female. In turn, the female will flash back as an indicator for the male to come closer. They exchange flashes until they meet and mate. Not all species flash and in some species only one sex has the ability to glow.
It is interesting to note that each species of firefly has its own flash pattern. Some have series of long steady glows or short flashes or mixtures of both at different intervals. This is to prevent cross breeding. There are females of certain species that can mimic the patterns of others. The male is lured by the flashing female and then killed by her.
How Fireflies Glow
Fireflies have a light-emitting organ on their lower abdomen. Oxygen enters their body through a tube in the abdomen called the abdominal trachea. Light is produced when the oxygen combined with the organic compound luciferin react to the enzyme luciferase. This produces a chemical called oxyluciferin. This process is called bioluminescence. Fireflies can control the brightness of the light they emit. It is not known if the light flash patterns are controlled by the oxygen supply or by the nerve cells.
The biochemical industry harvests fireflies in order to extract the luciferase enzyme. This chemical is used by forensic investigators to swab for traces of blood left on surfaces at crime scenes. Blood banks use it for testing their stock in order to determine if the red blood cells are beginning to break down.
Where Fireflies Glow
In temperate climates, fireflies can be seen in the summertime. The best places to find them are near streams or marshes, in the woods, bushes or in grassy areas. The larvae feed on slugs, earthworms, snails and any dead animal material so they will be most plentiful in this environment. The larvae are known to glow too. In the winter, the larvae live underground and emerge in the spring. In tropical climates, fireflies are found year round.
On summer nights, these little creatures put on entertaining show of blinking lights. If you are lucky enough to see a swarm of fireflies, the sight is incredible!
