The firefly or lightning bug is an insect best known for the green light it emits. Its green glow was a mystery for years, which caused many to believe it was a mythical sort of creature. The green light is now known to occur through a special gene, which codes for a protein called luciferin (from the Latin lucifer, "light-bringer").
It is a relatively small bug, that thrives in warmer areas. Although harmful to its predators, the firefly is harmless to humans. It is a bug that usually minds its own business, and leaves the curiosity to us. It is a type of beetle belonging to the Lampyridae family. The firefly's glow is used for many purposes. Not only is it a part of the mating ritual, but it is also a signal for predators. So while we fascinate over its amazing ability to glow, scientists try to find new ways to use the firefly's glow in biotechnology. Unfortunately, they have a relatively short lifespan of three years. If you are lucky enough to watch a firefly aglow at night, hopefully this will give you some insight into the amazing creature that God has created.
The firefly is an insect that has an exoskeleton, or hard outer covering, and a body with three parts. The three parts making up this body are the head, thorax, and abdomen. Together these segments enable the firefly to move easily, and swiflty. The firefly itself is a small insect that can range in size from 2 millimeters to 10 centimeters, and is mostly black. It has two red spots on its head cover. The head covers are usually a dark brown or black color, and lined in yellow. There are two pairs of wings which are concealed under wing covers on the firefly's back. The male is more likely to have full wings, and be smaller than the female. It also has two antennae, two compound eyes, and six jointed legs. As most of you know, the firefly lights up. This light occurs in the last section of the abdomen. This segment lights up and flashes producing a neon yellow green color. 
Reproduction of fireflies begins with the mating process between the male and female. This process starts with the blinking of the light. The fireflies blink their light to show agreement to mating with the other firefly. The female is usually the first one to do the blinking. She produces short rhythmic flashes that attract the male to her. Once this agreement has been reached, the two fireflies begin the reproductive process. The male while in copulating, sends some of his sperm into the females spermatheca. Here the sperm are stored while they begin to develop. The excess sperm are discarded in a special gland in the female fireflies body. The male fireflies unique sperm is spiral. As the sperm develops it eventually reaches a larvae state, at which it is able to glow. This occurs in most firefly larvae, but not all. In the past, researchers have tried to reproduce fireflies with no luck. They found that they are unable to reproduce them in controlled environments. Nature is the only way in which fireflies can reproduce. The firefly will stay at this larvae stage for two years so it can feed and develop. Once it is ready, the bug becomes an adult firefly that goes on to live for about a year. The last bit of its life is usually spent during the summer months, and then it will die completing the three year lifecycle.
The firefly's ecology is unique and separates it from other organisms. Today, there are about one hundred and twenty-three known species in the United States alone. Scientists are still discovering new species of this organism. To measure this large amount out, it has been divided into two different areas: 1,200 species in the Western hemisphere and 2,000 worldwide. Distinguishing the different types can become very difficult, especially when up to nine species can be living in one area. Fortunately, there are certain characteristics that can be used to distinguish the firefly. The height at which the firefly flies is an important characteristic. The bug itself can fly from one meter above the ground all the way up to the treetops. The air temperature and humidity of the firefly's habitat is also a crucial difference among species. The different species prefer habitats like fields, deep woods, or thickets. Typically, the fireflies most comfortable habitat is one of tropical or temperate conditions. They feed upon pollen and nectar, and are for the most part harmless. Although the firefly is not dangerous to humans, it has many predators. Some of these animals include birds and reptiles. In 1996 it was discovered that the firefly is very toxic. It has chemicals such as cardenolides and bufodienolides, that run through its bloodstream. The glowing produced by the bug not only acts as a mating ritual, but as a signal to predators.
The firefly is known around the world for its unique lighting. However, few people actually know the source of this light. The distinct glow comes from a pigment called Luciferin. This unique pigment is found only in organisms that have the ability of bioluminescence. The firefly, along with deep sea fish and microbes, are some of the only animals with this special gift. The actual light is produced when the luciferin is oxidised with the enzyme luciferase. The fusion of these two produces oxyluciferin and energy in the form of light, and as we know it, the firefly's glow. A unique substance called ATP is also required, but it is carried in the firefly so that no extra work is needed.
Luciferin was first discovered in 1949, by a professor named Bernard Strehler. He taught at USC and studied aging. With the help of William Arnold, Strehler found that all green plants are bioluminescent as a result of the reversal of the first stages of photosythesis. His amazing discovery of luciferin has led to many developments into the use of it. Most recently was the discovery of glowing tobacco plants. Scientists at the University of California were able to develop a genetic tag with the use of luciferin. The normal procedure used for monitoring gene activity was dangerous because it involved radioactivity. This is very risky, not to mention expensive. The new way which involves luciferase is quoted as being "100 to 1,000 times more sensitive" in the detection a gene's makeup. Luciferase, the finished product of the firefly, helped the scientists better understand the firefly and how it glows. It is hard to believe that a tobacco plant was actually glowing, but there is a specific process that the researchers used to get their final result. It began when they put the luciferase gene into bacteria, then produced the plant by putting the luciferase gene into the plants DNA. After these tests, success was reported. As you can tell, there are many uses for the firefly's unique gene. Scientists are studying it everyday, and hoping it will help in future discoveries as well. Now when asked how a firefly lights up, you can tell about luciferin and its fascinating developments.
- Website about the anatomy of the firefly10-21-08
- Website on the reproduction of the Firefly10-21-08
- Website on the anatomy of the Firefly10-21-08