Sunday, July 3, 2011

Wonders of the world (Firefly bug)

      Few years back when I was in grade one, me and my friends used to collect Tortoise beetles as our hobby. Whenever we caught a new Tortoise beetle which differed from others we brought them to school and showed them to others by saying that we got a new Tortoise beetles that you guys don’t have. And we explained how we caught them, from where we caught them, things they eat and that kind of funny stuff. Those are wonderful memories and i'm sure you also have those kinds of sweet memories with you. Back to story, but one day I caught a bug little bit different from Tortoise beetles. Usually, Tortoise beetles are hemispherical in shape and have bright colors. But the one that I caught was little bit elongated and thin. So I thought I caught a new Tortoise beetle that none of my friends have caught early. Since my friends don’t have such a Tortoise beetle with them, I was so happy. So that I can show my new Tortoise beetle and tell them about it.
I put my new friend with my other Tortoise beetles. So that I can take it to school on the next day. But at night I suddenly got waken up by a strange light emitted from my Tortoise beetle container. I was afraid and I called my mother to tell about this. She told me that she will explain it in the morning and asked me to sleep. But I couldn’t sleep all that night. 
Next day morning I hurried to my mother and asked about the last night incident. She told me that I have accidently caught a fire fly not a Tortoise beetle. Then I wanted to know how living animals emit light without having a bulb and a battery. I asked from my mother how it can happen. She replied with a smile and told that I'm too small to understand that therefore I have to be patient till I  find the answer in future. Since then I wanted to know how this little tiny bug emitted light at night.
With the grade five scholarship examination, me and my friends were busy with studies and so was our parents. So when I passed grade 3 my interest about collecting Tortoise beetles and knowing about fireflies faded away. At that time  the only thing in our mind was  to pass the scholarship examination and make our parents happy. Even after scholarship examination we were forced to go for classes to have 10 A’s in O/L examination. What we will be doing in the future depends on our education. So we let our other interests lay beside and hurried to school then to classes and back  home. After finishing the O/L again had to study for A/L. Luckily I did Bioscience for A/L’s, there I learnt about insects and light emitting chemical compound. So I tried to combine what I learnt and tried to come up with an idea to explain how fireflies emit light. But I was failed.  But when I got selected to the university I had a chance to learn about advance scientific concept such as biochemicals and mostly about enzymes that emit light that I haven’t learnt for A/L. With those advance concepts in hand I searched about fireflies in internet.
Firefly bug is an insect which belongs to the family Lampyridae order Coleoptera. Now people who don’t have a background on biology might get confused. For them just think those fireflies are insects. Most firefly species are form larviform (like a worm) females which differ from larvae (young stage in life cycle) by having compound eyes, and beetles like males whereas males can fly but females cannot. But in some firefly species  both males and females can fly. Most of firefly species are nocturnal (active in nights) they emit light with great intensity, some fireflies are diurnal (active in day times) usually they don’t produce light but some diurnal fireflies also produce light not in great intensity but in low intensity. These adult fireflies produce light in light organs that are located under their abdomen. It occurs through a bioluminescence process which is a biochemical reaction which involves enzymes and several bio molecules and other chemicals. This is how it happens; fireflies produce an enzyme called luciferase in light emitting organs. This luciferase acts on luciferin to give out the light when cofactors like Magnesium (Mg2+), ATP (Adenosine Tri Phosphate) another bio molecule and Oxygen (O2) are present.
 It happens in two ways one is Oxygen can directly react with luciferin to give oxyluciferin and light
luciferin + O2 → oxyluciferin + light

 If not initially luciferin reacts with ATP to give luciferyl adenylate and two phosphate groups. Then this luciferyl adenylate react with oxygen to give oxyluciferin, AMP (Adenosine mono phosphate) and light
luciferin + ATP → luciferyl adenylate + PPi
luciferyl adenylate + O2 → oxyluciferin + AMP + light
 Fireflies use this bioluminescence process throughout their life cycle in many ways. When they are in larvae form they use this bioluminescence as a warning signal to predators since many larvae contain toxic and distasteful chemicals. In adult stage they use this processes in mating selection and some use to attract prey. I told you that fireflies that are diurnal usually do not emit light so how can they use light in mating selection; instead of light they use pheromones. That’s why firefly bug is a wonder of this earth. Firefly bug is  only one wonder of the nature; there are so many beautiful creatures on earth so love them, care for them, study about them and preserve them for our future generations.