A major question that always aroused…discussed with friends, but we all never got an answer to it!!!
Supposedly many people have tried answering it and the most convincing way out to these widely observed phenomenon is that…usually if you see the natural sources of light they are practically at infinity…e.g.-sun…so all the rays that are coming from the sun are parallel to each other. Now for tracking a linear path the simple logic is to make constant angle with the rays of light…! Now back on earth we have various other artificial sources of light tube lights, bulbs etc. and the rays that are coming out of such sources are given out in all directions and are basically not parallel to each other!!! Now for an insect in order to follow a linear path as it always does…it is constantly trying to maintain a constant angle with the rays…and since the rays are not parallel and radiating from a single point…the angle keeps on changing…due to which they follow a spiral path and finally land up at the source of light!!! The reason our tube lights are full of insects!!!
BUT, since generations of these insects end up at the source of light and seem to get nothing out of it…why don’t they learn to avoid such situations??? Another obvious question…and the reason for this behavior lies in the fact that…it’s a place for aggregation of so many insects…so it might be acting as mating grounds…wherein you can look out and choose for your mates and mate!!!(a very important part of life cycle)
BUT, as I mentioned in one of previous blogs about such areas being feeding grounds of lizards (strategic locations)…there is a risk involved in landing up in such areas from an insects point of view!!!
Again, usually if observed there is just a single lizard at such location …showing territorial dominance and thus benefiting the insects..owing to the fact that the probability of getting eaten by a lizard decreases tremendously when hundreds and thousands of your type are present…to be eaten up! Also..the fact that since there is a single lizard and it has a limited appetite…and the number of insects are always in large excess… such that a lizard is satisfied…much before not more then half of them are eaten up (may be? coz half to me seems a large extrapolation…but still in spite of it the insects seem to be benefited!!!)
Everyday phenomenon…simple observation…logical analysis…complex interactions!
well insects using a point source of light at infinite distance for navigation sure makes them revolve... but 1 Q that arises is why in spirals?? why not circles?? cause logically they are trying to maintain a constant angle with the light source, not moving towards the light, so ideally they should be moving in circles.....also tubelights are stuck on walls and the computer/TV screens arent lit at their backs... so insects are not moving in circles....they are directly attracted to light. may be insects like moths equate light to heat and so most frequently fly straight to light.... no circles... and lay their eggs there.... This i have seen so many times when before monsoons the windows are literally covered by moths and the next morning the glass is dotted with moth eggs...
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