Phototaxis
- Phenomena by which insects or organism reacts towards light, has 2 types: Positive & Negative Phototactic.
If insects attract towards light then it is positive phototactic (example: Termites or eesal) and if not, then it is negative phototactic (example: Cockroach).
Why do insects are attracted to Light?
Theory 1:
According to the entomologist, insects navigate from one point to another with reference to the moon with a constant angle. Though the moon’s distance from insects are too long, they move in a straight path without changing the angle ie., Transverse Orientation. By this technique, long years ago in the northern hemisphere, sailors travel with reference to the northern star.
After the invention of bulb, insects can’t differentiate bulb and moon, made bulb as the reference point with difficult to maintain constant angle, it rotates the bulb.
Though this theory explains, some insects stay on the bulb for longer time. Why??
Theory 2:
If you are struck in a dark room with small light coming out, we think that’s the way to get out. Like that only some insects stay on the bulb to get out from there.
Theory 3:
Insects are more active at night than the day and to get warm (temperature is low at night) they are scattering around light. Even some entomologist says light are like beautiful attractive flowers and its the mating point for them.
Like that there are many theories stocked one upon other. Till now no one entomologist can say this the only reason that insects are attracted towards Light.
Now a days, you can see fly catchers like this…
Due to the fact that insects are attracted to light, the electric line inside this trap provides the electric heat necessary to kill them.
You may raise a doubt that why lights are only in Violet, Blue and in UV. Because these lights has wavelength that are sensitive to them.
