Why are some bugs attracted to light?

Question

If animals have developed through evolution, then a bug's attraction to light should have some sort of evolutionary advantage. I cannot think of anything advantagous to being attracted to light. Given that today's technology is less than a microsecond of the evolutionary timeline, all the light that would affect the evolution of this attraction would be natural light. The moon (in the sky or reflected off water), a forest fire, the light at the end of a cave, or other luminescent organisms such as fireflies or glow worms. Any Ideas?

Answer 1

From what I've been told, insects will use the moon as a reference for navigating at night. This worked great until we came along and invented the light bulb. Now our man made sources of light compete with the natural sources of light and confuse the insects.

Like you said, today's technology is an eye-blink in evolutionary time. What has happened is that we have changed a major factor in the environment of insects, so what was once a very useful instinct has become something of a detriment.

Answer 2

Insects are attracted to light as they use light to navigate. Scientists "believe that insects that fly at night evolved over millions of years, before humans existed. Before humans existed, there were no artificial lights at night. The only light was the moon, and insects that fly directly towards the moon at night will travel in a straight line. This was therefore a useful behavior for them, helping them navigate in the dark. It is an *instinct*, meaning they don't think about it, they just do it, because over the millions of years they've existed, insects that could navigate at night did better than those that couldn't. Insects that fly towards an artificial light, however, will crash into it, and often hurt themselves. They can't avoid it, because it's an instinct. If we had another few million years to watch the process, eventually insects might stop doing it - but not yet; it's only been a few hundred years." "Light and colour play an important part in the reactions of insects. The reaction to light is called phototropism. It is well known that many insects are attracted to light, the response to which is often greater than life itself. Light of short wavelengths, such as blue and violet, is usually more attractive to insects than other colours. Experiments have shown that all lights of the same colour do not attract insects proportionally. Much depends upon the intensity. Although moths are attracted to artificial light, they keep away from sunlight. Butterflies on the contrary are attracted to sunlight but are repelled by artificial light. Butterflies are tuned to high intensities of light and moths to low intensities, so that the bright light attracts the butterflies and feeble light attracts the moths. Insects generally orient themselves with their heads directly toward or directly away from the light source. Scientists observed that the moth is not attracted by the light but is oriented by it and, in constantly adjusting its head to the light, is drawn into it.

Answer 3

Why do they circle the light? They hold the light as a fixed distant reference point, and keep a fixed angle to the light. Bright lights in the environment instead of in the sky at night may eventually shift the survival advantade.

Answer 4

Light helps for orientation

Answer 5

accualy they attract to the light where the places aren't so clean and even that's a natural behavieour for them so that's normal