If a moth only comes out at night why is it always attracted to a light?

Answer 1

First, there are many moths that come out in the day.

They end up at lights because they use light to navigate. For the hundreds of millions of years during their evolution the only light for them to use to navigate was moon light (or sunlight for a "day" moth). Since the sources of light were so far away the moth used the angle of the light to know where it was going and the angle didn't change as they flew.

Then people came along and made light bulbs and now with a close sources of light when the moth tries to keep the same angle of light coming into its eyes it ends up spiraling toward the light.

Answer 2

Moths do need light even during the night for at least two purposes. Since the sky is practically always lighter than ground, they use light to tell which way is up. They also use the moon as an important reference point in the sky, and may mistake any human-made lights for the moon, flying towards it. They can't reach the moon, obviously, so they don't expect to bump into a light bulb or burn their wings in a flame.

Answer 3

day dwelling moths are attracted to light.,

http://www.madsci.org/posts/archives/1996-12/843354316.Ev.r.html

Answer 4

for the warmth.