Why do bugs fly toward light?

An insect flying north, for example, could judge its direction by keeping a natural source of light such as the sun or moon on its right side. This method works well as long as the source of light remains constant and at a distance. If an insect encounters a round incandescent porch light, however, it becomes confused by the light source. It will continue to circle a light because it instinctively wants to keep the light on a certain side of its body while navigating.

For Kids:

They can find their way. The light Looks like the moon of sun. The bug becomes confused by the light. It will go around the light because the want to keep the light on a side of their body while searching around it.