Insects probably mistake artificial light sources for the sky and try to align their flight behavior with it. This ends with dizziness – or even worse.
Researchers have placed reflective markers on moths, dragonflies, fruit flies and other insects. They then filmed the animals using high-speed cameras as they interacted with artificial light source. In a world without humans, where the sun or moon are the brightest light sources, turning their backs to the light source is an effective way for insects to bring themselves back onto a straight trajectory.