Why do moths fly in circles around lights?
The answer to why moths circle lights is unknown.
The leading hypothesis is that some moths use celestial lights, such as the Moon or a bright star to navigate. They orient themselves to this light source by maintaining the same intensity of light in each eye based on the desired angle relative to the light as they travel. For a celestial light, this angle will not change significantly as they travel, so they will fly in a straight line toward their destination.
When they encounter an artificial light, as they get closer, the amount of light reaching each eye will change noticeably and they will try to adjust their flight angle to counteract this change. As they get closer to the light, this will result in a circular path around the light as they continue to turn in the same direction to try to restore the correct balance of light in their eyes for the angle of flight they originally were following.
