No one knows for sure why moths (along with other winged insects) will make a beeline for lightbulbs or burn up in candle flames. The most popular theory is that moths navigate at night by flying parallel to the brightest light source, which in the time before man-made campfires and electricity was the moon or stars. The moon makes a good navigational aid because it never gets any closer, helping the moth keep a straight flight path. Trying to fly parallel to a streetlight or flame short-circuits the moth’s flight computer, causing the moth to fly in tighter and tighter circle until it eventually bounces off the light or burns up.
Picture Credit : Google