Why my porch light is always surrounded by moths

Eran Levin in front of a blacklight screen.

Eran Levin, a postdoctoral researcher at the University of Arizona studies Hawk Moths. He used a technique called backlighting to catch them and in the process catches numerous other insects as well.

Moths navigate by keeping bright objects like the moon and stars at a constant angle. It turns out that artificial light disrupts the moths's detection of moonlight. They end up using the artificial light source as a navigation cue and as a result wind up circling the light bulb to keep it at a constant angle.

Check out his blog entry in Scientific American for more information on backlighting and to see additional images of the insects he attracts using backlights.