Why are many bugs attracted to bright lights during the night?

Senior Moments

According to Jim Liebherr, professor of entomology at Cornell University, insects aren't actually attracted to your porch light, despite all of the little moth carcasses you may see inside the globe. Over the millenia, certain insects have learned to use the largest natural night light (which, up until about 100 years ago, was most usually the moon) to navigate. Moths will fly above the treetops, keeping the moon in a fixed location, allowing them to determine their line of movement. Unfortunately for the moth which happens to find itself in your front yard, the light sources that people create are often brighter than the moon. The insect attempts to keep your porch light at a fixed position relative to its body, but because the light source is relatively close to the insect, the result is an ever more violent spiral leading directly to the light. Aug 11 03, 1:54 AM