Insects Don't Swarm at LED Lights — and That's a Problem

Outdoor insects once swarmed incandescent bulbs because those lights emit ultraviolet wavelengths, which insects mistake for moonlight and use to stay upright in flight. LEDs emit almost no UV, so they attract far fewer bugs. A 2016 University of Bristol field study found LEDs drew significantly fewer insects than tungsten filament or compact fluorescent lights, with no real difference between cool- and warm-white LEDs. The upside: less light-driven disruption to nocturnal insects, a suspected driver of population decline.