They emit a yellow light, although you wouldn't expect that from looking at them when they're not on. I don't see any moths or other insects swarming around or under the bulb at night. The built-in auto-on feature is great! I just leave the switch on and don't have to remember to turn them on at night or off in the morning. Lightbulbs aren't on 24/7 just because I forget to turn them off. It would be nice if there was information on how much power the sensor lights use during the day when the LEDs are off.