Few things spoil an outdoor evening faster than hordes of flying insects attracted by your outdoor lighting. Tiny midges, giant June bugs and moths of all sizes are among the nocturnal insects that become confused by conventional outdoor lights and flutter around your porch or patio. You can install special yellow bulbs in your outdoor lighting fixtures to make the lights less noticeable to bugs.
Insects and the Light Spectrum
Night-flying insects see a different part of the visible light spectrum than humans see. Ordinary light bulbs shine across the entire spectrum so they are easily seen by both humans and insects. But our eyes are more sensitive to the red-orange-yellow end of the visible light spectrum so we can readily see by yellow light. Night-flying insects are more sensitive to the blue-indigo-violet end of the spectrum and many nocturnal species are nearly blind to yellow light.
The yellow bulbs don't actively repel insects, they simply appear to most night-flying bugs as too dim to notice. This greatly reduces the number of bugs flying around your light bulbs. Some nocturnal bug species are sensitive to any color of light and they're the ones that will notice and fly around yellow lights. The only sure way to deter all night-flying bugs is to turn outdoor lights off when you don't need them.