Bugs that skitter away when a light is turned on, like cockroaches, have what is called “negative phototaxis.” Bugs that move toward light and circle around it – mostly moths and flies – have a “positive phototaxis,” according to Vulcan Termite & Pest Control.
The type of light that a bug can see depends on its type of eye structure. Adult insects have either bichromatic or trichromatic eyesight. Bichromatic eyesight means they have two types of color receptors, whereas bugs with trichromatic eyesight have three color receptors. In general, the lower the wavelength of light, the less visible it is to most bugs. That means red, orange and yellow are the colors least visible to a bug.
Humans usually want more light than what they can get with a red bulb, so the best compromise for a light that won’t attract bugs is to switch your porch light to a yellow bulb. Blue light, on the other hand, is more visible to a bug, so that would not be a good choice. If you happen to have an ultraviolet light bulb, bugs will be more attracted to that wavelength even more than blue.
Entertaining guests outdoors during the evening hours doesn’t have to be a problem. Eartheasy says that amber LED bulbs will not attract bugs. If you do not have these bulbs, try placing your light source away from your home. For instance, if you are hosting a pool party, place lights in the trees and perimeter of your yard to attract bugs to those areas. Another idea is to use a light that shines downward onto the porch or patio rather than a direct beam pointing into the yard area, which is an open invitation to insects.
Yellow incandescent, high-pressure sodium and regular incandescent lights radiate less blue and ultraviolet light, thus reducing the attraction of insects to the area. Remember that even if you do not use a porch light during the evening and nighttime hours, insects can still be attracted to the lighting inside your home. If you have the door to your patio open and have light shining from a kitchen light, the insects will likely cluster against your screen door trying to get to the light they can see.
This Yellow Bulb specifications