Why is it that insects are drawn to artificial lighting like … well, like moths to a flame? Science isn’t 100% in agreement on what’s behind this particular attraction, but the most likely explanation seems to have to do with the insects’ use of sunlight and moonlight to help them navigate. By keeping these steady light sources at a constant angle, insects are able to fly straight, and to maintain a consistent flight path.
Unfortunately, artificial lights interfere with an insect’s navigational ability in a couple of ways. Because artificial light sources are generally brighter than their natural counterparts, particularly at night, they make it difficult for insects to detect those natural light sources, and the bugs are drawn to the false light rays as a directional aid instead. But like strobe lights on a dance floor, artificial light fixtures end up causing mass confusion in the bug world because they radiate light on all sides, and make it impossible for insects to keep their rays at a constant angle. The bugs simply get caught up in a never-ending dance around the light bulb, which often proves to be fatal. Many groups believe that unrestrained light pollution is even causing the decline of certain insect species.
In terms of commercial outdoor lighting, insects definitely contribute to maintenance costsin that lenses must be continuously cleaned of bug detritus to allow lights to perform at their peak efficiency. Is LED lighting the answer to cutting back on bug-related maintenance? Are insects less attracted to LED light than to other forms of artificial illumination?
Does LED Equal Bug-Free?
We know that insects are particularly drawn to UV rays – those blue light bug zappers are an ideal example of this knowledge in action – and while it seems reasonable to believe that LED lights should hold less attraction for insects, since they give off little to no light in the UV range, this factdoesn’t necessarily lead to any practical gains.One 2005 study at the University of Agriculture in Pakistanoffered some interesting insight into this subject. After examining the quantities of bugs trapped on a series of illuminated screens over a period of time, the study concluded that while 60-70% of insects in the area did indeed prefer light at the blue end of the spectrum, a full 18% headed for the white light source instead,and 8-10% were happy to settle for the yellow rays.
The bottom line seems to be that, even when offered a choice of light rays, some insects will invariably end up littering the lenses of your LED lighting fixtures, and possibly more so if LED light happens to be the only game in town. The upside may be that, because LED lamps give off little heat, there’s less chance that insects will be burned onto lenses, and they mayexpire only after becoming physically trapped or exhausted. This is an advantage that can result in faster and easier fixture clean-up duties overall.