Previously, it was believed that LEDs do not attract bugs during nighttime operations. But now, new sources suggest that insects are drawn to light-emitting diodes (LEDs), with emphasis on specific wavelengths and color temperatures.
UV Output and Wavelengths
Bugs are heavily attracted to UV light. The creatures can see light in the 300-650 nm range, but are especially drawn to wavelengths ranging between 300-420 nm. By comparison, humans can perceive light in the electromagnetic spectrum between 400-800 nm, which does not include UV light at 350 nm. This is why most bug trappers that use light to attract insects rely on UV or black light bulbs. It is crucial to note that high light output and cool Kelvin temperature ratings increases the chances of attracting bugs.
Bugs mostly perceive the following colors of light: UV, blue and green. They are drawn to bright white and bluish lights, such as white fluorescent and mercury vapor lamps. Yellow and warm white lights closely resemble sunlight and are not attractive to insects. This is because bugs that are active at night use the moon as a point of reference. Any visible light between the moon and the tiny animals, including artificial light from a lamp, serves as a distraction, and forces them to gather around the area.
A 2005 study from the University of Agriculture in Faisalabad, Pakistan, solidified the industry’s theories surrounding this issue. Researchers collected insects and trapped them in illuminated screen containers, measuring one square meter in two separate locations at six meters apart. The bugs were trapped for 30 minutes and exposed to a wide range of lights that emitted different wavelengths. The results of the study showed that between 60-70 percent of the animals preferred blue lights. Roughly 18 percent gathered around white lights, and eight to 10 percent felt comfortable with yellow lights. Only two percent stuck with red lights.
LEDs and Bugs
LEDs emit a broad range of wavelengths, between 350-700 nm, depending on the specifications of the fixture. During light output, the units utilize a combination of colors, instead of directly producing white light. For example, some LEDs that emit cool white produce bluish tones, which insects find very attractive. These types of LEDs are known to entice bugs, but only in small numbers. LEDs that are manufactured to produce UV light, including mosquito trappers, fixtures for plant cultivation, paint spray booth lights and curating lamps in dental facilities, are also notably efficient in luring bugs.
When it comes to mainstream lighting, insects are attracted to UV LED spotlights and neutral colored LEDs. In residential settings, most LEDs emit very little UV light; and as a result, only attract small groups of insects. To prevent bugs from flying around light in your home, it is recommended to choose LEDs that display warm white, or yellowish light tones with low Kelvin temperature ratings.
In addition to the light’s wavelength, insects are also drawn to heat generated by the fixtures. LEDs, with their superior heat management properties, are better choices in this aspect of attracting bugs, compared to incandescent and halogen variants that produce light using hot filaments.