Light Color and its Effect on Attracting Bugs around Entrances

Lights are notorious for attracting bugs. The level of attraction varies, depending on the color of the light, the color temperature rating of the bulb and the type of insects in the area. Keeping bugs away from entrances requires the observation of strategic practices that discourages tiny pests from loitering around entry points.

Read on to understand why bugs are attracted to specific light colors and which lighting configurations are most effective in keeping bugs away from entrances.

Bugs and Light Attraction

Before diving into light colors, it is important to first understand why bugs are attracted to light. Insects primarily use light from the sun and moon for navigation. Other bugs are sensitive to specific spectrums of light while hunting for food. Furthermore, some insects, like fireflies, use light for mating signals. When it comes to using light as a navigational aid, insects are known for using natural light as reference points. For example, moths rely on moonlight for guidance and are prone to flying at a specific angle in relation to the moon’s light rays. This allows the insect to fly in a fixed path with minimal effort.

The introduction of artificial lighting has disrupted such natural occurrences and characteristics of bugs. Taking moths again as an example, if it encounters a nearby fixture, the insect will use it as a reference- because it appears brighter than the moon (the bug’s original reference). It is crucial to note that insects aren’t actually trying to fly to the moon. The act of moving towards light is an innate characteristic in bugs that allows it fly in a generally straight course.

Light Colors and Wavelengths

Bugs are naturally engaged by specific wavelengths of light and colors. As a rule of thumb, the higher the wavelength, the less likely insects are able to see the color, resulting in less attraction. Light colors in the high end of the light spectrum includes yellow- 570 nm, orange- 597 nm, and red- 650 nm (note: this is why manufacturers designed “bug” lights with yellow bulbs). On the low end of the light spectrum, one will find blue- 475 nm, violet- 445 nm, and UV- 350 nm. Bug zappers utilize blue and UV light, because the wavelengths are very effective in luring bugs into the electric net.

The efficiency of specific light colors when used to attract insects was proven in a study from the University of Agriculture in Faisalabad, Pakistan. The 2005 study tested various colors of the light spectrum in a controlled environment, while exposing bugs to the colored bulbs. During the trials, researchers monitored the number of insects flying around the light sources. The results of the study revealed that over 70 percent of the bugs were drawn to the blue bulb. Only 18 percent were enticed by the white bulb, and 10 percent swarmed towards the yellow bulb. Lastly, two percent of the bugs were lured by the red light.

Lamp Applications and LEDs

The type of lamps installed on the location may also influence the level of attraction that nearby bugs are susceptible to, when flying around the area. A study from the American Association for the Advancement of Science highlights the application of different light bulbs and their ability to attract insects. This was the first major study (led by Michael Justice from the University of North Carolina) that directly compared an array of lighting technologies in outdoor residential settings. During the trials, bulb samples were individually installed outdoors with a funnel trap. Scientists then observed and counted the number of insects inside the trap, which contributed to the lamp’s capture rate.

The results of the tests showed that incandescent lights had the highest capture rate, followed by CFLs, halogens and LEDs with high color temperature ratings. LEDs with warm, low color temperature ratings had the lowest capture rate in the batch of samples. This type of light debunked the original hypothesis of the scientists, that conventional yellow “bug” lights would outperform other bulbs in the study (the “bug” lights came in second, next to warm LEDs).

There are several reasons why the specific type of LED bulb performed significantly better than other light sources in the trials. The type of light that the LED emitted was warm and yellowish. This decreased the amount of blue wavelengths in the beam- a color that was earlier established as a highly attractive color for insects.Moreover, LEDs generate very little UV light- another spectrum that bugs are naturally drawn to. The last factor that make LEDs superior in attracting less bugs is heat. As mentioned earlier, insects are enticed by light due to a wide range of factors, with one of them being heat. When it comes to heat, LEDs are known for generating very little amounts during operation. Traditional luminaries tend to generate and waste energy on heat (sometimes up to 80 percent), which is why they did not perform well during the trials.

Installing Lights near Entrances

Lighting systems near doors and entrances can be configured to attract less bugs. From afar, the three most attractive components on a building for insects include odor (from food or sanitation), the physical properties of the establishment (size, color and shape- just to name a few) and exterior fixtures. With focus on the last component, below are some tips to consider when installing luminaries near entrances:

  • Avoid installing white light within 50 feet of the building
  • Near entry points, yellow fluorescent and warmLEDlights are optimal
  • Mount fixtures on the hinged side of the door, in order to prevent outdoor light from entering the home when the door is open
  • For intense lighting needs (such as perimeter or security systems), high-pressure sodium fixtures are considered to be least attractive for bugs
  • When installing flood lights, it is best practice to place the fixtures as far away from the building as possible (maximum of 50 feet), while shining the light beam on the target area

Alternatively, individuals may also consider tinting windows around the entrance to prevent enticing bugs from outside. This may also prevent swarms of insects from loitering around the door and windows. This is highly effective for buildings that rely on bright, white light inside the facility.