With LED lighting as the dominant light source of today, people have adopted it but how does the insect world like LED? Are bugs attracted to LED lights just like other light sources or could there be further benefits to this technology by being less attractive?
We ask do LED lights attract bugs by reviewing two University led research studies and apply their combined findings to draw an interesting conclusion.
Bugs and insects can be attracted to light, dependant on the species.
The primary reason why bugs are attracted to light is due to phototaxis, which is the ability of an organism to move towards or away from light.
Some insects are positively phototactic, which means they are attracted to light, while others are negatively phototactic and are repelled by light.
The results of studies do show that overall LED lights attract less bugs. However, insect behaviour is species dependant.
In 2016 Dr Andy Wakefield led a University of Bristol study into whether domestic LEDs attracted fewer insects than conventional light types. The study field tested 4 types of light source overnight in 18 locations around the south of England, using a Warm white LED vs Cold White LED vs Compact Fluorescent vs Tungsten.
Dr Wakefield reported: “From our results we’ve concluded that of the lights we tested, LEDs attracted significantly fewer insects”.
The results showed that LEDs attracted four times fewer insects compared to incandescent bulbs, and half as many as were attracted to a compact fluorescent light sources.
Wakefield continued: “We were surprised by the number of biting flies drawn to the traditional tungsten lights. We do not know why this is but we know that some insects use thermal cues to find warm-blooded hosts in the night, so perhaps they were attracted to the heat given off by the filament bulb.”
Just 2% and 3% of a known biting species of fly were drawn to the cold and warm white LED, with over 80% attracted to tungsten.
It is also the type of wavelength of the particular type of light emitted by the LED that also plays a role. Particular color temperature’s or hue of white LED light will attract bugs more than others.
White light is created from a varying combination of red, orange, yellow, green, blue, indigo and violet light or scientifically understood as varying visible wavelengths on the electromagnetic spectrum; between 400-800 nanometers (nm).
Each recipe of white light will resulting in variable hues of white, each with a specific combination of wavelengths.
Researchers from the University of Southern California published results in the Royal Society of Publishing claiming that blue, violet and ultraviolet wavelengths in LED lights were the most attractive to insects, while yellow and green lights were less attractive.
So in practice, the warmer white hues use a wavelength combination that is less appealing to bugs, seen in legacy halogen and tungsten sources, and this quality can be captured by LED as long as the blue wavelength is avoided or reduced in the mix of white light.
However, the Bristol University study found that there was little difference between the insect attraction to a domestic bulb cold white LED which has the more appealling blue shorter wavelength light in it, compared to the warm white LED bulb.
What we do know is that manufacturers utlise UV light to create insect light traps, grow lighting, UV disinfecting LED lights as seen used during the Covid pandemic and UV sterilization lighting products.
Whilst UV light is not visible it can still be a wavelength used in the LED light white light recipe, and therefore attract some bugs.
So although LED is less attractive to insects, some LEDs are more appealling than others. It’s the blue and daylight color white LED lights that are more attractive to insects as they are similar to the wavelengths of light emitted by the sun and the moon.
Many insects use the sun and the moon for navigation, so they are naturally drawn to these bright types of light, especially in the darkness of night.
The USC study also showed that blue enriched white LED lights can interfere with the circadian rhythms of insects, which can cause them to become disoriented and attracted to the light.
Insect vision is shortwave shifted, “so in theory they should not be as attracted to longer wavelengths from the orange and red colors within a warm white light mix,” reported Dr Wakefield.
It’s important to note that although the wavelength of LED lights may have some influence in the type of general LED lights used domestically, they are not necessarily more attractive than other types of lights that create more heat, such as halogen and incandescent lights.
The warmer white colors of LED are less attractive to insects as they will generally use less blue wavelengths but more red, yellow and green. Therefore it is the color spectrum choice behind the color that is the influence.
Yellow and green LED lights emit longer less attractive wavelengths of light, as they are not as visible to insects and bugs.
In general, brighter lights are more attractive to insects than dimmer lights, regardless of the color or wavelength of the light. This is because brighter lights emit more photons, which are more likely to be detected by some insects.
However, the effect of brightness or intensity on insect attraction can vary depending on the type of insect and the specific LED light being used.
Some insects, such as moths, are attracted to bright lights because they mistake them for the moon or the sun, which they use for navigation. Other insects, such as mosquitoes, are not necessarily attracted to bright lights, but are more likely to be drawn to areas where there is a lot of activity or movement, which is often associated with brighter lights.
LED lights are overall less attractive to bugs, probably because they run cooler.
The very blue enriched daylight white LED lights can be more attractive due but the type of insects that are attracted depends on the species of the insect and the wavelength of the light emitted by the LED.
If you are concerned about bugs being attracted to your LED lights, you may want to consider using warmer white LED lights which combine more of the red yellow and green wavelengths which are known to be less attractive to insects.
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