Revealed: The mystery of why insects flock to lights — and how to keep them away

The moonlight navigation hypothesis suggests that insects use the moon to orient themselves while flying, he adds. “Because the moon is far away, its light is constant to the insect’s path, helping them fly in a straight line. Artificial light sources, such as street lamps or porch lights, confuse the insects. Instead of guiding them, these closer light sources cause the insects to spiral around the light to maintain a consistent angle, ultimately leading them to become trapped in the light’s vicinity.”

Another theory points to circadian rhythms. Singh mentions that some insects are more active at night and are programmed to follow natural light cycles. Artificial lights can disrupt these cycles, luring insects to them when they would otherwise be resting or searching for food.

One of the most effective approaches is to switch to LED lights with a warm colour temperature, such as those in the yellow or amber spectrum, which are less attractive to insects (Source: Freepik)

Do different types of light attract bugs in distinct ways?

“Yes. The wavelength or colour spectrum emitted by different light sources plays a major role in how bugs perceive them. Insects are particularly attracted to ultraviolet (UV) light, invisible to humans but highly perceptible to many species of bugs, such as moths and mosquitoes,” elaborates Singh. 

Fluorescent lights, which emit higher levels of UV light, tend to attract more insects than LED lights, which emit very little UV light. In contrast, warm-coloured LED lights that emit longer wavelengths of light (in the red and yellow spectrum) are less attractive to insects because they fall outside the range of light that most insects are sensitive to. 

How to modify outdoor lighting to reduce its attraction to insects without compromising visibility

Singh informs us that several strategies can be employed to reduce the attraction of insects to outdoor lights without compromising visibility. “One of the most effective approaches is to switch to LED lights with a warm colour temperature, such as those in the yellow or amber spectrum.” 

“Additionally, using shielded lights that direct the beam downward, rather than allowing light to spread in all directions, can minimise the area impacted by the light and limit its visibility to insects,” he says.

Another option is to install motion-activated lights, Singh adds, which only turn on when needed, reducing the overall exposure to light pollution. “Finally, placing timers or dimmers on outdoor lighting systems can also help limit the time and intensity of light exposure, mitigating its impact on local insect populations while maintaining adequate visibility for human activities.”

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