Why Are Bugs So Attracted to Electric Lights?

If you have ever turned on outdoor lights at night, you’ve probably noticed something almost immediately: bugs flocked to the lit-up space in unfathomable numbers. One of the biggest challenges of lighting your patio with electric lights of any kind is dealing with the unwelcome deluge of insects and other pests that come to crash the party almost as soon as it gets started. Why does this happen, and is it possible to keep bugs away while still being able to enjoy electric lights outdoors? This blog will explore this behavioral phenomenon so you can better understand it and use it to your advantage to keep the bugs away.

Eyes Unlike Our Own

Why are bugs so attracted to bright lights? To better understand, we need to take a closer look at insect biology, specifically their eyes. Light is perceived visually, so electric light would need to provide some sort of irresistible stimulus to insects in order for them to exhibit such a consistent and repeatable behavior. And the eyes do tell an important story, specifically one of how insects can actually see a different spectrum of light.

Specifically, insects can see into the ultraviolet spectrum of light. UV radiation is generally invisible to the human eye, as it is made up of light waves with frequencies above the violet spectrum (the edge of what we can see as humans). The light receptors in our eyes don’t respond to this type of light, and thus they can’t send a signal back to our brain for our brain to interpret. However, the receptors in an insect’s eyes do respond to this type of light, and that means they can actually see more on this higher end of the light spectrum than we can. However, this fascination and attraction to ultraviolet light, while irresistible, can also be a bug’s downfall.

Conversely, while bugs can see into a higher spectrum of light than we can, we can see into a lower spectrum than them. Some bugs do not have visual receptors that are capable of responding to red light at all, and that means pure red lighting can be anywhere from super-faint to downright invisible to bugs. For this reason, red lamps (such as those used for effect or party lighting) are much, much less attractive to bugs. The only downside: they’re also pretty unattractive to humans, and can give many people a headache due to oversaturating one particular set of visual receptors in our eyes. This means red bulbs are not the most practical choice for functional outdoor lighting.

Keeping Bugs Away

Virtually all electric lights emit some level of ultraviolet radiation—it’s almost impossible for them not to. And because insect eyes are so proficient at seeing this type of light, this is what draws them in to take a closer look. However, not all types of light emit the same amount of UV radiation. By installing lights that emit less attractive light, fewer bugs will be drawn to the light, giving you a more peaceful and pest-free outdoor space.

As a good rule of thumb, the “bluer” a light’s color, the more attractive it will appear to various types of bugs. In other words, light temperature will dramatically change how attracted bugs are to your outdoor lighting. Warmer light hues, such as yellows, golds, or soft whites, are generally closer to red on the spectrum, and thus are far less attractive to a bug’s eyes. Cooler light temperatures, such as daylight white, cool white, or even blue lights, are generally more attractive due to higher concentrations of higher-wavelength blues and violets in the light itself.

Therefore, if you’re struggling with bugs in your outdoor spaces, one fix to try is to change your lightbulbs to a warmer, softer tone like a golden white or yellow. While “daylight” types of bulbs may be a little brighter and provide a more even, color-free tone, they do attract a lot more bugs. Considering you can generally buy bulbs of almost any light temperature from nearly any home improvement store, this simple fix typically isn’t too difficult.

Bug Zapper Lamps

A bug’s attraction to ultraviolet light is the exact principle that makes bug zapper lamps work so effectively. A bug zapper lamp features a specialized bulb that is typically blue in color, and as we have learned, blue is the color that tends to attract bugs the most due to the highest concentrations of light that they can see. These bulbs also emit higher levels of UV radiation, just for good measure and for maximum attractiveness. When bugs catch a glimpse of these lights, they are often drawn to them straight away, even when other bigger, brighter lights might also be present (such as outdoor patio lighting).

When bugs move toward this extremely attractive light, they are greeted by an electrified metal grid that sends a good jolt of hundreds (or even thousands) of volts straight through the bug, killing them almost instantly.