Moths often flutter erratically or bump into people, which can feel like an “attack.” This behavior is largely unintentional, stemming from their natural instincts and responses to their environment.
The Allure of Light
Moths exhibit positive phototaxis, meaning they are instinctively drawn towards light sources. Many nocturnal insects, including moths, use distant celestial light sources like the moon and stars for navigation, a method known as transverse orientation. They maintain a constant angle to these distant lights to fly in a straight line.
Artificial lights, such as porch lights, confuse this natural navigational system because they are much closer than celestial bodies. As a moth attempts to maintain its constant angle to a nearby artificial light, it flies in spirals, drawing closer to the source. This disorientation leads to erratic flight patterns and unintentional collisions with objects or people positioned near bright lights.
Are Humans a Moth Magnet?
While light is the primary attractant, humans can possess secondary cues that might draw moths. Moths, like many insects, are sensitive to carbon dioxide (CO2) emissions, which humans exhale during breathing. Some moth species use CO2 to locate host plants for laying eggs, suggesting a general sensitivity to this gas.
Additionally, certain human scents, though typically minor, could play a role. Moths are highly sensitive to pheromones for mating, and some components found in human scents or perfumes can also be present in moth attractants. However, these factors are usually negligible compared to the overwhelming pull of artificial light.
Are Moths Dangerous?
Adult moths are generally not dangerous. Most adult moth species lack the necessary mouthparts to bite humans and do not sting. The perceived “attack” is typically an unintentional consequence of their disoriented flight around light sources.
While some moth larvae, or caterpillars, can cause skin irritation through their spiny hairs or be agricultural pests, adult moths themselves pose little direct threat to people.
Minimizing Moth Encounters
To minimize unwanted moth encounters, address their primary attractants. Turning off unnecessary outdoor lights, especially at night, significantly decreases their attraction to your home. If outdoor lighting is needed, opt for yellow or amber light bulbs, as these wavelengths are less attractive to moths than white or ultraviolet light.
Physical barriers also play a role in prevention. Ensure windows and doors are closed, particularly after dark, to keep moths from entering living spaces. Installing or repairing screens on windows and doors provides ventilation while maintaining a barrier against insects. For indoor issues like pantry moths, storing food in airtight containers and maintaining a clean environment by regular vacuuming can help manage infestations.