Are Moths Attracted to Light and UV Light?

a welcoming home entrance and balcony lit up at night

Insects like moths can be a pesky problem for homeowners! Clothes Moths and Pantry Moths are especially problematic, as they damage clothes and textiles made from animal based fibres and dry food goods inside the home.. Many people use bug zappers and UV light to attract and kill insects outdoors. This begs the question: are Pantry Moths attracted to UV light, and can these bug zappers help you with your pest problem? What about Clothes Moths? Can you lure Clothes Moths out with a black light? We will explore this and more, in-depth below!

Are moths attracted to UV light?

Some species of moths are strongly attracted to blue radiation and UltraViolet (UV) light. In fact, you have probably noticed that many types of moths are even attracted to regular white light bulbs. Black lights and mercury vapor lights are particularly enticing to some kinds of moths. These lamps emit a broad spectrum of light which will increase the amount of signal that some insects can detect. With that being said, not all moths are attracted to UV light or any kind of light at all for that matter.

Does light attract Pantry Moths, and can you lure out Clothes Moths with UV light?

Unfortunately, no. Although many kinds of moths are attracted to light, this phenomenon does not apply to all species. Some pestilent species of moths, like Clothes Moths and Pantry Moths, are not attracted to light (UV or otherwise) in any way.

So why is this? Well, Clothes Moths and Pantry Moths are both weak flyers that prefer to crawl about in the shadows. They are not especially attracted to lighting at all, and when disturbed, will usually hide away. Indeed, these pesky and destructive moths avoid lighting, sound, and motion. For this reason, infestations of Pantry and Clothes Moths can go undetected for quite some time!

a close up of a Clothes Moth

Even worse, Pantry and Clothes Moths are most destructive in the larval stage. This is when the moth larvae will destructively chew through all kinds of expensive clothing and shelf-stable pantry items. To be sure, you can not lure out moth larvae with UV lights.

In summary, does UV light attract moths? Most definitely, it does. Does light attract Clothes Moths or Pantry Moths? Not so much.

You can use light sources and bug zappers to lure in moths and insects outside at night but inside the home, pestilent insect species often avoid light and take cover in dark, quiet spots.

Why are some bugs and moths attracted to UV light and others are not?

Many types of insects are attracted to UV light. In particular, nocturnal insects (like moths) seem to be drawn in by UV light. Some speculate this is because of its wavelengths, while others say it is because of mating behaviours. Indeed, the tendency of certain insects to gravitate toward light is the reason that bug zappers are so popular among campers, picnickers, and people staying in cabins deep in the woods.

a man fixing up lights in his garden at night

But why does this phenomenon take place? Well, there are many differing opinions on the matter. When an insect is drawn toward a light emission source, it is known as a phototactic behaviour. Phototactic behaviours cause bugs to move toward lights, sometimes with reckless abandon. There are many theories on why this happens.

One study suggests that female moths of certain species emit UV light when looking for a place to lay eggs. Other studies suggest that insects are disorientated by light and are trying to reach the contrasting corners toward the edge of a light source. Still, other researchers believe that an insect’s decision to fly toward lights at night may have something to do with the moon. In any case, insects that are attracted to light implement positive phototaxis (like Miller Moths), while insects that avoid light (like Clothes Moths) have negative phototaxis.

Moths and UV Light: FAQS

Now that you know why some moths are attracted to UV light, let's go over some frequently asked questions on this particular subject so that you can figure out whether using ultraviolet light to kill insects is a viable solution in your situation.

Are moths attracted to UV light?

insects flying around a bright light in the dark

Yes, some species of moths are powerfully attracted to UV light. These same species of moths are also often attracted to soft white light, blue radiating light, black lights, and mercury vapor lights. These are “phototactic” and display what’s called positive phototaxis. In simpler terms, these particular species of moths (and other insects) are usually nocturnal and tend to be strongly attracted to lights at night.

The phenomenon of phototaxis is why you often see moths and bugs flying around street lights, porch lights, etc. However, not all moth species have positive phototaxis. Nocturnal (active at night) insects are more likely to be drawn to lighting sources than diurnal (active in the day) insects. Clothes Moths and Pantry Moths are not attracted to UV Light.

What light kills moths?

the UV light of a bug zapper

Some lights, such as bug zappers, emit UV light that attracts insects. The bugs are lured to the centre of the zapping device where they are electrocuted. So, in a way, UV light can be used to kill nocturnal flying insects. Shortwave blue light can also be used to irradiate insects and kill organisms. So, if you want to kill nocturnal flying moths outside at night, a bug zapper can work.

With that being said, bug zappers can also lure mosquitoes to an area and may kill beneficial insects as well. Bug zappers do not work on pestilent moths such as Clothes Moths or Pantry Moths inside the home. If you want to kill these types of moths, you will need to use Clothes Moth Traps, moth-killing sprays, fumigation products, insect removal powders, or other extermination methods.

Will ultraviolet light kill insects?

Wondering if UV light can kill bugs? The short answer is yes, it can. As a matter of fact, UV (ultraviolet) light is used in bug zappers and other insect zapping traps. However, this kind of light is not 100% efficient when it comes to getting rid of certain insects. Not all bugs are attracted to the wave outputs of ultraviolet light. Moreover, some insects can adapt to ultraviolet light exposure and will avoid bug zappers in time.

About MothPrevention

MothPrevention® speak to customers every day about their clothes moth issues - clothes moths are a species that are ever increasing and that can cause significant damage to clothes, carpets and other home textiles.

To date, we’ve helped over 150,000 customers deal with their moth problems. We have developed professional grade solutions including proprietary pheromones engineered in Germany to the highest production standards.

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