Touching a moth for the first time can lead to some confusion and tension. It feels as if their skin is crumbling into dust and coming off. This might give an unsuspecting person the impression that touching a moth will kill it. But is that true?
Simply touching a moth will not kill it instantly nor will it permanently damage it. The dust particles you feel are tiny scales that naturally peel off the moth. But if the wings get damaged by your touch, the moth cannot fly as well or at all. And a flightless moth is essentially a dead moth.
Moths have fascinating anatomy that makes them stand apart in the large pool of insects. And their colorful wings are a big part of their appeal.
So, we are going to look at them more closely and explain how they react to human touch. We explore the functions of their scales and whether they possess any threat to humans. And hopefully, we can get rid of some misconceptions about these creatures along the way.
Dust on Moths: The Purpose
Some may think that moths are dusty because they reside around trash piles. Or they get dust when they are flying through the air or when they land on dirt. But this dust you feel on moths is actually part of their biology.
Moths have tiny scales or hairs that cover most of their wings and parts of their body. They belong to the Lepidoptera class of insects and this word quite literally means “scaled wings” in Latin. So, the “dust” on these insects is an extension of their anatomy, similar to nails and hairs.
But these hairs are very loosely attached to the moth’s exoskeleton and wings. As such, the slightest touch is enough to dislodge them. So, why have them at all if they are so fragile?
Camouflage and Protection
Well, these scales are responsible for creating the diverse and often intricate patterns you see on the moth’s wings. Many species of moths have adapted their wing pattern to match their surroundings. Thus, giving them effective camouflage and potentially protecting them from prey.
The scales protect the moths in a different way as well. A common tactic of avoiding predators in nature is to make yourself look scared or toxic. And some of the moths use the design on their wings to confuse and startle their predators, which are usually lizards and birds.
Reproduction is one of the primal instincts of any animal and different species have different methods of achieving this. Moths rely heavily on their colorful and patterned wings to attract the right mate. After finding a suitor, the moth mate and proceed to lay eggs. Thus, ensuring that its heritage lives on.
Escaping Spider Webs
Though the research for this is not adequate, many believe that the scales on the moths help them escape a sticky situation. For instance, getting caught up in a spider web. By shedding their scales, they can slip out of the hold and fly off to live another day.
The tiny hairs also function as moisture repellent by keeping the drops apart. The structure is so small that the water tension is sufficient to avoid the drops of getting in contact with the true surface (like a nail board). This keeps the moths dry and reduces their wait so they can continue flying.
The hairs do also have an astonishing effect during rain. They break up the raindrops on impact and let them explode in all directions – keeping the wing safe. (You can see it in a slow-mo and read more about it here: Moths And Water And Rain)
Will a Moth Die Without the Dust?
So, the scales on a moth serve several functions that are all necessary for them. However, research has shown that the scales have little to no effect on their flight capabilities. So, even if they lose a significant portion of their scales, they will not become incapable of flight. Nor do they feel pain when losing the scales.
However, the dust or scales play a vital role in continuing the species by attracting mates. Without it, the moths will either have to alter their method of mating or face possible extinction.
Plus, without scales, a moth is far more likely to be eaten by frogs, bats, birds, etc. Because they will have no way to hide or scare off their predators.
Moths won’t die without scales necessarily, but their survival chances are decreased.
So, the moths are not physically hurt when losing their scales nor does it affect their flying. But losing scales will hinder some important biological functions that are important for the species as a whole.
Can Moths Rebuild the Dust?
Despite the massive importance these scales have, moths are constantly losing them for various reasons. They shed scales when trying to hatch from their pupa, or when they scrape any obstacle or trying to escape a spider’s web. Even a strong gust is enough to scatter some of the scales in the air.
This is why some people can have certain allergic reactions to touching a moth or even being around them. The scales can get into their lungs or attach themselves to the skin of people. Thus, causing a great deal of irritation and discomfort.
Yet, the moths are in no rush to grow them back. In fact, a moth may lose most if not all of its scales during its lifecycle, and still complete all its biological needs. It is common to see an old moth, who is near the end of its lifecycle, have clear spots on its body. This is because that specific area has lost a lot of its scales and thus, becomes colorless.
Now, the scales they lose naturally do not hinder their behavior significantly. They are still able to fly perfectly fine. And they have plenty of scales left to present themselves to potential partners or hide from becoming prey.
Moths do not need to grow scales back.
Also, adult moths are the only stage that has wings. And they typically have a short lifespan. So, there is not enough time for all the scales to fall off or for them to regrow. They are most important until the moth can find a partner and pass on its genes.
Of course, an accident can cause them to lose most of their scales at once, which can hamper their normal activity. But chances are such an accident will probably do more direct damage to their wings. So, the effect on the scales will be negligible at that point.
Why is Touching a Moth Dangerous to Them?
Now, just because it is natural for moths to shed scales when you touch them, it does not mean you should handle them without caution.
Similar to many other insects, moths do not possess a sturdy exoskeleton. They are strong enough for the moth to get by in a natural habitat, but not enough to withstand the full grip of a human. This is especially true for their wings, which are even more delicate than the rest of their body.
So, something as apparently harmless as rubbing their wings may end up damaging them permanently. And their wings are most crucial to their survival. Because if a moth cannot fly, then it cannot find a mate, search for nectar, or hide from predators. It becomes vulnerable to all sorts of threats, which makes it impossible for them to survive.
And moths cannot regrow their wings. So, once they lose them, they lose it for good. Even a damaged wing disrupts their mobility drastically, making them easy prey.
So, the next time you want to touch a moth, make sure you are not putting too much pressure on the little guy. If you feel too much dust is coming off, that is a good sign that you are being excessively rough with them.
Why do Moths Turn into Dust When You Kill Them?
The short answer is that they do not. This is another misconception that can easily arise if you press a dead moth.
Other than the extremely large but rare species of moths, the most common varieties are small. And without their wingspan, they would seem even smaller. So, their internal organs are equally minuscule.
If a moth’s body is crushed with force, it does not leave much noticeable residue. The thing you notice instantly, however, is the “dust” that gets scattered all around. And if you were to touch, you will mostly feel this dust more than any hard structures or bony substance.
Because insects do not have a bony skeleton. And compared to other bugs like beetles or cockroaches, the exoskeleton on moths is considerably weaker. So, you will not hear the crunch or snap sound that you can normally hear when a cockroach is crushed.
The fragile body coupled with the dusty remains gives the illusion that moths are turning into dust as soon as they die.
But in reality, there are remains of internal organs and external skeletons.
Furthermore, their body is so small that it only requires minute volumes of blood to survive. And this blood is not the usual red color that we associate with animal blood. Instead, insect blood is more green, yellow, or sometimes colorless. So, the lack of recognizable blood and moisture also helps to sell the illusion that there is only dust remaining.
Moth dust is a natural part of a moth’s biology and so is losing some from time to time. Just make sure you are not crushing the body or wings when handling a moth and you will be good to go.