FACTORALY - E119 MOTHS

Episode Date: December 18, 2025

Moths are not what you think. They're helpful, beautiful things that are everywhere. Whilst butterflies get all the good songs, moths are the ones doing the heavy lifting. In this episode, we look into the wonderful world of the moth.Tto flutter through some brilliant moth information, go to the show notes here: https://www.factoraly.com/post/e119-moths Hosted on Acast. See acast.com/privacy for more information.

Hello, Bruce. Good-day, Simon. How are you today then? I'm feeling fantastic. Thank you very much. How are you? Jolly good. I am feeling all right.

And hello to everyone listening to us. We hope you are all well. Welcome to another episode of factorily. What is factorily, Bruce, as if anyone out there didn't already know. Factorily is two twits talking about tripe. I'm trying to think of an adjective that begins with tea in order to finish that sentence off. True. Very good.

So, yeah, so every week we'll come to you with something that we thought was either very dull or very interesting and we'll either make it a bit more interesting or a bit shorter. Yeah. And this week is no exception. No, indeed. Because I didn't think very, I mean, apart from them eating my kilt. I didn't think that much about moths, really. No, no.

I've always thought moths are a little bit dull and boring, but they're not. They're very interesting things. They are lovely things, actually, when you start to get into moths and you ignore the kilt thing. Okay, I feel this needs exploring, Bruce. I feel this and pent up rage. No, it's fine. Don't worry about it. It'll be invisible mending, we'll sort it.

Do you have a slightly moth-eaten kilt then? I may have a slightly moth-eaten kilt. But then they're supposed to be moth-eaten, so that's okay. You clearly haven't been using your balls. Well, no. Can you still buy moth balls? You can. They are made of a different substance these days.

They used to be made of something which was quite harmful, not just to the moth, but to your own environment. But now you get these, like, sort of little bits of wood. a cedar wood and things like that that are supposed to... Yeah, the smell kind of deter them rather than a toxin killing them. Yeah, deterrent is always better than killing, I feel. So tell me about the origin of the word muth. Muth. That sounds French.

It does sound French. Muth is not French at all. It's old English via a little bit of Norse and German. it's always been roughly moth sometimes slightly more moth or motha but old english moth coming from a germanic word which is also related to the dutch word for it the norse word for it pretty much everyone used to have the same word for it and it sounded roughly like motha and it might or might not be related to maggot it might or might not be related to midge lots of other little insecty words beginning with m yes but um up until the 16th century, the word was primarily used to refer to the lava and the caterpillar phase of the creature's life. Okay. Which is why you get moth eaten because this has always bugged me. Bugged. Bugged. Very nice. Moths, the flappy things, don't eat your kilt. Right. The larvae, the little things that turn into. It's always the children. It's always the children. Those are the

things that eat the kilt. So it's always bugged me why they're called moth-eaten, not larvae eaten. But that That explains it, because up until a certain point, moth or moth referred to the larvae. I found a fantastic word. The definition of a moth is not entirely accurate, but we'll ignore that. I found a definition that says a moth is a nocturnal lepidopterus insect. And I've looked up lepidopterus and lepidoptera means moths and butterflies. Butterflies. Yes, because there are lepidopterists, aren't there, who collect.

moths and butterflies there are yes and that word itself comes from ancient Greek leopard means scale Teron with a pea means wing So scaly wing Scaly wings Very good

Yeah So nothing to do with leopards Nothing to do with leopards or Teradactyls As soon as I saw silent pee At the beginning of a terror Excellent They're quite prevalent

aren't they moths There are a lot of them, aren't there? Do you know how many? Seven. There are seven moths in the world. Or is that just in your kilt? I think that may just be in my kilt. There are lots of species of moth. They've been around since before the dinosaurs.

Really? We've had moths for longer than we had dinosaurs. Yeah, we've had moths for 190 million years. Gosh. That's a lot of moths. That's a lot of moths. I understand 1,750 species of moths. Right. So I've seen a lot of different figures from this,

and there seem to be a lot of people that disagree. Right. According to different reports, there are somewhere between 150,000 and 250,000 species of moth. Isn't that mind-blowing? Huge. It's phenomenal. Compared to only 20,000 species of butterfly. Yes. So there's like five times as many.

Butterflies. We need a butterfly when you've got a moth. Exactly. That is a lot, isn't it? It is a hell of a lot. I took a bit of a look into the difference between, moths and butterflies because I think moths get a bit of a raw deal

you know I think of a moth and my image of a moth is that it's in comparison to a butterfly as if the butterfly is the proper thing yeah and the moth isn't you put a brown dusty thing little brown dusty thing is a moth that you only ever see at night yeah and a beautiful coloured

extravagant thing and that is that is largely true but there are exceptions there are very very colourful moths that fly during the day and there are some very dull butterflies that only fly at night. So that is largely a true difference, but it's not exhaustive. But one of the main differences is also in the antennae.

Butterflies have sort of thin, stalk-shaped antennae with a clubbed bit on the end. Moths don't. There's usually a bit thicker, often hairy and fluffy. A butterfly rests, generally speaking, rests. with its wings closed and vertical of its back. And moth rests with its wings open. So yes, those are kind of roughly the differences, but it's only quite rough.

Moths are really, really important. I mean, they are one of the biggest nocturnal pollinators that we have. Really? I mean, there's bats. We talked about bats in our episode on bats, and bats are also nocturnal pollinators. Yes. But so are moths.

And they go to flowers or flowering plants that open their flowers at night and service those flowers at night. Now, isn't that interesting? I didn't think to question that when we were talking about bats, but it's just popped into my head. What flowers open at night in order to be pollinated? There are a few. They're also delicious. Well, they also eat loads and they're also delicious. Well, the bats quite like them. Yes, bats like moths a lot. And moths like insects a lot. Oh, okay. Or some do, anyway.

There are some moths that are fly eating. They're carnivorous. Oh, really? Mm. Oh, I find it interesting what a variety of different things they eat. And at different stages of their life as well. You know, we've already mentioned the larvae eating your kiltz. This almost feels like the wrong way around.

You know, for us humans, we sort of have a liquid diet when we're young and then we move on to solids. With moths, it seems to be the other way around. So the larvae eat more solid matter, like plants, leaves, roots, natural fibres such as wool and silk, hence your kilt. Adult moths, when they're in the flappy phase. They go for nylon. No. They go for more liquidy things.

So they go for nectar. They go for tree sap. They go for rotting fruit. Okay. With their probiscus, which is one of my favorite words. It's a good word. That long tuby drinking straw thing. So yes, they sort of go from a more solid,

to a more liquidy diet as they, as they're older. They're very adaptable as well. Are they? So there are some moths that lay their eggs under water. Oh, really? And their larvae grow up underwater. Ooh. There's a thing called a water veneer moth.

Okay. Which I like the idea of a veneer moth. Yes. It should be polished. Yes. So they lay their eggs under water And then the eggs hatch and the larvae sort of live underwater for a bit And then they sort of when they come out of the water

And they turn into moths They then become sort of airborne How interesting And then there are other moths Which look like shit I mean you know We all look like shit from time to time But there are camouflaged moths

Oh they actually look like feces And they actually look like bird droppings And they're under things like hornets and stuff don't notice them and things. Yes, okay, yeah. There are some moths that have eyes on their wings, not proper eyes, but wings that look like eyes. Oh, their patterns, yeah.

Yes, yes. And then there's the buff tip, which I love this. The buff tip moth actually looks like twigs. Okay. A bit like a stick insect, but it's got like twig shapes on its wings. Oh, wonderful. That's great.

Yes, they are quite good at camouflage. There are a number of moths that look slightly waspish. Yes. They sort of have a yellow one. and black stripes. There's one particularly called the Hornet Moth. And goodness me, it looks like a hornet. You know, it's even got clear wings that are, you know, that look just like a hornet's wings. And these things have simply evolved to deter predators. You know, they've, evolutionarily speaking, they've latched on to the fact that Hornets are right little buggers

and things stay away from them. So they've adapted to look like those in order to deter predators. Yes, although Hornets can go for a small moth, which is why they tend to They look like bird droppings. So there's that as well. Right, okay. There's an amazing one which I love, which is to do with us. Oh, I know the one you're going to do. Go on.

I'm going to do the peppered moth. I didn't know it was going to be that one. Okay. So there's a peppered moth that started off a fairly light colour. During the industrial revolution when everything went black with soot, it evolved. Because obviously the lighter coloured ones were eaten. and the darker coloured ones weren't. So the peppered moth turned black

over the Industrial Revolution. Wow. To camouflage itself against the buildings, which were covered in soot. That's amazing. And then when the building started to be cleaned up, the black ones started to show up on lighter buildings.

So the light ones started to re-emerge. So the peppered moth has gone through this cycle of being light and then dark and then light, thanks to us. that's incredible that's a really quick response evolution isn't it you sort of think of evolution as being something that happens over hundreds thousands millions of years but that's well if you think about the life cycle of a moth yeah true oh yes it's many many many many generations a lot of generations yeah yeah wow I wonder whether they've been called the pepper moth because they have

this black and white thing could well be some some scientists somewhere has gone okay it was white and now it's black maybe it should be pepper The one I thought you were going to mention was called the Death's Head hawk moth. Oh, hawk moths are great. This particular one, the Death's Head hawk moth, it has a pattern on its back that looks a bit like a human skull. As far as I can tell, that's not an evolutionary thing that it uses to deter predators, because other predators don't care that it looks like a human skull. That would be irrelevant.

So it's just us putting our impression on it. but yes it looks menacing so it's got this thing sort of on its back in between its wings that looks a bit like a human skull it emits a high-pitched noise when it's threatened

which sounds a little bit like a tiny scream so you put those two things together and you know people think it's an omen of death and all that sort of thing in Greek it's called the Akharanita Atropos I hope

which derives from one of the fates who governed the underworld and determined the lifespan of humans and so on. So it's a real, you know, menacing thing. And that's actually the moth that appears on the artwork of Silence of the Lambs. Oh, wow. Covering over the person's lips. Yes. So that's a death's head hawk moth. But hawk moths are great. They're actually one of the moths that migrates. Oh. So we get hawk moths in the UK that have come from North Africa. Oh, really? And from southern Europe. They come all the way up to England for a,

or to Britain for a holiday. Wow. So they don't actually sort of spend the larvae phase here? No. So they're eating sort of Greek tunics. Keeping their hands off our kiltz. I discovered what I think is possibly the cutest, most adorable moth. It's called the rosy maple moth.

Which sounds adorable already. And it's pink and yellow. It just, it looks in time. made up. It's pink and yellow. It's got a fuzzy yellow head with pink patches on its wings. And it lives in maple trees in North America. And it eats maple sap and essentially it lives off maple syrup. Yes. Wow. In its caterpillar phase, it's called a green striped maple worm. Okay. Which is equally, I think, a really adorable name. They're just cute little things. Go and have a look at them. Going back to hawkm, because you were talking about the noises that some of these

there is a hawk moth that has a great defense against bats because bats eat moths we've said so how can you defend against a bat well bats use ultrasonics don't they to find their prey yes they do so there's a hawk moth that plays an ultrasonic song by rubbing its genitalia which deters bats it basically it's like a jamming it's like a jamming signal yeah yeah that's incredible again i sort of evolutionarily speaking i wonder, who was the first hawk moth who realized this? It's flying around, it's being chased by a bat. I don't imagine

what they were doing at the time. Exactly. There's also a mandolin moth. Is there? Which is like mandolin shaped and it can actually play its wings. No way. Yeah. Wow. Obviously, it's not much of a tune. No, sure. But still. It's a hell of a moth. That's interesting.

Oh, there's lots of different types of moth. There are so many. And they've got great names. I don't know if it's just that the lepidopterists actually just have a sense of humour. But there's one which is a slightly sort of reddish colour that flies quite high. Right. And it's called the ruddy high flyer. Ruddy high flyer.

That's great. So it flies ruddy eye. It's a ruddy eye flyer. That's wonderful. There's another one which has like a, it looks like hair on the top of its head. It's slightly unruly and sort of an orangey colour. And it's the Donald Trump moth. Oh, it isn't, is it?

Yes. It's called the Trumpie eye or something like that. Because its head looks like it's wearing Donald Trump's hair. That's wonderful. There are some cracking ones. There's even vampire moths in Siberia. Oh, really? Suck the blood of actually very small things.

There are a couple of moths that drink the tears of sleeping birds. Oh. So what they do is they very, very gently land on the back. of the heads of the birds and they extend their tongue round to the eye of the... I don't know what I'm doing with my head. They extend their tongue round to the eye of the bird. And just in the corner of the eye of the bird, they just have a little sip of the tears of sleeping birds. I just want to talk briefly about moths and the moon.

Okay. Or moths and light in general. Okay. So we have a phrase like a moth toward a candle flame. Yes. Or words to that effect. Yes, drawn like a moth to a flame. Exactly like that, yeah.

Used in Shakespeare, it kind of implies something is attractive. It will lure you in, but it's a bit dangerous and it will burn you. Because, historically, moths have a tendency to fly towards candle flames and then get burned as they get too close. And that's obviously not a good thing. And for centuries and centuries, we've thought that's what it is. We've thought that moths are drawn toward light because they like the light. they're drawn to it. Turns out they're not.

It's essentially accidental. So when a moth is flying at night, it uses the position of the moon to keep itself level. They have evolved to automatically tilt their head upward in the direction of light. And that tilting of their head upward in relation to where the moon is, shows them which way is up, essentially.

Okay. So that they can fly properly. And artificial light, which will, obviously isn't as bright as the moon, but when it's closer, it seems brighter, it causes them to tilt their head up. And that source of light suddenly becomes their sort of reference point. And so they start spiraling around whatever, I don't know why I'm doing this with my hand either. It's a podcast. They start spiraling around this artificial light source with their heads tilted up. It causes them to get clumsy and disoriented. And eventually they fly into the light source.

If it was a candle, obviously it burns them and they die. Nowadays, they just sort of look like they're flying around and around and around a light bulb. And that's the case with quite a lot of other nocturnal insects as well. You get lots of different types of moths and flies and all sorts of things that do that. But it's not that they're particularly attracted to the light. It's that they're disoriented by the light because it interferes with their ability to watch the moon for their level. That makes sense. Hmm, I think so.

I had a wee look into the production of silk. Oh. This isn't really anything I've ever thought about looking into. I just accept that silk exists. Silk is a naturally occurring substance produced by silkworms. The most prevalent type of silkworm is one that grows into a moth called the silk moth. There are other varieties as well. But it's basically the stuff that they use to build their cocoons with.

It's, you know, they produce it naturally. They build a cocoon, they wrap themselves up in this cocoon, they turn into the pupae stage, and then they emerge as a moth. And at some point or other, people started harvesting these little cocoons to use for weaving silk into making clothes and so on. And I hadn't really realized the process of it, but basically it's, I don't want to say it's totally inhumane, but people harvest these cocoons. So they feed the larvae on mainly mulberry. leaves, for whatever reason. They seem to be a good source. And they have thousands upon thousands of these things feeding on these leaves. They all wrap themselves up in a cocoon. They harvest the cocoon. They drop it into boiling water in order to loosen the fibers in order to make it

into a thread in order to use it. But in doing so, they kill the pupy in the process. They don't wait until it hatches and emerges as a moth. This is why silk isn't vegan. Yes, exactly. Yeah. And I hadn't realized that. I didn't know that was a thing. But if they do wait, for it to emerge from the cocoon it breaks the fibres it breaks the long continuous thread so they boil them whilst the thing is still in there and it takes so many of these things to make silk i've found a statistic that says it takes between 1,500 and 3,000 cocoons to produce one pound of raw silk yes this is one of the things that you weren't allowed to bring out of china was it On the silk road, which is named after the fact that the Europeans stole pupae of silk moths and brought them to Europe.

Right. Because the Chinese were very keen that the Europeans didn't get their hands on Chinese silk. Oh, I see. Obviously for trade purposes. Yeah, of course, yeah. I found that there's something called Ahemza silk or piece silk. Right. And that's made by waiting for the moths to emerge naturally and then harvesting the silk.

But because it breaks the cocoon, it breaks the structural integrity of the thread. So it produces a lower yield and a much higher cost. Yes. What's the biggest moth you can think of? Well. Is it an aeroplane? That's not where I would have gone, no. Is it a tiger moth?

Oh, very good. There are tiger moths who are moths. Oh, so the tiger moth plane is actually named after a type of moth? Yes. Oh. made by the De Havelin Aircraft Company. Yes, indeed. Designed by Geoffrey de Haverland,

operated by the Royal Flying Corps and the Royal Air Force. And basically, they were used to train. I mean, you see pictures of people flying tiger moths in battle, and they did do that, although that was more gypsy moths, or cirrus moths or genet moths, or moth majors. There's so many moths.

But they're actually mostly used for training purposes. Right. Because they were two-seaters. So the pilot was sitting in the backseat and the trainee was sitting in the front seat. Yes, I can picture that. The problem was that the engine was very tall. So for the trainee to see over the engine

to see where they were going was quite tricky. Yeah. So what they did was they inverted the engine so that it actually didn't stick out quite as high up the airplane. Right. And then they had to produce a kind of a way of pumping the oil up. Normally oil falls down. So they had to pump the oil up into the bottom of the engine, if you like.

for it to kind of drip through. Yes. So they're fascinating things. And I've actually been up in a tiger moth. Oh, have you? I have. Wow. I was at a car thing and then suddenly this whole flight of tiger moths, tiger and gypsy,

both landed on the field next to where we were looking at cars. Huh. And the pilots said, you know, would you like to come up for a flight? Oh, my goodness. Yes, please. I went up for a flight. It was amazing. That's wonderful.

thing is that they land on their tails, tiger moths. So you know how normally you see an airplane? They sort of land on the front wheels and then the back end sort of goes down after it started to slow down on a runway. Yeah. With a tiger moth, you land the other way. You land like back end first

and then plonk the front wheels down. Oh, right. Okay. How interesting. So both a tiger moth and a gypsy moth are actually both types of moth that the planes are named after? Yes. I'd never really put two and two together there. So the reason why it's called

a gypsy moth was because it was actually used on ships because you can actually fold the wings up so that it would fit on a ship better oh that's fantastic you know rinaldo the football player the football player not personally but i'm aware of his existence okay there was a football match but what they've done is they left the floodlights on all day so obviously lots and lots of pictures of the moon for the for the moths to kind of go for the moths to kind of go for Yes. And there was this inundation of moths on this pitch. Right.

Loads of them. And there's one picture, which I'll put in the... Actually, we have show notes. Oh, yes, we do. So if you go to our show notes on the blog at factorily.com... Factorily.com? No, factorily.com. Oh, factorily.com.

Sorry. Yeah. I thought you said factorily.com. So if you go there, you'll see a picture of Ronaldo with a moth on his face. He's either had just been tackled or just been tackled somebody. and he's on the grass and a moth just flew up and and just attached itself to his face great within 25 minutes there were about 30 parody Twitter accounts of ronaldo moth oh my goodness what's wrong with the world i don't know there are some very strange people on the internet

q ed i mean we're here well yes that's true yes it's lump our selves in with them Are you got any records for us? I have got some records for us, yes. They're all about size, really. Okay. From the largest moth to the smallest moth. And there are some disputes over this because it depends on how you're measuring your moth.

A problem we've all had in life. Head to foot or side to side. Exactly, yes. It's usually a wingspan, though, isn't it, with these things? It's usually a wingspan. There are some that have a really big wingspan, but they have a lower head-to-tail length or whatever. But the world's largest moth in terms of overall.

is called the Atlas Moth which is native to Southeast Asia their wingspan is about 30 centimetres 30 centimetres a foot wide moth? Yeah it's a ruler Wow

I've seen pictures of these things sitting on somebody's forearm and you know it's practically as long as their forearm it's absurd There are a couple of others that have a similar wingspan but you know smaller body so it's disputed as to whether or not they get the record one of which is called the White Witch

which is worth mentioning just because it's a cool name. This is what I'm saying about moth enthusiasts. Yeah. They're loving, giving them weird names. Yeah, exactly. There's one called the Hercules Moth. So I've got Atlas and Hercules. Yep.

Okay. The Hercules Moth has a smaller wingspan, but it has a larger surface area, if you like. It has more wingage. Yes. Even though the wings are not as broad. More square inches of wing. Exactly that, yeah.

Yes. So that's the biggest one. The smallest ones, suffer from exactly the same problem. How are we measuring them? But a few contenders, not quite such interesting names. The small ones seem to have much more Latin, scientific names for some reason. We've got the Stigmela Maya of Mexico, the pygmy sorrel moth. That's better. That's better. Yeah. And the Porfirazela alternata, also of Southeast Asia,

and they have a rough wingspan of 2.5 to 2.8 millimeters. They're like the size of a midge. And then we've got lifespan, the shortest lifespan of a moth. There's a species called the rain moth, and it lives for a few hours. Literally just a few hours. Once it's hatch, yeah, from emergence to death. Yes. Okay. By contrast, the Arctic woolly bear moth,

just such great names, has the longest lifespan of up to seven years. Wow. A large chunk of that is spent in the cocoon. yeah because of the cold waiting for the nice weather to arrive exactly yeah but yes again from a few hours to several years there's quite a range

so yes those are all my records fantastic do you know what I really like moths I do yeah I think they're interesting they're welcome to my kilt you should buy a spare kilt just in order to let them have it maybe I should or maybe I should just buy a nylon one

if they're not into the man-made fabric There you go. There's an option. I think all of my moth-related facts have hatched and flown away. Yes, I have nothing fluttering by me at all. So what we would like you to do now is give us a review. That would be lovely. A five-moth review? I'm sure it's worth every moth. It's worth every moth. What else could they do, Simon? They could also tell their friends about this show. I'm sure you all have equally nerdy, fact-loving friends who'd like to tune into this and learn more week by week. Then there's subscribing on your podcast player.

Click on subscribe and then there's never a week when you're going to miss this. Exactly. We know we've got at least one thing wrong in this episode. We're not going to tell you which one. But if you know what it is, please write to hello at factorily.com. There's the Facebook page. We've even got an Instagram link now. So many ways to get in touch.

So thank you all so much for tuning in. We hope that you will come again next time for another. fun-filled factual episode of Factorily. Bye-bye. O'Vois.