The Infinite Monkey Cage - Moths v Butterflies - Katy Brand, Jane Hill and Chris Jiggins

Episode Date: August 13, 2025

What really separates a moth from a butterfly? Is it just a matter of day and night, or is there more to this fluttering feud than meets the eye? Professor Brian Cox and Robin Ince flap into the fabulous world of Lepidoptera with Professor Jane Hill, Professor Chris Jiggins, and comedian Katy Brand. Together, they chase colourful wings through science and storytelling, uncovering epic insect migrations, the secrets behind dazzling wing patterns, and most importantly, why Katy has a butterfly tattoo on her arm!Producer: Olivia Jani Series Producer: Melanie Brown Executive Producer: Alexandra FeachemBBC Studios Audio Production

BBC Sounds, Music, Radio, Podcasts. Hello, I'm Brian Cox. I'm Robin Ince, and welcome to the infinite lepidopterinaeum, or at the very least, the very, very, very big butterfly house. Lepidopterineum. That's why I should have said very, very big butterfly house. To be fair, you can pick me up on that, but you were the one who said,

there's no way I'm saying that line, because I won't be able to pronounce it, and now you've pronounced it in front of me, yet again, making fun of the arts with your cold, cold physics mind. Lepidopterium. Lepidoptererian. Lepidoptererian.

Let's go to our guests who have not yet been introduced, so we'll merely be phantasmus. Leopoctoritarian, lepidototterian. I've never used any of those words. Oh, no. We've got the wrong guests. Now, regular listeners will know that In our unashamed quest for a larger audience,

every so often we pitch two animals against each other in the title of the show before delving immediately into scientific detail and thus faithly undermining the populist conceit. So we start off by trying to be like WCW, then we become an open university. So it's the equivalent of starting off with the idea of an illegal East End lockup dog fight,

but then actually it turns out that it's just a battle between which dog salivates first when Brian rings his little bell and he does like to ring his little bell kind of like Pavlov's dog fight it's Pavlov's dog fight exactly so so far we've pitched bats versus flies we've had dogs versus cats

wasps versus bees which ended up pretty much being for the wasp which was quite a surprise there but it was a great argument tonight is a whole new cocoon of worms because we are asking which is better moths or butterflies Wow Thank you

Just because this is Radio 4 Is it which is better Or which are better It sounds wrong enough Is it which are better Which are better Which are I'll tell you what

Why don't we change the subject Then we say Now on Radio 4 We ask the question Which is better Is or are Presented by Stephen Fry Anyway

Today. Today, we are exploring those most ubiquitous lepidopterer. What is the difference between moths and butterflies? How do they fit into the tree of life and what really is metamorphosis? And who is the hungriest caterpillar of all? To feud over the fratilleries and tiger moths, we are joined by a lepidopterist, an entomologist and an expert on watermelons. I believe that's what she is. And they are. I'm Chris Jiggins, Professor of evolutionary biology at the University of Cambridge. And I've spent most of my career chasing butterflies around the jungles of South America to study their evolution and their fantastic colour patterns and how different species evolved to look similar to full their predators.

So my favourite butterfly myth is that the Aztecs believed that the monarch butterflies were the souls of their dead warriors who were coming back to visit the living. And I'm Jane Hill, Professor of Ecology at the University of York. My research is focused on both butterflies and moths, understanding how they respond to climate change. And my favourite story about a moth involves someone called Bernard Kettlewell, who was an entomologist in the 1950s. At the time, people were very interested in migration.

They knew that moths turned up in the UK, but they didn't know whether they came in one big flight from further south or whether they came in a number of jumps, of breeding and flying and breeding and flying. So he was interested in this and he used the opportunity of the French atomic bomb test in the Sahara in the 1950s

and then started collecting moths the following spring and testing them with his Geiger counter and came across a moth that did have radioactive particle in it and to cut a long story short worked out that that's where it had come from so he concluded that this was a moth that had come

all the way from the Sahara in one go. And of course, now we have lots of other ways of looking at moth migration. We know something about the amazing journeys that they go on. I'm Katie Brand. I'm a writer. Sometimes I'm a comedian, but not often. But my favourite story about butterflies currently is I have a tattoo of a butterfly on the inside of my right arm that I got for my 30th birthday.

And I also have a tattoo of an anchor on the inside of my left wrist that I got a couple of years later. A couple of years after I got the anchor, I was interviewing a pop star for a TV show, and he lent over to me, and he went, oh, your tattoos, butterfly in an anchor, what do they mean? And I was about to tell him, and he answered for me, and he said, is it freedom and stability

and the need for balance? And I said yes. That's exactly what it is. and so ever since then I've been able to smugly tell people that's what my tattoos mean so that's my favourite. And this is our panel. As is traditional in something versus something, we have a boat at the start and a vote at the end. Could you raise your hands if you are for moths? Or you could do a sound which will be more effective for the radio.

I just say, I really love the way they turned on all the electric lights. for the moths to put it out. Robin is, of course, correctly, he wouldn't be better. But what sound? Well, I'll tell you what, if you make a sound as you imagine a moth might make.

Yes, this will be interesting. This might lose a few. So, who is for the moth? Moose. Someone's for the cow over there. And now for the butterfly. Woo!

Well, I think it's, It's currently the cow moth. So I reckon, would the audience agree that currently the butterfly is in the lead? Well, it could all change, Brian. Yes. So, Jane, your job is to make the case for the moth. It's a really hard thing to do. I work on both butterflies and moths, but I'll step up to the plate and foot forward the argument about why moths are just absolutely fabulous.

And I guess at the end of the day, well, butterflies are job. just moths that happen to fly during the day. So we could say that this is a sort of pointless comparison. Pointless time. Jane, to be quite honest, we should have done the research call with you before the listing was put in the Radio Times. Because it was only once it had all been confirmed that we were told you do know the butterflies are just moths.

So just accept that throughout, everyone's a winner today. Welcome to the world of light entertainment. But there's about 180,000 lepidoptera, and about 90% of those are moths. So just on numbers alone, we should all be saying moths are just absolutely fabulous. The other thing about them is I think people think that they're drab and brown,

but they're so colourful. If anybody's ever run a moth trap, it's just an amazing colour of them. And I love the names of them as well, much more mystical than perhaps some of the butterfly names. So you have a Mervais du jour, The Wonder of the Day, or the burnish brass, or one of the ones I quite like is the old lady. And also Mother Shipton, coming from Yorkshire,

it has the image of rather charmingly what is called an old hag on the wings. And of course Mother Shipton's cave in Nersborough was where she lived. we've talked already about lights and about moths coming to light and one of the amazing things is why they're doing that and that's because they can navigate using the moon and using the stars and they undergo these amazing migrations where they just fly up several hundred meters above the ground they select the ideal wind and they just go with the wind

and they're traveling the ground speed of about 50 kilometres an hour heading to their destination. And then the final thing, I would say as an ecologist, again, going back to the sort of 1920s and 1930s, there were people working at Rothamsted, which is in St. Holbans, in North London, and they were running moth traps, and they were noticing these really interesting things that got them thinking about really fundamental questions about ecology. So if you run a moth trap, you know that most individuals are just made up of very few species. So this idea of why some species are common and why some species turn up or not.

And that led to some really fundamental understanding that we use today about patterns of relative abundance and about patterns of species richness. And that all came about because people were interested in running moth traps and looked at their observations and just came up with these really, really interesting things. So moths are fabulous. But that Mrs. Shippton is one, old mother Shippton.

It's fascinating because I understand, you know, there are some moths you look at and you go, isn't that incredible? It looks like an owl's face, so that will put off a predator. But the idea that you would look like Mrs. Pepper Pot is a really, oh no, I can't attack that. It's a small old lady. How did that evolve? So, now, Chris, what? Well, I was going to show you my owl butterfly look. So it's actually a myth that they're called owl butterflies, the Kalegos.

But actually, they never sit like that in the wild. They always sit with their wings together. So you never really see the two eyes, actually. So they look like owls when entomologists spread them out and stick them in a drawer. Which means they lost the battle of the predator already, doesn't it? Kind of missed the moment, really, haven't they? Yeah, but actually in the wild, they always sit with their wings closed like that,

and you can't see the two eyes. So at no point would that have been any use whatsoever, really? Well, I think there is something that these eye spots come up again and again in butterflies. and I think there's something quite striking about just suddenly seeing this eye when a peacock butterfly, for example, has its eyes on the upper side, and it flashes that pattern, and you see those eyes appear. But these have got the eyes on the underside,

and so you don't really see them together like that. But maybe it's still a bit of shocking to a predator to see that big thing, flashing eyes. But Chris, so your job, you have a minute or so to make the case for butterflies. So they are all the lepidoptera, that's true, and the butterflies are. a small group within the lepidoptera. And lepidoptera means scaled wings. But, I mean, look what the butterflies have done with their scaled wings.

They're amazingly beautiful. This is a morphobus fly, which I'm holding up here. It's got this iridescent blue color, which you can just, you know, in the sun of the rainforest in South America, you can see them from kilometers away. So they're remarkably diverse in their colors and patterns and shapes of their wings. And it's really because they've evolved to live during the day,

so they've evolved to a visual world. So I think that's why we can relate to them because they see in the same mode that we do. And they actually have amazing vision. So we have three photoreceptors, which gives us our colour vision. Some butterflies have up to 15 photoreceptors, even multiple photoreceptors that are sensitive

in the ultraviolet light. So that means there are whole wavelengths that they can detect colours and shapes and sizes and things that we can't even see, which I think is extraordinary. And that's all evolved for them to signal to each other, and for the males to find females. So they're very visual organisms.

I think that's why we as humans can relate to them. So they've taken what moths do and just taking it to another level. So is that the primary difference? Is it just night, day, essentially? That's not a very satisfactory definition because there are some moths that fly during the day. And actually these owl butterflies that I was showing

are dusk flying, so they're not quite night flying, but they fly when it's getting dark. So it's not a clear-cut definition. mission. But taxonomically, there is a group of the lepore that's nested within the bigger lepidopatra that we call butterflies. To an expert, what is the difference? How do you decide? If you see a specimen you've never seen before, for example, well, they have clubbed antennae. Butterflies have clubbed antennae, whereas moths generally have just sort of pointy or fluffy antennae. So that's maybe one of the defining features. But, yeah, essentially, as we were saying

before, you just kind of know, those are moths and those are butterflies. It's hard to. It's hard to pin down a single defining feature for the group. Basically, because evolutionarily, butterflies are nested within the moths, right? So they're not kind of completely distinct groups. I love that scientific. It never sounds that scientific, doesn't the definition of, well, you'll know it when you see it. Well, most of the definitions are they generally do this. So butterflies generally fly during the day, and moths generally fly at night, except for when they don't.

And then, as Chris says, they have different antennae. And then, of course, moths have their pupa surrounded by silk, which is where silkworms and silk comes from. And butterflies generally don't. And then they have different posture. So you'll see when a butterfly comes to rest, it puts its wings behind it, whereas a moth has its wings flat, generally. and yeah

Motta generally hairier you said about their eyes being sensitive to different wavelengths so does that mean that the beautiful colours that we see

are only part of the pattern to another butterfly it's more magnificent some of them have UV patterns which we just can't see some of the yellows

and the whites for example just will look plain yellow or plain white to us but actually they have detailed and rather intricate patterns in the UV that we can't see at all

yeah So Katie, you are the arbitrator today, so at this early stage, and also because your tattoo, because it's all filled in, you could also pretend it's a moth. So it won't change, it won't mean you have to have laser surgery. Okay. So at the current stage, where do you sit in terms of butterflies versus moths, take into account the fact that that's actually a false division? Right. Well, I don't know. I guess I'm leaning currently towards butterflies, but that's because that's what I walked into the room with, right?

So I'm very much open to being persuaded. I also have a guilty conscience about moths because I went through a short but quite intense phase of cutting up dead moth when I was about 11. They were dead already, can I just say? And I would collect them and then later on with a kitchen knife I would try to dissect them. But usually what happened is that it would just disintegrate into kind of moth-coloured dust. So I guess I sort of harbour some guilt, maybe possibly a bit of resentment about that early on because I never cut up a butter. I never found a dead butterfly. I'm aware also, though, and quite seduced by the sort of mythical, spiritual aspects of moths.

You know, we're all now, I don't know, doing lots of spiritual things and stepping into your empowerment and, you know, leaving a glass of rosewater by a full moon so that you can snog the boy you fancy, stuff like that. You're really taking this away from the science. Yes, no, sure. Brian's twitching a lot now. Yes, I get it. I get it. But I just, I think these things are important, you know, in terms of. of our emotional engagement with moths and butterflies so i'm a bit i'm a bit attracted by that side of the mothness so we've got all to play for is what i'm saying i do have a question about

butterflies and and moths it's about the nature of consciousness and i heard on the radio someone talking about butterflies i'm talking about the way um i'm sorry about the terminology correct me please is does a butterfly have a cocoon or a chrysalis cocoon puper they're all words So the caterpillar turns entirely to pulp inside mush and then reforms itself as a butterfly or moth. Is that sort of it? I think there are still structures there. There are still structures.

But what I heard on this radio thing before you leap in with all the expert analysis, right, which I am anxious for. But the question is, experiments have been done where certain stimuli have been presented to a caterpillar to maybe bright lights or loud noises or whatever caterpillars

don't like. I'm sorry, I'm unsure. And it had reacted to that stimuli as a caterpillar. And then post-pulp and reforming as a butterfly, they showed the same creature, the same individual creature, the same stimuli, and it reacted the same as the caterpillar had. And the suggestion in this piece was that the consciousness of the caterpillar had somehow survived the pulpiness, the total goo, And when it had reformed as a new creature, the awareness of something that had happened to it as a caterpillar in terms of its consciousness was still intact. And I don't really know what my question is,

other than, is that true? Yeah, there are structures, the adult structures, already there in the caterpillar. So I'm not sure about consciousness, but certainly, for example, the wings are little balls of cells. And if you're so minded, if you snip in the right place in the caterpillar, you can pop out this little ball of cells, which is going to be the wing of the adult butterfly.

So it's not true that they all dissolve completely into pulp. They're already forming the adult structures in the caterpillar, but they do then dissolve all those caterpillar structures that they don't need anymore and reuse those nutrients to build those adult structures within the pupa. So it is the most extraordinary transition. It's ecologically extraordinary. They just live in completely different environments and do completely different things. Because I didn't realize this either.

think Katie, which is we'd kind of been taught that he'd become entirely liquefied and that all of and what you're actually saying is that whatever we want to call the consciousness the, you know, the nerve endings, whatever, that that actually, if you found a caterpillar in a cocoon and you cut

it open with your 11 year old scissors and all that kind of stuff, you would be able to monitor certain features that had not been liquefied. That's right, yes. Okay. Well, thanks for dashing that mystery. Explaining it. Explaining it. No, I thank you for that. I've been interested in that for a while.

From an evolutionary perspective, butterflies and monster insects, so could you just outline the evolutionary history of lepidoptera? Well, they're related to things like mayflies and cadis flies, which are also, obviously, what are called hollermatabalous insects, which go through a pupation stage. How old are the lepidoptera? So I would say about 300 million years. About 300 million years ago. The butterflies originated sort of just over 100 million years ago. Oh, so they're quite ancient organisms

and that's a long... The diversification of the butterflies roughly coincides with the diversification of the flowering plants, the angiosperms. And their diversification is closely tied to the plants that they eat because really the thing that defines them ecologically is the plants that the caterpillars eat.

That's what diversifies them. So they're tied to this diversification of plants. Perhaps we could explore that a bit. They essentially co-evolve the story. there's a constant sort of evolutionary arms race between the plants and the caterpillars and the plants are evolving

these toxins and other defences and so for example we study these butterflies which the reason they're brightly coloured is because they have cyanogenic compounds the little sugar molecules that release cyanide when they get attacked they get those molecules they can either make them themselves or they get

them from the plants they feed on so the plants have evolved an enormous chemical diversity of these synogenic compounds trying to evolve new compounds that the butterflies can't sort of deal with and then the butterflies some species evolved to deal with it

and then they also use there's one species of paciflua which has hooked trichomes little hooked hairs and it's just like Velcro actually you stick the leaves to your shirt and they stick like Velcro and most of the caterpillars just get pretty gruesome they get

kind of caught up in these hooks and they sort of pulls there cuticle open and they start bleeding and they die very quickly. They can't survive at all. But there's a couple of species that have evolved do really thick cuticles and they can sort of stomp around on these hooked trichomes work we're doing at the moment where one of the

species that can walk on it but it can't eat it. If it tries to eat it, it dies. But then there's one species that's managed to walk on it and eat it and it's got really thick kind of cuticle in its guts to deal with these nasty little hooks that get into its stomach. Because you've got a cassapilla

and then the bus fly or the moth. then ultimately, I suppose, they become pollinators. Right. And they're then happy. So the same plant might be trying to attract the butterfly at one point in its lifestyle. But they don't really want to attract them too much because, of course, the adults are also laying the eggs that produce the caterpillars. So they have, you know, they have...

It's brutal. You know, they produce scents and colours to attract the pollinators. But they also, one cool thing they do is the plants produce fake eggs. So you don't want to lay. your egg on a plant that already has eggs on it because the larvae are cannibalistic. So if you lay your egg where someone else has already laid an egg, you're likely to get eaten by the one that's already there. So the plants make these little structures that look like butterfly eggs

to try and sort of deter the other butterflies from coming and laying eggs on them. This must be sort of immense stress for the butterflies. I like to look in my garden at spring. Two little butterflies going together like this in the sky. And I always thought they were kind of dating or courting. or at the talking stage at least. And now I just feel like they're having a massive row about whether that plant's got fake eggs on it

or whether they can lay it there. That's the thing about nature, isn't it? Where you hear all these and watch all these things and go, what a pretty thing doing pretty stuff? When you first find out about what the dawn chorus is really saying, you go, oh, it's rather a rough night in Newcastle on the Friday. I'm not going to tell you about the dawn chorus really saying. But frankly, those birds are not as innocent as you might imagine.

I think my friend Nick Rebel used to basically translate the dawn chorus as Do you want some? Do specific butterflies pollinate specific plants? So is it very, very tightly? That's sometimes true, yes. It's very true of the caterpillars,

so very often the caterpillars can only feed on one species or a couple of species of plants. And that's because of this very tight co-evaluation of the chemistry of the plants and the ability to deal with that chemistry. So they evolve to be very specialist in the things that the caterpillars eat and that can also be true

of the adults, the pollinators as well. And if the caterpillars feed on several host plants, they're usually closely related phylogenetically those host plants. So there's obviously a challenge as Chris is saying to break down the defences of the plant and so once you're specialist on

a particular group you probably can eat other ones as well. Jane how can we talk about the evolution there as well and I'm just wondering, you know, going back 100 million years how exact or inexact is our understanding of what butterflies and moths look like because I would imagine they are something

within the record of what is left behind something like a butterfly or a moth there's a fragility to it thinking about those ones that look like an owl's face understanding that journey how much can we know about what the butterfly of the moth of a hundred million years ago would have been

wouldn't look like an owl would it because there weren't any owls certainly it's just be a bit of patience can't it I'm not coming off this tree until. But no, but that's what I mean is, you know, so there will have been a point, you know, in all of these different changes. Yeah, so there are some fossil butterflies, but not many, because it's quite hard to preserve something with such a soft body and no bones and so on. I guess we don't have particularly good understanding about that because

there is just so little from that time. And the only information we have is what we can infer from sort of genetic information now? Yeah, evolutionary biologists try to infer it from the present-day species in their relationships, but the patterns evolve so fast. It's actually quite difficult, yeah. And you mentioned earlier, but I was going to say, it's difficult to talk about evolution, isn't it?

The purpose. Let me use the word. So the patterning itself, the colours, because it is tremendously intricate. So what is the point of that complexity? You mentioned maybe attracting other, butterflies. Is there more to it than that? Well, these guys actually have a lot of mimicry. They're brightly colored and different species

involve the same patterns. And they're sending a signal to predators that they're bad to eat. So they're actually all, there's two different kinds of mimicry. There's mimicry where you're pretending to be something nasty and you're actually, you're edible, but you're pretending to be something you're not. And then there's kind of a more mutualistic mimicry where you're kind of all joining in to send a common signal, actually you're all nasty. Yeah, so they're evolving the same patterns to send a common signal to predators but one of the weird things about these butterflies that

we study in South America is the pattern that they have in the same species just changes rather randomly every few hundred kilometres so you go either side of the Andes in Ecuador the same two species look identical where they live together but completely different on the other side of the Andes and I think it's just fashion right it doesn't really matter

you just want to look like everyone else doesn't really matter what it is as long as it's kind of bright and gaudy and the birds recognize you so I'm glad because That's what I was thinking. I was thinking that kind of moths are like goths, and butterflies are the new romantics, right? So, because you're mentioning the mimicry,

is that Batesian mimicry? Because I remember watching a thing of Batesian mimicry, very much like what Chris was saying. And to me, it's such a fascinating thing, that that bit where you go, you know, you don't have to evolve to be poisonous, but to evolve to look like something that's poisonous. And that was the first story I heard, I think, of Bates

and the research that he did. It's very, very inspiring. don't actually have to be nasty, as long as you look nasty. People will broadly leave you alone. It's the face I do when I walk past the Scientology Centre. Right, yeah. Just to not get given any leaflets. Not today.

Yeah, not today. So is there a suggestion here that somehow they're cheating? Well, I suppose nature so often is a cheat, isn't it? That's the thing, which is if you appear to be poisonous, it takes less energy as such than actually being the poisonous creature. But of course you have to get the frequency of those rights Because otherwise birds or whatever's eating you Will start to realise that that's not necessarily a good cue to being poisonous

Now you're ostentatious and gaudy and you're edible And that's not very good Not really not what we're looking for So that is why the new Romantics died out The goth scene is still very strong I was interested to know something Not science, quite so science-based It's maybe science adjacent.

I can't name any of the books specifically now, but the number of books that would have a butterfly collector and it would always sort of signify something about that person's character or a sort of lost youth. I'm sort of interested to know from both of you as scientists. Where do you think that character archetype comes from? Well, I suppose what you're really saying is like John Fowles' book The Collector

is about somebody who collects butterflies and then kidnap someone and tries to force them to love them. And in silence of the lambs, it actually is a serial killer who's, with them. So what we're saying is, are you more likely to kill? I suppose there is some... Is that roughly a summary of what you will need? I'm sorry. I had a couple of gentler kind of literary archetypes. But yes, there is also this use of the idea of catching something beautiful and free and pinning it to a board. And maybe that is psychopathic. I don't know.

Would you care to comment? Perhaps I could give an example to sort of counteract that, which is the story of Lady Eleanor Glanville, who's a real person, so we're not talking about stories here. And we have a Glanville fritillary in this country. So historically, she was an avid collector. She was really interested in butterflies. So after she died, her family contested the will because they said she was obviously mad. Oh, really? I could turn this, perhaps, into an actual question.

Which is... Come on, it's a conversation. I'm going to do it. What role did collecting butterflies and moths play in our understanding of evolution? That's not the same question at all. That's a totally different question. Sorry, no, no.

No, no. I'm asking... The first... No, no, what I'm actually asking is, do you know what the first evidence or sign of humans mythologising or spiritualising butterflies is? Is it involved in cave art? Is there any...

Did Neander talk? do this? The Greek goddess psyche was the goddess of the soul and she was always depicted with butterfly wings but following on from that what role did the collection of the surprise Thomas

I think the fact that they're so iconic and the people are attracted by them has meant that people have collected them so we've understood them much better than many other groups in the UK we have amazing records of where butterflies have lived over the centuries which is some of the best data sets we have for tracking climate change and how the impacts of the changing world on species distributions.

Yeah, so museums contain vast quantities. If you go to the Natural History Museum, you'll see masses of butterflies and moths, all which have been catalogued, all very carefully named and the location. You have this amazing amount of information going back hundreds of years telling you where those butterflies and moths were found. And then, of course, you can look to see whether they're still there today and understand which species have disappeared, which ones have arrived,

and understand a lot more about the biodiversity, whether it be in the UK or whether it be elsewhere in the world. So although the sort of fashion for collecting and pinning has gone and actually it's mostly frowned upon, I mean, you know, we've got apps on our phone that we can take photos and identify things. Arguably, we don't have to go out and kill things and put pins through them.

So is that a bit taboo now in your world? So if you go to museums, you'll find that most of the collections stop around the 1980s, something like that. And is that something you did, like, as a community of scientists, just sort of organically decide this isn't, we don't need to do this anymore?

So I think in many cases there was no need to do it because you can identify things without catching them and killing them. And I think also the fashion has changed in terms of, you know, seeing a whole load of dead things pinned out in a tray is perhaps not the same as going out into the field and seeing them flying around. But yet it's a resource, a historical record. Yes. And of course those specimens have genetic information associated with them as well. So now the techniques are possible to extract genetic information from this museum material.

While that sort of looking back into the past tells us a lot about biodiversity now. I wanted to ask you quite a specific question, Jane, really. When I was a little boy, my dad loved doing wildlife photography, and he wanted to try and take photos of every butterfly in the UK and say, I think it would probably be 1979 or 1980. I remember we went on holiday in Dorset, and I would be walking behind him in these kind of, you know, these fields of hay and he would have his camera out.

That's how he wanted to pin and mount the butterfly. was to get a photograph of it. And I wonder what would I have seen then that I would not see now and what might I see that would not have been there in 1980? Well, we know that the ranges of butterflies and moths have changed hugely as a consequence of human-caused climate change. Some species are heading northwards in the UK really fast.

So I guess which species have arrived and which ones have gone depends on where you are, but where I am in Yorkshire, over the loose 40 years from the sort of 1980s, been quite a lot of species turning up from further south, so things like gatekeepers and speckle woods. So these are residential species. They're not migrants moving at quite a rate. They're roughly speaking, they're moving at about two kilometres a year as they're tracking the isotherms as they're moving northwards, which means they're not keeping track of the climate, but something

like a comma is, it's going about 11 kilometres a year, something like that. So you're getting all of these southerly ones moving north as it warms up, and then you have some butterflies, just a few in the UK that like it cold. You get them in Scotland or mountains,

and they're moving up the mountains and disappearing off the tops. That brings us very nicely onto migration. One of the most remarkable abilities of butterflies and moths, this is a question, is that the distances they will migrate. You mentioned the monarch butterfly earlier. It's an astonishing migration. So the monarchs are extraordinary. They go all the way from Canada down south to spend the winter in Mexico. So the same butterfly will fly all the way from Canada down to Mexico to exactly

the same woodland where its predecessors spent the winter. After spending a period of cold and actually can replicate this by cooling the butterflies down in the lab, they then completely switch their desire. And in the spring, when they wake up, they want to fly north. But actually, there's several generations before they get back to Canada. So it might be five or six generations. So they lay eggs on milkweed, and then the new butterflies come out, and then they fly a bit further north. They lay eggs. So actually, if you think about that whole migration back down to the same bit of woodland, it's not the same butterfly doing that. It's encoded in their DNA somehow, that they can know exactly where to go back. It's

the same valley, isn't it? In Mexico, and then the same woodland in Canada. But multiple generations. It's even more astonishing to me. I can only assume they'd left each other little pamphlets. Like Hansel and Gretel

they left as a little bit of culture. Is it understood that? How it's encoded, we have no idea. I mean, that's just extraordinary. We know a bit about how they find their direction. Well, the navigation. The navigation. So they they do have a magnetic compass so they can use a magnetic north-south

but the most important signal is what's called a time-corrected sun compass so essentially you know what direction the sun is in and you know what time of day it is you can tell which directions north and south and they can tell which direction the sun is in even when it's cloudy because they can detect the polarisation of light so they can know

where the sun is and they detect the time of day using a circadian clock a bit like we do you know we have a sort of inbuilt clock and of course you have to entrain your clock on daylight hours, obviously why you get jet lag when your clock is sort of out of sync. And we entrain our clock very sensibly, it seems, by molecules in our eyes which detect the light. Strangely, these monarch butterflies use their antennae, even though they have eyes, they actually have light detectors in our antennae that is what they use to entrain

their day-night cycle. And if you cover the antennae with little bits of tinfoil, well, it's an obvious experiments. Do they start believing conspiracy theories? So I can understand how you can navigate north, south, the magnetic bit of the time-corrected compass and so on. But the specific location is a particular valley. But that's probably particular to do with the monarch. And I'd like to stress that there are many moths that are doing this type of migration. And they're doing it

at night at very high altitudes, which is even more impressive. I'm going to argue. Doing everything a butterfly does, but backwards and in heels. Yeah, yeah, exactly. But don't necessarily have to end up at exactly the same location to overwinter. So this idea that it has to be incredibly precise in order for the migrants to persist is perhaps most true in monarch, but not true in other species. I just went to ask you because we haven't talked about the moths so much, but you said they navigate as well, so they're not using the sun because they're flying at night.

So they're using star compass and the moon, but the same principles apply about being able to work out where you are and the direction you're moving in. I mean, that's a remarkable thought for something, a moth. Can you imagine how it feels, Katie, when it bashes into your kitchen window? Yes. I do it all the time. Because it presumably thinks it's got to the moon.

Yes. And it wasn't expecting that. And then it sees you with your scissors going, what is that 11-year-old again? That question, though, we should ask it because it gets asked an awful lot, doesn't it? Why the moths? The moth and the flame.

Why do the moths go to the light? So they're using the moon and the stars to navigate by, and that then means that when we put artificial light out, it confuses them. and they get attracted to lights at night in people's kitchens and street lamps and so on and very often they get eaten at that point because bats or whatever will hang out around street lamps and eat them unfortunately we've just about run out of time so we have to go back to say well because obviously the overwhelming sense was that the butterflies won I'm now going to claim that the moths

because the moths are astronomers. Clearly. A higher level of being. So can we have a lot to feel that because we've not really in any way talked about butterflies versus moths, we've really found out that butterflies are moths and that they are remarkable.

Yes. That we kind of have yet again ruined the conceit of a show that started off on such. Can we agree that they're both magnificent. things. What do you think, you are the arbitrator? Are it moth or are it butterflies? Well, here. Or is it moth or is it

butterflies? I started off very much on the side of butterflies with my tattoo but I've sat and I've listened to all of this and I have decided that butterflies are moths anyway and that moths do astronomy is quite remarkable

so I as the adjudicator I'm going to come down on the side of moths We asked our audience a question If you were going to emerge from a cocoon What would you like to emerge as I've got here Brian's essence At the end of this Could I leave first

Whatever bug secretes the silky material They make Brian's hair from Right I'm actually off now I've got a bee as stings can only get better and I've got a cheese because things can only get feta so there we are the idea that you can come back as anything fatter cheese

thank you to our panel Professor Jane Hill Professor Chris Jiggins and Katie Brand Now if if you would like to set up a match between two species, then send in your suggestions. I did actually suggest that we do a show where we do an illegal Cox fight, where we go to the back of an East End pub, possibly the grey mare,

and Brian Cox fights, Brian Cox. But that wasn't allowed for health and safety. So we're going to have an illegal dock fight instead, in which a bare-chested Robert Winston takes on Dr. Pimple-Popper. So, come on, Spotty, I'm going to get you. Anyway, thank you very much, everyone. We'll see you next time. Bye-bye.

Thank you very much, everyone. We're going to talkie Kate. Do you're now nice again? Hello, I'm Melvin Bragg, and just before you go, I wanted to let you know about another podcast from the BBC that I think you might like. It's called In Our Time. And each week, three expert academics join me to discuss ideas

from culture, science, history, philosophy, religion. At the end of each podcast, there's more discussion we couldn't fit into the live program. So if you're curious about the world around you or you simply want to win your next general knowledge quiz, subscribe to In Our Time on BBC Sounds.