Hello, my name's Lindsay Turnbull and I'm an associate professor in the Department of Plant Sciences
at the University of Oxford, and we're right in the middle of this very serious corona virus crisis right
now. And my students are all stuck at home and we want to keep them in touch with biology
and keep in touch with us. And so we're going to make a new series of videos and they're going to be called back
garden biology.
Hello, welcome to this episode. Back on Biology, and today we're going to be looking at moths
now Multa, one of those groups of insects that most people don't know a lot about. And part of
the reason for that is that a lot of moths are nocturnal. So the adults anyway, we don't see
them around flying during the day very often, but also kind of unsung heroes.
They're actually really important pollinators for lots of plants. We just don't see them doing it.
We see the bees, but we don't see the moths. That doesn't mean that they're not important.
Now, if you're a gardener, they're all some moths that you might be familiar with. And sometimes it might
be because you see the caterpillars. So one of the most sort of prominent caterpillars that
you might see in your garden is this. And this belongs to a moth called the Mulan
Moth. And they specialise on eating melons. And their Latin name for Mullan's is for Bascome.
And they're quite common garden plants. So they form a nice rosette. Now, these lovely woolly grey leaves
and then they Boltz and they produce these big flower speiser and yellow flowers and are very popular with gardeners
and may get eaten voraciously by these Moland moth caterpillars. So you may have seen
those in your garden or when you're out and about because Mullin's are wild plants as well. And that
is one of the things I want to emphasise this week as well. I know that not everybody has a garden. I'm very lucky
to have a garden. And when I started this series, obviously, I couldn't go anywhere else because
we were in the really tight lockdown. But we're not doing that anymore. And I want to go out of my garden
a little bit in order to open up this programme to people who do not have a garden. Now, as
well as Meulen moth caterpillars, you might be lucky to find one of these annual garden all wandering
around in the countryside in August. This is an elephant hawk moth caterpillar, and
it's really, really beautiful. And we happened to see one in August last year when we were having a walk in the countryside.
Elephant Hawk moths are spectacular adults as well. That pink and green, there's actually
a common elephant hawk moth and also a small elephant talk mouth. And you can see them here.
And the caterpillars have this extraordinary defence mechanisms. They've got these eye spots and
they can actually swell up and sort of the ideas they're trying to startle predators
and people phone up the wildlife trust every year saying, oh, my goodness, think I'm out of a snake in my garden,
then actually it's just one of these caterpillars. But they are beautiful. They're sort of velvety and smooth and lovely
and handling warm was a really nice experience. Now, this second caterpillar belongs
to the goat moth. And frankly, when we stumbled across this on a footpath, we thought, what the
heck is that? It looks like a giant maggot, not a caterpillar. And it's
a little bit repellent to handle. I did pick it up, but I wanted to move it off the path so it didn't get trodden
on. I mean, I only found out later because I didn't know what it was. When I found that it actually belongs
to quite a ram off the goat moth and it lives inside trees eating
away at wood. So there are actually caterpillars that are wood boring. They don't all
just eat leaves. And there are other kinds of moth that live inside leaves
that are really tiny. I mean, mine leaves from the inside out and are going to do a little piece on that.
So in today's episode, you're going to see four little sections. One is about the leaf mining
activities of a particular caterpillar. One is me going on a hunt for the Hornet
moth. And that is one of the coolest, most amazing, most charismatic moths in Britain. And I'm going
to show you that you can find really cool stuff like that in the most mundane places.
So I'm going to show you how I managed to track that down in my local park literally next to the dog poop.
I'm also going to go and visit Doug Boys, who's a real moth expert, and he's doing his pitch day on moths
out at Y term. And he's going to show us a little bit about what he's doing for his research and how he traps
moths in order to count them and have good records. And finally, we're going to see Ben Sheldon,
who is a professor in the Department of Zoology who runs a moth trap in the back of his garden, a light trap.
And we'll be able to see him, how he sets that up and how he empties out every morning. And we'll be up to find out what
he's been catching.
So I want to begin by talking about a moth called the horse chestnut leaf miner. And if you
pay attention to those chestnut trees, you'll notice that at the moment they're starting to look exceedingly worse for wear.
And that's because the caterpillars of the horse chestnut leaf miner have started to attack
the leaves. And a leaf miner is an insect that lives inside the leaves.
And it's not just moths that are leaf mining. In fact, they're not the communist group. There are various flies, their various beetles
and various moths that all engage in leaf mining. And what they're trying to do is mine
out the good stuff and leaf. So let's have a look at this was chestnut leaf and see what they're doing. So you can see
here's the nice Greenleaf. And here are these are these ugly brown stains
they almost look like. But what's actually happened is an insect has got in. It's eaten out
all of the green cells. So then no longer green and it's peering out the undigested
bits. And that's what all the brown stuff is. So insect poo is called frass. So the minds
are filled with France. And as the year goes on, these holes, chestnut leaves can be almost entirely
destroyed by miners. Now, this moth only arrived in Britain
in 2002. So the horse chestnut itself is an introduced tree. It's not native to Britain,
but for the first couple of hundred years that it was here, it was beautiful and pristine. And I certainly remember that when
I was a kid or even a sort of middle aged 20 years ago or more, that you could see wonderful
horse chestnut trees with perfect, unblemished leaves. But you can't see that anymore. So let's have a look.
It's a cross section of a leaf that was drawn by Pandora. We can see what they're doing. So you
can see this is the cross section of the leaf. This is the upper surface. This is the lower surface. This is the little
hole, the stem after where gas exchange happens. So air moves in
and out of the leaf. And all these leaves have lots of air spaces to allow
the free diffusion of gases and of water vapour. And the veins are here
and the veins are often very tough. So the cells that make up the piping of the leaf
are tough and fibrous and not very digestible. And so the miners avoid all of those. They just
get in and they all these G.S. sounds that are packed with chloroplasts and
they leave this cuticle intact to protect themselves
from birds trying to get at them. So they're kind of sealed away. They're using the leaf's
natural protection to protect themselves while they mine away all
the goodness inside the leaf. So the horse chestnut leaf miner is a bit of a baddie in a
way, is probably the moth in Britain that causes people the most problems.
Say, I got interested in moths when I was 12, and I just love the idea that.
But there is actuality of putting out a bright light in the evening
and then the next morning, you know, this truck filled with hundreds,
sometimes of moths of all sorts of different species. It's quite accurate.
Maybe I'm just lazy ducks. But, yeah, I've sort of from that
moment, each trial, I've sort of got off track. My next birthday.
Yeah. And doing it ever since. Yes. My page is looking
at the impacts of light pollution on moths. It's a field
sort of light pollution ecology has really exploded
in the last 10 years or so. You've been steadily declining since
since the late 60s. Been since we've been monitoring them.
We suspect climate change is probably important. We suspect that land use changes are important.
But people have often suggested that light pollution may also be playing a role. But that's just not
really the evidence at the moment. So I sort of want to. Yeah,
that that would be my not quite how I judge. I've done a good job on my page. But if
I can just get a bit closer to answering my question, that would be that would be great.
So this is my hunt for the whole night moth. And I'm just in the little park nearby
and this is the kind of park where kids play football and and adults bring their children to
play. It's a very ordinary place. But in the corner, there are three large poplar trees.
And that's what drew my attention. And I had a look round the base of them and I could see holes,
holes that looked like this. And if you see holes like that in a tree, those are exit holes. That's where
some adult insect has emerged. And Hornet moths lay their eggs on
poplar trees and the caterpillars go into the wood and they eat the wood.
And so then not like the leaf miners taking the good stuff. That would be my way through the hard core stuff.
And that's why they live for two or three years as larvae before they emerge as
a moth. Now, of course, just finding the exit holes doesn't tell you that this colony is active. There's
no way of knowing that. I just had a hint that there might be something going on. And I was lucky
that it was the right time of year that I knew well, if they're here, they might be coming out around now.
And so that's the first thing I did. I have to decide. Okay. I've seen the holes. I'm going to have
a go at finding those moths. So it's the 21st of June. And I am back to look at my
the holes in the bottom of the trees. I've been sick that day. And tonight for the first time, I have
found a peaceful case. So what happens is the future is covered in spines
and it manoeuvres its way to the exit hole, ready for the moth to emerge. I mean, it breaks
clear of the exit hole and the moth itself emerges, leaving that people case behind.
Outside the holes. I found one of those. That means their lawn is being set for six o'clock tomorrow morning. I
am getting off, see if I can find one of these incredible moths.
So I did indeed set my alarm. Six a.m. I rushed down here. I brought a book with me
and my cataract sits on and felt like I was trying to read my book if I look too strange sitting standing
around this tree. But as soon as I arrived and looked around the tree trunks. This is what I saw.
And this is a newly emerged horn moth. And you can see the mimicry is astonishing.
These big fiery moths that look exactly like a hornet or really are more like a queen
wasp to me than a hornet. But you said you got a massive hit right there. Mimicry is excellent.
And she hasn't pumped up her wings properly yet. They're still sure to not fully expanded.
And I watched her do that for around half an hour. And I went back with a song in
my heart. I've just been down to the popular trees and I was filming one of these amazing Hornet
moths emerge. When I got home, look what was attached to my jumper. I have absolutely
no idea how it got there because it was not the one I was filming, which was in a more advanced
state. You can see that this one is just pumping its wings out now and stretching
them out for their full length. So I have no idea how much a rack on the ground.
I don't know whether it crawled out onto that and carried it home unwittingly. Obviously,
I am going to take it back. Wow.
So once I discovered that and I came back to the tree, I put my horn moth next to the one I'd
watch demerging. The two females together. And then a male just descended out of nowhere
and started to mate with one of the feedback holes, which was truly incredible.
I came back even later again to find that my female, the first male, was still there with his
female, but my female, he'd be taken home by accident. Now, also, how to partner with that one
morning I actually saw full of these incredible Hornet moths. And I think it just goes
to show that even just around the corner from you, in a very ordinary place,
cars going past, people walking by bicycle and everything else, there are truly
incredible things. I can honestly say that Hornet Moth, one of the most beautiful things I've ever
seen and I know there was such a fleeting moment for me that makes it even better in a way. I
probably won't see them for another year if ever again. You have to have that bit of luck. You've got to track down
your colony and have the patience. But that's like all these amazing natural history moments. You always
need that bit of luck, but put in the effort to and you might get this fantastic reward.
Well, good evening. So it's like June. Just after midsummer.
Beautiful, warm evening here. Blackbird singing away here and I'm here in my back
garden in Oxford. So this is a 100 basis from County
Road. So it's a terrorist house in East Oxford. And what
I've done here is to set up a moth trap here in my back garden. So something I do
most nights in the spring and summer. Particular if the weather's warm like like now says that the
water be warm during the day. It's got me warm at night. And those are really good conditions for
catching moths. So I set the trap that we're just going to have a look at it. So is the back
garden. So it's a fairly standard suburban
terrace garden. You know, quite a few trees here. We've got Big Bird
Cherry Tree above me here. Crop up. There's lots of things, some fruit
trees. So I think quicker than usual. And here on the garden table, so it's been pressed into service.
So you to hold this moth trap. So this is what's called a Skinner trap. It's basically
a plywood box. And mounted on top of it is a
fluorescent tube light. So that produces a light. I'll turn it on when it
gets dark and not light for reasons that are still a bit of a mystery attract
in moths and other insects as well. I can see that basically it's got a couple
of perspex sheets that acts as a sort of holding
mechanism for most miles to get attracted and fall through this gap in the trap
and inside the box. Here are lots of old egg boxes. Let's
provide something for any moths that do get attracted to this trap to crawl into
and shelter during the night. So we'll set this up going when it gets dark.
And we might have a little bit of assistance from over here. Who's enjoying playing in the garden?
OK. So just an update. It's about 11 o'clock. Put
the trap on about an hour ago and it's running over there on the table. So you can see that that
it's not a very bright light, but when it gets properly dark, it will become a bit more visible.
So we'll leave that running all night and we'll cheque it first thing in the morning to see what we've caught.
So it's quit by 6:00 the following morning and just
turn the truck off. We can go along and look and see if we caught anything at all.
OK, let's go. So could we get an idea
if there's very much just from looking outside? You can see there
might be some moths inside. You can see the red, black and white thing there.
That's a scarlet tiger. And
I can see a few of the moths inside, but we're ready. Good idea. When we open it up
and go through the egg boxes one by one. So let's stop
taking the first perspex sheet out here.
See what we've got.
So think on that first box that can see something
sitting on this box here. So I got my thoughts.
A moth called a coronet, so-called because of the shape of a patch of white
on the wings.
Small off there. So people divide moth's into into two groups.
They're called the makram offs, the large moth's and the micro moths and Microsoft.
So generally easier to identify someone. Micro moths come in and
fight as well. That's part of it. I agree for about a dozen species. The Scapa rates,
which are a little bit tricky, but I might have to have a closer look at that one later.
So we've been through all the Trump about an hour later and I've gone through
a few. Taking some photographs to try to identify some of the trickier ones. What I do once
I've actually gone through the trap is to tap all of the boxes off into the bushes surrounding here,
give them off somewhere to kind of hide during the day so they can recover and then fly off.
As it gets dark following evening. So that was quite a good hold last night, actually. So
a total of 27 different species that we call here in this this little average back
garden in Oxford now. Yeah, that's a it's a pretty good number. So
on a really good night, we might get here. Something up around, say, 50 species on
some of the best nights I've ever had here. If you trap this sumba air in
a more rural habitat, like, for example, a woodland cave, this marsh nearby, you
might get even up as many as 150 species in a single night. One of the striking
things about moths is that they're very, very seasonal in their appearance. So that species appear
at particular times of year so that the species we get now are different than those we've got even two
weeks ago. And those that we'll see in a couple of weeks time. So over the course of a year, you really
get amazing diversity. So even in a back garden like this. So I've been
looking at the moths here and not not going over the top with it. Yeah, I'm fairly
interested in them, but I've probably seen getting on for about 450
species in the back garden here. There's about two and a half thousand species in Britain, though, so
I've got a long way to go still before I've really kind of completed the set.