Horizon (1964–…): Season 50, Episode 1 - What's Killing Our Bees? A Horizon Special - full transcript

CHATTER FROM NEWSROOM

'I'm Bill Turnbull.

'This summer, I set out to get
to the bottom of a story

'that's captured the headlines...

'..and it's one I've got some
experience of

'because I'm also a beekeeper.'

There. Is that good? Perfect. Oh, I
hate squeezing them like that.

'I met some scientists doing some
extraordinary experiments -

'putting tiny antennae onto bees.'

She's out, she's out.
There she goes.

This is just a part of an attempt



to understand what's happening
to our bees.

It's the biggest mystery

to hit the countryside
in living memory.

Bees are dying in their droves
and we don't know why.

'I'm going to be examining
the evidence

'that points at three of
the main suspects.

'First, a deadly invader that's
devastating colonies.'

I know from bitter experience
that if you see one of those
in your beehive,

you know you're going to be in big
trouble, because they can pretty
much wipe out a colony

in a couple of months, really,
can't they? Very short time, yes.
Kiss of death, isn't it?

'Second - pesticides, their use is
causing huge controversy.

'And finally, the changes we have
made in how we farm our land.

'What is clear is that
these extraordinary

'creatures are dying
in their billions.'



This is a film about what's
killing them.

I've been keeping bees for better or
worse for 12 years now.

I've always found them to be
beautiful, intricate creatures.

Think of this - a bee
in a single day will visit
several thousand flowers.

Its wings will
beat at 200 times a second,

they'll fly 15 miles an hour
up to four miles from the hive

in the search for food, and yet
they'll always find their way home.

And this for my bees is home.

They don't live very long -
on average just
a few weeks in the summertime -

but in that time, they'll fly 400,
maybe 500 miles in total.

And here's the best part, they're
the only insect to provide us

with food,

in the form of liquid gold - honey.

But our bees are clearly
in trouble.

'I've come to Heather Hills Farm
in Perthshire

'to meet commercial honey producer
Mark Noonan

'and to find out what's been
happening to his bees.'

You've got a fair number of bees
down here, haven't you?

Yes, this is one of our sites

just outside Blairgowrie and we've
probably got about 40 hives here.

They've been
here for about three or four weeks.

'It's June and Mark is
lending his bees

'to a local farmer to pollinate
hundreds of acres of raspberries.'

So what is the deal between you
and the farmer, then, here?

Well, it's a natural symbiosis
where he knows that

if our bees pollinate his fruit,
he'll get a lot more fruit.

He'll get a better quality
of fruit and we get

the nectar from the raspberries,
which makes a fantastic honey.

'It's a deal that works well
for the bees and for the farmer.'

So these have been in full flower
the last two or three weeks.

As you can see, the fruit has
started to form already.

It's looking really healthy, there's
nice shape to the berries there.

And that's going to produce
tonnes of raspberries.

'But all is not
well at Heather Hills Farm.

'Mark's bees are dying and he has
the empty hives to prove it.'

So you've had a tough year?

We have, Bill, yeah, it's been
an incredibly bad winter

and that's compounded with probably
the worst summer

we've ever
had as well last year. Right.

So these boxes should all be out,
full of bees working?

Yeah, they've been brought
back from the fields

because the bees didn't survive the
winter, which went right on to May.

It must have been devastating.

It was very depressing, yeah.

We reckon we lost 300 or 400 hives
just this last winter.

And we've had five bad years
in a row.

So Heather Hills should
have 1,300 hives in operation

at this time of year, and we've got
less than half of that.

And that's pretty common
throughout not just Scotland

but the whole of the UK.

I've heard stories of someone
losing 96%. Right.

BUZZING

And one less bee there!
It just flew in my ear.

So a very difficult position
for you.

What are you going to do to survive?

Come and have a look.
Here we have some imported bees,

just arrived this morning
all the way from Italy.

They've probably been on the road for
two or three days, I would have said.

I would think they're pretty fed
up by now, aren't they?

'Seeing this really brings home
to me

'the problem that we have
with bees here.

'Mark's loss is an
all-too-familiar story that's being

'replicated around Britain.

'Today I'm going to help him

'put a hundred thousand
newly arrived bees into his hives.'

That's it. In you go, girls.
That's it.

I don't like banging them around,
but I suppose it has to be done.

It has to be done and that's a kilo
and a half of bees.

Will they be all right in there?
Yeah, yeah.

'Mark puts the losses on his farm
down to the bad summers

'we've had in recent years.'

The thing is, bees are very
sensitive to the weather.
If the temperature falls

below 14 degrees or if it rains,
they just won't leave the hive.

The nectar output of flowers is also
temperature-dependent,

so if it's colder, there will be
less nectar and therefore less food.

And if the weather's bad

when new virgin queens go
on their mating flight, it can mean

poor fertilisation and a weaker
colony which may eventually die out.

Add all these factors together
and a bad summer can mean

the bees will fail to survive a mild
winter, let alone a harsh one.

'The number of honeybee
hives in England alone

'fell by around about 50%
between 1985 and 2005.

'Different studies indicate
a decline in total bee numbers

'over the past 50 to 80 years.

'So in terms of the weather
on its own, it clearly doesn't

'explain what's killing our bees -
there have to be other factors.'

CHATTER IN NEWSROOM

'My colleagues at BBC Breakfast
think I'm a bit obsessed.

'But I want to give them
a sense of what could happen

'if we keep losing our bees.

'It's Monday morning
and the Breakfast crew have been up

'since before dawn.

'This is our normal breakfast,
but not today.'

Right, chaps, here comes breakfast.

'Today they're going to be
offered a menu

'which only includes food that
doesn't need bees to produce it.'

Right, help yourselves, tuck in.

No butter. No butter.

Dry toast. I feel like I'm in prison.

Mmm. Thank you.

No milk with my tea?
No milk. No milk.

You may be wondering what else there
is. Do you want to know what else
there is?

Go on. Nothing. That's your lot.

'All they have to choose from this
morning is brown bread,

'white bread and black tea.'

We just want some fruit.

No fruit. There's no fruit
available today.

Could I have some tomatoes on my
toast? Tomatoes, no. No, absolutely
no tomatoes.

It's a fruit pollinated by bees.

Like it? Are you enjoying your meal?

LAUGHTER

Not really. No.

It's a little bit dry,
Bill. OK. Bit bland.

You may know,
I've been looking into, er,

the disappearance of our bees
and what's been going wrong,

and I thought I'd have a...
an experiment to see what the impact

would be on our lives if there were
no honeybees here in Britain.

And this is the result.

So, without bees,
not much pollination goes on,

so that's all that you're left with.

But to make up for it, here's
the breakfast that you can have

while we've still got honeybees.
CHEERING

So tuck in. That's good.

'To be honest, this is a bit
of a treat - it's not
what they're used to.

'Take away bees
and you risk losing this.

'Most fruit, but not bananas
and pineapples.

'And most vegetables,
along with protein-rich beans.

'And because most animal feed is
made from plants pollinated by bees,

'it means meats and dairy products
could also become more scarce.'

So, we really do need
to save the bees if, er,

we want to have breakfasts like this.

'It does give you a sense of
just how important bees are.

'I want to track down the most
ground-breaking research

'into what's killing our bees in
such numbers.

'I'm starting at a rather
special place.

'Rothamsted Research - they've been
studying bees here for 90 years

'and they've recently invented
some rather ingenious
ways of observing them.

'I'm here to look at the first
suspect in our mystery...

'..the varroa mite.'

This tiny parasite has led to
the spread of some of the most

contagious and widely
distributed viruses on the planet,

killing billions of bees and truly
earning its name -
Varroa destructor.

It can be utterly devastating.

'The first step is to try to really
understand the enemy.'

Poor little bee.

So, Jean,
where is it on this bee there?

OK, I think if you look, even with
a naked eye, just to this side

of the abdomen.

Yes, oh, on the belly there?
That brick-red-coloured... OK.

Gosh, it looks like it is carrying
a football on its stomach, isn't it?

It's huge. It's at least two
millimetres across.

So they hang on there
and they sort of feed on the...

Puncture the soft tissue
and then start...

Feeding on the bodily fluids.
That's right.

I know, from bitter experience,

when you find one of those,
you're going to be in big trouble,

cos they can pretty much wipe
out a colony in a couple of months,
really, can't they?

Very short time,
yes. Kiss of death, isn't it?

'Jean Devonshire uses one of the
most powerful instruments

'in her lab -
a scanning electron microscope.

'She freezes the bee with
liquid nitrogen,

'then coats it with an ultra-fine
layer of conductive gold.

'Now we can view every tiny
detail of our enemy.'

What we're looking at now
in the centre of the image there

is the actual varroa,
and if I focus it finer,

we can see the hairs on the body
obviously very easily there.

You can see these sternal plates
and the varroa sitting in the centre.

And the head is digging in there,
so it's feeding now?

It's probably...
It's probably... Yeah.

The varroa knows that if it slides
itself underneath these plates,

it can actually puncture
the soft tissue parts.

'The varroa mite arrived in the UK
in 1992. Its spread has generally

'been linked to infected bees being
imported around the world.

'And our bees had no resistance.'

Once it's finished munching, it
leaves these open sores, which then

leaves the bee open to infection,
so it's a clever little fiend,
isn't it?

It is.

'Thankfully, the mite
on its own can be treated.

'But when you look more closely,
you can see what could be

'the real culprit...

'..a virus.'

Here are the virus particles.

We're looking at this at about
40,000 times magnification.

Obviously there will be
a lot of them in their body,

which will eventually
cause their demise.

'And this is the sort of thing they
can do.

'This bee is suffering from
deformed wing virus.

'You can see
pretty easily what's happened to it.

'But what makes the varroa mite
so sinister

'is that it can cause something much
more difficult to spot.'

The viruses carried by varroa mites

can have all-too-obvious,
devastating effects

but, in reality, these are only
seen in extreme cases.

And what worries researchers now
is that these may be just

a tiny minority of all infections
and that many more bees,

apparently healthy,
may be affected by them

in less visible ways, which are just
as devastating for the colony.

'What they're trying to find out
here is what happens

'to these infected bees once
they leave the hive.

'To do that, they've invented
something pretty remarkable.'

Jason, it looks like we have
some kind of

military espionage station here.
What is it?

Well, this is a specially designed
radar that we developed that

allows us to track the flight paths
of bees once they leave their hive.

You can very easily study
what happens

when the bees come back to the hive
and leave

but what happened when they were on
their foraging flights

at some distance away was always a
great challenge to study

and it wasn't until we developed
a system such as this radar

that we were able to accurately
track their flight paths

over distances of hundreds of metres,
even up to a kilometre or so.

How does it work, then? There
are millions of insects out there

in the area that you're sweeping,
but you target specific individuals?

That's right, and so we have an
individual honeybee

which will be carrying this very
small, fine antenna on its back

and as the wavelength of the emitted
radar beam hits that,

the little diode in the centre
converts the incoming signal

to a unique signal which is half
of the wavelength

and so we can listen to that signal
with a special receiver dish,

and therefore just track the
individual insect

without it being swamped by echo.

That is almost as long as a bee
itself.

Isn't it a bit too big for it?

Honeybees have evolved over millions
of years to carry heavy loads.

They can carry pollen loads almost
half their body weight

and this tag only weighs
about a tenth of the body weight

so it's very easy for them
to carry that weight

and it doesn't affect
their behaviour in any way.

'But for me, seeing is believing.

'The man at the other end of the
experiment is Dr Stephan Wolf.'

So, here we have the bee. Yes. She
can't get through there, can she?

She can, but... OK. ..you know.

It's just trial...
We'll be here all day!

There! Yeah. Is that good?
Perfect, wonderful. OK.

I just...hate squeezing them
like that.

Hold the transponder
at the white bit.

At the white bit? Yes.
At the bottom, OK.

OK, and just stick it on there,
really lightly.

Like that? There we are.
And down she goes, go on.

It's a bit like running round

with broomsticks on the back
of your head, isn't it? Perhaps.

'This technology has already
revealed some of the secrets

'of the life of a bee.

'In particular, one of the great
mysteries about these creatures -

'how, when they first leave
the hive,

'they manage to find their way
out and their way back,

'visiting up to 2,000 flowers
in a day, without getting lost.'

She's in a landscape that she's
never seen before

so she starts with very small loops
in the beginning around the hive,

and then extends these loops ever
further in order to build up

a memory of the landscape that will
enable her to get back to the hive.

And here it is,
the flight of the humble bee.

This is what's called
its exploratory path,

the route it takes as it circles
around the hive for the first time.

Over several days it builds up
a mental map

of more than ten square kilometres
around the hive.

The radar allows us to see this
with unprecedented precision.

What's been found is that
their orientation flight

is very, very efficient, to explore
the biggest area

with the shortest time effort

and the shortest energy effort,
obviously.

'I'm here to see Stephan's
latest experiment.

'He wants to find out if the viruses
carried by the varroa mite

'will affect how the bees fly.
And that's important,

'because if they can't navigate
properly, some of them will die.'

So, what we have,
we have a colony in here,

and in that colony live bees which
have various levels of diseases.

These bees have only lived
in that cage.

They don't know the landscape
around.

'The bees here are all healthy
enough to fly. The question is,

'does the virus affect
their exploratory flight?'

So, here you have
a not-quite-so-willing volunteer.

Nearly dropped her there! OK, Jason.
The bee's equipped. Have a look.

JASON ON RADIO: Oh, yeah. There.
Here she goes.

OK, Jason. She's out, she's out.
Warming up a bit.

There she goes.

OK, she's off, she's off, Jason.

OK, bee is flying,
the one bee is flying.

Flying away from the cage.

She's out there somewhere.

You definitely saw her taking off,
did you? Yes.

Bee's making a loop.
Er, bee stopped, bee stopped.

'As bee number one goes to
ground for a while,

'it's my chance to head for the
radar station across the field.'

Hi, Jason. Hello. How's it going?
Yep, fine. Right.

'To the bottom left of the screen,
a red spot marks the position

'of the hive just over 200 metres
from the radar.'

300 metres away, now.

'And each time the radar
sweeps past,

'a white mark reveals
the position of the bee.'

OK, bee is coming back,
the white bee is coming back.

'The radar records each successive
loop the bee makes,

'until she returns
safely to the hive.'

The bee is at hive,
the bee is at hive, Stephan.

So, now the bee's come back
to the hive? Yes, exactly. Yes.

'Over the summer, Stephan
and his colleagues

'will be trying to find out if
the virus

'DOES affect the bees' flight. We'll
have to wait for those results.

'But this system, which allows us
to track bees

'in a way we've never done before,

'should provide some important
clues.'

We can test for whether the flights
are close to an optimal flight
or not.

This is what we want to show
with this experiment,

whether the diseases
actually do change one

or all of these aspects,
or perhaps none.

What we do know
about the varroa mite then,

is that it has killed
billions of bees.

We know it does spread viruses

but we don't yet know what the full
effect of those viruses may be.

'But I don't think this is
the whole picture...not yet.'

Professor Simon Potts has brought me

to the Oxford University Museum of
Natural History...

..to show me one of the biggest
collections of bees in the UK.

Some of these don't look like
bees...

well, like the bees that we
would expect. No, exactly.

So it's because they're incredibly
diverse in what they do.

Here's a really good example of how
big a variety you get.

We actually have 250 species,

which many people
will be surprised about.

Some people will see honeybees in
the garden,

maybe the occasional bumblebee, but
actually there's 250 to look at.

Some of these look terribly small,
almost as if they're mosquitoes.

Yeah, they could do,

but as you get to see them they've
got two pairs of wings

and actually they are proper bees.
How do you define "bee", then?

So, er...
BILL LAUGHS

Well, essentially it's a hymenoptera

so it has a small, pinched waist
that you can see.

All of these bees have that.
They're always very particular

about their figure, bees,
aren't they? They have a waist. Yes.

They do a lot of flying around,
burning off a lot of calories.

And they go out and they collect
pollen and nectar

so they're vegetarian

whereas their kind of close
relatives, the wasps,

they're very often carnivorous.

And when it comes to crop
pollination,

these are the unsung heroes of the
pollination world.

Honeybees DO make a contribution
but actually it's the wild bees

particularly that are doing
most of the work.

So for instance, in the UK, think
about the huge areas of oil seed

and beans and apple crops and also
all the soft fruits we have.

We've only got enough honeybees

to pollinate an absolute maximum,
a third. So, who does the rest?

It's these guys. They work
so hard to ensure that we get

everything pollinated. Not just
crops, but all our wild flowers.

Do these bees suffer from varroa?
They don't suffer from varroa

but these guys are in real trouble
as well.

It seems what you're saying is

even if we sorted out the varroa
problem... Mm-hmm?

..we'd still have a major issue
on our hands? Absolutely.

The honeybee and hundreds of other
species, are all in decline.

But those other species
don't suffer from the varroa mite.

There's no doubt that varroa
is lethal.

As it's spread across the globe
over the past 50 years,

it's resulted in the death
of billions of honeybees.

In some countries, including the
United States,

it's been linked to the
disappearance of entire colonies -

what they call
colony collapse disorder.

Here in Britain, though,
it's a rather different story.

For a start, varroa only affects
honeybees, not wild bees,

and they've been in decline here
as well for some time.

And crucially, it only arrived here
about 20 years ago

and we know our bees have been
dying off for much longer than that.

So, while it's true that varroa
has put an added strain

on the honeybees, the evidence
would indicate

that it's not responsible
for the whole problem.

Our second suspect, pesticides,
are the most controversial.

This year, the European Commission
announced the two-year ban

on the use of certain pesticides
called neonicotinoids.

They said the evidence now showed
that they were

an unacceptable danger to bees
feeding on flowering crops.

And THIS is what's generating more
heat than anything else -

neonicotinoid pesticides.

Often, they come coated on
the seeds, like on this rape seed,

so that as the plant grows,

the chemical spreads throughout
the organism through the roots,

the leaves, the flowers,
even to the nectar and the pollen.

Now one of the terms scientists use
to measure just how lethal

these things are is called "LD50" -
the dose that is lethal to 50%,

half of the test subjects.

And the lethal dose for a bee

is just four billionths of a gram,

which raises an important question,

just what are these things
doing to our bees?

Neonicotinoids are nerve agents,
and they only affect insects.

They were introduced in the 1990s
to replace more harmful pesticides.

When used properly,

they cause deadly paralysis
in small pests like aphids.

But if they do that to aphids...

..what's the effect on the bees?

There's a scientist in Germany
investigating just that.

40 years of research have made
Professor Randolf Menzel

a global authority
on the nervous system of bees.

One thing that's excited him
for many years

is just how advanced
their communication is.

Especially
their famous waggle dance.

Returning from a foraging trip,
this bee is telling its co-workers

precisely where
she found her pollen.

They just
use the body to, uh,

inform the others
about any important place

out in the field -

a wonderful flower
or a pollen place.

As she circles,
the bee repeatedly waggles

during one phase of her dance.
Here, walking straight upwards.

It is this phase which codes
the direction relative to the sun

and the distance.

Walking upwards while she waggles,
tells the other bees

to head towards the sun.

The number of times
she moves from side to side,

tells them how far to fly.

The brain
controlling this sort of behaviour

is clearly rather sophisticated.

This kind of cognitive processing
requires the highest order

of neural processing
in this little brain.

That means anything
which is disturbing

on these fine network processes
should have a high impact.

With the radar technology, Randolf
and his team have been investigating

whether neonicotinoids
could affect bees' brains.

They're testing their ability to
find their way home after feeding.

This is our feeding place.

That means bees have been
trained from the hive,

and we train them step-wise
to this location.

We catch it in the moment it arrives
here, put it into a container

like this which con...contains
50 microlitres of sugar solution.

The bees are fed
one of two different solutions.

We have groups which are fed
with the pesticide

delivered in the sugar solution,

and other groups which are not fed
with the pesticide.

And we compare them.

The bees have made many trips
to the feeding station.

And that means they know how to
fly in a straight line

between here and the hive.

They do this on auto-pilot, using
what's known as their vector memory.

So, when she is ready, uh,
to take off,

she will just fly back to the hive
using her vector memory.

That's all that she would do.

And she expect the hive
in 500 metres in the northwest.

But today, Randolf is setting out
to confuse the bees a bit.

He's going to take them
several hundred metres away from

the place where they normally feed.

And then track their attempts
to get back to the hive.

OK, we are at release site now.

So, let's say
that this is the release site.

The feeding station was over there

and this is the hive
in this direction.

So, let's say this is the feeding
station, this is the hive,

and they have learnt to fly
along this vector over 500 metres.

Now, we release them here.

Which means they use their memory
for the vector

and that means
they fly along this route.

But when they arrive there,
there is no hive.

So, the question is,
if the animal's released here,

how do they find home,

and what is the effect of pesticides
on this behaviour?

First, he releases a control bee
that hasn't been fed the pesticide.

As the bee tries to find her way
home, she's tracked by the radar.

She flies on auto-pilot
500 metres northwest.

She gets to where she thinks
the hive should be...

but because it's not there,

she has to use a different
navigation system to find it.

One that uses landmarks in the
countryside to find her way home.

So, she is...
is still flying towards the hive?

Yeah, she's landing there now.
OK, she has arrived already.

I think she's already here.
OK, she is already there.

Before she can disappear
into the hive,

our radar bee is intercepted

and the antenna is removed.

Next is a bee
that HAS been fed on the pesticide.

It quickly becomes apparent
that something is up.

So that means she comes back.
She turns back towards north.

Rather than heading straight home,

she starts to make a series of

erratic changes of course.

West. OK.

Where is she now?

So she is flying further north.

After a few minutes, the bee
appears to be completely lost.

She's cruising around us,
undecided which direction to fly.

She has not done
what we expected of her to do,

to fly along the vector direction,

which would have meant that she
would fly exactly in this direction.

Over two years of study, Randolf's
shown that, at these doses,

neonicotinoids DO affect bees'
higher cognitive processes.

Especially their memory
of the landscape around them.

We've tested about 200 bees,
both control bees and, uh,

pesticide treated bees.

And we found the control bees
are just fantastic.

They find home quickly,

they use the vector and the
landscape memory and they do fine.

Now, the treated bees,
depending on doses and substance,

we find that they are
kind of more confused.

They usually do quite well when
they fly along the vector,

but when they need to
refer to the landscape memory,

then usually they are lost.

They change their behaviour in a
very strong way. And so that simply

means to me, that neonicotinoids
ARE endangering honeybees.

It's work like this that lies
behind the European Commission ban.

But one thing I've learned
in this detective story,

is that it's all too easy
to jump to conclusions.

Despite this research, though,

neonicotinoids are still at
the centre of a HUGE controversy.

The UK Government did not support
the EC ban on neonicotinoids,

it said there wasn't enough
evidence to justify it.

Let's find ways of how farming
can co-exist with nature.

This is what we're talking about.

'As a beekeeper and journalist, it's
a debate I've followed very closely.

'Tonight, the British Library

'has asked me to host a discussion
on the subject.'

We are facing
a difficult situation

with bees and other pollinators
in Britain, at the moment.

'The argument in favour of a ban was
made by one of the scientists

'on the panel.'

There are these pieces of evidence
which show really serious impacts

from levels of neonicotinoids
that bees,

wild bees could be exposed
to in the wider environment.

'And the argument
against the ban was laid out

'by one of
the pesticide manufacturers.'

These trials show that there is no
risk to, to pollinators from

those products when they're used
correctly in the environment.

'There was a lot of concern
in the audience.'

I'm very worried I still can
go into my local supermarket

and buy litres of garden spray which
contain various neonicotinoids.

'It's clear to me

'that even though
many of the people here tonight

'had differing opinions,
there is a hunger for clarity.'

So I'm heading
back to Rothamsted...

..where there is another group
of scientists looking at pesticides

from a completely DIFFERENT angle.

'These dimly lit red corridors
are the first line of defence

'against a very dangerous
collection of insects.'

Why the red light?

Insects don't really see red light,
so to them this corridor is dark,

which means

they're not going to fly out here.
It's just additional security.

The rooms are sealed anyway...

'Professor Lin Field
wants to show me

'how we underestimate
the value of insecticides.'

This room here.

So what have we got here?

OK. So this is actually
a Chinese cabbage plant,

and this is a plant that we've only
just introduced the pest to,

and this is one that's been in the
cage with the pests

for maybe a week, and you can see
there's very little left.

And with most of the crops we grow,
somewhere between 30-40%

would be lost
to pests and diseases

if we made no effort
to control them.

So in your view,
we really need these pesticides?

In my view at the moment.

I think there are some alternatives

but most of our crop protection
does rely on modern chemistry,

which are
very effective insecticides,

very safe,
very low mammalian toxicity,

and they play a big role
in our food production systems.

Lin's recently become
Rothamsted's spokesperson

in the neonicotinoid debate

The big advantage of neonicotinoids,

is that you can plant the seed
already treated.

It means the farmer
doesn't have to spray.

If you've got to spray,
that's expensive,

it's got a high carbon input,
you have a risk of drift,

you have to wait
for the right weather conditions,

whereas if the plant
is protected by the chemistry

coming up as it grows,
you avoid all of those steps

From the farmer's point of view,
it's really useful.

It is VERY useful.

You'll be familiar with
Professor Menzel's work in Germany,

where he's shown that neonicotinoids
can have

an effect on the bees'
navigational ability.

And that may explain why we've been
losing so many bees.

It might explain it

and I'm not in any way
questioning his data.

I think at certain levels

they will have
sub-lethal behavioural effects.

Whether the amount
that bees pick up

by foraging in crops
that are treated with neonics

are at the same level to give that
effect, I don't know,

and I don't think that's been shown.

Why have some of them
been banned by the EU?

In my view the lobbying -

that went along with the fact that
neonicotinoids were suspected -

was so strong that, in the end,
they got banned

on a precautionary principle,
on a just-in-case principle.

A lot of people are looking
for clear and simple answers as to

whether neonicotinoids are to blame

but the way that creatures
as sensitive as bees interact

with their changing environment
is a complex one.

For instance in France,

neonicotinoids were banned
for a decade

and yet the decline continued,

whereas in Australia the pesticides
are still widely used

and the bees remain generally
healthy. It just is complex.

For me the most important question
here in Britain,

is about dose

and the effects that neonics are
having at low levels,

the sort of levels
you'll find in the countryside.

That's why I'm heading to
East Sussex.

'I've heard about an experiment
happening right now, to establish

'how much pesticide
bees are really getting in the wild.

'So I'm joining
Professor Dave Goulson and his team,

'to find out
how they're going to do it.'

The dispute largely focuses on
the fact

that pretty much all
the experiments done today have...

exposed the bees to the
pesticides in an unnatural way.

And what we really don't know is
actually what wild bees, natural,

free-flying bees
are actually exposed to.

Cos obviously in the real world,

they have a choice about
where they can forage.

There are lots of
different flowers around.

They might, for example, avoid
ones with pesticides in them.

If they did, then that would
mean that, actually,

they might be exposed to less
than we think.

'To find out how much pesticide
wild bees are really exposed to,

'he's set up a series of bumblebee
nests in fields around East Sussex.

'Each started with just
a handful of bees.

'Three weeks later, they're
flourishing - new colonies,

'packed with nectar and pollen

'collected from
the surrounding fields.'

I'm always told bumblebee stings are
more painful than regular bees,

is that right? I don't know.

I don't think there's much in it,
they're both... They both hurt.

So what we need to do is get
a pollen sample

and a nectar sample
and a sample of the wax.

And then, when we've got all
the samples in,

we're going to analyse them all

to detect these tiny traces
of pesticides.

'The bees will have this all
patched up in a day or two.

'The team will collect samples
every few weeks.

'But this will give them the first

'REAL measure of the dose
that wild bees are getting.

'They've chosen to study
bumblebees for good reason:

'because each colony
lives for just one year.'

So the nest is founded by a queen
in the spring and she rears up

her worker daughters to start with.
And then, after about three months,

the nest produces males and
new queens and the nest dies off.

So that discrete life cycle, uh,
actually enables us

to do an experiment in just
a few months and measure

the effects of pesticides
on the colony performance.

'As well as analysing samples,

'they're going to measure
the growth of each colony.'

So that's 674 grams.

'They have 40 boxes in East Sussex.

'And another 40 in Scotland.

'Dave will be able to compare
the growth rates of each colony

'with the levels of pesticide
measured in them.

'It'll be September
before the results are analysed.'

We know the levels that are found
in oilseed rape crops.

It's between about one
and six or seven parts per billion.

What we don't know
is where else

these pesticides are
in the environment.

One of the kind of concerns is
that they can last for years

in soil. And then, subsequently,

if flowers,
wildflowers for example,

grow in that field. So, um,
poppies, in the field just here -

that had a wheat crop in it
last year

that was treated with pesticides,

so it seems quite likely that
there'll be small amounts of

neonicotinoids in the pollen
and nectar of this poppy as well.

So is banning neonics a good idea?

I think that the moratorium

that's just about to come into place
is better than nothing.

But even if we stopped using them
completely right now,

it would be years before they're
gone from the environment.

So two years is not enough to detect
any kind of benefit

to the environment
from stopping using them.

So it's very unclear
how we'll decide what to do

in two years' time and really, um,

we've just kind of deferred
the decision, as far as I can see.

'This is one of the most
important experiments taking place.

'The one that could help us
understand the degree

'to which research done so far
is relevant to bees in the wild.'

So what do we know so far?

There's a good argument for saying
that disease and mite infestation

could be playing a bigger role
than we'd previously thought.

The image there
is the actual varroa...

Meanwhile, the results of Professor
Menzel's experiments with pesticides

would appear to be persuasive,

but we'll have to wait for more
evidence from the work

of people like Dave Goulson and his
bumblebees before we can make

a convincing case about the effect
of neonicotinoids.

And then you have to think about
the effects that banning

pesticides could have on agriculture
and the cost of food production.

It could end up doing
more harm than good.

With so many potential suspects,
it's no wonder

there's so much debate and confusion
amongst the scientific community.

And just as we think
we're getting to the big picture,

we've come across another
entirely different

scientific angle on the story,

which raises
the rather troubling question

as to whether we've missed
the real issue altogether.

There are some bees
which are doing surprisingly well.

In places you might not expect.

If we can work out
why these city bees are doing well,

it might give us the clues
as to what's happening

to the rest of the bee population.

Steve Benbow is an urban beekeeper,
and his bees seem to be doing OK.

Now, that's pretty lovely.

He puts that down to his honeybees'
rather unusual habitat.

We're on the roof
of Tate Britain here

and these are some of the bees
that I look after for the Tate.

I have to say, and congratulate you,

on having really very, very polite
and friendly bees.

Here we are,
standing in front of the hives

and they're just floating around.

I've never been able to do this
with anybody else's bees.

Oh, good.
No, they are particularly polite,

but a little bit different
when you go in them.

And they love this aspect.

It's lovely and light and sunny

and there's a lot of good forage
in this area here.

Is the city really a good place
to keep bees?

Most people would think,
well, loads of steel and glass

and concrete and roads and traffic
in the city

would put bees off,
what are they going to feed on?

If you look out here,
there's chestnuts here

and they'll start on those
early in the year.

And then the bees are all heading
this way at the moment

and there's a lot of lime trees
over that way.

And there's less insecticides

and there's an abundance
of pollen and nectar.

There's a real medley, I suppose,

as well,
with all the different parks

and avenues
and people's gardens as well.

So, they do incredibly well.

Evidence from all over the world
is showing that urban environments

are bucking the trend when it comes
to the decline in bees.

In the UK, for instance,
honeybees produce more in Birmingham

than they do in surrounding areas.

And hives in Paris
yield roughly twice as much honey

as colonies
in the French countryside.

For now, the research seems to
suggest that it's the varied diet

that city bees are getting that may
be keeping their numbers up.

And the evidence of how different
habitats affect honey is very clear.

So, we've got a Wapping honey
here from E1,

and this is
quite a toffee-like honey.

I love that. You've got it
all down you, but I love it.

This is a good honey.
It's a very good honey, yeah.

And then this is a honey
from the roof of the Tate Modern.

Tate Modern? Yeah. And Wapping -
that's not very far, is it?

Mm!

Now, the distance between
the hive that produced this

and the hive that produced that -
how far?

A mile and half, I'd say.

How is it that you can get such
a different variety of honey,

though, in such
a small, short distance?

In urban areas especially,
there's the most, you know,

fantastic array
of flowering plants and trees.

I couldn't pass up the chance
of showing off my own produce.

Do you want to try my honey now?
Of course I want to try your honey.

This is from Buckinghamshire.
Deepest...

Not deepest... It's only just
outside the M25, really.

I love the label. It's like there
should be some sort of warning.

Could be toxic.
Could be toxic. No, it looks great.

It's a couple of years old -
I didn't get any honey last year.

It's a mature... Mature. Lovely.
It's been getting better in the jar.

It hasn't crystallised at all.

Oh, now, that's rather good, Bill.
Is it? That is rather good.

Really lovely.

I think Steve's
probably being generous.

This fact that bees are doing well
in cities could, of course,

be hinting at what's happening
in the countryside.

And I'd like to find out a bit more
about how that habitat is changing.

'060 degrees, 11.'

Thank you.

Dr Deepa Senapathi
has being studying

the changes in land use
in the countryside.

Cool. Isn't it cool? Yes! I love it.

'Traffic from 172 operating
in the vicinity of Milton Keynes.'

To demonstrate what she's found, she
wants to give me a bird's-eye view.

So, we're flying over
some mixed woodland here,

which you'd think would be a pretty
nice place for bees to live.

What's the picture been here?

This site, historically, was
woodland, and very little has changed

and less than 5% of this site
has changed over time.

And yet,

there's a 35% decline in species
richness that's been recorded.

So, more than a third
of the different kinds of bees

that once lived in this woodland
have now disappeared.

What's intriguing here

is that their immediate habitat
has barely changed.

What do you think is causing that?

If the habitat here
is friendly enough, what's happened?

What's happening around the site
is really important for bees.

So, bees could nest within this site,
but they might forage

up to a kilometre or two
outside of the site.

And what is really striking

is the level of agriculture
has gone up by about 30%.

So, if I were to show you
an old map...

This is what this area used to
look like in the 1920s and '30s.

All the light green bits that you
see are meadowland and grassland

with a little bit of agriculture,
which is the brown bits.

But if you look out of the window
now, the entire countryside

is turned into quite intensive
agriculture and farming.

Deepa's research has been repeated
around 23 other sites in the UK

and they all show the same thing.

Although this landscape
may look greener,

it's what ecologists call
a "green desert".

Over the years,
plants that bees do feed on

have been replaced by vast expanses
of plants that they can't feed on.

It is quite counterintuitive,
because you look at green,

you look at the swathes of plants
you can see there

and you think that must be really
good for bees and pollinators.

The logical conclusion would be,
then, that we need to rethink

our entire system
of modern agriculture,

of the way we grow things.

I think it's just a slight shift
in, perhaps,

thinking of more wildlife-friendly
farming methods,

not saying, "Agriculture is bad."

It's just, there are ways
to improve agriculture

in a way that it might be
more useful to biodiversity,

it might be more friendly.

So, you won't be surprised to hear
that scientists

aren't simply looking at
why are the bees are dying.

They're also trying to work out
what we can do about it.

One of the first things
they've looked at

is taking place in the grounds
of the University of Reading.

They're hand-pollinating
strawberry plants.

It might seem strange,
but hand-pollination is something

that's already been tried out
in southwest China,

where wild bees have been completely
eradicated due to loss of habitat.

Perhaps it could be
an answer for us.

Take some pollen from there.
So, here on the outside? Yeah.

These... These are the anthers
that actually produce the pollen.

OK. Where shall I go?
Let's try this flower here,

so right on the centre.
Right on the centre.

That one? Yep.

And you dab it on there gently

and you'll have rubbed some pollen
onto the stigmas

and that will help develop
and fertilise

and you'll start a strawberry.

I can see straightaway,
though, that it's not exactly

the same intricate talent
that a bee would have!

We're clumsy. We're clumsy.

What the bees do perfectly
is spread the pollen very precisely

and evenly across the stigma
of the flower,

which is extremely important when
it comes to the finished product.

So, as consumers,
what do we like to have?

We like to have nice, large,
perfectly formed fruit,

that's what we're after, and you
need good pollination to get that.

And here's an example,
this is quite an extreme example,

but this hasn't been
pollinated properly.

Is that appetizing? No. Not really.

So, given the world where
we've got declining pollinators,

we wanted to ask the question,
how much would it cost

to replace that service
that bees are giving?

So, we trained up some students
and we gave them paintbrushes

and we timed them
to pollinate different crops -

strawberries, apples, oilseed
and so on.

And then we calculated

how many of those flowers there are
flowering in a year in the UK

and putting that together,

working out what would be
the minimum wage we could pay them.

We came up with a figure
of £1.9 billion a year

to replace the service that bees do.

So, it's pretty clear
hand-pollination isn't practical

and we really can't do without bees.

But there is a second option,

to find ways of creating
a more bee-friendly environment.

There's another research group
at University of Reading

who are trying
a very different approach.

Scientists Vicky and Jenny Wickens
are investigating a way to help bees

thrive on prime agricultural land
without affecting the way we farm.

So, what have we got here?

This is a sown flower strip,
so these flower strips are put in,

so they can boost the natural
pollinators in the area.

In fact, with bumblebees, we've
found 500% more bumblebees here

than we do at grassy field margins
in comparison.

They're conducting a trial
across 16 different farms.

And where they planted
these flower strips,

they found the number of solitary
bees went up by about a third

and bumblebees increased fivefold.

We see what the bees get out of it.
What's in it for the farmer?

They get improved yields.

We have put potted plants

in both the flower strips
and in the field boundaries,

so just typical grassy field
boundaries, and we are looking at

the number of seeds that
are produced by these potted plants.

We found a 50% increase
in the number of seeds

in the flower strips
rather than the field boundaries,

and this just proves

how important these flower strips
are to the farmer.

So, if successful, these flower
strips could not only give bees

a home in the countryside,
they could actually increase

the amount of food
farmers can produce

without changing the way
they grow their crops.

But there's another potential
solution in the pipeline

which, in the long-term,

could be rather promising,
although it is some way off.

Lin Field is doing something
which might make us

less dependent
on traditional pesticides.

She's creating
genetically modified plants

which she believes could one day
replace pesticides

and help protect our bees.

Here we're trying to use a natural
compound that aphids produce

to warn other aphids
that there's a predator around,

that there's some sort of risk.

This compound,
which is called (E)-beta-farnesene,

is a pheromone,
an alarm pheromone,

and it's normally secreted by the
aphid and other aphids detect it.

We can demonstrate to you
how it does that,

so if you take the syringe,
which has got the compound in it,

and I take off this little clip cage
so we can see the aphids,

and you put the drop onto there.

And what we've done is,
we've engineered into a crop plant

the ability to make this compound,

so that the plant itself
gives off the smell

and aphids don't attack it.

So, it will naturally scare
the aphids away? It will.

So, the colony that was there,
some of them are still there,

but most of them have moved away.

They're coming around the edge side
of the plant.

Indeed, a lot of them
have dropped off.

It's using a natural system
that the aphid has evolved to detect

in a situation
that will help protect our crops.

So, what does this mean
for the bees?

The bee will be completely
unaffected by this compound.

The bees don't detect this compound,
they wouldn't respond to it,

so it wouldn't be affecting bees.

Both these strategies
will take years to implement

but it's hoped they could help
reverse the decline in bee numbers.

So, what is killing our bees?

These beautiful, complex creatures
are ultimately very sensitive

to any fluctuations
in their environment.

We live in
a rapidly changing world

that they are struggling
to cope with.

Viruses, chemicals
and modern agriculture

form a fatal combination
for these fragile insects

on whom we depend so much.

What strikes me

is that there's a common factor
behind these three, and that's us.

We've helped to spread
the varroa mite,

we've developed pesticides,

we've changed
agricultural practices.

Perhaps it's what we're doing
ourselves that's killing the bees.

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