What's Killing Our Bees? A Horizon Special Horizon

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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