Attenborough and the Empire of the Ants Natural World

The Jura Mountains

on the French-Swiss border

are in the grip of winter.

The ground has been frozen solid for months.

This is a tough place in which to live.

I'm told that clearings like these could be the home of a real giant.

At this time of the year, it'll be in hiding.

But evidence of its existence - these strange mounds -

is everywhere.

Inside here, deep down and protected

from the cold, the giant is asleep.

Beneath the thatch of spruce needles

lies a maze of tunnels and chambers -

the home of hibernating wood ants.

Individually, they are tiny,

but they're members of a giant super-colony.

When temperatures rise, over half a billion of them will emerge

and dominate this landscape.

Scientists are only just working out how ants manage to survive up here.

But in fact there's a much greater and more profound mystery

that has brought me up this mountain.

Among ants, co-operation between colonies is very rare.

Warfare is common.

Yet these nests over a great area live at peace with one another.

This may sound like an epic tale of war and peace

but does it also contain an echo of human nature?

These ants, in some extraordinary way,

have exchanged war for peace.

It's now recognised

as one of the largest of all insect super-societies,

and its very existence conflicts with some of the laws of evolution

as we presently understand them.

It's been a long, cold winter here in the Swiss Jura Mountains.

It's hard to believe

that any insect could survive in this frozen landscape.

But now change is in the air.

Soon, ant nests all over this mountain will come to life.

Some of these mounds are independent colonies

but others are part of one huge super-colony.

Over the coming months, I'll be looking at the differences

between these two wood ant societies -

one that wages war with all its neighbours,

and the other, which welcomes them and lives at peace.

As the grip of winter eases,

sentries emerge from the mounds to check on conditions.

They detect the sign that they've been waiting for -

the temperatures are rising.

Spring is on the way.

The ants survive the winter thanks to their own central-heating system,

warmth given off by the slow decomposition of the dead vegetation

in the nest's fabric,

and that prevented them all from freezing.

Now, by swarming all over the surface of the nest,

they are recharging their batteries,

absorbing heat directly from the sun's rays.

This behaviour only happens over one or two days in the early spring.

The worker ants have emerged into the sunshine

and are now clumping together.

And they're not just sunbathing.

It could well be that the ultraviolet rays of the sun

cure them of any infections from viruses or fungi

that may have happened during their long sleep underground.

You can almost feel the enthusiasm

with which these little creatures are enjoying their sunbathe.

This is unusual enough but now here is something truly extraordinary.

There is a queen.

She's almost twice the size of her subjects.

She's also the most important member of her family.

And what's more, there's another.

To see a queen exposed and vulnerable outside the nest

is very rare indeed.

There's one.

And there's another...

..shining wonderfully in the sunshine.

A normal wood ant nest usually has just a single queen

who lays all the eggs - but clearly this is not so here.

There's another. There's another. Several of them.

Amazing.

After a few moments in the sunshine -

the only time they see daylight in the whole year -

the queens disappear

and make their way back to the chambers deep in the nest.

Those unwilling to go are dragged back.

We may call them queens but there's no sovereign rule here.

The workers govern by consensus,

and they decide when and where the queens will go.

There may be hundreds of queens in this single nest,

and there over a thousand such mounds as this, all interconnected.

So, across the super-colony

there may be as many as a million queens.

It's now early April.

The queens' return below to prepare for the egg-laying

started a race against the clock.

They must complete their most important work below

in the next two months.

Using infrared light, which is invisible to the ants,

we can watch them inside their nest without disturbing them.

Most of the first eggs to be laid

will produce the next generation of breeding individuals -

the queens and the males -

both of whom will have wings.

Inside the thousand nests of the super-colony,

over half a billion mostly unrelated worker ants

co-operate to make sure that the queens and the males will be ready

for their mating flights in mid-June.

With all these developments on the way, it's imperative

that the workers collect more food as soon as possible.

But many of the mounds are still surrounded by snow...

..so the workers can't reach their feeding grounds.

But there's something they can collect -

heat.

The nest needs more heat

than that which comes from the rotting vegetation

if the eggs are to hatch in time for their June appointment.

Now, however, the ants have another source of warmth.

Using their bodies as solar panels,

the ants harvest the sunlight.

We have a heat-sensitive camera that detects differences in temperature.

The nest appears black

because it's hotter than the surrounding environment.

It shows a similar difference in the ants.

Those going down into the nest are black

because they've been heated by the sun,

whereas those coming out are white because they're cold,

having transferred their body heat to their charges

in the chambers below.

It's this kind of selfless collaboration

that is the key to success of any ant colony.

In normal ant colonies,

all the workers are related to one another and to the queen,

and the theory is that that is why they all co-operate.

But that is not the case here.

There are hundreds of queens here.

Over one thousand have been counted in a single nest,

so all the workers can't have the same parents -

and genetics have confirmed that this is so.

It's this co-operation between unrelated ants in a single colony

that appears to be rewriting the rules of insect evolution,

but we still don't really know how this has come about.

Spring is now well on the way.

The snow has disappeared,

and colour comes to the meadows.

By late April, there are piles of eggs in the nest

and the first larvae are hatching.

The workers labour unceasingly to ensure that the growing brood

will be ready to emerge in six weeks' time,

at the peak of the short Jura summer.

But not every ant nest on this mountain can be so focused.

Some will soon have to deal with threats to their very survival.

Just a short distance away,

on the borders of the super-colony's woodland territory,

there are other wood ants.

The mounds here on this side of the mountain look exactly the same

as those of the super-colony,

and so do the ants themselves.

The inhabitants of each nest here are all the offspring

of its single queen,

and the colonies compete aggressively with one another.

After the winter hibernation,

the territories between that nest over there and this one here

have become blurred, and the frontier has to be re-established.

And in order to do that,

workers from both nests are now scouring the ground,

and that brings neighbouring ants

into contact for the first time this season.

When foragers from the different nests meet,

they immediately recognise that they're from rival families.

They then dash back to their nests and within minutes both colonies

know that territory on their frontier is being disputed.

Armies assemble.

This...is war.

And the weapons being used are chemical.

Formic acid.

I can smell it in the air.

They're squirting it from the ends of their abdomen,

and if they can bite their opponents

so that the formic acid gets beneath the outer shell of an ant,

it will dissolve its internal organs.

As they grapple, each tries to restrain its opponent

by clamping its jaws around a leg or an antenna.

Soldiers from both sides tug at their opponents' limbs.

It can take seven ants to subdue a single enemy.

One holds each leg,

and the seventh uses its mandibles

to cut open sections of their opponent's exoskeleton,

exposing the insides.

An attacker brings forward its abdomen under its body

and squirts acid onto its victim.

Battles are going on everywhere.

Each colony carries its own chemical badge, invisible to our eyes

but clear to the ants' sensitive antennae.

Fighters touch each other to confirm whose side they're on.

Here and there, individuals clamber up the vegetation.

Are they having a rest,

or are they surveying progress to see where help is needed?

The smell of formic acid reaches the colony,

and more ants from both sides run to join the battle.

These wars can continue for over a week.

At their peak, many thousands are fighting and thousands are killed.

The victors will certainly have enlarged their territory...

..but some say they have also gained other rewards.

They're taking off the bodies of their victims

and carrying them back to the nest over there to feast upon them.

Both sides have suffered heavy losses.

For the ants in the meadow, it has been a costly start to the year.

Higher up the mountain, in the territory of the super-colony,

the inhabitants of different nests are also meeting.

But here, things are very different.

These ants come from a mound about half a mile away.

If that mound was a separate, independent colony,

then these, when they land there,

would be savagely attacked.

But let's see what happens.

At first, the resident ant makes an aggressive gesture.

But then the other strokes the first's antennae.

That gesture is a request for food, and the other obligingly feeds her.

This behaviour - known as trophallaxis -

is in itself not unusual.

Most ants do it at times.

What is unique is that these ants are almost certainly unrelated,

yet they treat each other as if they were from the same nest.

They do this because they share the super-colony scent,

a chemical signature that is transferred together with the food.

In one experiment, scientists fed a distinctive chemical to a nest

on one side of the super-colony,

and eight weeks later that same chemical appeared

far away on the other side.

It's this sharing of food between over half a billion individuals

that makes this super-society so truly remarkable.

Because of this, super-colony ants can move freely between mounds,

and they have, as a result,

created over 100km of trails

that link over 1,000 nests.

These trails not only allow the ants to make new nests

deep in the forest,

they also give all the members of the super-colony

access to resources of great value to them.

It comes from the spruce trees.

The ants don't feed directly on the spruce trees.

They become farmers.

And these...are their flocks.

Aphids.

The presence of the ants keeps insect predators at bay

so the aphids can feed unmolested.

They drink the tree's sap

and excrete what they don't need as a sugary liquid called honeydew.

And the ants love it.

Just as human farmers milk their cows,

so the ants stroke the aphids with their antennae

to persuade them to release their honeydew.

Once the aphids are milked

and the ants have drunk as much honeydew as they can carry,

they head down the tree, abdomens bulging, and return to the nest.

The honeydew is not only food with which to sustain themselves.

Some use it to raise the heat of their bodies well above normal,

and so warm the atmosphere within the nest -

a valuable ability in the fickle climate of the Jura.

The spruce trees themselves also produce a substance

that the ants can use directly.

These ants have collected little flakes of resin.

That's a sort of gum that oozes from the broken twig

of a coniferous tree.

The tree uses it to seal off an injury.

But what are the ants using it for?

Inside the nest, the extra warmth produced by honeydew

helps the queens to keep laying

and the larvae to keep growing.

However, constant warmth can create problems.

Despite regular cleaning, diseases can thrive.

The ants have a remarkable solution to that problem.

They cover the surface of the mounds with tiny nuggets of resin,

and also take it into the chambers below.

One nest contained over four kilos of it.

It is, in fact, ant medicine.

The ants combine acid from their bodies with the resin

and so produce a very effective antibiotic.

This is one of the most sophisticated animal pharmacologies

known to science.

It's been shown that wood ants living in nests that contain resin

are better able to survive diseases than those that don't,

and their eggs are far less likely to be infected by fungi.

This immense, peaceful super-colony has few enemies.

But now, at the end of May, a new threat has arrived.

BELL JANGLES

COW MOOS

The Jura is famous for producing some of Europe's finest cheese.

For generations, farmers have made small clearings in the woods

to create meadows where cattle can graze.

Only now is it warm enough

for cows to be brought up to these high pastures.

Somehow, the ants need to make sure that they're left alone,

and that nothing damages their nests.

And that's a considerable challenge, even for a super-colony.

But these ants are very determined.

When one squirts its acid, others follow suit.

The result is a co-ordinated barrage.

The cows are not harmed, but they do get a dose of acid in the nose -

which they don't like -

and they tend thereafter to avoid these mounds.

By now, in June, the larvae have become big and greedy.

They must be given special care

because they will produce the next generation of royalty,

so the workers labour hard to meet their demands.

In summer, hundreds of thousands of eggs are hatching every day,

and honeydew is not enough.

The ants go in search of something else. A supplement.

Fresh meat.

The lush green hills and mountains of the Jura

are now teeming with all sorts of life,

and nearly all of it is potential food.

The ants spread out from the nest,

scouring every square inch of ground in search of prey.

As the hunters approach, those that can, take flight.

The ants' vision is not very acute.

They can only see a target if it moves.

A wolf spider, however, can see the ants clearly.

But as long as she doesn't move, they won't know that she's here.

She's carrying a little sack full of eggs.

She decides to run for it, and her sudden movement alerts the hunters.

That first fleeting touch by an ant left a faint scent mark,

and now fellow hunters can home in on their target.

The spider has a venomous bite, but that is no use now.

Eight powerful legs are her only hope,

but her speed is the very thing that enables the ants to follow her.

Slow motion reveals the basic ant-hunting technique -

lunge with jaws open and hope for the best.

At last, an ant manages to grab her.

Like a pride of lions taking down a buffalo, the ants surround her.

Two restrain their catch,

while another delivers the flesh-dissolving acid.

The wolf spider is just one of many victims.

Alone, an ant can take only the smallest prey.

But by working as a team,

they can capture creatures many times their size.

A super-colony can make hundreds of millions of kills every year.

Beetles, caterpillars, worms, flies -

they will tackle almost any living thing.

Whatever the prey, it's first cut up and eaten by the workers,

who then regurgitate it to feed to the larvae.

Once they have grown to full size,

the larvae spin silk cocoons for themselves.

Inside each, a featureless larva is changing into an adult.

Their time in the sun is approaching.

Wood ants live in one of the most highly organised

and complex of insect societies.

They fight wars over territory,

they hunt in packs, and farm other species.

They build complex homes with central heating,

they produce their own medicine,

and one group of them, we now know, has made another advance.

The super-colony has extended this collaboration beyond the frontiers

of the family to form a super-society of such dimensions

that we can perhaps begin to compare it with that other

great social creature on this planet - ourselves.

People studying the origins of human culture suggest that shared myths

were one of the factors that bound early human societies together.

But what about ants?

Well, in many species it is certainly the case

that all the individuals are very closely related to one another.

But that is not so in the super-colony,

and in some days in June,

such colonies continue to break the rules.

As midsummer approaches,

the Jura briefly becomes a paradise of wild flowers.

And something new appears inside each of the nests - wings.

The royal generation, male and female,

has finally hatched and both will be able to fly.

Winged individuals are the only ones that are capable of breeding.

The males are little more than animated insemination devices,

and they will soon achieve their purpose and die.

But the females, which are emerging just now,

this is the beginning of a long life of servitude.

When the weather is just right - sunny and not too windy -

the nests suddenly become covered with winged ants.

There's an excitement in the air.

The males, which have matte black bodies,

are incapable of feeding themselves.

So once they leave the nest they only have a short time to live.

There's no time to waste.

The virgin queens, who are also black but splendidly shiny,

have a rather clumsy beginning to their lives.

They're heavy with fat reserves and swollen ovaries.

So getting airborne is not easy for them.

This is the most important flight of their lives -

but it's also their first.

Many test their wings before takeoff.

They may need several attempts

before they achieve complete flight control.

Over a few days, half a million winged ants of both sexes

take to the air and head off for new territory.

They then all assemble here, in the heart of the super-colony.

It's not clear how they find this meadow but, year after year,

virgin males and females from across the super-colony

are drawn here for their nuptial flight.

The queens congregate in small patches of taller plants

and begin to release sex pheromones -

airborne chemicals that attract males.

Detecting this scent on the wind, the males home in on the females.

The virgin queens may only get the chance to mate once,

and they need to obtain enough sperm to fertilise the eggs

they will be producing for years to come.

But with plenty of males in the meadow,

they can afford to be choosy.

The males are so driven,

they even try to mate with females who are already doing so.

Those males fortunate enough to couple quickly

make the most of their few remaining hours of life.

Once they've mated, their service to the colony is over,

and they die of exhaustion.

The queens now have no further use for their wings,

and they try to get rid of them.

But they are, necessarily, rather firmly fixed.

Trying to remove a backpack with your feet,

even if you have six of them, is clearly a frustrating process.

Eventually, the meadow is marked

with little drifts of discarded wings.

Such breeding swarms are fairly typical of ants generally,

but now the queens of the super-colony

do something much less common.

To understand why they behave so differently,

we must first return to the spring battlefields

of the ordinary wood ants outside the empire of the super-colony.

The warring colonies on this side of the mountain

have now accepted their frontiers,

and summer brings a brief pause in their battles.

The mating system they use may seem at first sight

to be the same as that of the super-colony but, in fact,

it's fundamentally different.

Every decision taken by a mated female is fraught with danger.

The colony this queen comes from is at war with all its neighbours,

so if she meets any of them, they will try to kill her.

She needs a home, but she can't build it without help.

Her solution to the problem is extraordinary and radical.

Under this rock, a different species, field ants,

have built a nest.

These small ants, less than a third of her size, are common,

and live in meadows on the edge of the forest.

The only way this wood ant queen can get her own nest

is by taking over one of theirs.

She will become a parasitic queen.

She lurks near the nest,

trying to pick up the scent of the field ants.

She avoids groups of them, because they could overpower her.

Instead, she tackles individuals.

There's a brief duel, and then she retreats.

But each time, she's left with a trace of their scent,

so that she slowly begins to build up a chemical disguise.

These contests go on for several days.

Gradually, her disguise becomes more and more convincing.

The entrance to the field ants' nest is unguarded.

Cautiously, she enters.

Inside, she is vastly outnumbered.

Wood ant behaviour inside a field ant nest

has never been observed in detail before, let alone filmed,

so what happens next must be interpreted with caution.

There are fights, and most wood ant queens

are in fact killed at this stage.

But after she has endured repeated attacks,

some of the field ants become less aggressive towards her.

Eventually, a confused field ant worker

feeds the wood ant queen, and when it does that,

the fate of the nest is sealed.

The wood ant queen has now acquired the colony's scent.

She oozes queenly pheromones,

and the field ants seem entranced by their new foreign queen.

The gamble has paid off, and she has a fully functioning nest,

ready to receive her first batch of eggs.

Taking over a nest of field ants

is the way typical wood ants start a new family.

But how about the queens from a super-colony,

with their multi-family, communal nests?

Have they found a more peaceful strategy?

Each mated female has to set out on her own journey.

If she's to become a true queen,

she has to find a nest that will accept her,

and that is where the tolerance of the members of the super-colony

is tested once again.

Being already in the heart of a super-colony,

these newly mated queens don't have to walk far

before encountering their own kind.

But even for a super-colony queen,

walking straight up to a busy trail is risky.

If the workers she meets are not in a welcoming mood,

they will tear her to pieces.

Slowly, one by one, workers come to investigate her.

Some seem uncertain whether to attack or not,

but others lick and clean her.

After a few tense moments, a worker starts to drag her towards the nest.

This is a sign that she will be adopted.

And now scientists have made a further discovery.

Many nests in the super-colony shortcut the whole process.

The winged males and the queen ants don't even bother to leave the nest.

Many different families live here,

so there's no need to fly away to avoid inbreeding.

The winged queens can simply mate

with one of the males that hatched here.

Perhaps this unusual behaviour is the next stage

in the evolution of the super-colony.

With these innovative mating systems,

the super-colony queens don't take the same risks

as normal wood ant queens.

They don't need to infiltrate the nest of field ants

to start a family.

The workers just build new nests where needed,

enabling the super-colony to extend deep into the forest

where there are no field ants.

It's changes in behaviour like this

that most likely gave rise to the super-colony in the first place,

and colonised this new habitat with all its riches.

It's possible that this kind of co-operation

between different nests is becoming more common among ants.

New super-colonies are still being discovered

in different species across the world.

Are we perhaps witnessing the next stage of

the social conquest of the Earth?

The super-colony consists of literally thousands of

different families, all working in co-operation.

It's a development that mankind achieved a very long time ago,

and could be seen as one of the reasons why

we have come to dominate so many parts of the planet.

Could it be that peace is the winning strategy

on this ant mountain too?

Much about the super-colony remains unknown,

and for good reason.

These ants move incredibly quickly.

So you can see why they're so difficult to study,

and even more difficult to film.

At around 8mm in length,

these are bigger than many ants but, to us,

they're still tiny, and rarely stay still for more than an instant.

To keep track of their frantic movements while also

getting down to eye level with their world

needed a very special camera...

..the brainchild of filmmaker Martin Dohrn.

This is Frankencam.

It's a device for positioning tiny cameras and

small wide-angle lenses into awkward corners

with extreme precision.

It's called Frankencam because

it's got so many different bits in it.

It has been said that it is an unholy alliance

between other bits of equipment that should never have been put together.

Now known by all of us as Frank...

OK, bring Frank to me.

..it enables us to follow tiny creatures

as they go about their lives without disturbing them.

I first met Frank back in 2005

when filming for the BBC series Life In The Undergrowth.

Back then, he wasn't quite as sophisticated as he is now,

but he still allowed us to see ants in a new way.

12 years on, the equipment has grown into this,

and this enables us to enter the world of the ants

in a way that has never been achieved before.

Martin, there's a lot of things going on over here.

And long cabling allows operators to take the control box

away from the camera so that biting insects are less of a problem.

What's going on?

But of course, it doesn't stop the ants coming to us.

-SHE LAUGHS

-I'm covered in ants!

I'm finding it a little hard to concentrate.

And with Frank's fluid movements,

keeping the action in focus is far simpler than it would be

using a conventional close-up camera.

It's incredibly easy to fine-focus, to go right in for the close-up

so we can pull out for the wide shots,

and we can see the detail, we can see the distance,

we can put the whole scene in this meadow

so we can see it's this meadow,

and it makes it easier to feel as if you're there.

And now, for the first time,

the ants are in focus no matter where they're moving,

and even I am too!

However, while Frank's body parts cost many thousands,

and its construction needed the help of a mathematician

and an engineer, ironically,

the lens used for many of the most spectacular images

cost just £8 on the internet.

This wasn't a cost-cutting measure.

This lens has an amazing abilities, and it's perfect for the job,

but it's only so cheap because lenses like it are made

in their many millions for the cameras on your mobile phone.

One of the clever ways Frank's lenses takes us into the ants' world

is by changing the way we see distances.

To an ant, five feet might as well be half a mile.

VOICEOVER: This behind-the-scenes image, recorded on a normal camera,

shows just how close I'm sitting to the nest.

But if we view the same scene using Frankencam,

it appears as though I'm much farther away.

..which are emerging just now.

It's this magnifying of distances that allows the operator to steer

so precisely between every blade of grass

and enables us to appreciate the world on ant scale.

But even with Frank, there's one factor

which affected every aspect of the ants' behaviour

that we couldn't control.

The weather up here is extraordinarily unpredictable.

You never know what's going to happen.

This morning, there was lovely sunshine. Look at it now!

Difficult to believe, but yesterday,

these meadows were under three inches of snow.

So you have to be prepared for anything,

whether you're an ant or, indeed, a naturalist!

The ants have worked out how to survive here.

We're novices.

It was meant to be spring now,

and this was meant to be the shoot we did six weeks ago.

With the weather so variable,

predicting the ants' behaviours was difficult.

We've just arrived and found the nest covered in winged ants,

which we weren't expecting at all.

We were kind of expecting them to come out in about

a week or two weeks' time.

Even the scientists are pretty surprised.

Matters aren't helped by Frank being just as fickle as the weather is.

Unfortunately, Frank is temperamental, and sometimes,

he's brilliant, and then as soon as you admit that he's brilliant,

he decides to stop working,

which is exactly what happened this morning.

The focus box has received a knock, or it's been, you know...

..it's decided to stop working, anyway.

Kit failure is always a concern,

but when there's only one of your camera in the world,

you just need to find a way to carry on,

and doing so enabled us to record behaviour

scientists can't normally observe in such detail.

Like the intricacies of antenna movements

when ants interact.

Or following a parasitic queen through the undergrowth

as she slowly builds her chemical disguise.

To obtain new observations leading to a new understanding

of the ants, the team filmed for over 100 days,

spread over a year.

And the ants love it!

Thank you. I'm happy. Great. Lovely. Thank you, guys.

With the help of Frankencam,

they took us into the world of the super-colony

and, remarkably,

using a tiny lens just like the one on the phone in your pocket.