Original subtitles

(mysterious music)

A teeming ant colony.

A society where worker ants labor blindly

for the good of the colony,

just cogs in a living machine.

A huge collective with a single-minded purpose.

The ultimate stuff of sci-fi movies.

(mysterious music continues)

Scary, ruthless, relentless.

Truly alien.

But look closer,

an ant colony has the run of the whole of this house,

giving a unique look

at the lives of these intriguing little insects.

These colonies are far more sophisticated than we imagine.

Not a dystopian nightmare at all,

but a caring society.

(dramatic music)

In the nurseries, workers tend huge piles of eggs,

keeping them clean and free from infection.

Others wait on the queen.

The only one to breed.

Collecting her eggs as soon as they're laid

and taking them straight to the nursery.

Some workers care for the pupae,

about to emerge as fresh recruits to the vast workforce.

This is why social insects are so distinctive.

All these individual insects cooperate closely

for the good of their whole society.

It's one for all and all for one.

Without a selfish thought in any kind of head.

(dramatic music continues)

Working together in large colonies like this,

makes social insects the most successful of all insects.

Yet only two different groups of insects

have ever evolved such complex societies.

We're most familiar with the ants, bees and wasps

and they all belong to one insect group.

Societies operating with military precision.

They dominate their world.

In some rainforests ants outweigh

all the land vertebrates by four times.

And not just in remote wild places.

Teamwork means these insects conquer our world as well.

But these ant colonies don't reign unchallenged.

Termites.

They also live in vast societies just as successful

as those of the ants, bees and wasps.

Working together, some termites build gigantic castles.

They shape the whole landscape

as much as any of the bigger animals.

The total weight of all the termites in the world

is about the same as that of all humans.

How did evolution produce these bustling societies

of insect overachievers?

It's not just in huge colonies.

It turns out the cooperation of one sort or another

is surprisingly common among insects.

In the Australian Bush, there are close knit families

that show the beginnings of cooperation.

(kangaroo grunts)

Some insects really hate to be on their own.

Spitfire bugs are the larva of sawflies

and they stick to each other like glue.

(mysterious music)

When they move,

they keep their tails wrapped around each other.

If one does get separated, the rest drum on the plant,

a powerful homing signal to guide the straggler home.

(caterpillars drumming)

They feed on the leaves of eucalyptus trees

which are packed with pungent oils.

Although that doesn't seem to worry the Spitfires.

But if they feel threatened, they all rear up

and spit drops of fluid,

concentrated eucalyptus oil, nasty stuff.

They even thrash their tails

to coat their bodies in the oil.

So anything that comes too close

will get coated with stinking fluid.

This show of solidarity is enough for most predators

to leave them well alone.

They're much safer in a group, a basic society.

But a society where members of the same generation

work together doesn't go much further

than these bands of feisty caterpillars.

It takes a different kind of community

for evolution to really work its magic.

A bond built across the generations

between parents and offspring.

Meet the world's biggest roach.

(roach scuttling)

These four inch rhinoceros roaches

only live in these Australian forests

where they feed on dried gum leaves.

(mysterious music)

The bulldozers of the insect world.

They have powerful front legs to dig burrows

in the hard-packed earth.

Very deep burrows.

(mysterious music continues)

Following a winding path

it descends below the forest floor,

deeper and deeper.

Eventually, more than three feet below the surface

is her nest chamber and her family.

The baby roaches are happy to see her, it's dinner time.

She drags these unappetizing dried leaves all the way

down to the nest and the young feed

on the fragments that she chews off for them.

But this diet is really hard to digest,

at least without help.

Just like cows, these roaches need guts

packed with microbes to break down the leaves.

The problem is the young don't have their own microbes.

They need to get them from their mother.

The only way to do that is to eat moms poo.

This tough cellulose diet means that young cockroaches

must hang around their parents

until they have their own gut flora.

They'll stay with their mother

for the whole of the summer.

But if the kids never leave home

the family just gets bigger and bigger.

Which is exactly how termites evolved.

(mysterious music)

Termites are just social roaches.

Very, very social roaches.

These are Darwin's termites,

the most primitive and the largest of all termites.

This is all one family of brothers and sisters.

They'll never leave home and never breed themselves.

They'll spend the rest of their lives

helping their mother, the queen.

Some are specialized soldiers

with powerful jaws to defend their colony.

But the rest just chew on wood.

Hollowing out entire trees.

Darwin's termites are one

of the most destructive termites in the world.

Termites don't care whether wood is growing as a tree

in a forest, or has been turned into a home.

It's all just food to them.

Dry wood termites like these,

are much smaller than Darwin's termites,

but still cause millions of dollars worth of damage

in the world's warmer regions.

Like their roach ancestors,

they also have guts packed with microbes,

so termites can digest anything made of wood.

The chewed off fragments of wood

are pulverized further by a muscular gizzard.

Then pass along the gut where the termite's

own enzymes begin digestion.

Then the fragments are handed over

to protozoans and bacteria.

So many, they make up nearly half the termites weight.

This tough diet of wood and dried plants

forces the young to stay at home for a long time

to inherit these vital microorganisms from their parents.

A long lasting bond between parents and young

gave termites the opportunity to evolve

their complex societies.

A few billion bacteria and protozoans

keep these vast colonies sustained

by nothing more than dry wood.

Although we don't usually appreciate just what

extraordinary little creatures termites really are.

(wood creaking)

(wood fracturing)

(objects clattering)

On the other hand, everyone loves bees.

Bee societies are just as complex as those of termites

but came about in a very different way.

(gentle music)

The Sonoran Desert in the American Southwest is bee heaven.

A thousand different kinds of bees live here.

(bees buzzing)

We think of bees as living in huge super colonies,

but most kinds of bees are actually very antisocial.

And that includes cactus bees.

There may be thousands of bees in this one patch of desert,

but it's every bee for herself.

She's only focused on digging her own nest.

(gentle music continues)

A tunnel in the hard, dry, desert soil.

They're all crammed into this one neighborhood

because the soil here is easier to work than elsewhere.

But not that easy.

It's hard work moving boulders bigger than you are.

And once that's done, the nest must be stopped with pollen.

Cactus bees specialize in cactus flowers.

She dives headlong into a sea of anthers.

Laden with pollen.

When she emerges, she's covered in the stuff.

She packs it all onto her hairy hind legs

to carry it back to her nest.

Each nest must be filled with enough pollen and nectar

to feed all her larvae until they're fully grown.

But she's being watched.

A bee fly, with a simple mission in life.

Avoid all this effort

and instead exploit the hardworking bees.

(dramatic music)

The fly is a precision bomber.

She flicks her egg towards the bees nest.

And it's a hole in one.

When the fly's grub hatches, it'll eat the pollen store

and kill and eat the bee's own larva.

And this strange creature also has designs

on the bee's larva.

It's a thistledown velvet ant, another parasite.

When the bee leaves to collect yet more pollen,

the velvet ant slips in to lay her own egg deep in the nest.

Parasites like these are a real problem for the bees,

but because they're only concerned with their own nests

they don't look out for each other.

(bees buzzing)

Even with thousands of them packed together,

there's no neighborhood watch.

Bumblebees have solved that problem by becoming social.

A bumblebee nest is never left undefended.

It's always humming with activity.

Like termites, this is just one extended family.

But bee workers are all female.

All daughters of the queen.

She lays her eggs into specially prepared wax pots.

Right away, the workers move in to take care of them.

This army of workers all cooperate to build

and defend their nest.

And they also nurse the growing larvae,

their younger sisters.

By working together, insect societies can prosper and grow.

Though most of these colonies must begin life

with just a single parent.

The time of most danger.

(thunder rumbles)

A green tree ant, a queen, all alone.

For most kinds of ants, a young queen starting a new colony

hides in a crevice or a hole in the ground.

But a green tree ant lives in trees.

With fewer places to hide, she has no choice

but to stand over her first batch of eggs

and try to look intimidating.

(tense music)

With no help from workers or guards,

only a tiny fraction of new queens survive

to found a new dynasty.

But one day, if she's lucky, she'll be head of an army

of maybe half a million.

Now, working as one, they're the scourge of the treetops.

(ominous music)

Nothing is safe up here.

Even big insects are overwhelmed by sheer force of numbers.

These ants really show what's possible with teamwork.

If they come to a gap too wide to cross,

they work together to bridge it.

A few ants brace themselves as anchors.

Then other ants climb over their bodies

and take a firm hold.

Yet more ants pile on

until they have built the living bridge.

Now the army can stream across,

to lay waste to a new branch.

Legions of ants carry the prey back to the nest.

And their nests themselves, made of folded leaves,

couldn't be built without even closer cooperation.

(suspenseful music)

Each ant grabs the edge of leaf.

On its own, a single ant

isn't strong enough to bend the leaf,

but like a well trained crew of sailors hoisting a sail,

they all heave together to fold the leaf over.

Now all they need is a way

to fix the leaves in place permanently.

More ants arrive at the construction site,

carrying fully grown larvae.

And these larvae can spin silk.

The workers use them like glue guns,

moving them between the leaf edges.

Slowly building up more and more strands of silk

until they're thick enough to stitch the leaves together.

Before long, they've built a secure treetop home.

Most other ants build their homes below ground.

Even though they're more elaborate,

all that shows on the surface is a tiny hole.

But beneath the surface...

(gentle music)

These are aluminum casts of underground networks

of tunnels and chambers made by different kinds of ants.

The casts have been made by pouring molten aluminum

into the entrance hole of an abandoned nest.

Then digging out the solidified metal sculpture

to reveal ant art.

(gentle music continues)

This is another advantage of social living.

Working together, these insects can build

elaborate, secure homes

where they live and rear their extended families.

And from the safety of this base

they can set out to conquer the world.

Theirs and ours.

(traffic rumbling)

Ants are perfectly at home

in the heart of our biggest and busiest cities.

In fact, there are far more ants here than people.

13 different kinds of ants thrive on the streets

of downtown New York, where like us, they crave junk food.

Chemical analysis of these ants has shown

they're eating the same food as the people here.

Like us, they are hooked on burgers, hot dogs and bagels.

The most abundant are pavement ants.

They're tiny, just a fraction of an inch long.

But so efficient, they do a great job

in keeping the sidewalks clear of all the food we waste.

Along just Broadway and West Street, these ants dispose

of over half a million discarded potato chips every year.

These super societies can exploit any resource

so efficiently because they're always

in contact with each other.

This means they can profit quickly

from any opportunity wherever they find it.

Scouts are always searching for a convenient meal.

When these first ants find an all you can eat buffet,

they sample what's on offer.

Then return to the nest with the good news.

On their way back, they lay down chemical trails.

And now hundreds of workers can simply follow

these sign posted ant highways to the feast.

In no time, it's swarming with ants.

Each playing its part in the supply chain

back to the nest.

These efficient bands of foragers are crucial

to the survival of all these insect societies.

So every new recruit counts.

Another worker is about to join team bumblebee.

With a little help from her sisters.

She's a bit disheveled at first

but it doesn't take her long to dry off and fluff up.

And then she's ready to play her part

in keeping the colony well stocked.

(bee buzzing)

It's an awfully big world out there

and to be an effective team member

she has a lot to learn in a short space of time.

She'll probably only live for a month or so.

Bumblebee societies are fueled by pollen and nectar,

but there's a vast choice of flowers in this meadow.

How on earth can she ever learn which ones are the best?

(gentle music)

A young worker learns from other more experienced bees.

Even bees of different species.

If a honey bee thinks this kind of flower is good,

maybe worth checking it out.

The young bumblebee samples any flowers

that she sees other bees feeding on.

So it doesn't take her long to learn for herself

which are the best sources of nectar and pollen.

She soon becomes an efficient forager.

By now the pollen sacks on her back legs are bulging,

time to get these supplies back to the nest.

She scrapes the pollen into one of the storage pots,

and she's ready for her next mission.

Bumblebee colonies are small,

rarely more than a few hundred workers,

the bee equivalent of a small village.

But in some places,

bees build up much larger cities.

In the tropics, there's a year round supply of food

which feeds a thriving metropolis of stingless bees.

(bees humming)

They nest in hollow trees

and build a narrow entrance tunnel

which is constantly manned by guards.

Only members of the colony are allowed to pass.

The tunnel leads to a sophisticated, intricate nest.

It has graceful spirals of brood cells.

And the whole structure is braced by arches and struts.

But the most complex structures

are not made by bees or ants.

(go-away bird calling)

Not all termites tunnel through wood,

some build skyscrapers.

Using mud and feces mixed with saliva,

these mounds tower 10 feet or more above the ground.

On the termite scale, this is nearly double

the height of the world's tallest building,

but this isn't even their nest.

That lies mostly underground.

At the bottom of the tower,

a network of galleries packed with workers

and at the center, the queen, huge, bloated,

just an egg-laying machine.

(mysterious music)

Inside the tower, there's a network of tunnels,

but they're more or less deserted,

just a few maintenance crews repairing any damage.

So why have the termites made such an effort

to build this huge structure?

To answer that we need to see inside the tower,

which we can, using 3D scans that are built

up in the same way as MRI scans.

This is a real termite's nest

as if we could see through the mud walls

to reveal a labyrinth of tunnels inside the mound.

On the side facing the sun,

the air inside the tunnels heats up.

The warm air rises then sinks again,

down through the cooler tunnels on the shady side.

The sun creates a circulation of air

around the inside of the tower.

As the sun tracks across the sky,

it heats different parts of the tower,

so over time, the circulation changes.

The tower is a giant lung.

As the air moves through the tunnels,

stale air leaves the mound through pores in the walls

and fresh air flows in

while the termites all stay safe in their fortress.

But these castles of clay are not entirely secure.

The termites are not alone in the landscape.

(dramatic, tense music)

Not far from the termite mound,

an ancient baobab tree marks the site

of another underground city.

This one belongs to Matabele ants.

And the two greatest insect societies,

the ants and the termites, have been at war with each other

for millions and millions of years.

Matabele ants hunt termites.

And this is a raiding party.

(tense music continues)

The column is following a trail, laid down by their scouts.

And it's heading straight for the termite nest.

(tense music continues)

But this won't be an easy victory.

Termites have well-armed soldiers

and they fight hard to defend their home.

But resistance is futile.

The ants sting the termites in their heads

to paralyze their powerful jaws.

The termites are eventually overrun.

The Matabele ants have also suffered heavy casualties.

In ant colonies workers are normally expendable,

but not in this society.

Many of the ants aren't dead, just wounded.

And Matabele ants practice battlefield triage.

The fallen ants are assessed.

The fatally injured are left to die,

but comrades who were less badly hurt

are medevacked back to the nest.

Other ants bring home the spoils of war.

Back in the nest,

the casualties are treated by their sisters.

And then, even more unexpected,

(gentle music)

these ants produce an antimicrobial secretion

that they smear onto the wounds.

It prevents infection.

And ants treated like this,

more often than not make a good recovery

and live to fight again.

Once insect societies reach this level

they can take the ultimate step.

A queen honeybee never has to face the dangerous challenge

of starting a new colony without any help.

When she leaves the hive,

she's escorted by thousands of workers.

First, they form a temporary home,

a bivouac of living bodies.

(bees buzzing)

Somewhere deep in this swarm,

the queen is protected by a blanket of stinging workers.

Now she's safe, others set out to find a secure hole,

big enough to house the new colony.

A bit run down.

Too small.

But this looks perfect.

The workers report back to the swarm

and tell their sisters the good news,

by dancing.

The famous waggle dance is normally used by a worker

inside the hive to guide her sisters

to a good source of pollen or nectar.

But now the dance gives them directions to their new home.

The worker's dance on the vertical face of the swarm

but their waggle walk isn't straight up or down.

It's at a precise angle to the vertical and that's the angle

to the sun that the other bees will need to fly.

And the distance is given

by the length of the waggle walk.

GPS for bees.

Now the bees all know where they're going.

(bees buzzing)

They can abandon their temporary nest

and decamp to their new permanent home.

But even with such enhanced security

sometimes that's still not enough.

(ominous music)

Asian hornets specialize in hunting honey bees.

Honey bees deploy guards.

They must stop the hornet

storming the hive and destroying the brood.

(ominous music continues)

Some brave souls even face down their giant attackers.

It might look like a no fly zone out there

but the bees have no choice.

They have to leave the hive to find food for the colony.

And that means a dangerous flight through hostile air space.

Some bees are nimble enough to avoid capture.

But many more are not so lucky.

Alarm spreads through the colony.

A narrow escape, but in her panic she misses her landing.

A successful mission bringing in provisions,

but fewer and fewer make it back.

Asian Hornets are so ruthless

they can soon destroy a whole hive.

Honeybees in Europe

didn't have to face this menace until 2004.

When a single queen Asian hornet was accidentally carried

to France, hidden in a shipment of plant pots from China.

And from there, they spread rapidly

to threaten hives across the whole continent.

(somber music)

Simple carelessness threatens the very existence

of one of our oldest insect allies.

Honeybees have been important to humans for millennia.

Before we refined sugar,

their honey was the sweetest thing in our lives.

And now these industrious workers

pollinate many of our crops.

But they're not the only insects we depend on.

Bumblebees.

Hundreds of colonies of bumblebees are employed

pollinating tomatoes in vast commercial greenhouses.

In Queensland, stingless bees are given the job

of pollinating macadamia nut trees.

Even solitary bees, like these alkali bees

can be encouraged to nest in their millions

if farmers create the right soil conditions.

These are bee beds.

And in return for a home

the bees pollinate the alfalfa crops.

Our lives depend on these bees

and many other insects like them.

Around three quarters

of all our crops are pollinated by insects

and yet we're deliberately making their lives

almost impossible.

Bees along with most other insects

are struggling to survive in the world we've created.

Most of the flower-rich meadows have gone.

Plowed under.

The countryside has been drenched in insecticides.

In many parts of the world, insect populations have dropped

by three quarters in just the last few decades.

Vital pollinators like bumblebees are disappearing

across much of their range.

Meadows rich in flowers were once common

but now only a few remain.

Both flowers and insects have been forced to retreat

to the very edge of our world.

Places like the outer Hebrides in Scotland,

where land is still farmed traditionally

and creates a riot of wild flowers.

In Britain, this is now virtually the last refuge

of the most spectacular of all bees:

the great yellow bumblebee.

These remote sanctuaries are the only places

it can find the flowers it needs to feed its family.

The same story is being told all around the world.

Every day we lose untold billions of tiny lives.

Yet insects are amazingly resilient.

They've been around for well over 400 million years.

They even survived the mass extinction

that wiped out the dinosaurs.

If we learn to appreciate them, to value them

and to give them a chance, they'll always repay us.

They are after all,

the little creatures that run the world.

(dramatic music)