Empire of the Desert Ants Natural World

Like all good stories, this one has a dark and stormy beginning.

THUNDER RUMBLES

Arizona's blistering summer has come to an earth-shattering end.

This is the first rain to fall here in six months.

It heralds the birth of a new empire.

Imagine a world deep underground, ruled by a ruthless queen.

Over eight years, she and her armies will unleash a reign of terror.

Building an empire of epic proportions.

Eliminating rivals with brutal efficiency.

Thousands will perish in defence of her realm.

This is the story of her rise to power.

The morning after the storm,

a lone honey ant queen wanders the still-damp desert.

Triggered by the rain, she emerged from a distant underground nest

just a few hours ago.

Chance has carried her to Horseshoe Canyon,

a dramatic backdrop for her first, faltering steps.

The rain has softened the hard-packed soil

just enough for her to begin digging a nest.

Where she digs is perhaps the most crucial decision of her life.

If she picks a good spot, these excavations will become

the foundations of a great empire, but if she makes a bad choice,

she won't last for long.

With the odds stacked against her, she needs help.

It comes in the shape of another newly-emerged ant queen.

She is inspected with the formality her regal status requires.

The new recruit is allowed to join.

Usually aggressive towards one another,

co-operation like this is very unusual for most ant species.

More recruits are drawn to the scene,

perhaps attracted by pheromones.

In just a few hours, the queens have sealed themselves into their bunker

and a life of perpetual darkness.

For the founding queen,

sharing her nest with all these rivals seems like madness.

But the economics of desert survival is a numbers game.

And for the moment at least,

this communal life is the key to her future.

Each queen now lays her first batch of tiny eggs,

each no bigger than a pinhead.

Many new nests contain two or three queens,

limiting the initial brood to less than 100 eggs.

But these ten queens have produced well over 300 eggs.

And when they hatch, the colony will become an instant superpower.

For the founding queen, this is the main advantage to taking in lodgers.

If the eggs are not kept clean and coated with antibiotic saliva,

they would quickly be smothered by fungi and rot away.

The eggs soon hatch.

Fed by the queens, the voracious larvae grow quickly and then pupate.

A few weeks after the eggs were laid,

the first tiny, pale workers emerge from these silky cocoons.

All ant workers are female and sterile.

Unable to reproduce themselves,

their sole purpose in life is to serve the queens.

They darken as their bodies become harder

and then, they are ready to take up their duties.

Some stay underground,

tending to the queens and to the remaining brood.

Others head for the surface,

for a first look at their strange new world.

Their entire kingdom encompasses just a few square metres.

They must get everything they need to survive from this territory.

In the darkness, the queens are slowly starving to death.

They have been breaking down their own muscles to stay alive.

So, any food the tiny workers can bring home is crucial.

They struggle with huge loads.

These meagre supplies allow the queens

to regain some of their strength and to start laying more eggs.

By pooling their resources,

the queens have survived their first major challenge,

but this coalition can't last.

Tensions are already on the rise

as the queens jostle for position within the royal court.

The weaker crouch submissively before the more dominant,

including the founding queen.

So begins the delicate manoeuvring

that will soon take on a deadly significance.

Those at the bottom of the hierarchy

have little chance of surviving the coming trials.

Another struggle for control is also beginning, above ground.

The Corral nest is not the only one in Horseshoe Canyon.

The desert floor is littered with similar sized colonies

and there's not enough room for all of them.

Now, the darker side of the honey ants emerges.

It's time for the Corral colony to mount a pre-emptive strike

on its nearest neighbours.

Flush with victory, they're ready to take on all comers.

Harvester ants are big and heavy-jawed.

But honey ants punch well above their weight.

Their weapons of choice?

Nipping jaws and formic acid, sprayed in fine droplets

from the tips of their abdomens.

This has a devastating effect on anything it touches.

Still only a few hundred strong,

the Corral colony is starting to flex its muscles.

For the queens, the real benefits of joining the coalition are clear.

There's strength in numbers

and the nest with the most firepower always wins.

Soon, the Corral colony has destroyed

all the other honey ant nests in the neighbourhood.

The foundations of the empire have been laid.

Underground too, events have taken a darker turn.

One of the queens lies dead in the royal chamber.

It's not clear why, but the workers

have started singling out the weaker queens for special attention.

At first, it's all very subtle -

one isn't fed so often, or cleaned as diligently.

But then, the workers start bullying and harassing their chosen victim.

Finally, it spills over into direct attack,

and the workers tear the chosen queen to pieces.

Nothing can go to waste, even a royal carcass.

Workers carry hungry larvae over to feast on the dead queen,

including many that must have been her own offspring.

As the weeks pass, the revolution continues.

Only the most dominant royals seem immune to attack.

They just watch and wait,

as the workers go about their gruesome business.

Winter means hard times for all the canyon's inhabitants.

To conserve energy, the colony has more or less shut down.

No-one ventures above ground to gather food,

few eggs are being laid and the workers go onto reduced shifts.

They could be down here for six months or more,

eking out a living on the most meagre of supplies.

By winter's end, only the two strongest queens are left standing.

In some honey ant nests,

multiple queens can work in coalition for years.

But not in this one.

It's time for the final reckoning.

Perhaps sensing some weakness in one of the queens,

the workers move in for the kill.

Compared with the slow, lingering death

of the queens purged earlier in the winter,

this is a swift and brutal assassination.

The founding queen now has complete control of the nest

she began to dig all those months ago.

All the workers, no matter who they are descended from,

must be loyal to her.

But to be absolute ruler is not enough.

She needs to produce heirs,

and to do that, she first needs to build up her empire.

The spring rains have transformed Horseshoe Canyon.

It's time for the Corral colony to resurface

after their winter of deprivation.

The swelling ranks of workers leave the nest each day to gather food.

They now range over an area the size of a tennis court,

and nectar is their main food.

Honey ant workers have expandable abdomens,

reservoirs that allow them to carry liquid food back to the nest.

It's crucial they gather as much as they can

during this brief period of plenty.

All this activity around the nest

has attracted some very unwelcome attention.

A horned lizard has taken up temporary residence

on their doorstep.

It can eat hundreds of ants in a single sitting.

It will only move on when the sun gets too hot,

or it's eaten its fill.

But for the queen, these losses are more than offset

by the production of new workers, deep underground.

And now, she's starting a new strategy.

The queen is putting together an army of specialists

that will form the backbone of her growing empire.

Pumping out an egg every hour, the colony now numbers over a thousand.

Her kingdom is co-ordinated largely by pheromones,

cocktails of complex chemicals passed from mouth to mouth.

They are used to direct every activity within the nest.

Under the influence of these royal commands, some larger workers

are about to take on a very special role in the colony.

Returning foragers seek them out

and force-feed them load after load of nectar.

Their abdomens become distended,

until they are the size of garden peas.

As they fill, these super-sized ants, called repletes,

haul themselves onto the chamber roof, to avoid being damaged.

They become prisoners in their own nests.

Once hanging, they refine the nectar,

removing water, concentrating it into a thick honey.

Then, when supplies run low

during the long winter, or in drought years,

these living larders regurgitate their contents

to feed the hungry colony.

It's the honey ant's elegant solution to desert survival.

The queen now heads a formidable and efficient machine.

But as the riches of spring dwindle away,

this machine is stalling.

This time of year can be ferociously hot in southern Arizona.

Despite the intense heat, the topside workers must keep foraging,

to feed the queen's soaring ambitions.

With the flowers gone, there are few easy meals left.

The oak trees near the nest now become the focus of activity.

Gall wasps have infected the oak's acorn crop.

Their larvae use the plant's own tissues

to create for themselves a protective nodule, a gall.

The growing galls secrete a sugary liquid

that the worker ants can't resist.

By attracting the ants in this way,

the gall wasp larvae gain a degree of protection

from predators and parasites.

But these few, precious drops will never be enough

to satisfy the colony's spiralling demands.

The Corral colony workers need to look further afield.

Casting the net wider means taking bigger risks,

but holds out the possibility of huge rewards.

The gatherers are about to become hunters.

Scouts soon stumble upon another honey ant colony.

The Corral colony sends in a raiding party.

It's a fast, co-ordinated attack.

The smaller colony doesn't stand a chance.

The spoils of war are dragged out into the sunlight.

Not everyone gives up without a struggle.

But resistance is futile in the face of such overwhelming odds.

Nothing is left behind.

Eggs, larvae, workers, pupae are all carried back to the Corral nest.

Loaded with honey, the repletes are the most valuable plunder of all.

Some are dismembered and drained underground.

Others are dragged to the surface

and hauled back to the victors' nest.

But they can be a real challenge to manoeuvre across no-man's land.

This is how most clashes between honey ant colonies are played out.

Invariably, the winner is the one that has the superior numbers.

The raid couldn't have come at a better time.

It's filled the Corral colony's larders,

ensuring its 2,000 inhabitants

will be well-fed through the approaching winter.

But just as importantly,

a rival nest that could have threatened the queen's reign

has been eliminated.

For the next few years,

life in the canyon follows its own particular course.

The seasons ebb and flow.

But through it all, the Corral queen continues to build her empire.

The queen now reigns over a formidable force

that dominates this part of Horseshoe Canyon.

Together, they have built a complex underground city.

Just beneath the surface

is a network of chambers and linking tunnels.

From these, a single, vertical chimney extends two metres

down into the concrete-hard earth to reach the colony's nerve-centre.

This deep, the soil is still moist,

the air cool, despite the soaring surface temperatures.

This is the very heart of the queen's empire.

This year, the colony has reached a tipping point.

For the first time in its six-year history,

there are male as well as female ants in the nest.

The Corral queen has finally succeeded

in producing her first generation of winged princes and princesses.

All the work of the queen and her army over the last few years

has been to reach this one, pivotal moment.

Soon, these winged royals will fan out across the desert

to establish new colonies.

They have already been packed in down here for weeks.

Workers keep them fuelled up

and their wings in prime condition for their maiden flight.

All they need now is a trigger, to send them on their way.

And that trigger is brewing high in the desert sky.

THUNDER RUMBLES

Around here, it's called the monsoon season.

These torrential downpours can dump several centimetres of rain

in just a few hours.

The normally hard ground is softened by the deluge.

Over 180 ant species are found here

and this is the moment most of them have been waiting for.

The air is filled with millions of flying insects...

..as virgin queens and male consorts

seek each other out.

The mass emergence continues throughout the afternoon.

As the day begins to cool, the time has finally come

for the Corral honey ants to put in an appearance.

Workers pour out to secure the perimeter of the nest-hole,

creating a protected launchpad.

The queens and much smaller males move up through the tunnels

towards the surface and out into the light.

Still deep underground,

the queen won't witness these momentous events,

but her winged sons and daughters are about to spread the royal line

far across the desert.

In a few frenetic minutes, hundreds take to the skies...

..mate with the other honey ants

emerging from nests along the canyon...

..and then tumble back to earth.

Most will perish within a few hours.

They can meet their end in many different ways.

The massive rate of attrition is why the Corral queen

must produce so many winged offspring.

Like so much else in honey ant life,

starting new colonies is all about numbers.

Some even get picked off by other ants.

The weak and the injured are quickly recycled.

Despite such heavy losses,

hundreds of new honey ant nests will be excavated along the canyon.

These queens are the lucky ones,

retracing the steps the Corral queen took six years earlier,

when she first landed here.

But few will last as long, or be as successful.

For now, their main concern is to get themselves underground,

before the soil dries and becomes unworkable.

By the next morning, the emergence in Horseshoe Canyon is over.

There won't be another until it rains again next year.

This summer,

the Corral queen has played the numbers game to perfection.

There's a good chance some of her daughters will have survived

long enough to start their own colonies,

and her reign is far from over.

With luck, she could live for another 15 years.

But after this year's triumph,

the Corral queen's luck is about to change.

By the eighth year, the colony's fortunes have plummeted.

The rains have been sporadic and light.

The streams have run dry.

The vegetation parched.

The canyon is held tight in the grip of drought.

The intense heat is making life

almost impossible for the Corral colony.

The workers run the risk of being cooked alive,

if they stay out foraging for too long.

The only way to survive is to take repeated time-outs

from the lethal heat.

Temperatures a few centimetres above ground

can be several degrees cooler than at the surface.

So, the ants must climb or die.

A few minutes up here,

and they've cooled enough to risk venturing back down

to resume their search for food.

Even the wind brings no respite to the hard-pressed colony.

As the scorching air swirls around the canyon, getting back

to the sanctuary of the nest can become a life or death struggle.

With so little rain, the food supply has dwindled to almost nothing.

The canyon is slowly turning into a dustbowl.

After enjoying years of success,

the queen is now facing her most severe challenge.

No winged ants have been produced this summer.

Egg-laying has slowed to a trickle.

Under the intolerable stress,

even the precious larders are being drained.

The Corral colony is no longer the force it was

and for the first time, the queen is vulnerable.

By late summer, the Corral tanks

contain the only standing water for miles around.

The canyon's more mobile insects are drawn to this one, last oasis.

For those able to travel, this water is a life-saver.

Bees and wasps can carry the water back to their distant nests.

But this tiny pool of water

lies just beyond the boundary of the Corral colony's territory.

With no end in sight,

such desperate times call for desperate measures.

As the search widens, a small group of Corral workers

head towards the trough.

This is unfamiliar ground for them

and they are heading toward disaster.

Near the trough, they stumble across other honey ants

and then, a nest entrance.

It's only 40 metres from the Corral colony,

but that's been enough to keep the two nests in mutual ignorance

for all these years.

These new honey ants are unlike any the Corral workers

have encountered before.

They are big and aggressive.

Instead of backing down, they meet the challenge head-on

and the encounter begins to escalate.

They begin the delicate posturing

that allows them to assess each other's strengths and weaknesses.

It soon becomes clear

that this Trough colony is the stronger.

Perhaps living close to permanent water

has given them a crucial advantage.

For the first time in its history,

the Corral colony may have met its match.

This is not good news.

Increasingly excited,

one of the Corral workers fires poisonous spray at the nest.

But this only galvanizes the Trough ants

into launching an all-out counter attack.

Sensing the worst,

the Corral workers begin to fall back towards their own nest.

The Trough workers go on the offensive.

The retreat quickly turns into a rout.

Stragglers are picked off.

The fight is carried right to the entrance of the Corral colony.

Even here, on their own doorstep, they can't hold their ground.

The attacking Trough workers drive on into the nest.

As news of the attack reaches the Corral queen,

she withdraws to the deepest chambers,

her entourage of nurses in tow, carrying the valuable brood.

The battle spreads down into the tunnels.

Slowly, inexorably,

it spreads down through the shafts,

towards the deeper part of the nest.

The repletes are slaughtered...

..or dragged away to be eaten later.

Some dead workers are carried off for processing.

The invaders take everything, from eggs to newborns.

They empty chamber after chamber.

Finally, the invaders overcome the last resistance

and break through into the royal bunker.

The Corral queen and her broods

are trapped and completely helpless.

Held by each leg, the queen is on the rack.

First stretched,

then dismembered.

It is a gruesome and ignominious end

for this once-great ruler.

In just a few hours, the Corral colony has been annihilated.

The nest, emptied.

Too late for the Corral colony, the drought finally breaks.

THUNDER RUMBLES

A great storm heralded the start of the Corral queen's story

and now, eight years later,

another marks its brutal end.

But somewhere out in the desert,

the queen's royal daughters are fighting their own battles,

continuing her dynasty.

The queen may be dead, but her empire lives on.