Original subtitles

When the sound of buzzing fills the air in Central

Europe, it's summer, high season in the insect kingdom.

A time to feed and a time to breed.

But, as it gets colder,

life gets tough for insects.

Some birds head south while some mammals hibernate or

endeavor to survive, but where do all the insects go?

It's late summer, harvest time.

Buzzing and humming fills the air.

Insects gather nectar and pollen.

The color and shine of ripe fruit proclaims that they're ready to be eaten.

Apple trees are the star attraction here. Their sweet fruit

provides a chance to load up on calories before winter

comes. It's heaven for many hungry insects.

Each has evolved its own special way of dealing with the

coming winter. Their paths will soon separate as they use

different strategies to survive.

Fallen apples are a favorite of hornets. Although adult

hornets are predators, the juice of apples is an energy-rich

food they don't pass up. Gathering this food source is the

fuel to prepare their colony for the winter. Hornets often

build their nest inside hollowed trees.

A guardian hornet at the entrance checks who's coming and

going and fans fresh air inside. The nest construction has

been underway since the spring. Workers constantly expand

their home with a pulp made of chewed wood, but this

residence isn't permanent. The colony will only live

here for this one summer. Inside the nest with its single

entrance is the nursery, which fills the entire structure.

There's no food storage here, and the workers

tirelessly feed the larvae the harvested apple juice.

Residing over the colony is the much bigger queen.

She continuously lays eggs, each into its own cell. Now in

late summer, the nest is home to as many as 700 workers.

This is their peak population, but none of the workers and

not even the queen will survive the winter, but their hard

work will ensure a new queen and a new colony next spring.

Right next door, there's another outpost of the insect

kingdom, a honeybee hive. Bees have a different strategy

than the hornets. Their plan is for the whole colony to survive the winter.

Workers with yellow pollen sticking to their back

legs return to the hive to unload their bounty.

But some members of the colony are barred from entering.

At the hive entrance, a cruel drama is unfolding ahead of

winter.

Guards stop all the drones, the male bees, and ruthlessly

expel them. Now that the mating season is over, all drones

are expelled from the hive, since they are no longer of any

use. Drones are unable to feed themselves, so would be a

drain on the hive's food reserves. They're left to starve

in exile, sacrificed to ensure the colony survives winter.

Meanwhile, the worker bees busily stock up on winter

supplies. Unlike hornets, bees have vast areas of the hive

dedicated to storing food. Some cells hold protein-rich

pollen, while others hold nectar, which will thicken into

honey.

These stores are necessary to support the

hive, which can be home to up to 60,000 bees.

While the queen can live up to five years, her workers will

only live for six frenetic weeks in summer, preparing the

hive for winter.

It's also that these larvae can become winter bees, which

can live up to six months, ensuring the hive survives the

cold season.

The days still feel pleasantly warm. But as the sun sets, temperatures comply.

Morning arrives, clad in a layer of fine, cool mist.

And dew laces leaves, blossoms, and even the wings of

dragonflies. Like all insects, they are cold-blooded, their

body temperature changing with the air temperature.

The cold night leaves them stiff and unable to

move. They sunbathe to reach operating temperature.

Most adult dragonflies live for only one summer, dying when winter sets in.

It's their larvae, known as nymphs, that survive the winter.

The nymph lives underwater, and depending on the species,

can remain there for up to four years before leaving the

water to become an adult dragonfly. It breathes by drawing

water into its body and over internal gills. In contrast,

the great diving beetle must visit the surface for oxygen.

It captures air under its wings like a scuba diver,

and can then stay submerged for longer periods of time.

Above water, as fall approaches, other species

of the forest are just reaching maturity.

Mushrooms stretch their caps out of the ground, spreading

their spores and propagating the next generation.

They spend most of the year beneath the

earth's surface as mycelium, a root-like weave.

Still deeper under the forest floor, a strange creature is stirring.

This is the larva of a famed beetle. It looks nothing like

its parents, and to the untrained eye, there's no clue to

the animal it will become. The larva lives underground for

up to six years, feeding on decaying wood and building up

fat reserves. The insulated earth provides a perfect home,

especially in the cold winter. After about five years of

growth as a larva, it digs out an underground chamber in

the soil to begin a dramatic transformation. With the early

autumn, this larva prepares to pupate, the final stage

of its metamorphosis, the jaw structures revealing the

impressive adult it will become, a stag beetle.

Autumn paints the leaves in a rich palette of colors. The

fruits of the forest ripen, only to be hidden by a jay in

his winter larder. The dormouse forages for beech nuts,

life -saving fat reserves for the long winter sleep.

Fog dances, blanketing the woods.

Leaving the valley cloaked with mist.

The meadow saffron or autumn crocus emerges, a rare splash of vibrant color.

As the weather grows colder and wetter, the hornets embark

on some home improvements to their nest ahead of winter,

reducing the size of their front door to prevent heat. And heat loss.

But they're doomed. Unlike their cousins, the honeybees,

neither their colony nor their nest are designed to

stockpile supplies and keep them warm during the cold winter

months. In the nest, significantly fewer workers are now

active.

But there's still a gruesome job to do. They drag live larvae from their cells.

And dump them outside the nest to die.

They no longer need new workers.

Outside, the larval cemetery grows.

A lucky few larvae still receive food. They're the only ones

left in the colony who have a chance to survive, as next

year's queens.

As the hornets clean house, ladybugs prepare for the big chill.

With no nest to speak of, they need another way

to survive the winter cold. They hunt for shelter.

Following aggregation pheromones to nooks and crannies

between boulders and wall cracks. In popular spots, they

often gather in the hundreds. This helps reduce dehydration.

They are one of the amazing creatures capable of producing a

type of antifreeze, which allows them to cope with

temperatures as low as minus 10 degrees Celsius. In their

secure niches with antifreeze pumped through their bodies,

they will cease to eat and enter a type of suspended

animation. They'll stay here for months, not venturing

outside to forage even on warmer winter days.

As fall progresses, cranes are among the many species

of birds flying south, where food is easier to find.

In northern climates, barely anything blooms in fall,

except the ivy, which unfurls its most modest blossoms.

Butterflies and bees, wasps and hoverflies arrive in droves,

attracted by the last food source before winter tightens its

icy grip. The red admiral tops up its energy reserves on

nectar, ready for an epic long-haul flight. It's one of the

last butterflies seen before winter, and just like

migratory birds, it flies south for the cold season,

leaving central Europe to travel an incredible 1,000 kilometers.

They cross alpine passes over 2,500 meters high to start

a new generation of admirals in the frost-free climes of

southern Europe. While they're heading south, groundhogs

retreat into sometimes elaborate padded nest chambers to

hibernate until spring.

North of the Alps, autumn still has some golden days in store.

Vineyards glow, and the fall sun ripens the final grapes of the season,

which prove irresistible to the last surviving hornets. The

fermenting grapes provide a drunken farewell feast for their

final days of life.

Only the new young queens that have emerged have any chance

of surviving the winter. Like many insects, they take

shelter deep underground, where they're protected by the insulation of the earth.

There's the promise of new life here, too.

A clutch of tiny earwig eggs lies in an underground incubator.

A tasty meal for an earth runner, a predatory centipede.

But the mother of the eggs is here to protect them. The

earwig is a dedicated mother, a rarity in the insect world.

Agitated by any trespassers, she spreads her pincer, ready to defend her offspring.

The intruder retreats.

An earwig clutch holds up to 70 eggs.

Every one barely one and a half millimeters long, smaller

than the head of a matchstick. The mother constantly brushes

the eggs with her mouthparts.

Cleaning off molds and keeping the clutch

damp so it doesn't dry out in the winter air.

Unusual for an insect, she'll care for her clutch throughout the cold season.

In woodlands, falling levels of chlorophyll turns the leaves

from green to gold. In the clearings, the roars of rutting

red deer can be heard.

It's a few weeks since the alien larva transformed in its

cozy chamber, 30 centimeters underground. It's now a fully

developed male stag beetle. He lies quietly on his back,

in his mother's arms. In his cradle, barely moving to save

energy.

He'll remain hidden in the warmth and security of his little

chamber, safe from the ravages of the winter, until spring

comes.

Because outside, it's getting cold. The dormouse has long

since withdrawn into a cave for winter sleep, curled up into

a ball to stay warm.

As the temperature plummets, the fog turns into

hoarfrost, a frozen water vapor that covers the landscape.

Most insects have disappeared.

But for some, the first frost is an incredible wake-up call.

As soon as the temperature drops below freezing and night

falls, a spectacular event unfolds. The winter moths emerge.

At first, the males of these two centimeter long insects

swarm around the trees.

Later that night, winter moth females crawl up the tree

trunks. They look like a completely different species. It's

time for them to find a mate, but their small stub wings are

useless for flying. Instead, they stay put and emit strong

smelling pheromones into the air, which can attract

males from a distance of up to one kilometer. In sub-zero

temperatures, the oddly matched couples mate.

Shortly after, the females lay their fertilized eggs in cracks in the bark.

Both males and females die within days, without eating a

single meal. They emerge only to produce their eggs, which

will withstand the winter cold and hatch in the spring.

The first snow falls.

Underground, insulated from the icy outside world, the

temperature is slightly warmer and more stable, the key to

survival for underground insects. A tiny spider has entered

the breeding chamber of the earwig. It's got its eye on a

tasty egg.

The mother is already on her guard.

She alternates between cleaning...

...and attack.

But the spider won't give up. The mother attacks again, raising her tail to strike.

A blow from those pincers could kill.

The spider retreats, leaving the clutch of earwig

eggs unharmed. Mother and young are safe for now.

The snowy landscapes look tranquil and beautiful.

But winter can be deadly.

Mammals have evolved to have a thick, life-saving layer of

fur. It's a struggle to reach food, and the cold means they

need more energy than usual.

As the temperature plunges,

streams start freezing.

But under the ice, the water temperature is relatively warm,

and the stream bed never gets cold. It never gets colder

than four degrees Celsius.

The dragonfly nymph has retreated here for the winter. The

cold dramatically slows its metabolism, so it lies still and

waits, surviving off what it ate earlier in the year. It

won't need to eat again until spring. This same tactic is

also used by the great diving beetle. The ice stops its

surfacing for air, but there's enough stored in these scuba

tanks under its wings to last right through winter. A slower

winter metabolism requires less oxygen and no food. They

calmly lie on the stream bed, waiting for the thaw.

A thick layer of snow now covers the land. Somewhere under

this white blanket, the young hornet queen has buried

herself under the earth and endures winter.

Her former home, long abandoned.

But the old hornet nest has a visitor.

The shrew can't hibernate. It must stay active, hunting

for insects all year round, or it will freeze to death.

It scours the empty hornet nest to find some dead

larvae, a nice package of protein in the lean winter.

Next door, the hive is humming. In fact, the colder it gets,

the louder the buzzing. The bees huddle together in what's

called a winter grape for warmth. Even in sub-zero

temperatures, it's a cozy 20 degrees Celsius on the inside.

The colony has shrunk, but it's still alive. It still has about 20,000 members.

The bees flap their wings to increase their body temperature

and generate heat, like thousands of tiny stoves.

It's warmer at the center, so they rotate places to

make sure every bee gets some time in the hot spot.

The heat from their beading wings melts the honey they

stored in the summer. The honey is stored in the beehives.

They pass it to one another from mouth to mouth.

Thanks to teamwork, somewhere in the middle of the teeming

hive, the most important member of the colony survives,

their queen.

As temperatures creep above zero, the worst of the freeze retreats.

Spring is still a long way off, but it only takes the

faintest hint of warmth for snowdrops and crocuses to bloom.

The tiny hike in temperature is enough for life to start

stirring underground. Brown dots appear in the earwig's

eggs.

A shell bursts open, and a baby earwig struggles to emerge.

The brown dots are the eyes.

Like the dragonfly, the larva is called a nymph, a poetic

name for a larva that already resembles its imposing

parents. It's still quite transparent.

But with every casting of its skin, it will look more and more like its mother.

Above ground, sunshine unfurls the leaves and blossoms, a

supply of food for the first bees venturing out. They must

replenish the depleted stocks of food back in the hive.

They return home to a gruesome scene.

Inside, the colony prepares for summer. Having survived the

winter in the safety of the hive, the queen is already doing

her job of repopulating it. She lays one egg after another,

as many as 2,000 a day. By the end of the year, she will

have laid up to 200,000 eggs. Every egg has its own private

cell. There, the workers look after it until the larva

reaches the pupa stage.

In another cell, the big moment has arrived.

Attended by workers, a summer bee is emerging.

It must chew its way out of its waxy cell.

Like all new workers, it will spend its first few days

helping to groom the queen, before flying out to forage for

food.

Outside, greenery bursts forth as the temperature rises.

Taking advantage of the warmer weather, the earwig mother

has foraged above ground and brought home a breakfast of

fresh leaves for her brood. Earwigs aren't just predators,

they're omnivores.

And the growing nymphs are always hungry.

Their shells are still translucent, so as they eat,

their vegetarian meal turns them a vivid green.

Above ground, the weather springs a surprise.

It's not falling blossoms, but the return of snow.

Unwilling to give up yet, winter mounts a comeback.

The sudden chill could spell disaster not

just for blossom trees, but also for insects.

In the breeding chamber of the earwigs, the return of winter brings a sacrifice.

But winter only has a brief reappearance.

As the days get longer, love is in the air. Birds choose their partners.

And the first chicks hatch.

The blooming season brings food from nearly all over the

world. There are many species. Marsh marigold, catkins,

and aquatic plants.

As the mercury surges upwards, different species of

dragonfly nymphs emerge from the water to climb the reeds

and clamor out of their exoskeleton.

After pumping up their wings and allowing them to harden,

they are ready to fly and

find a mate.

Out in the meadow, a young hornet queen who survived the

winter has found a suitable tree hole to start a new colony.

She must start from scratch, single-handedly, build the

nest, forage for food, lay the eggs, feed her growing

larvae. It's a round-the-clock job, and it lasts for weeks.

Finally, 14 days after laying her first egg, the hard work pays off.

Returning to the nest with food, she finds her first

hatchling, which immediately starts looking after its

sibling larvae.

Now, the queen has a nanny in the nursery.

She's still the breadwinner, bringing food she pre-choos for the infants.

But they both share feeding duties.

A few days later, she gets a second helper.

There are many hungry mouths to feed.

Two or three days after they pupate, new workers will join the hunt for food.

Treesap is perfect, full of energy-rich sugar.

In the forest, many trees are budding. A giant oak unfurls

its leaves. The winter moth caterpillars have emerged on the

oak tree. They're little more than feeding machines. They

must consume all the calories they can, so that when they

briefly emerge as moths next winter, they'll have enough energy to meet.

On the forest floor, a fire salamander appears, having

survived the winter sheltering in a frost-free fissure or

cave.

A dormouse wakes from its hibernation. And finally, the stag

beetle that waited patiently on its back now emerges from

its subterranean winter home. Its first instinct? To find

a mate. He picks up the pheromones of a nearby female. But

he's not the only one attracted to her scent.

When two males meet, the stage is set for battle.

The male's antlers are actually part of its jaw. But

like the deer they take their name from, they use them as

weapons.

The aim is to throw their rival on his back, or right out

of the tree. The winner's prize is to mate with the female.

A male stag beetle is enormously strong for its size, able

to lift 100 times its own weight. Its jaws exert huge force.

A bite can kill its rival.

This loser is lucky. He survives the fall.

Nourished on the sap of growing trees, the hornet colony

expands. Dozens of workers now bring not only food, but also

decaying wood bitten off with their sharp jaws.

Mixed with saliva, and thoroughly chewed, the wood

pulp is the bricks and mortar for the growing nest.

These intricate castles can reach as much as half a meter

high. The workers work hard to make their way to the nest.

The workers constantly add new floors and chambers. When

it's finally ready, this year's new queen can fulfill her

primary role. To fill the cells with her eggs.

Laying his hungry work, so the workers regurgitate

the food they have gathered to feed their queen.

It's all to ensure their colony grows and thrives.

Becoming a hornet nation for one brief summer.

Colour and life is everywhere now. Providing a sumptuous

feast for the baby earwigs that forage above ground.

And the red admirals are back. Not the ones who migrated

south, but the ones who came from the north. They moved

south before the winter, but a new generation hatched in

southern Europe and now back in the north for the summer.

Buzzing and humming fills the air. A time to feed,

to breed, and to prepare for the next winter to come.

Music