All language subtitles for Insect Worlds 2of3 1080i Making Worlds

Our planet is the greatest
living puzzle in the universe.

A collection of worlds
within worlds.

Each one a network of relationships
and connections

between all their living parts,

leading to the diverse
and complex world we live in.

And at the heart
of many of these worlds

is a very special group of animals...

..the insects and their
close relatives, the arachnids

and crustaceans -
classed together as the arthropods.

Together they account for 80%
of all animal species on our planet.

In these three specials, we're going
to explore the connections

and relationships
that they have with us,

our planet...

..and with each other.

Ultimately to understand
how this group

hold the key to life itself inside
nature's microworlds.

At least one species of Arthropod

can be found
in every microworld on Earth.

From baking deserts
and lush rainforests...

..to open oceans...

..and dark caves.

And although seemingly insignificant
in size...

..the influence they have
on our planet is immense.

But to understand how arthropods
have come to play such a vital role,

we must explore
a wide variety of ecosystems.

And we'll investigate
the arthropods'

greatest influence of all.

Could they be responsible
for the richness and diversity

of nature's many microworlds?

There's one microworld

where the impact of a single species
of arthropod is evident -

the Argentinean Pampas Grassland.

A landscape that's been created
almost solely by one tiny creature.

Grass cutter ants.

These insects are only
one-and-a-half centimetres long

and yet they achieve something
few animals are capable of.

Through their activities,

they have completely altered
their own environment.

Grass cutter ants are the farmers
of these grasslands

and like farmers,
they shape the vegetation.

Each year,
a single colony will harvest

over half a tonne of grass cuttings.

Surprisingly,
these ants don't actually eat grass,

but they have found a way
to cultivate their crops

and this happens underground.

Their nests dominate
the subterranean environment

with tunnels extending
over seven metres deep.

Here they share their chambers

with a special fungus
that's found nowhere else on Earth.

And this fungus can digest grass.

The ants feed their grass harvest
to the fungus

and in return
the fungus produces edible gardens.

These fungus gardens
are prolific enough

to feed the whole colony of ants.

All 5 million of them!

But their impact does not end there.

They also alter the landscape.

The fungus releases carbon dioxide -

lethal in large concentrations.

But the ants have a clever way
of combating its build up.

They construct massive towers
that help draw fresh air in

and suck stale air out,

effectively acting like
air conditioners.

These grass cutter ants,

with their incredible building
and farming skills,

have completely shaped
this microworld.

An ecosystem which, without the ants,
would not even exist.

The arthropods' domination
of an environment

is not always so complete

but it can have
just as big an impact.

In the most expansive ecosystem
on our planet,

an arthropod plays such a key role
that, without it,

the largest animal that has
EVER lived could not exist.

Life within the ocean evolved 3
billion years prior to life on land.

And today it's the home of 230,000
marine animal species.

Arguably
the most important of these,

the ones that are the key

to this whole interconnected
oceanic ecosystem are...

..the krill.

Found across the world's oceans,
from the tropics to the poles,

these arthropods fuel the ocean's
food chain.

The reason they're so vital
to sustaining life in the oceans

is their ability to consume
phytoplankton on a massive scale.

Phytoplankton
are microscopic organisms -

the sea's equivalent of grass.

So vast in number,
their blooms can be seen from space.

And krill are the ocean's
biggest consumer of phytoplankton.

Just one species,
the Antarctic Krill,

has a combined mass
of 379 million tonnes.

That's over 90 million tonnes
heavier

than the biomass
of the whole human race.

Few large animals can feed
on the ocean's phytoplankton

but they can feed on krill.

So these tiny arthropods
are a critical link

at the bottom of the ocean's
food chain.

The krill feed the fish,
which feed bigger fish,

which feed the birds and seals,

and so the food chain continues.

But sometimes the number of links
in the chain is remarkably small.

The blue whale.

The biggest animal
that's ever lived on the planet

has short-circuited
the ocean's food chain

and gone straight for the krill.

Rather than teeth,
these ocean giants are equipped

with a fine mesh of bristles,
called baleen,

which allow each whale to filter out
up to 40 million krill a day.

Without these tiny arthropods, the
blue whale may never have evolved.

Arthropods play a pivotal role
in the underwater web of life

but their influence
isn't just confined to the sea.

On dry land, arthropods are also
the key food source

for a whole host of other animals.

Birds...

reptiles...

amphibians...

and mammals.

Like the blue whales,
there are also land-based animals

that have special adaptations
for feeding on arthropods,

like the pangolin
with its powerful digging claws.

And the giant anteater
that has a 60cm long tongue,

perfect for reaching into
ant and termite mounds.

But there's an even more surprising
group of predators

that rely on arthropods
for their food.

And they don't even belong
to the animal kingdom.

One species can be found
in the boglands of Scotland.

The soil here is waterlogged
and lacking in vital nutrients,

especially nitrogen.

Under such conditions
few plants can grow

but thanks to the presence
of arthropods,

one species has found a way.

This strange-looking plant
is the sundew -

so named because of the dew-like
droplets on its leaves -

but they're also extremely sticky.

Their sweet smell
attracts many insects.

As mosquitoes emerge
from the boggy water,

they're drawn straight into
a sticky trap.

Sensitive to touch, the tentacles
quickly wrap around the prey.

Eventually, the insect dies
in the sticky fluid.

With the help of enzymes,
its body is absorbed by the sundew.

Without insects,
this plant would not survive.

And without arthropods, many of our
planet's food chains would collapse.

While the arthropods' role
as a food source

is crucial to the survival of
millions of animals

and even some plants,

it's only a part of the giant jigsaw

that makes our planet's
ecosystems tick.

Nutrients form
the building blocks of life.

So, for a microworld
to maintain its balance,

it's vital that these nutrients
aren't wasted.

This is where our next team
of arthropods

play a critical role
as the recyclers.

Within the rainforests of Borneo,

a giant cave is home to a staggering
3 million wrinkle-lipped bats.

With over 37 tonnes of insects
consumed every night,

a huge mound of bat droppings
builds up.

But this waste isn't wasted.

Reaching up to 100 metres in height,

this nutrient-rich mound fuels
a seething mass of cockroaches.

One of the densest concentrations
of cockroaches in the world.

Working with bacteria and fungi,
they break down the faeces.

This is how they keep
this giant mound under control

and keep the nutrients moving around
this tightly connected microworld.

It's the recyclers that hold the key
to this cave's ecosystem.

But their influence is perhaps
even greater 5,000 miles away,

on the plains of Africa.

This is the Serengeti...

..home to the big five...

..and the dung beetles.

Using their remarkable sense of
smell, they hone in on their target.

True to their name, dung beetles
are the masters of recycling dung.

They don't need to eat or drink
anything else,

as dung provides all the moisture
and nutrients they need.

As the beetles roll off
and bury their own food balls,

the dung patch quickly vanishes.

But for these beetles, dung isn't
just a good source of food.

This male is building a giant brood
ball, to help him entice a female.

Mission accomplished!

And now the female has
the perfect place to lay her eggs.

While the beetles' circle of life
is centred around dung,

the grasslands' entire ecosystem
is centred around the dung beetles.

Without these amazingly
efficient recyclers,

the daily dose of 5,000 tonnes
of dung

would soon swamp
the African plains.

Thanks to the cleaning up operations
of dung beetles,

the grasslands are nurtured,

allowing the grazers to be fed,

which in turn sustain the predators.

And it's in death where another team
of arthropod recyclers

come into their own.

Blow flies can smell a dead body
from up to a mile away.

As soon as they arrive,
there's a frenzy of egg laying

as each female deposits
up to 300 eggs on the carcass.

In just under 24 hours
the eggs hatch,

allowing the voracious maggots
to get to work on the flesh.

Using special enzymes
and their claw-like mouthparts,

they can break down proteins
in next to no time.

In less than a week,
they'll have moulted twice,

consumed 60% of the carcass

and increased tenfold in size.

With feeding over, the maggot begins
its next stage of life.

Within a few days, a fly emerges.

This will go on to mate and produce
the next generation of recyclers.

So efficient are these recyclers
that, despite their size,

arthropods process more flesh

than all the large carnivores
put together.

By cleaning up dead animals,

the waste disposal teams
of the arthropod world

limit the spread of disease

and ensure the return of nutrients
back into the food chain.

This is all part of keeping
nature's microworlds in balance

but there is a twist in this tale.

The arthropods' efficiency
and ability to reproduce quickly

means that their populations
could easily spiral out of control.

So who keeps the arthropods
in check?

The answer
is the arthropods themselves.

The woodlands of England.

Spiders mostly prey on insects
and other spiders

and they use a range of strategies
to capture their prey.

The best-known is this -
the sticky web.

An orb web can contain
up to 60 metres of silk

and involve 3,000
different attachments.

It takes about an hour to build
and then it's just a waiting game.

She sits at the centre
with her legs resting on the spokes.

Ready to pick up
the tiniest vibration.

As soon as a tremor spreads down the
web, she pulls on different spokes.

In this way, she can work out
exactly where her prey has landed.

With her feet coated
in a special oil,

she can move freely across her web

to secure
and then devour her victim.

While this capture
has gone perfectly to plan,

it's not always the case.

About half the potential prey
manage to escape.

But there's another web
that's a more effective trap

and it's designed
by the aptly-named triangle spider.

Its web may not look as impressive
as the classic orb web

but it is far more deadly.

The spider's body forms
an essential link in her trap.

But to be effective,
she has to ratchet up the tension.

Tighter...

and tighter.

On this web,
flies don't get a second chance.

Their impact triggers
the spider's release,

causing the web to fire
and entangle the prey.

Few flies manage to escape.

Which is pretty good
for an individual's web

but when spiders team together,

the results
are even more impressive.

In the rainforests of South America,

a section of the canopy is enveloped
in a massive tangle of webs.

This tree-top death trap

is the work of tens of thousands
of tiny spiders.

Spanning three metres across,
it can capture a whole host of prey.

Including this cricket,

which is several hundred times
larger than the spiders.

But that doesn't put
these spiders off.

Working together, they can kill prey
many times their own size.

They squirt glue
from their spinnerets,

immobilising the cricket,

and then they inject their venom.

Before long, their victim is dead

and now they begin
their communal feast.

Numbering over 40,000 species,

spiders are found across the globe
and exist in nearly every habitat.

Thanks to their silken traps
and venom,

these predators play a pivotal role

in keeping the planet's
many microworlds in balance.

The controllers of the arthropod
world are a key piece of the puzzle

that keeps our planet ticking over

but they're not the most important.

To find out what is,
we need to explore

a far more harmonious relationship,

one that began in prehistoric times.

140 million years ago, the world
was a very different place.

The plant kingdom was dominated by
a few species of conifers and ferns.

For these plants, sexual reproduction
relies upon either the wind or water.

With millions of tiny pollen grains

dispersed in the hope
that some are intercepted

by individuals of the same species.

Rich in oils and proteins,

pollen grains are expensive to
produce and the majority are wasted.

But then an incredible
relationship began,

which would change the colour
and diversity of our planet

and ultimately create
the richest ecosystem of all.

The presence of insects allowed
a new kind of plant to evolve.

The flowering plants.

To reduce the squandering of pollen,

these plants no longer relied on
wind or water for pollination,

instead they recruited insects
to pollinate them

with nectar-loaded flowers.

Tailoring their advertisements
to match insect senses,

a burst of colour and smell
quickly spread across the planet.

In the fields of southern France,

sunflowers grow
to face the rising sun.

One after another,

hundreds of individual florets
produce pollen-covered stamens.

As these bees busily feed on nectar,

they brush against the stamens
collecting pollen

and then carry it
from flower to flower.

The sunflower's fertilised
and the bee is fed -

it's a win-win situation.

Over the generations, this
mutually beneficial relationship

has created some incredibly
specialised partnerships

between arthropods
and the flowers they pollinate.

One of which can be found
in the grasslands of England.

The pyramidal orchid
keeps its nectar rewards

at the end of long tubes
formed by the petals,

so that a long tongue is needed
to get it out.

The burnet moth has one such tongue.

As it feeds, a horseshoe-shaped
package of pollen

clips onto its long proboscis.

The only way the moth
can remove the pollen

is by visiting other
pyramidal orchids.

This time, as its tongue
reaches for a nectar drink,

the pollen sacks come into contact

with the flower's sticky
female surface

and a speck of pollen is transferred
across.

The flower is pollinated.

But an even more
elaborate partnership

has evolved in the rainforests
of Central America.

This strange-looking flower
is a bucket orchid.

Instead of nectar, it has another
offering for its arthropod partner.

The euglossine bee is attracted
to special fragrant oils

on the orchid's petals.

It gathers these oils into pouches
on its legs

and will later use this perfume
to attract female bees.

Other creatures are attracted
to this flower

but after slipping into the flower's
fluid-filled buckets, few survive.

While the bee depends
on the orchid for its reproduction,

the orchid likewise depends
on the bee.

Unlike other insects,

falling into the orchid's trap
is not fatal for this bee.

The bucket orchid
has an escape route

specifically designed
for its partner.

Most of the flower
is covered in a slippery fluid

but tiny knobs, which the bee
can grab onto, guide it to an exit.

And, as it squeezes through the gap,

just big enough for the bee,

the flower's pollen
is glued onto its back.

With its precious cargo secured,
the bee prepares for flight.

On its next visit
to a bucket orchid,

the bee fulfils
its part of the deal.

While gathering more aromatic oils,
it's lured into the flower again.

And this time, as it leaves,

the pollen packets are deposited
onto the new flower.

The orchid is fertilised.

And it's through this process,
pollination,

that arthropods have exerted
their greatest influence of all.

For over 100 million years,

the pollinators and their flowering
partners have evolved,

diversified...

..and spread across the planet.

With their success
came an explosion of life,

as they created new opportunities,

new habitats

and new ecosystems.

Today there are over
a quarter of a million species

of arthropod pollinators.

80% of all plant species on Earth
depend on them

and without them some of the richest
ecosystems on our planet,

including the tropical rainforests,

would not even exist.

From the harvesters and providers

to the recyclers and controllers...

..each group of arthropods
has a truly astonishing influence

on the workings of our planet.

But it's ultimately the pollinators

that have the greatest
influence of all.

Subtitles by Red Bee Media Ltd