(light dramatic music)
Narrator: Tonight, there's magic in the air.
(light music)
Insects in search of partners.
The world is a very big place,
and insects are very small.
To make more insects,
they somehow have to find each other.
No matter how hard it is or how far.
But they're obviously really good at it.
Insects have been around for hundreds of millions of years.
In that time,
they've evolved all kinds of ingenious ways
to make sure partners get together
and to guarantee the survival of future generations.
(light music continues)
(gulls cawing)
There are a few places on the planet where insects
can really achieve their true potential.
(light music)
Like Mono Lake,
high in the Sierra Nevada Mountains of California.
The water here is so alkaline
not many creatures can survive at all.
But try telling that to one particular kind of insect.
(flies buzzing)
Brine flies, they breed in numbers that defy belief.
They blacken the shores in their hundreds of millions.
(flies buzzing)
And they fill the air with dense clouds.
An all you can eat buffet for the locals.
(gulls cawing) (light dramatic music)
California gulls gorge themselves on clouds of flies.
(light dramatic music continues)
But they make no impact at all on their numbers.
(flies buzzing)
This alien landscape is the realm of insects,
but insects everywhere are very,
very good at making more insects.
Especially when we provide them with five star
board and lodging.
(light dramatic music)
These green bottle fly's eggs will hatch and grow
and transform into pupae in just a few days,
A couple more days and the next generation
is ready to emerge from the pupae.
An inflatable forehead breaks through the tough outer case.
(ominous music)
And these flies are ready to start the whole process again.
(flies buzzing)
Each female can lay 2,000 eggs in her lifetime.
Eggs that will soon turn into more flies that can each lay
2,000 eggs of their own.
If none died, in just two generations,
that's two million flies.
(ominous music)
(flies buzzing)
All insect populations could reach such unimaginable
numbers, but thankfully,
most of their offspring don't survive.
Otherwise we'd all be knee deep in insects.
It's not always this easy.
For many insects, even finding a partner
can be a real problem.
Emperor moths live on open heathland.
The terrain is endless.
The nearest partner could be miles away.
Somehow, two tiny moths must find each other
across a vast featureless landscape.
No problem.
The female moth releases a scent,
a sex pheromone from an organ at the tip of her abdomen.
(light music) (air whooshing)
Caught on the breeze, it drifts down wind
until it's picked up by a sophisticated tracking system;
a male emperor moth's antenna
They're branched like feathers,
which gives them an enormous surface area.
Combining micro x-ray techniques with data
from a scanning electron microscope,
we can see these structures in intricate detail.
They're covered in tiny hairs.
They trap any pheromone molecules wafting past the antennae.
Nerve fibers run inside each hair,
and when a pheromone molecule is trapped on the hair's
surface, it triggers the nerve to fire a signal.
A male moth's antennae can detect
a single molecule of the pheromone.
Sensitive enough to smell a female more than a mile away.
(light music) (birds chirping)
But he doesn't react until he detects more of her scent
until he's certain she's in range.
He flies upwind tracking the scent plume wherever it leads.
Many kinds of insects use sex pheromones,
but each is different.
So each male knows he's tracking
a female of his own species.
The further a male travels,
the stronger the scent becomes.
Triggering more and more hairs on his antennae.
Drawing him further and further upwind towards the source.
A virgin female.
But not for much longer.
(light music continues) (wings rustling)
It all seems so simple, but it's not foolproof.
(birds chirping)
The scent of a female wasp is drifting
through this Australian woodland,
and it's been picked up by a male.
It certainly smells right for his species.
So he sets off on the trail of a female.
(light dramatic music)
Or so he thinks.
But he's going to be disappointed.
The scent is coming from the flower of a wasp orchid.
Still, it definitely smells like a female wasp.
So worth a try.
He tries to mate with the flower, and in his passion,
a packet of the orchid's pollen gets stuck to his back.
Another flower and the poor wasp is fooled again.
This time he scrapes off some of the pollen
and pollinates the flower.
Another successful mating,
but not for the wasp.
(light music continues) (birds chirping)
So maybe there's a more secure way
to send messages over long distances.
Light travels a long way and is easily seen at night.
And it's not at the mercy of the wind
or of deceitful orchids.
(crickets chirping)
(light music)
In their search for romance
some insects put on spectacular light shows.
(light music continues)
Fireflies light up the evening forests.
There might be a dozen or more different kinds
in this one forest, all signaling for a mate.
So, to avoid confusion,
every species needs its own unique code.
Each kind of male flashes at different rates
and at different intervals.
Insects invented morse code long before we did.
When a female sees a pattern she recognizes,
she signals back to identify herself.
And she must also use the correct code for her species.
That way a male knows he's closing in
on one of his own kind.
(light music continues)
The males of some fireflies synchronize their flashing.
Each male is triggered by his neighbors to light his own
lantern and waves of illumination ripple through the forest.
(light music continues)
Seen over the course of the night,
fireflies paint the forest below
and stars paint the sky above.
(light music continues)
Coded signals can also be sent with sound.
(bugs chirping)
After dark, these forests in India are alive
with the love songs of insects.
But this tree cricket has a problem;
to attract a mate, he needs to make himself heard.
To stand out above the din.
Still, he has a plan.
He cuts a hole in the center of a carefully selected leaf.
Then he lines up his wings with the hole and sings.
(crickets chirping)
The leaf works as a baffle.
It stops the sound coming from the rear of his wings
from interfering with the sound coming from the front.
(crickets chirping)
It makes his song much louder,
so it penetrates further through the noisy forest night.
He's one of the very few insects
that have learned to use tools.
And it works.
A female is impressed by his efforts.
After mating, he even offers her dinner;
a secretion from glands between his wings
that are packed with nutritious food.
It will help her produce bigger and better eggs.
(bugs chirping)
It's important for a female to choose the best male
to father the next generation.
For a tree cricket, the volume of the male's song
is a good guide.
(crickets chirping)
(thunder rumbling)
How else can you decide on your perfect partner?
Female stag beetles leave nothing to chance.
(thunder rumbling)
(light dramatic music)
They expect their partners to prove themselves in combat.
Male stag beetles grow their mandibles to sizes out of all
proportion to their bodies, just to impress females.
(suspenseful music)
(light dramatic music)
They use their mandibles like a stag uses
his antlers to fight a duel.
(light dramatic music continues)
(thunder rumbling)
Only winners get to mate,
so evolution has favored ever larger jaws
and bigger heads packed with powerful muscles.
(light dramatic music continues)
And it's not just female beetles that want
to pick the winner.
(woman speaking foreign language)
These fights are so spectacular that across many Asian
countries they've become a kind of sport.
(light dramatic music)
Many of these gladiators are collected
from local rainforests,
but some come from breeders that hope
to raise champion fighters.
(both speaking foreign language)
Bets are placed, sometimes worth a thousand dollars or more.
(light dramatic music)
(suspenseful music)
For the beetles, the loser is the lucky one;
he's returned to the rainforest
while the winner will face another contest.
(light music) (birds chirping)
There are more genteel ways to impress a lady.
In late summer the air is full of the songs of grasshoppers.
Of many different kinds.
(grasshoppers trilling) (light music continues)
Each species sings its own distinct song
in this grassland chorus
to attract females of his own kind.
(grasshoppers trilling) (birds chirping)
But for this rufous grasshopper, a song alone isn't enough.
He needs to perform a whole song and dance routine.
His black and white tipped antennae
and his conspicuous mouth parts are all part
of his dance regalia.
(grasshoppers trilling)
First a twirl with his mouth parts.
Then a bow with his antennae.
(grasshoppers trilling)
The female is obviously impressed.
She sings her own song,
and its meaning is pretty obvious.
(bottle popping)
(light music) (birds chirping)
Dancing is all the more effective with flamboyant costumes.
In the rainforests of Central America
both sexes of the paddle-legged mosquito
wear sparkling blue plumes on their legs.
When a male lands close to a female,
he waves his colorful legs to impress her.
If she likes what she sees, she invites him to mate.
(light music continues)
Then the female leaves him to find a tree hole
filled with water.
She flicks her eggs inside one at a time
with thoughtless accuracy,
Some insects can't afford to waste time
on a romantic courtship.
(light music)
A male ivy bee, and he has a problem.
Female ivy bees only mate once,
so he's going to have to look sharp.
The trouble is there are rival males
emerging all around him.
(bees buzzing)
Male ivy bees emerge from their burrows before the females.
And soon the air is full of hopeful bees
all waiting to spot the first female.
(bees buzzing)
(light music)
When a female does emerge,
she's pounced on by dozens of eager males
all desperate to mate.
(dramatic music) (bees buzzing)
In their frenzy these bees form mating balls.
Sometimes of dozens of male bees.
And somewhere inside the creche, a female.
Eventually, one lucky male wins,
usually the biggest.
(bees buzzing)
The female didn't have to work too hard to find a mate.
All she had to do was to stick her head above ground.
But now she has to dig herself a nest burrow all on her own
while the males hang around for their next opportunity.
(bees buzzing) (birds chirping)
Having a big get together like this certainly makes
finding a partner a lot easier,
but sometimes even the biggest gatherings
still face problems.
The River Danube in Hungary.
These mayflies have spent a year on the bottom of the river
feeding and now they emerge from the water
and turn into adults.
(light music)
They'll only live for this one night, but what a night.
As dusk falls, an insect orgy begins.
(light music continues)
Millions of mayflies dance over the river.
Their only purpose is to breed and make more mayflies.
Mayflies have been around since before
the time of the dinosaurs,
but today they face a very modern problem.
Bright lights on bridges over the river
draw them away from their dances.
It's a blizzard of mayflies.
Many crash onto the road and will die here
without ever getting a chance to breed.
(traffic humming) (light music)
In the last few years,
even brighter lights have been installed
below the bridges.
Now the mayflies are drawn to these,
but the new lights have been specially designed to keep
the mayflies over the river where
they can fulfill their life's mission.
(light music)
After mating, females dip onto the water's surface
to release their eggs.
Eventually, exhausted, they can no longer take off again.
They've only been adults for a few brief hours,
but their job is done.
Billions of eggs sink to the riverbed
where they'll soon hatch into the next generation of larvae.
For most insects, reproduction simply depends
on huge numbers.
(car horn honking) (traffic humming)
Lay hundreds or thousands of eggs,
abandon them to their fate, and hope a few survive.
(dramatic rhythmic music)
This female vapourer moth is nothing more
than a bag of eggs.
She has no wings and only lives long enough to lay her eggs.
But insects can improve the odds for the next generation
by being careful where they lay their eggs.
A lackey moth arranges hers in a precise band
around a twig of the bush she knows
her caterpillars will eat.
A large white butterfly stacks
hers neatly under a cabbage leaf;
her caterpillar's favorite food.
This Necroscia stick insect makes sure no one
will ever find her eggs.
She holds each huge egg at the tip of her abdomen.
It looks as tough as nails and that's exactly how it's used.
The stick insect hammers it into the trunk of a tree.
Once she's made a dent, she screws the egg into the wood
until it's completely hidden.
A green lacewing has an even more ingenious way
of hiding her eggs.
She lays each one onto the end of a strand of silk
so they aren't noticed by marauding ants.
The eggs themselves are like mini survival capsules.
Magnified a hundred times
they're exquisitely engineered.
Reinforced with struts and braces for strength.
Inside this egg of a large white butterfly,
a tiny caterpillar is developing and growing.
In less than a week it fills the whole egg.
Its soon so big it has to fold in half just to fit inside.
Now it's time to hatch.
When they emerge, most young insects are on their own.
(light music)
(light dramatic music)
They might look tiny and frail,
but they have plenty of tricks to help them survive
in the big, bad world.
If you're a caterpillar, try not to look like a tasty grub.
(light music)
Spines and hairs put off some predators,
but some take the whole disguise thing to extremes.
These really are caterpillars.
A lot of the time young insects do just fine,
but not all insect parents are so remiss.
Some go to a lot more effort.
In North America, this wasp is busy digging out
a burrow to serve as a nest.
Once it's finished, she'll stock it
with a lifetime supply of food for her larva.
These wasps are called cicada killers.
(light dramatic music)
So it's no surprise she hunts cicadas.
But she's not a killer.
She stings them with a venom that paralyzes them.
They won't die, not just yet.
They'll stay nice and fresh,
but they can't escape their fate.
They'll be eaten alive by a wasp grub.
Each larva will need several cicadas to sustain it,
and each nest contains several larvae.
So she has plenty of work to do ferrying cicadas
back to the burrow.
She can even fly with her prey,
even though it might weigh twice as much as she does.
When she's finished, the undead cicadas are sealed
in what will become their tomb.
(dramatic music)
And she starts the whole exhausting task over again.
(light music)
Half a world away, on the plains of Africa,
the big things are busy providing more opportunities
for the little things.
(light dramatic music)
Adult dung beetles feast on dung, and so do their lavae.
And this pile is plenty to feed both
the beetles and their next generation.
But it's not the endless feast that it might look.
There's a mad scramble for any fresh offering.
What's needed is a way to avoid the crush.
Each beetle parcels up dung into a ball
that can be rolled away from the crowd
to a more secluded spot.
To avoid going round in circles,
a dung beetle uses the sun as a compass,
even compensating for its passage across the sky.
In this way, it follows as straight a line as possible.
This male is joined by a female who follows him
and his precious ball of dung.
And they keep going through the night
using the Milky Way as a guide.
Eventually, the two beetles bury the ball
and she lays an egg.
The female stays with the ball to keep the grub growing
insides safe from harm.
(birds chirping)
Across the plains of Africa,
game herds are converting plants into food
for many different kinds of dug beetles.
(light dramatic music)
And antelope dung comes in neatly packaged,
handy, rollable balls.
So convenient that this dung beetle specializes
in burying antelope dung for its larvae.
But sadly, this beetle's been duped.
He's not rolling dung at all.
The seeds of this South African plant look and smell exactly
like antelope dung.
Enough to convince a dung beetle to roll
them away from the plant.
The seeds are rock hard and will provide no sustenance
for its larvae,
but the beetles are so completely fooled
that they bury the plant seeds anyway.
The perfect little gardeners.
(light dramatic music) (wind whistling)
Some dung beetles have abandoned dung altogether.
This species feeds its young on millipede flesh,
which is a problem
because it can't kill a millipede by itself.
It needs to hire an assassin.
(suspenseful music)
Millipede assassin bugs.
(dramatic music)
Assassin bugs even work together to overpower
a really big millipede.
(suspenseful music)
They stab it with their sharp mouth parts,
then they injected with fast acting lethal toxins.
Once they've finished,
there's still plenty left for the beetle family.
It uses its webbed shaped head and powerful legs
to separate the millipede into convenient chunks;
small enough to bury, but big enough to feed its larvae.
(light dramatic music)
And maybe a little bit more appetizing than dung.
(light music) (birds chirping)
Family life among insects takes on many forms.
There are even tender moments happening
right under our feet.
(ominous music)
The common earwig is a model parent.
Mother tends the eggs,
cleaning them and keeping them free from mold and infection.
She sits with them like a bird on the nest,
protecting them from danger like centipedes.
And if anything threatens her clutch, she'll defend them.
(light dramatic music)
She's having none of it.
Her sharp pincers soon see it off.
But just to make sure her clutch is safe,
she now moves her eggs, one by one, to a quieter spot.
(light dramatic music)
(birds chirping)
Thorn bugs raise their families out in the open
where it's even more dangerous.
Mother stands guard over her brood.
She has to be really alert.
(ominous music)
The biggest threats to her family are predatory wasps
always on the lookout for fresh meat.
(ominous music continues)
If the family senses danger,
they drum on the twig by jumping up and down all together.
Their mother responds immediately to their distress call.
First, a warning.
(wings rustling)
A wing buzz.
(light dramatic music)
Back off or else.
(wings buzzing)
She's armed with a sharp thorn,
but that's not her most impressive weapon.
(light dramatic music)
She's a highly skilled kickboxer.
She draws her leg back and kicks.
(dramatic music)
It's so fast that even slowed down 40 times
the action is just a blur.
(dramatic music)
She hits with such a powerful blow
she leaves the wasp reeling.
If she wasn't so vigilant,
predators would soon eat her entire family.
But there is a way to avoid all this stress
and still make sure your babies are well protected;
employ babysitters.
Or, in the case of imperial blue hair streaks,
more like a well armed security force
of rainbow ants.
These butterflies can even recognize the right species
of ant and won't lay eggs on trees
without the right babysitters.
(light dramatic music) (bugs trilling)
As soon as they're laid, the eggs
have ant guards standing over them.
And once they hatch, the caterpillars are never
without an ant escort wherever they go.
But the ants don't provide this service for free.
The caterpillars have special organs that produce food
packed with essential nutrients for the ants.
In return, the ants defend the caterpillars
against any other insects that come too close.
(light dramatic music)
Even when they turn into pupae they still produce ant food,
so the ants continue to guard them.
Imperial blues can pupate out in the open
and in big groups thanks to their guards.
And when they emerge,
the butterflies don't have far to look
for willing babysitters.
(light dramatic music)
But the earwig has to face the trials
of parenthood on her own.
She's more than up to it.
Her maternal instinct is as powerful as any.
She puts everything into raising her family,
even though earwig toddlers can be quite a handful.
(light dramatic music continues)
If they stray too far,
she gently coaxes them back home
with touches from her antennae.
She even carries them like a tiny cat with its kittens.
(light dramatic music continues)
And she feeds them on predigested food
until they're old enough to venture into the big wide world.
It's a touching sight, such a gentle mother.
She's just one example of the ingenious ways that insects
have evolved to make sure the next generation
have the best start in life.
(light music)
They've been producing generation after generation like this
for well over 400 million years.
Over that time they've turned planet earth
into planet insect
thanks to the unparalleled ability of insects
to make more insects.
(light music continues)
(light dramatic music)