(soft music) - [Narrator] Elegant and graceful, small but approachable, and infinitely varied and colorful. Butterflies never cease to
fascinate and impress us. And yet these exquisite beings begin life as little more than worm-like creatures. Ever-hungry caterpillars that munch their way through our gardens. (playful music) What is the secret behind
their curious lifestyle and why do they use their
wings not just for flight, but as a canvas for some of the most
striking patterns in nature? (dog barking) A garden shed, an unlikely
place for butterflies and yet it offers warmth and protection during the colder months. (soft music) A red admiral has overwintered here and now stretches its wings
as it wakes from a long sleep. It tries to head towards the light. At last, guided by the fresh
air, it makes its escape. The buds of the blackthorn
bush are about to open but within its thorny branches, something else is breaking
out of its cocoon. (birds chirping) A small emperor moth. It climbs up the stem
to pump up its wings. The feathery antennae
indicate that it's a male. He will use them to pick
up the scent of a mate. (chimes tinkling) The larger cocoons are
those of the females. They will emerge a few days later. The female has the same
large eye spots as the male but not the broad antennae and at the end of her abdomen, a special gland emits an enticing perfume. It will attract males from
several kilometers away. The small brightly colored
males waste little time. They have no mouth parts and can't feed, so they need to mate before
their energy reserves run out. A peacock butterfly has no such problems. It can refuel at any time and has come to the blackthorn bush to feed on its sweet nectar. The female emperor moth will lay her eggs within hours of mating. (soft music) Unlike the males, she only
really becomes active at night. Under cover of darkness she lays her eggs on a
branch within the hawthorn, close to where she mated. (birds chirping) Each month sees the
arrival of new butterflies. The common brimstone has come
to this wet woodland to breed. During the mating season, males defend territories against rivals but in the excitement, innocent passersby sometimes
get caught in the crossfire. The female deposits her eggs
on an older buckthorn bush. The unassuming tree is crucial to the survival
of her caterpillars when they hatch. The older buckthorn is the sole food plant of brimstone caterpillars, so plant and butterfly
often go hand in hand. After two weeks, the empty
egg case is left behind. The caterpillar is already munching away on the leaves of its host plant and will increase its weight
2000-fold over the next month. To avoid detection by predators, it often rests along the midrib of a leaf where it's difficult to spot. But not all caterpillars are fussy eaters, some have a more varied diet. (eerie string music) The hairy hatchlings of the vapourer moth first consume the remains
of their egg cases. Then they spin a silk thread and climb up to the nearest leaves. (mid tempo string music) In this case, the leaves
of a small birch tree. The vapourer moth is widespread
and common across Europe. Feeding on a great variety of plants, it can live in all kinds of habitats. (soft music)
(birds chirping) One of the most widespread
and successful plants is our common stinging nettle. The stinging leaves are in
fact packed with nutrients. They contain more protein
and minerals than most and they're the perfect
baby food for caterpillars. (mid tempo orchestral music) The caterpillars of the peacock butterfly feed together as a group, stripping off the leaves one at a time. There's safety in numbers and the squirming mass confuses predators. Rows of black spines
also act as a deterrent. (birds chirping) The caterpillars are being watched. The barred warbler has not been put off, she has too many hungry mouths to feed. A red admiral has also chosen
a nettle to deposit her eggs but she lays them singly, one at a time. It takes about 10 days for the small caterpillar
inside to develop. Once it has hatched, it spins a little tent around itself and begins to feast on
the nettle's leaves. It might appear that
plants have little defense against the tiny chomping mouths, but recent research
has revealed otherwise. Plants, it seems, can detect
vibrations made by caterpillars feeding on neighboring plants. They respond by producing
defensive chemicals and stop an attack on their own leaves. After three to four weeks, the caterpillar is ready to pupate. It draws together the edges of a leaf and forms a tent around itself. Here it will be safe from predators and can change into its adult form. (suspenseful music) Drawing fine silk threads from
a special gland in its mouth, it glues the leaf together. Finally, the caterpillar
sheds its skin one last time and turns into a pupa or chrysalis. (soft music) A small tortoiseshell caterpillar is also disappearing into its cocoon. Within a few hours, its case has hardened and turned into an exquisite sculpture with a metallic golden sheen. (soft music) Barely two weeks later and
the pupal case splits open, releasing the perfectly
formed adult butterfly. The insect's body still
needs to harden in the air and the feeding tube,
which is split in two, must be zipped together. Like the admiral and peacock butterfly, the tortoiseshell depends on the nettles as food for its larvae. The stinging leaves are in fact a defense against grazing animals, but they make an ideal
habitat for insects. The caterpillars can safely
move between the spines and there's little danger
of being eaten by a grazer. Even agricultural crops attract their own kinds of butterflies. A field of cabbage appeals to one of our most common species, the cabbage white. The caterpillars are the
bane of farmers everywhere and can decimate entire fields. But where pesticides are not put to use, natural predators will
soon come to their aid. Wasps need protein-rich insect
food for their own larvae, so a juicy caterpillar
makes a perfect meal. She bites into the plump body
and sucks up its inner fluids. With a belly full of protein juice, she flies back to the nest. (wasp buzzing) She is greeted by the other workers and regurgitates the
green caterpillar pulp to feed the larvae. Not everyone is happy to
have wasps in their garden but those who are can be assured they'll
help control insect pests. Unlike their caterpillars, most butterflies are not fussy eaters and will happily feed on a
variety of garden flowers. (soft piano music) The nectar-rich blossoms of the lilac tree are a magnet for all kinds of butterflies, like the European map, the painted lady butterfly, and the red admiral, a frequent
visitor to our gardens. Hovering above a flower is the aptly named hummingbird hawk-moth. Its smaller cousin, the bee hawk-moth, flies in a similar way. But there is one hawk-moth that is after something
sweeter than nectar. (bees buzzing) The death's-head hawk-moth has picked up the alluring scent of honey, but getting past thousands
of armed soldiers is no easy task. Astonishingly, the large moth
simply walks into the hive straight past the
seemingly unconcerned bees. The cunning thief mimics
the scent of the bees, tricking them into thinking
it's one of their own. It's the perfect adaptation
for a life of crime. And chemical camouflage
is not its only tool. A short, thick feeding tube is useful for piercing the honeycomb to suck out the sugary liquid and a thick skin helps
in case you get caught. It protects against the punishing stings. The hawk moth has mastered
the perfect honey heist. The death's-head hawk-moth
is one of our largest moths and also one of the craftiest. (suspenseful music) After three months of
gorging on blackthorn leaves, the caterpillar of the
emperor moth has become huge. Special salivary glands on its lower lip now produce fine strands of liquid silk, which dry and harden in the air. (mid tempo music) The caterpillar spins an
intricate mesh of fibers around itself, entombing its body in a silken cocoon. It will stay inside this protective casing until the following spring. All across the countryside,
in every bush and tree, the caterpillars of moths and butterflies are preparing to change
into their adult forms. (birds chirping) Some are transforming not
just their own appearance, but that of their surroundings. Wispy white drapes cover
the tree trunks and bushes. (playful music) The larvae of the ermine
moth are busy spinning. Underneath their shroud-like web, the small caterpillars
can feed undisturbed. Only when they emerge do they run the gauntlet of hungry beaks. (birds chirping) But it's not just birds that
are after the small larvae. A parasitic wasp moves
gingerly across the web. It uses its long egg-laying tube to probe for caterpillars underneath. If it finds one, it thrusts the pointed
needle into the body and deposits an egg. When the eggs finally hatch, the wasp larva will eat the
caterpillars from the inside. (wasp buzzing) The brimstone caterpillar has already undergone a
remarkable transformation. It's one of nature's miracles, a worm-like caterpillar is turned into a delicate
creature with wings. The ermine moths have also emerged from their ghostly webs. They now cover the trees in vast numbers, just as their caterpillars
did some weeks ago. The white adults will
only live a few weeks, just long enough to produce another generation
of hungry caterpillars. Woodlands provide a home for
many kinds of butterflies but their favorite plants
often grow in open clearings. The withered leaf on a
honeysuckle is not all it seems. Hiding within is a small caterpillar that has spent the winter
asleep in a leafy tent. (soft music) Now it starts to move and
emerges from its secret hideaway. All it wants to do is feed. Thorny spikes on head and body
protect it from hungry birds. The caterpillar of the
white admiral butterfly feeds solely on honeysuckle leaves. By the time the plant flowers, the caterpillar has eaten all it needs and is ready to undergo a transformation. (playful music) Its new body has taken
on a green metallic form. Hanging motionless from a leaf, it appears lifeless and
is perfectly camouflaged. Two weeks later and the pupa has turned into a black
alien-looking creature. It's hard to imagine that from this will soon arise a thing
of exquisite beauty, a white admiral butterfly. Many hungry beaks comb the
leaf canopy for insect prey. Those that are not well
camouflaged will end up as a meal. (birds chirping) One caterpillar has come
up with a most unusual ploy to avoid being eaten. The larva of the comma butterfly has a large white patch on its back. From above, it looks
much like a bird dropping and most predators give it a wide birth. Others, like the Ruby Tiger moth, defend themselves with poisonous bristles (mid tempo music) and the long hairdo
sported by the miller moth is also an effective armor. Most predators dislike a fuzzy mouthful. Caterpillars with a furry coat, it seems, can go about their business undisturbed. (dramatic orchestral music) But one hunter is not put off
by a caterpillar's hairy back. A large ground beetle, the
forest caterpillar hunter, and it has an insatiable appetite. (eerie music) (tense music) With strong jaws and
defensive armor of its own, it makes an easy meal of
the hairy caterpillar. With so little light and warmth getting through the woodland canopy, flying insects like butterflies are drawn to the sunlit
glades and clearings. It's also where they find
an abundance of flowers rich in nectar. They're a haven for all
kinds of butterflies, The green-veined white
and the large skipper, painted ladies, and the
lesser purple emperor. The woodland brown butterfly
is a rare sight today. It needs sunny forest edges and clearings. For centuries, large grazers like horses kept woodland clearings short and open. They created a mosaic
of different habitats perfect for butterflies. A sunlit forest canopy also
attracts other wildlife. A black stork is raising its
chicks in the fork of a tree. The nest seems to attract
woodland butterflies. The stork droppings are
rich in salts and minerals, which the butterflies need
to produce their own eggs. And it's not just storks that leave behind such valuable gifts. A fox den provides a regular
supply of fresh manure. It may be less sweet smelling
than the woodland flowers, but it's just as nutritious
in its own right. Forest tracks and rides
offer sunny refuges within the closed canopy
of pine plantations. Flooded with sunlight, they allow flowering
grasses and shrubs to grow and butterflies to make the
most of their biggest asset, their colorful wings. Butterflies come in a whole
kaleidoscope of colors and striking patterns, but their true display
is invisible to our eyes. (ambient music) Some of their colors extend
into the ultraviolet spectrum, which butterflies can detect
but we can't even imagine. Under ultraviolet light, the male brimstone has bright patches on the
underside of his wings and yet, to our eyes, he appears a uniform yellow color. But the brimstone pays a price
for such a flashy signal. Birds can also see in the ultraviolet and his display could
attract unwanted attention. The lighter female takes no such risks and appears a dull brown
under ultraviolet light. (eerie music) To avoid detection by
hunters, the brimstone, like many butterflies, rests with his wings folded. Under ultraviolet light, many wing patterns look very different, but exactly how butterflies
perceive these colors is likely to remain a mystery. A thick stand of nettles
at the woodland edge provides good cover for caterpillars and the developing pupae. It's the birthing pool
of many butterflies. Inside the chrysalis, the caterpillar's body is undergoing an extraordinary change. It's broken down into a nutrient-rich soup and reassembled to form
the parts of a butterfly. It's one of nature's
most remarkable events. The Alp mountains form a
natural barrier across Europe but numerous migrating
butterflies cross the high peaks every year. For other animals the mountains are not
a barrier but a home. The alpine ibex, a wild mountain goat. A cave high up in the mountains is home to some unusual inhabitants. Tissue moths spend
eight months of the year in the dark and damp. We still know very
little about their lives. Each spring, they fly
down the mountainside to breed in shrubs and bushes, where conditions are a little milder. But after the adults have hatched, they return to seek out the
darkness of the cave again. On the lower slopes of the mountain, rich alpine meadows erupt
in a colorful display of summer flowers, (soft acoustic music) and with them come the
bees and butterflies. It's a short season for
the alpine residents, so they quickly get on with their business of feeding and breeding. With such an abundance of nectar, that poses little difficulty. Some parts of the alpine landscape have remained virtually
unchanged for centuries. The small Apollo is a
high altitude specialist often found near mountain streams. It rarely flies, clinging
to the vegetation to sit out cold and windy weather. When temperatures rise
the female comes to life, crawling about at the water's
edge to deposit her eggs. The yellow Saxifrage, which grows in abundance here, is the food of choice for her young. At these high altitudes the
summers are very short indeed, so the Apollo's larvae overwinter as eggs and continue their life
cycle the following spring. Alpine meadows are among the
richest habitats in Europe, teeming with insects and insect hunters. The warm sunny slopes are a
favorite with butterflies. Large, colorful swallowtails so spectacular they were once the target of butterfly collectors. The males use thermal currents
rising from the slopes to lift themselves up into the canopy. From a high vantage point, they patrol back and
forth in search of females and rival males. High above the treetops
is their mating arena and aerial chases serve to
settle any disagreements. Other insects also make
use of thermal currents to get some lift. The owlfly has an
ungainly lumbering flight and needs much energy to stay airborne. When the sun slips behind clouds, the effort is clearly too much. All insects are cold-blooded and need the sun to warm up
their bodies to become active. So when the sun reappears, the owlfly spreads its
wings to soak up the warmth. The owlfly is a curious mix
between butterfly and dragonfly but it doesn't feed on
nectar, it's a hunter. The tall flower head
simply serves as a takeoff and landing pad. Wildflower meadows are a paradise for
insects and butterflies. Hundreds of grasses and flowers offer an abundant supply of nectar. Not surprisingly, there are more butterflies
to be found here than in any other habitat. But even in paradise, the
sun doesn't always shine. (thunder rumbling) A thunderstorm can bring gusty
winds and large raindrops. For a butterfly, it's no trivial matter. They try to protect their delicate wings by folding them together (raindrops pattering) and when the storm has passed, they open them up and dry them in the sun. (soft music) The marbled white butterfly
was once a common sight in every dry grassland. The striking black and
white checkered pattern makes it stand out from the crowd. But like most grassland
species, it's now in decline. Meadow Browns once danced
over our grasslands in their hundreds and thousands, while others formed part of
a rich and colorful community of life, fluttering in the summer breeze. In the last two decades, we've lost nearly half of
our grassland butterflies. These magical creatures that
have given us such delight may soon become a thing of the past, and their decline is largely the result of our own careless actions. Modern farming techniques have changed the face of our landscape. They've pushed aside much of our wildlife and the habitats they depend on. As wildflower meadows have disappeared, so have many of our butterflies. (eerie music) Vast swaths of crops now
stretch across our countryside, they're devoid of food for butterflies. In patches of grassland
bordering the fields, the struggle for survival continues. A wasp spider, and it's
not just after wasps. A red admiral has been
trapped in her sticky web. (dramatic music) (tense music) The spider tries to reach
its victim for a lethal bite. (suspenseful music) A miraculous escape. (soft music) The spider is left with
just a fragment of wing. Spiders are a natural
part of the ecosystem and don't threaten the
survival of a species, not even that of the false ringlet, a rare and endangered butterfly. For millions of years, the ringlet has lived in
grassy bogs and marshes across Europe, rarely straying from traditional sites. Now, the draining of wetlands and intensive farming of the land have triggered an alarming decline. (birds chirping) But not all farming practices
are harmful to wildlife. Traditionally managed grasslands have a richer diversity
of plants and animals than those abandoned and
left to their own devices. A wet lowland meadow carpeted
in crimson flower heads. The blood-red blooms
attract insect pollinators and there is one which
is dependent on the plant for its entire life cycle. The dusky large blue butterfly
not only feeds on the nectar but also mates on top of the flower head. It even lays its eggs right amongst the tightly packed blossoms. When the tiny larvae hatch, they quickly disappear
inside the flower head. Here, the caterpillars
feed on the unripe seeds and quickly take on the
flower's crimson red color. After three weeks, the large maggots have
consumed everything there is and need to find a new home, But trapped high above the ground that's easier said than done. The only way down is to abseil. The resourceful caterpillar
now spins a silken thread and attaches it to the blossom. Far below, the reception
party is already waiting. Anchored to her thread,
she begins her dissent. The rope has snapped but the thick moss softens the landing. The caterpillar now needs the help of an unlikely babysitter. A red ant is attracted to
the scent of the pink grub. The caterpillar mimics the
smell of the ant's own young and, in a case of mistaken identity, is carried back to the nest. The sneaky imposter
will live among the ants for the next few months and surreptitiously feed on their larvae. The following spring, it will emerge as an adult
dusky blue butterfly. Grasslands that are mown later in the year when the caterpillars have
disappeared underground, ensure that the dusky
large blue can breed. (mid tempo music) Without human intervention, the grasses would soon be smothered by larger shrubs and bushes. So the survival of this rare butterfly depends on the careful
management of its habitat. (birds chirping) A flock of migrating starlings has descended upon a plum tree. They are frenetic and messy feeders. The half-eaten fruit is soon set upon by decomposing fungi and bacteria. A red admiral is attracted
to the fermenting plum. The sweet juice is a welcome energy drink before it sets off on its migration south. Summer is nearly over but there is still plenty
of food for insects, including butterflies. (wasps buzzing) The sweet sugary sap oozing
from the wound on a birch tree draws in a multitude of hungry creatures. And late summer has other things to offer. A Buddleia bush come into bloom with a spectacular
display of lilac flowers. It's also called the butterfly
bush for good reason, the fragrant blooms seem
to be an irresistible lure. By this time of year, the wings of many are tattered and torn. These red admirals are unlikely to make the
migration south again. A Dark Crimson Underwing is
also attracted to the Buddleia. It could easily be mistaken for an admiral but is in fact a rare moth. Many of us plant flowers in our gardens to attract butterflies, and even non-native plants
will supply ample nectar. Michaelmas daisies are
native to North America but happily cater to the
needs of our own insects. This peacock butterfly requires
fuel of a different kind. It flies on wind energy alone and is a particular
favorite with children. Inside the warmth of the house, another less popular
creature is bedding in. The larvae of the common clothes moth, evolved to feed on the
fur of dead animals. Not surprisingly, our woolen
jumpers are a good substitute. By late autumn, most butterflies
and moths have disappeared, but there is one that only
makes an appearance now. (soft music) The winter moth. Despite the increasingly chilly nights, the male is on the wing
looking for a mate. A pheromone gland discharges
perfume into the air. The strange wingless creature
is a female winter moth. She climbs to the tip of a
branch to deposit her eggs amongst the closed buds. The small white mothballs
will remain here all winter. In spring, the young caterpillars will emerge, eating holes in the leaves
and blossoms of fruit trees, often causing extensive damage. (soft music) With the first fall of snow,
even the winter moths die. Not so the common brimstone, wrapped in snow and ice it
doesn't move, it's asleep, waiting for spring. The winter landscape is
devoid of butterflies. Many have migrated south,
others are dormant and asleep. But a few seek out warm spots
in our homes and garden sheds. Red admiral butterflies have
started to overwinter with us and are one of our more adaptable species. But to continue seeing a
colorful variety of butterflies in our meadows and gardens, we need to look after them
all just a little more. (soft orchestral music) (ominous music)
