Sky Hunters, The World of the Dragonfly - The Secrets of Nature

[Music] [Applause] this is one of the most successful life forms on our planet they existed a hundred million years before the dinosaurs [Music] [Applause] they're skilled at aerobatics and their merciless predators their appearance and their lifecycle are so strange they could be visitors from another world these are the dragonflies science has given them colorful names broad bodied chaser for spotted chaser scarlet dragonfly some glimmer like liquid metal [Music] [Applause] others seem to be fashioned out of stained glass or enamel [Music] these are creatures that have barely changed in hundreds of millions of years from the very beginning they have been perfect sky hunters in 1558 the French naturalist Johann delay noted a distinct resemblance between the hammerhead shark and a small insect the first mention in scientific literature of dragonflies and the smaller damselflies their habitats are just as varied as the forms they take but they always have to be close to freshwater that plays a vital part in their lifecycle all dragonflies are excellent fliers but they fly in different styles the smaller damselflies tend to be more cautious they're not known for daring aerobatics or sudden swooping attacks they move in a graceful weightless ballet [Music] big dragonflies look like marauding fighter planes they patrol their territory at more than 50 kilometers an hour they hover like a helicopter and dart off at top speed from a standing start they beat their wings so slowly only about 30 flaps a second we don't hear a hammer a buzz but a sizzle [Music] their body design makes them perfect predators 300 million years of evolution have given them the tools to devour any insect prey they wait at raised observation points on the lookout they hunt anything they can overpower that includes flies wasps butterflies even their own species dragonflies have a well-earned reputation as cannibals wherever there's water there are not just dragonflies but also potential prey a dead fish on the riverbank attracts an army of flies within a few days their maggots would have consumed it from the inside but these bluebottles leaping on and off the body are being watched by a female data [Music] [Music] her razor-sharp mandibles consume the best parts in minutes the biggest species need plenty of nutrition to provide energy for their powerful bodies and there's no shortage of larger prey such as butterflies in some places for instance on Greek islands there are real mass gatherings of moths like these Jersey Tigers Jersey Tigers tend to gather near water sources and that's also the perfect habitat for dragonflies but even in ordinary fields species like the peacock butterfly are anything but safe [Music] [Music] even big moths are quickly consumed this one will soon be gone [Music] scientists have been collecting dragonflies since the 18th century but there's always been a difficulty dragonflies quickly become deathly pale they lose all their color that's why collectors have usually preferred to concentrate on butterflies they're more colourful and don't lose their pigment when they die the reason is that their wings are covered in colored scales [Music] the scales lie on top of each other like roof tiles many shimmer brightly depending on the angle of the light of course there are exceptions the wings of the glass moths have very few color scales they look a lot like the transparent wings of a dragonfly [Music] dragonflies are found on all continents their flying skills are astonishing at the end of the Middle Ages humans set out to discover new continents dragon flies were way ahead of them some have been found in mid-ocean 550 kilometers from land they can fly from Libya to Iceland in four days with the wind behind them their speed has been measured of more than a hundred and thirty kilometers an hour many dragonfly species are based in the tropics in South and Central America there's no shortage of fresh water and long stretches of swamps and rainforests hundreds perhaps thousands of dragonfly species are still unknown to science dragon flies stand out many other animals in the rainforest notice them even if they aren't on their menu [Music] capuchin monkeys are very observant and flitting dragonflies are a good source of entertainment [Music] dragonflies are found in equatorial regions right around the globe of course in East Africa the big animals are more conspicuous and more popular easy to forget that dragonflies have lived in Africa for so much longer than the great mammals they were here long before there were rhinos giraffes or elephants dragonflies have settled in the most inhospitable places like the Sahara dragonflies have something vital in common with human civilization both depend on freshwater [Music] this ancient civilization flourished thanks to the River Nile its papyrus marshes have always offered a home to dragonflies [Music] you [Music] the ancient Egyptians worshipped their gods in the form of animals [Music] insects also played an important role for them three thousand four hundred years ago they immortalized dragonflies in their tombs [Music] we humans have four million years of history a history we know so little about dragonflies are 80 times as old as we are they originated an astonishing 320 million years ago in those distant times there was just one single supercontinent Pangea [Music] at that time the greatest variety of life was in the waters of the ancient oceans where life began some of the most complex creatures were the Crustacea transparent jellyfish - swam in both the oceans and the coastal regions [Music] but it would take considerably longer before life could establish itself on land the conquest of the land by plants was a slow process [Music] about 330 million years ago evolution came up with something new forests covering huge stretches of the earth in the Carboniferous fernand club boss trees covered wide areas horsetails grew up to 10 meters but these jungles contained relatively few animal species fish breathing through lungs had made the move from water onto land becoming primitive amphibians and there were giant scorpions as well as huge spiders and 2 meter long multi limbed arthropods but the fern forests concealed other Giants the ancestors of today's dragonflies even 300 million years ago their body plan was so perfect that it has barely changed since except in size the giant dragonflies of the Carboniferous had a wingspan of more than 70 centimeters it was a time of permanent geological change when the earth eroded and shifted if a dragonfly died without being eaten by a scorpion or some other creature there was a good chance it would be preserved quite quickly it was buried in sand and other materials geezers and mud often did the rest before long the body would be completely covered the makeup of the earth and the lack of oxygen hindered decomposition the mud deposits turned into a time capsule over hundreds of millions of years the organic layers turned to stone and their contents to fossils [Music] but although the dragonfly's bodies left perfect imprints or we have from the Carboniferous period our traces in relief about 200 million years ago in the Triassic period the world got a new look giant gingko forests now covered large parts of the earth but the triassic also brought a revolution among land animals the first dinosaurs arrived on the evolutionary scene they will rule the earth for a hundred and seventy million years resin seeps out of wounds in the bark of the ginkgo trees slowly the viscous fluid whose is down dripping off leaves onto the ground everything this sticky glutinous fluid touches is doomed in places resin flows like lava trapping tiny particles on its way when dragonflies come into contact with it their delicate wings can't help them escape [Music] more and more resin lands on them until the Dragonfly is completely covered perfect airtight conservation [Music] this million-year-old resin survived to be washed up on the shores of the Baltic and the Caribbean we know it as amber and very often there's something trapped inside these ancient prisoners are proof that dragonflies have barely changed over the ages you and the reason that time has had no effect on the shape of the dragonfly is that its body design is virtually perfect it's entire body is covered in armor made of chitin the most notable feature is its head it's dominated by two gigantic eyes but they work quite differently from a mammals each eye is composed of up to 30,000 honeycomb dyes forming a hemisphere these compound eyes give almost 360 degree vision dragonflies probably see better than any other insect but the most amazing thing about dragonflies are its two pairs of wings they're constructed around a network of lateral and longitudinal arteries a transparent parchment-like membrane is stretched between them a thin waxy sheath creates the Lotus effect preventing particles of dust sticking to the wings [Music] dragonflies are fast tireless fliers they quickly open up new territories a dragonfly on a reconnaissance flight can reach a height of several hundred meters areas of reeds have an almost magical appeal but often the best habitats are already occupied by other dragonflies and they will defend their territory against any intruder dragonflies know only the law of the strong a battle for supremacy is inevitable the aim is to repulse the enemy the end often sees the loser falling into the water if it falls in deep enough it won't get out again the European Pond Terrapin has remarkable eyesight these carnivorous reptiles are not going to let a drenched insect get away in spite of all these losses enough dragonflies escape for the survival of the species they're complicated mating process is an ancient inheritance unique in the natural world the male grips the female behind its head with pincers at the end of its abdomen the female twists her lower body forward to unite with the male semen sac on the underside of his abdomen [Music] the unusual position that results is known as a mating wheel the males grip can last several seconds or as long as an hour all dragonflies and the smaller damselflies form the mating wheel many damselflies stay connected while they lay their eggs this usually takes place in the water for females poke their abdomen under the surface to deposit their eggs on water plants or leaves all this time the male still clasps the female behind her head at good locations eggs are often laid on mass dozens of couples gather they call these couples tandems because they fly around in this position many female damselflies dive underwater to attach their eggs to the plants they can stay down for up to 90 minutes these middle hawks have a different strategy males and females stay united in their tandem and individually tap their eggs onto water plants in some species of dragonfly the female lays her eggs alone they choose a variety of places sometimes on the water's surface at other times they stick their abdomens deep into the water to place their eggs but not all dragonfly species lay their eggs directly in the water some hide them in moss questions or between stones rain showers will eventually flush the eggs into the water the number of eggs varies between species from as little as 50 to several thousand but they're all tiny the biggest measure hardly more than half a millimeter [Music] Central Europe has more than 200 different species of widow their typical of wet zones they grow next to ponds in water meadows or along the banks of streams when they blossom in spring we know their flowers as catkins [Music] but in the middle of summer they attract a very unusual insect and demonstrate an ingenious survival strategy the willow emerald damselfly lays its eggs directly in willow bark when this happens the male and female are usually still joined in tandem each couple can lay up to 200 eggs for the parents that's the end of the matter deep inside the bark the clutch of eggs survives the winter snow and freezing cold make little impression by the following year in the springtime they're ready months later after the catkin blossoms tiny creatures emerge from the rind these are the micro larvae if they're lucky they fall straight into water where there's water there's life even at a man-made source in the middle of the city how did crows enjoy the bubbling waters not just as a drink but also as a refreshing bar so it's not surprising if dragonflies are found here too whether in the country or in town dragonflies often find their way through an open window into a building [Music] maybe even into the Natural History Museum for this lost insect it's a journey millions of years back in time when dinosaurs ruled the earth and were part of a dragonflies everyday experience thunderstorms a natural phenomenon most dragonflies experienced because most are active in early and mid summer when the sky darkens many stop flying and look for places to rest they'll most likely spend the night here too dragon flies are well protected from most environmental influences rain doesn't usually worry them thanks to the Lotus effect raindrops just slip off their wings but sometimes storms become real downpours [Applause] with the cooling effect of the rain dragonflies lose their strength and many can no longer hold on if they land in the water it's all over and when the Sun comes out again there's a feast on offer [Music] [Music] frogs aren't the only animals that snap up dislodged dragonflies ducks - happily scoop up a dripping morsel [Music] [Music] but most of the dragonflies survived the storm unharmed dragon flies have two lives they spend one of them as virtuoso aviators the other is lived in secret underwater [Music] the Dragonfly eggs have turned into larvae their body plan seems strange even extraterrestrial [Music] damselfly na'vi have slim bodies with rudder blades at the end these are covered with fine tracheal systems that function like lungs damselfly and dragonfly larvae can live in water for many months even years but they already have two things in common with adults of their species they're great compound eyes and they're predators instincts dragonfly larvae eat worms and fly larvae but also vertebrates tadpoles and small fish are on the menu too [Music] their potential prey may be many times their size dragonfly larvae can be several centimetres long when they spot their prey they creep towards it once the victims in range they act with lightning speed they have an extension to their lower jaw that can shoot forward in 20 milliseconds grabbing their quarry and dragging it into their mandibles [Music] there its dismembered and eaten alive this unique method of catching prey has inspired the design of many as sci-fi alien in the movies it may seem brutal but it's no different from the way a lion or a hyena kills its victims and tears them apart after several months or for some species several years the dragonfly larvae finally move on usually by climbing reed stalks or swamp plants it's time for the great metamorphosis that turns a larvae into a dragonfly pressure builds up inside the body until the larvas skin bursts and the shriveled dragonfly emerges [Music] it pumps blood into its wings and around its body to reach its final form [Music] this process can take an hour or more [Music] when it's chitin carapace has hardened it begins to shiver itself warm before taking its maiden flight the only memento of its earlier form is the larvas abandoned skin the XUV heir [Music] sometimes so many dragonflies hatch at the same time they make a swarm depending on the species they will separate almost at once or fly hundreds of kilometres together often towards the Mediterranean but many dragonflies die almost as soon as they hatch there are bird species that specialize in hunting large insects like bees these brightly colored birds breed in holes in mud cliffs and they're young and permanently hungry they don't only hunt stinging insects they're especially fond of dragonflies be eaters like to catch their prey in midair if they see a dragonfly it has little chance [Music] every day dozens end up caught in these sharp beaks these dangerous enemies are found close to water spiders even with their excellent eyesight dragonflies can't spot their webs in the breeding season losses are especially high the wasp spider is a very successful raggin fly hunter the first bite paralyzes this damselfly then the spider wraps it up like a mummy [Music] its fate is sealed it's now a ready meal to be eaten later but spiders aren't the only enemy in the thick vegetation of the riverbank preying mantises are just as dangerous they're lightning fast hunters pitiless eating machines but then dragonflies are really no different one predator vanquishes another but all these daily losses won't threaten the survival of the species [Music] fast flowing rivers and streams don't seem to be the ideal habitat for delicate dragonflies at first sight if there's enough greenery on the riverbanks this is where you'll find some of the most beautiful damsel flies the Demoiselles in contrast to other species their wings are not transparent but shimmer in metallic blues and greens and they're flying style is quite different from the others they don't zip from place to place but flit graciously like a butterfly it can only be appreciated in slow motion [Music] Demoiselles have a wingspan of around seven centimeters there are two kinds the beautiful then was a and the banded Demoiselles they live in similar habitats and show the same behavior these are social insects they often flock together in large groups riverbank plants now become very important serving as lookout posts Demoiselles have a highly developed sense of territory the male's sit on the most exposed twigs and leaves after a patrol they always return to the same place [Music] and then they start a rhythmic wing clapping experts think this is a form of communication within the group [Music] a male Demoiselles has only one priority to impress a female so he can mate with her and so guarantee the survival of the species [Music] it's hard to find wetlands that are completely untouched by humans spring fens and low Mooers are relatively unspoiled this mossy swampy terrain with its puddles and ponds is irresistible to dragonflies this is where the southern skimmer lives a rare species that needs a warm climate this bright blue dragonfly was discovered relatively recently by science the first description dates from 1837 an anonymous looking plant often grows among the moss the edges of its green fleshy leaves turn upwards to make them look like a canoe key this is the butter warped this inconspicuous plant is deadly to insects the soil here isn't nutritious so the but award compensates by catching insects it's leaves are covered in tiny sticky drops deadly traps for dragonflies at the same time the plant secretes a digestive fluid the Dragonfly is slowly dissolved and the butter water absorbs the nutrients Hill mores are an even more extreme habitat carnivorous plants are everywhere the round leaved sundew is the best known of them [Music] these glistening droplets look so inviting like Dew or nectar but they're sticky and if an insect comes into contact with them it usually can't get away [Music] bigger prey like dragonflies are overcome by several parts of a plant working together [Music] if the insect struggles more liquid is secreted [Music] this damselfly desperately tries to swallow the plants secretion but it won't help the sundews digestive enzymes simply get into the damselflies body and dissolve it even faster [Music] near the end of a dragonflies life it's often lost parts of its wings and the colors have begun to fade it's a brief existence seven or eight week old Ragan flies are ancient if they haven't been eaten by their natural enemies they'll eventually fall exhausted to the ground [Music] damselflies have an even shorter life not more than one or two weeks they fulfil a biological function even after day their food for other animals such as ants but the biggest enemy of dragonflies is autumn and winter as the temperatures drop dragonflies have no chance of survival they're cold-blooded and depend on a warm environment to keep their metabolism going with the first Frost's the Dragonfly season rapidly reaches its end further south close to the Mediterranean they have a longer lease on life often they live on small sometimes tiny rocky islands there may be no source of fresh water local vegetation has adapted to the desert conditions humans to have colonized these inhospitable islands using technology [Music] but how did dragonflies survive without freshwater the answer is simple and strange individuals constantly fly in from over the sea because without a supply of freshwater it's impossible to reproduce [Music] when winter takes hold in the temperate zones all the dragonflies have died the next generation spend the winter as larvae beneath the surface in waters that never freeze but some insects managed to survive the frost and ice like the brimstone butterfly they can be frozen stiff but will soar into life again in spring this is made possible by the glycol in its blood and the same is true of the winter damselfly of the thousands of dragonfly and damselfly species only two can survive the winter [Music] when the spring sunshine awakens the insects the ancient cycle of life begins again dragon flies will soon take to the air as they have for 300 million years unfathomable ages before the time of the dinosaurs all human beings [Music] you [Music]

Channel: The Secrets of Nature

Views: 1,879,209

Rating: 4.7108641 out of 5

Keywords: orf universum, documentary, blue chip, natural history, secrets of nature, planet earth, natura, naturaleza, documentales, wildlife, sky hunters, dragonfly, dragonflies, Earth (Planet), Nature (TV Genre), acrobats, flying, insects, british accent, Dragon

Id: knlXTU1R_rE

Length: 49min 48sec (2988 seconds)

Published: Tue Dec 02 2014

Reddit Comments

[u/andyr354]

TIL dragonflies have a very strange way of mating. 21 minutes

[u/ModisDead]

Blocked Countries:
Germany
Austria

[u/catfrog63]

That was interesting, thanks for sharing.

[u/Jasd1234]

Is this in HD anywhere? I'm going to have a quick snoop around now and see if I can find one, can't watch something like this in measly SD!

EDIT: No luck, did find that it was released in 2010 not 2014 though

[u/thyris]

Dragonflies are my favorite insects, so glad there's a doc about them! Thanks