0:00:02 > 0:00:05Our planet is the greatest living puzzle in the universe.
0:00:05 > 0:00:08A collection of worlds within worlds.
0:00:08 > 0:00:12Each one a network of relationships and connections
0:00:12 > 0:00:14between all their living parts,
0:00:14 > 0:00:18leading to the diverse and complex world we live in.
0:00:21 > 0:00:23And at the heart of many of these worlds
0:00:23 > 0:00:25is a very special group of animals...
0:00:26 > 0:00:31..the insects and their close relatives, the arachnids
0:00:31 > 0:00:35and crustaceans - classed together as the arthropods.
0:00:37 > 0:00:41Together they account for 80% of all animal species on our planet.
0:00:42 > 0:00:45In these three specials, we're going to explore the connections
0:00:45 > 0:00:49and relationships that they have with us,
0:00:49 > 0:00:50our planet...
0:00:52 > 0:00:54..and with each other.
0:00:54 > 0:00:57Ultimately to understand how this group
0:00:57 > 0:01:04hold the key to life itself inside nature's microworlds.
0:01:11 > 0:01:12At least one species of Arthropod
0:01:12 > 0:01:15can be found in every microworld on Earth.
0:01:16 > 0:01:20From baking deserts and lush rainforests...
0:01:22 > 0:01:24..to open oceans...
0:01:25 > 0:01:28..and dark caves.
0:01:33 > 0:01:36And although seemingly insignificant in size...
0:01:39 > 0:01:42..the influence they have on our planet is immense.
0:01:51 > 0:01:55But to understand how arthropods have come to play such a vital role,
0:01:55 > 0:01:59we must explore a wide variety of ecosystems.
0:02:04 > 0:02:06And we'll investigate the arthropods'
0:02:06 > 0:02:08greatest influence of all.
0:02:08 > 0:02:12Could they be responsible for the richness and diversity
0:02:12 > 0:02:13of nature's many microworlds?
0:02:21 > 0:02:22There's one microworld
0:02:22 > 0:02:26where the impact of a single species of arthropod is evident -
0:02:26 > 0:02:28the Argentinean Pampas Grassland.
0:02:30 > 0:02:36A landscape that's been created almost solely by one tiny creature.
0:02:39 > 0:02:40Grass cutter ants.
0:02:42 > 0:02:45These insects are only one-and-a-half centimetres long
0:02:45 > 0:02:48and yet they achieve something few animals are capable of.
0:02:51 > 0:02:52Through their activities,
0:02:52 > 0:02:54they have completely altered their own environment.
0:02:57 > 0:03:00Grass cutter ants are the farmers of these grasslands
0:03:00 > 0:03:03and like farmers, they shape the vegetation.
0:03:06 > 0:03:09Each year, a single colony will harvest
0:03:09 > 0:03:12over half a tonne of grass cuttings.
0:03:15 > 0:03:19Surprisingly, these ants don't actually eat grass,
0:03:19 > 0:03:22but they have found a way to cultivate their crops
0:03:22 > 0:03:24and this happens underground.
0:03:28 > 0:03:31Their nests dominate the subterranean environment
0:03:31 > 0:03:34with tunnels extending over seven metres deep.
0:03:35 > 0:03:37Here they share their chambers
0:03:37 > 0:03:40with a special fungus that's found nowhere else on Earth.
0:03:43 > 0:03:46And this fungus can digest grass.
0:03:47 > 0:03:50The ants feed their grass harvest to the fungus
0:03:50 > 0:03:54and in return the fungus produces edible gardens.
0:03:56 > 0:03:59These fungus gardens are prolific enough
0:03:59 > 0:04:01to feed the whole colony of ants.
0:04:01 > 0:04:03All 5 million of them!
0:04:05 > 0:04:08But their impact does not end there.
0:04:10 > 0:04:12They also alter the landscape.
0:04:13 > 0:04:16The fungus releases carbon dioxide -
0:04:16 > 0:04:18lethal in large concentrations.
0:04:18 > 0:04:22But the ants have a clever way of combating its build up.
0:04:24 > 0:04:28They construct massive towers that help draw fresh air in
0:04:28 > 0:04:29and suck stale air out,
0:04:29 > 0:04:32effectively acting like air conditioners.
0:04:34 > 0:04:35These grass cutter ants,
0:04:35 > 0:04:38with their incredible building and farming skills,
0:04:38 > 0:04:41have completely shaped this microworld.
0:04:41 > 0:04:45An ecosystem which, without the ants, would not even exist.
0:04:48 > 0:04:51The arthropods' domination of an environment
0:04:51 > 0:04:53is not always so complete
0:04:53 > 0:04:55but it can have just as big an impact.
0:04:59 > 0:05:02In the most expansive ecosystem on our planet,
0:05:02 > 0:05:06an arthropod plays such a key role that, without it,
0:05:06 > 0:05:10the largest animal that has EVER lived could not exist.
0:05:12 > 0:05:17Life within the ocean evolved 3 billion years prior to life on land.
0:05:20 > 0:05:24And today it's the home of 230,000 marine animal species.
0:05:28 > 0:05:30Arguably the most important of these,
0:05:30 > 0:05:32the ones that are the key
0:05:32 > 0:05:35to this whole interconnected oceanic ecosystem are...
0:05:37 > 0:05:38..the krill.
0:05:42 > 0:05:46Found across the world's oceans, from the tropics to the poles,
0:05:46 > 0:05:49these arthropods fuel the ocean's food chain.
0:05:51 > 0:05:54The reason they're so vital to sustaining life in the oceans
0:05:54 > 0:05:58is their ability to consume phytoplankton on a massive scale.
0:06:01 > 0:06:03Phytoplankton are microscopic organisms -
0:06:03 > 0:06:05the sea's equivalent of grass.
0:06:05 > 0:06:10So vast in number, their blooms can be seen from space.
0:06:12 > 0:06:17And krill are the ocean's biggest consumer of phytoplankton.
0:06:20 > 0:06:22Just one species, the Antarctic Krill,
0:06:22 > 0:06:28has a combined mass of 379 million tonnes.
0:06:28 > 0:06:30That's over 90 million tonnes heavier
0:06:30 > 0:06:32than the biomass of the whole human race.
0:06:34 > 0:06:37Few large animals can feed on the ocean's phytoplankton
0:06:37 > 0:06:39but they can feed on krill.
0:06:40 > 0:06:43So these tiny arthropods are a critical link
0:06:43 > 0:06:45at the bottom of the ocean's food chain.
0:06:47 > 0:06:50The krill feed the fish, which feed bigger fish,
0:06:50 > 0:06:52which feed the birds and seals,
0:06:52 > 0:06:55and so the food chain continues.
0:06:57 > 0:07:01But sometimes the number of links in the chain is remarkably small.
0:07:04 > 0:07:05The blue whale.
0:07:07 > 0:07:09The biggest animal that's ever lived on the planet
0:07:09 > 0:07:12has short-circuited the ocean's food chain
0:07:12 > 0:07:14and gone straight for the krill.
0:07:17 > 0:07:20Rather than teeth, these ocean giants are equipped
0:07:20 > 0:07:22with a fine mesh of bristles, called baleen,
0:07:22 > 0:07:26which allow each whale to filter out up to 40 million krill a day.
0:07:33 > 0:07:39Without these tiny arthropods, the blue whale may never have evolved.
0:07:43 > 0:07:48Arthropods play a pivotal role in the underwater web of life
0:07:48 > 0:07:51but their influence isn't just confined to the sea.
0:07:56 > 0:08:00On dry land, arthropods are also the key food source
0:08:00 > 0:08:02for a whole host of other animals.
0:08:05 > 0:08:06Birds...
0:08:06 > 0:08:08reptiles...
0:08:08 > 0:08:10amphibians...
0:08:10 > 0:08:12and mammals.
0:08:15 > 0:08:18Like the blue whales, there are also land-based animals
0:08:18 > 0:08:21that have special adaptations for feeding on arthropods,
0:08:21 > 0:08:25like the pangolin with its powerful digging claws.
0:08:29 > 0:08:33And the giant anteater that has a 60cm long tongue,
0:08:33 > 0:08:36perfect for reaching into ant and termite mounds.
0:08:43 > 0:08:46But there's an even more surprising group of predators
0:08:46 > 0:08:49that rely on arthropods for their food.
0:08:49 > 0:08:53And they don't even belong to the animal kingdom.
0:08:53 > 0:08:57One species can be found in the boglands of Scotland.
0:08:57 > 0:09:00The soil here is waterlogged and lacking in vital nutrients,
0:09:00 > 0:09:02especially nitrogen.
0:09:03 > 0:09:07Under such conditions few plants can grow
0:09:07 > 0:09:09but thanks to the presence of arthropods,
0:09:09 > 0:09:11one species has found a way.
0:09:13 > 0:09:16This strange-looking plant is the sundew -
0:09:16 > 0:09:20so named because of the dew-like droplets on its leaves -
0:09:20 > 0:09:22but they're also extremely sticky.
0:09:26 > 0:09:29Their sweet smell attracts many insects.
0:09:31 > 0:09:34As mosquitoes emerge from the boggy water,
0:09:34 > 0:09:36they're drawn straight into a sticky trap.
0:09:41 > 0:09:45Sensitive to touch, the tentacles quickly wrap around the prey.
0:09:49 > 0:09:52Eventually, the insect dies in the sticky fluid.
0:09:53 > 0:09:57With the help of enzymes, its body is absorbed by the sundew.
0:10:00 > 0:10:04Without insects, this plant would not survive.
0:10:04 > 0:10:09And without arthropods, many of our planet's food chains would collapse.
0:10:11 > 0:10:13While the arthropods' role as a food source
0:10:13 > 0:10:16is crucial to the survival of millions of animals
0:10:16 > 0:10:17and even some plants,
0:10:17 > 0:10:20it's only a part of the giant jigsaw
0:10:20 > 0:10:23that makes our planet's ecosystems tick.
0:10:30 > 0:10:33Nutrients form the building blocks of life.
0:10:33 > 0:10:35So, for a microworld to maintain its balance,
0:10:35 > 0:10:38it's vital that these nutrients aren't wasted.
0:10:41 > 0:10:43This is where our next team of arthropods
0:10:43 > 0:10:47play a critical role as the recyclers.
0:10:50 > 0:10:52Within the rainforests of Borneo,
0:10:52 > 0:10:56a giant cave is home to a staggering 3 million wrinkle-lipped bats.
0:10:59 > 0:11:02With over 37 tonnes of insects consumed every night,
0:11:02 > 0:11:05a huge mound of bat droppings builds up.
0:11:07 > 0:11:09But this waste isn't wasted.
0:11:10 > 0:11:12Reaching up to 100 metres in height,
0:11:12 > 0:11:17this nutrient-rich mound fuels a seething mass of cockroaches.
0:11:19 > 0:11:23One of the densest concentrations of cockroaches in the world.
0:11:27 > 0:11:31Working with bacteria and fungi, they break down the faeces.
0:11:35 > 0:11:38This is how they keep this giant mound under control
0:11:38 > 0:11:42and keep the nutrients moving around this tightly connected microworld.
0:11:46 > 0:11:49It's the recyclers that hold the key to this cave's ecosystem.
0:11:53 > 0:11:56But their influence is perhaps even greater 5,000 miles away,
0:11:56 > 0:11:58on the plains of Africa.
0:12:00 > 0:12:02This is the Serengeti...
0:12:05 > 0:12:07..home to the big five...
0:12:15 > 0:12:16..and the dung beetles.
0:12:24 > 0:12:28Using their remarkable sense of smell, they hone in on their target.
0:12:30 > 0:12:34True to their name, dung beetles are the masters of recycling dung.
0:12:36 > 0:12:38They don't need to eat or drink anything else,
0:12:38 > 0:12:41as dung provides all the moisture and nutrients they need.
0:12:47 > 0:12:51As the beetles roll off and bury their own food balls,
0:12:51 > 0:12:53the dung patch quickly vanishes.
0:12:56 > 0:13:00But for these beetles, dung isn't just a good source of food.
0:13:01 > 0:13:05This male is building a giant brood ball, to help him entice a female.
0:13:16 > 0:13:18Mission accomplished!
0:13:24 > 0:13:27And now the female has the perfect place to lay her eggs.
0:13:30 > 0:13:33While the beetles' circle of life is centred around dung,
0:13:33 > 0:13:38the grasslands' entire ecosystem is centred around the dung beetles.
0:13:42 > 0:13:45Without these amazingly efficient recyclers,
0:13:45 > 0:13:48the daily dose of 5,000 tonnes of dung
0:13:48 > 0:13:50would soon swamp the African plains.
0:13:53 > 0:13:55Thanks to the cleaning up operations of dung beetles,
0:13:55 > 0:13:58the grasslands are nurtured,
0:13:58 > 0:14:00allowing the grazers to be fed,
0:14:00 > 0:14:03which in turn sustain the predators.
0:14:16 > 0:14:20And it's in death where another team of arthropod recyclers
0:14:20 > 0:14:21come into their own.
0:14:30 > 0:14:33Blow flies can smell a dead body from up to a mile away.
0:14:36 > 0:14:38As soon as they arrive, there's a frenzy of egg laying
0:14:38 > 0:14:42as each female deposits up to 300 eggs on the carcass.
0:14:47 > 0:14:50In just under 24 hours the eggs hatch,
0:14:50 > 0:14:53allowing the voracious maggots to get to work on the flesh.
0:14:56 > 0:14:59Using special enzymes and their claw-like mouthparts,
0:14:59 > 0:15:03they can break down proteins in next to no time.
0:15:03 > 0:15:06In less than a week, they'll have moulted twice,
0:15:06 > 0:15:08consumed 60% of the carcass
0:15:08 > 0:15:10and increased tenfold in size.
0:15:13 > 0:15:16With feeding over, the maggot begins its next stage of life.
0:15:19 > 0:15:23Within a few days, a fly emerges.
0:15:23 > 0:15:27This will go on to mate and produce the next generation of recyclers.
0:15:30 > 0:15:33So efficient are these recyclers that, despite their size,
0:15:33 > 0:15:35arthropods process more flesh
0:15:35 > 0:15:37than all the large carnivores put together.
0:15:48 > 0:15:50By cleaning up dead animals,
0:15:50 > 0:15:53the waste disposal teams of the arthropod world
0:15:53 > 0:15:55limit the spread of disease
0:15:55 > 0:15:58and ensure the return of nutrients back into the food chain.
0:15:59 > 0:16:03This is all part of keeping nature's microworlds in balance
0:16:03 > 0:16:07but there is a twist in this tale.
0:16:07 > 0:16:10The arthropods' efficiency and ability to reproduce quickly
0:16:10 > 0:16:14means that their populations could easily spiral out of control.
0:16:16 > 0:16:18So who keeps the arthropods in check?
0:16:21 > 0:16:24The answer is the arthropods themselves.
0:16:27 > 0:16:29The woodlands of England.
0:16:34 > 0:16:38Spiders mostly prey on insects and other spiders
0:16:38 > 0:16:41and they use a range of strategies to capture their prey.
0:16:42 > 0:16:45The best-known is this - the sticky web.
0:16:47 > 0:16:50An orb web can contain up to 60 metres of silk
0:16:50 > 0:16:53and involve 3,000 different attachments.
0:16:54 > 0:16:58It takes about an hour to build and then it's just a waiting game.
0:17:02 > 0:17:06She sits at the centre with her legs resting on the spokes.
0:17:07 > 0:17:10Ready to pick up the tiniest vibration.
0:17:12 > 0:17:17As soon as a tremor spreads down the web, she pulls on different spokes.
0:17:19 > 0:17:23In this way, she can work out exactly where her prey has landed.
0:17:25 > 0:17:27With her feet coated in a special oil,
0:17:27 > 0:17:29she can move freely across her web
0:17:29 > 0:17:32to secure and then devour her victim.
0:17:35 > 0:17:38While this capture has gone perfectly to plan,
0:17:38 > 0:17:39it's not always the case.
0:17:42 > 0:17:45About half the potential prey manage to escape.
0:17:52 > 0:17:55But there's another web that's a more effective trap
0:17:55 > 0:17:58and it's designed by the aptly-named triangle spider.
0:18:01 > 0:18:05Its web may not look as impressive as the classic orb web
0:18:05 > 0:18:07but it is far more deadly.
0:18:09 > 0:18:12The spider's body forms an essential link in her trap.
0:18:12 > 0:18:16But to be effective, she has to ratchet up the tension.
0:18:17 > 0:18:18Tighter...
0:18:18 > 0:18:20and tighter.
0:18:26 > 0:18:30On this web, flies don't get a second chance.
0:18:32 > 0:18:35Their impact triggers the spider's release,
0:18:35 > 0:18:38causing the web to fire and entangle the prey.
0:18:39 > 0:18:42Few flies manage to escape.
0:18:42 > 0:18:45Which is pretty good for an individual's web
0:18:45 > 0:18:47but when spiders team together,
0:18:47 > 0:18:50the results are even more impressive.
0:18:54 > 0:18:56In the rainforests of South America,
0:18:56 > 0:19:01a section of the canopy is enveloped in a massive tangle of webs.
0:19:03 > 0:19:04This tree-top death trap
0:19:04 > 0:19:08is the work of tens of thousands of tiny spiders.
0:19:16 > 0:19:20Spanning three metres across, it can capture a whole host of prey.
0:19:26 > 0:19:28Including this cricket,
0:19:28 > 0:19:31which is several hundred times larger than the spiders.
0:19:32 > 0:19:34But that doesn't put these spiders off.
0:19:37 > 0:19:40Working together, they can kill prey many times their own size.
0:19:47 > 0:19:50They squirt glue from their spinnerets,
0:19:50 > 0:19:52immobilising the cricket,
0:19:52 > 0:19:54and then they inject their venom.
0:20:00 > 0:20:02Before long, their victim is dead
0:20:02 > 0:20:05and now they begin their communal feast.
0:20:22 > 0:20:25Numbering over 40,000 species,
0:20:25 > 0:20:30spiders are found across the globe and exist in nearly every habitat.
0:20:32 > 0:20:34Thanks to their silken traps and venom,
0:20:34 > 0:20:36these predators play a pivotal role
0:20:36 > 0:20:39in keeping the planet's many microworlds in balance.
0:20:42 > 0:20:45The controllers of the arthropod world are a key piece of the puzzle
0:20:45 > 0:20:48that keeps our planet ticking over
0:20:48 > 0:20:50but they're not the most important.
0:20:53 > 0:20:55To find out what is, we need to explore
0:20:55 > 0:20:58a far more harmonious relationship,
0:20:58 > 0:21:01one that began in prehistoric times.
0:21:06 > 0:21:10140 million years ago, the world was a very different place.
0:21:10 > 0:21:15The plant kingdom was dominated by a few species of conifers and ferns.
0:21:16 > 0:21:22For these plants, sexual reproduction relies upon either the wind or water.
0:21:25 > 0:21:27With millions of tiny pollen grains
0:21:27 > 0:21:30dispersed in the hope that some are intercepted
0:21:30 > 0:21:32by individuals of the same species.
0:21:34 > 0:21:36Rich in oils and proteins,
0:21:36 > 0:21:40pollen grains are expensive to produce and the majority are wasted.
0:21:47 > 0:21:49But then an incredible relationship began,
0:21:49 > 0:21:52which would change the colour and diversity of our planet
0:21:52 > 0:21:56and ultimately create the richest ecosystem of all.
0:21:59 > 0:22:02The presence of insects allowed a new kind of plant to evolve.
0:22:06 > 0:22:07The flowering plants.
0:22:10 > 0:22:12To reduce the squandering of pollen,
0:22:12 > 0:22:15these plants no longer relied on wind or water for pollination,
0:22:15 > 0:22:20instead they recruited insects to pollinate them
0:22:20 > 0:22:22with nectar-loaded flowers.
0:22:25 > 0:22:29Tailoring their advertisements to match insect senses,
0:22:29 > 0:22:32a burst of colour and smell quickly spread across the planet.
0:22:48 > 0:22:50In the fields of southern France,
0:22:50 > 0:22:53sunflowers grow to face the rising sun.
0:22:57 > 0:22:59One after another,
0:22:59 > 0:23:02hundreds of individual florets produce pollen-covered stamens.
0:23:05 > 0:23:07As these bees busily feed on nectar,
0:23:07 > 0:23:10they brush against the stamens collecting pollen
0:23:10 > 0:23:13and then carry it from flower to flower.
0:23:15 > 0:23:18The sunflower's fertilised and the bee is fed -
0:23:18 > 0:23:21it's a win-win situation.
0:23:24 > 0:23:29Over the generations, this mutually beneficial relationship
0:23:29 > 0:23:32has created some incredibly specialised partnerships
0:23:32 > 0:23:36between arthropods and the flowers they pollinate.
0:23:36 > 0:23:41One of which can be found in the grasslands of England.
0:23:44 > 0:23:47The pyramidal orchid keeps its nectar rewards
0:23:47 > 0:23:50at the end of long tubes formed by the petals,
0:23:50 > 0:23:53so that a long tongue is needed to get it out.
0:23:56 > 0:23:58The burnet moth has one such tongue.
0:24:00 > 0:24:03As it feeds, a horseshoe-shaped package of pollen
0:24:03 > 0:24:05clips onto its long proboscis.
0:24:07 > 0:24:10The only way the moth can remove the pollen
0:24:10 > 0:24:13is by visiting other pyramidal orchids.
0:24:15 > 0:24:18This time, as its tongue reaches for a nectar drink,
0:24:18 > 0:24:20the pollen sacks come into contact
0:24:20 > 0:24:22with the flower's sticky female surface
0:24:22 > 0:24:25and a speck of pollen is transferred across.
0:24:27 > 0:24:28The flower is pollinated.
0:24:45 > 0:24:47But an even more elaborate partnership
0:24:47 > 0:24:50has evolved in the rainforests of Central America.
0:24:52 > 0:24:57This strange-looking flower is a bucket orchid.
0:24:57 > 0:25:02Instead of nectar, it has another offering for its arthropod partner.
0:25:03 > 0:25:06The euglossine bee is attracted to special fragrant oils
0:25:06 > 0:25:09on the orchid's petals.
0:25:09 > 0:25:11It gathers these oils into pouches on its legs
0:25:11 > 0:25:15and will later use this perfume to attract female bees.
0:25:17 > 0:25:19Other creatures are attracted to this flower
0:25:19 > 0:25:24but after slipping into the flower's fluid-filled buckets, few survive.
0:25:27 > 0:25:31While the bee depends on the orchid for its reproduction,
0:25:31 > 0:25:33the orchid likewise depends on the bee.
0:25:36 > 0:25:38Unlike other insects,
0:25:38 > 0:25:41falling into the orchid's trap is not fatal for this bee.
0:25:41 > 0:25:45The bucket orchid has an escape route
0:25:45 > 0:25:48specifically designed for its partner.
0:25:48 > 0:25:53Most of the flower is covered in a slippery fluid
0:25:53 > 0:25:58but tiny knobs, which the bee can grab onto, guide it to an exit.
0:26:01 > 0:26:03And, as it squeezes through the gap,
0:26:03 > 0:26:04just big enough for the bee,
0:26:04 > 0:26:07the flower's pollen is glued onto its back.
0:26:18 > 0:26:21With its precious cargo secured, the bee prepares for flight.
0:26:33 > 0:26:36On its next visit to a bucket orchid,
0:26:36 > 0:26:38the bee fulfils its part of the deal.
0:26:42 > 0:26:46While gathering more aromatic oils, it's lured into the flower again.
0:26:50 > 0:26:52And this time, as it leaves,
0:26:52 > 0:26:55the pollen packets are deposited onto the new flower.
0:27:00 > 0:27:02The orchid is fertilised.
0:27:06 > 0:27:08And it's through this process, pollination,
0:27:08 > 0:27:12that arthropods have exerted their greatest influence of all.
0:27:16 > 0:27:18For over 100 million years,
0:27:18 > 0:27:22the pollinators and their flowering partners have evolved,
0:27:22 > 0:27:24diversified...
0:27:25 > 0:27:28..and spread across the planet.
0:27:38 > 0:27:41With their success came an explosion of life,
0:27:41 > 0:27:44as they created new opportunities,
0:27:44 > 0:27:46new habitats
0:27:46 > 0:27:48and new ecosystems.
0:27:50 > 0:27:52Today there are over a quarter of a million species
0:27:52 > 0:27:54of arthropod pollinators.
0:27:54 > 0:27:5880% of all plant species on Earth depend on them
0:27:58 > 0:28:02and without them some of the richest ecosystems on our planet,
0:28:02 > 0:28:06including the tropical rainforests,
0:28:06 > 0:28:08would not even exist.
0:28:08 > 0:28:11From the harvesters and providers
0:28:11 > 0:28:14to the recyclers and controllers...
0:28:15 > 0:28:20..each group of arthropods has a truly astonishing influence
0:28:20 > 0:28:22on the workings of our planet.
0:28:24 > 0:28:26But it's ultimately the pollinators
0:28:26 > 0:28:29that have the greatest influence of all.
0:28:57 > 0:29:01Subtitles by Red Bee Media Ltd