0:00:03 > 0:00:06'We are about to embark on an ambitious project.
0:00:10 > 0:00:13'Something that's never been tried before.
0:00:16 > 0:00:18'It will show us a hidden world.'
0:00:23 > 0:00:25I'm standing in the middle of something
0:00:25 > 0:00:27that you would never normally see.
0:00:29 > 0:00:32It's taken six months from planning to this.
0:00:38 > 0:00:41A new home for one million
0:00:41 > 0:00:44of nature's most extraordinary creatures.
0:00:47 > 0:00:49Ants.
0:00:52 > 0:00:57'They fascinate us. They build complex, organised societies.
0:00:59 > 0:01:03'And we've always drawn parallels between the world and ours.'
0:01:04 > 0:01:07It's basically an ant production line.
0:01:09 > 0:01:11'So what can we learn from ants?'
0:01:13 > 0:01:17One ant in two million, and we found her. Fantastic.
0:01:18 > 0:01:22To find out, we've brought a working colony of leafcutter ants
0:01:22 > 0:01:24from the tropics of Central America.
0:01:28 > 0:01:32We've recreated their nest so that we can see inside.
0:01:35 > 0:01:39And for one month, we're going to capture every aspect of their lives.
0:01:42 > 0:01:43'We'll track them.'
0:01:43 > 0:01:46This is going to be great, because this is going to tell us
0:01:46 > 0:01:48what these soldiers are doing in the ground.
0:01:48 > 0:01:51'We'll listen to them.'
0:01:51 > 0:01:52That little chirp?
0:01:52 > 0:01:53Yeah.
0:01:53 > 0:01:55'And get right up close to them.'
0:01:55 > 0:01:57One's gone down my front!
0:01:59 > 0:02:01'We'll go beyond our own ant metropolis
0:02:01 > 0:02:05'to meet some of the most impressive ants on the planet.'
0:02:07 > 0:02:09It's not just a group of ants holding on to each other,
0:02:09 > 0:02:11it's a survival raft.
0:02:11 > 0:02:13It is. It's a force to be reckoned with.
0:02:15 > 0:02:18'And discover the surprising ways in which ants
0:02:18 > 0:02:20'are helping us solve global problems.
0:02:25 > 0:02:27'I'm an entomologist, and even to me,
0:02:27 > 0:02:30'what ants can achieve is astonishing.'
0:02:32 > 0:02:36'Our project will show their world as it's never been seen before,
0:02:36 > 0:02:41'and reveal what they can teach us about ourselves.'
0:02:55 > 0:02:59Glasgow. Not the natural home for leafcutter ants.
0:03:01 > 0:03:02But over four weeks,
0:03:02 > 0:03:07the Science Centre here will play host to our ambitious project.
0:03:09 > 0:03:13Our goal, to unlock the secrets of the ant colony.
0:03:15 > 0:03:19Well, the stage is now set for our remarkable experiment.
0:03:19 > 0:03:21It's hot and humid in here,
0:03:21 > 0:03:24and everything you see here is based on real-life.
0:03:28 > 0:03:32Well, this is normally all you'd see of a leafcutter ant colony,
0:03:32 > 0:03:37the bit above ground - ants taking bits of leaf underground.
0:03:37 > 0:03:41Now, like an iceberg, the main event isn't the bit you can see,
0:03:41 > 0:03:44it's what's happening beneath, and that's a part of the ant colony
0:03:44 > 0:03:48that even scientists like me rarely ever see.
0:03:53 > 0:03:57In the wild, the leafcutters dig huge underground nests.
0:04:00 > 0:04:04We've used their natural design to inspire our own creation.
0:04:08 > 0:04:09Down below here, underground,
0:04:09 > 0:04:13we've tried to recreate what an ant colony would look like.
0:04:13 > 0:04:18These boxes represent chambers in the soil, and the walkways are tunnels
0:04:18 > 0:04:22in the soil by which the ants can access all parts of the colony.
0:04:27 > 0:04:32'But the leafcutters need more than just a nest. They also need to feed.'
0:04:34 > 0:04:38'We've built them a whole environment where they'll be able to search
0:04:38 > 0:04:41'or forage for food as they would do in the wild.'
0:04:44 > 0:04:49We've got plants in certain areas joined up to a main foraging area
0:04:49 > 0:04:51with these rope walkways.
0:04:51 > 0:04:53Now, in the real world, in the natural habitat,
0:04:53 > 0:04:56these would be creepers and other plans.
0:04:56 > 0:04:59Now, as you can see, there are no ants on it yet, but there will be.
0:05:01 > 0:05:04In a short while, we'll let the ants loose
0:05:04 > 0:05:07over this whole new world we've built for them.
0:05:07 > 0:05:11And over the next month, I'm going to be really interested to see
0:05:11 > 0:05:15how they take control of it and how the colony develops.
0:05:20 > 0:05:22'Joining me is Professor Adam Hart
0:05:22 > 0:05:24'from the University of Gloucestershire.
0:05:24 > 0:05:28'He's studied the leafcutters for over 15 years.
0:05:28 > 0:05:31'He's helped design a series of experiments
0:05:31 > 0:05:34'to uncover how the colony works.
0:05:34 > 0:05:36'And the first thing he's going to do
0:05:36 > 0:05:39'is help us see inside one of the boxes.'
0:05:43 > 0:05:46Adam, what's happening inside the box?
0:05:46 > 0:05:48Hundreds of ants are attacking this camera!
0:05:48 > 0:05:50Let's just try and wiggle it around a bit.
0:05:52 > 0:05:54Now that box is absolutely swarming with ants,
0:05:54 > 0:05:57and they don't seem terribly happy with your camera in there.
0:05:57 > 0:05:58No.
0:06:01 > 0:06:06'This is my first glimpse into the hidden world of our ant nest.
0:06:06 > 0:06:09'In the wild, this would be an underground chamber,
0:06:09 > 0:06:12'excavated by the ants themselves.
0:06:13 > 0:06:17'And inside here is something vital to the colony.'
0:06:20 > 0:06:22This grey material here is fungus, in fact,
0:06:22 > 0:06:24which they're farming inside the nests.
0:06:24 > 0:06:27They're using those leaves that they cut to help them grow this fungus.
0:06:31 > 0:06:35'Leafcutter ants, despite their name, don't eat leaves.
0:06:35 > 0:06:39'They bring them into the nest as a food supply for this fungus,
0:06:39 > 0:06:41'and it's the fungus that they eat.
0:06:43 > 0:06:47'Our ants are farmers, and the fungus is their crop.'
0:06:49 > 0:06:53This means I can see right into the nest,
0:06:53 > 0:06:58I can see the fine details of their normally hidden lives.
0:06:58 > 0:06:59This is just incredible.
0:07:07 > 0:07:09'In among the fungus, the white,
0:07:09 > 0:07:12'translucent shapes you can see are the brood.
0:07:12 > 0:07:16'That's the young of the colony, the eggs, larvae and pupae.'
0:07:20 > 0:07:22'Here we can see the adults attacking the camera,
0:07:22 > 0:07:26'whilst in the background, the brood is whisked away to safety.
0:07:30 > 0:07:35'All that brood, every single egg, is laid by one ant - the queen.
0:07:38 > 0:07:40'She's hidden somewhere deep within the nest,
0:07:40 > 0:07:43'and hopefully we'll be able to track her down later.
0:07:46 > 0:07:50'Right now, I want to open up this box and get my hands on some ants.'
0:07:52 > 0:07:55Let me just get a bit out. I'll try and avoid getting a big soldier.
0:07:55 > 0:07:58Try and avoid a soldier, yeah, I wouldn't like that very much.
0:08:00 > 0:08:04'The soldiers, as the name suggests, are ants who protect the nest.
0:08:05 > 0:08:07'They're big, and they bite.'
0:08:09 > 0:08:11I haven't managed to avoid a soldier.
0:08:11 > 0:08:13Haven't you? Oh, thanks. Oh, it just bit me! Thank you.
0:08:13 > 0:08:15- There's a big one there. - Yeah, a big one.
0:08:15 > 0:08:19One of them has just bitten my hand. Ah!
0:08:19 > 0:08:20Wow.
0:08:20 > 0:08:22There is a massive soldier -
0:08:22 > 0:08:25ow! - who has just found a crease in my skin,
0:08:25 > 0:08:30has sunk her jaws right into my skin, that's actually quite painful.
0:08:30 > 0:08:31Yeah.
0:08:31 > 0:08:38Now, you can see why the soldiers are so good at defending the colony.
0:08:40 > 0:08:42Adam, I think I've had enough of holding this.
0:08:42 > 0:08:43Shall we put it back?
0:08:43 > 0:08:45Yes, if you could scoop that out.
0:08:50 > 0:08:54'The soldiers are just one kind of ant in our leafcutter colony.'
0:08:57 > 0:09:00Now, the first thing that is really obvious when you look at an ant
0:09:00 > 0:09:04colony is that the adult ants seem to be of different sizes.
0:09:04 > 0:09:07Now, it's not because they're not fully grown,
0:09:07 > 0:09:09it's because they are different castes of ants,
0:09:09 > 0:09:13and under here I've got three different castes of worker ant.
0:09:14 > 0:09:18'In the insect world, a caste system means that individuals
0:09:18 > 0:09:22'differ in shape and size within a single species.'
0:09:25 > 0:09:30So you can see the range of size from the very, very small workers,
0:09:30 > 0:09:34to the middle-sized workers, and the very large workers here.
0:09:34 > 0:09:36And they're different sizes for a good reason.
0:09:36 > 0:09:39Each of these castes of ants have a different job to do.
0:09:43 > 0:09:48'I've already had a painful encounter with one of these, a soldier.
0:09:48 > 0:09:51'That head isn't filled with a large brain,
0:09:51 > 0:09:56'rather a massive set of muscles to power a fearsome pair of jaws,
0:09:56 > 0:09:59'or mandibles, strong enough to cut through my skin.
0:10:04 > 0:10:06'Going down the size scale,
0:10:06 > 0:10:09'this smaller ant is called a media worker.
0:10:11 > 0:10:15'These are the hands that collect and bring leaves back to the nest.
0:10:16 > 0:10:19'It's serrated jaws are just the right shape
0:10:19 > 0:10:22'for cutting into tough plant material.
0:10:26 > 0:10:29'At the very bottom of the scale are the minima,
0:10:29 > 0:10:31'the most numerous ants of all.
0:10:37 > 0:10:42'These tiny nest mates effectively turn the leaves into fungus
0:10:42 > 0:10:43'and tend to the brood.
0:10:47 > 0:10:50'So the first thing we learn from our colony is that the labour
0:10:50 > 0:10:52'is divided between all its members.
0:10:54 > 0:10:57'Each caste of ant has a role to play.
0:11:10 > 0:11:14'To allow us to investigate how all these different castes
0:11:14 > 0:11:17'organise themselves and work together,
0:11:17 > 0:11:20'we needed a supply of ants on an epic scale.
0:11:21 > 0:11:24'Not just a handful bred in a laboratory,
0:11:24 > 0:11:28'but a thriving, working colony from the wild.
0:11:28 > 0:11:31'And Adam was giving the job of tracking one down.'
0:11:42 > 0:11:45'I've come to Trinidad, just off the coast of Venezuela,
0:11:46 > 0:11:48'and I'm on my way to a colony of leafcutter ants
0:11:48 > 0:11:51'that sounds perfect for our project.'
0:11:53 > 0:11:54Leafcutters are native here,
0:11:54 > 0:11:58and they're considered a serious agricultural pest.
0:12:00 > 0:12:03The colony we found was about to be destroyed by a farmer.
0:12:04 > 0:12:07We want to rescue it and take it back to the UK.
0:12:13 > 0:12:17'But digging up a nest of this scale won't be an easy task.'
0:12:18 > 0:12:19They're huge.
0:12:19 > 0:12:22There's tens of thousands of very aggressive soldiers
0:12:22 > 0:12:24that will come out and bite you,
0:12:24 > 0:12:27but we're going to have to do it almost surgically when we begin,
0:12:27 > 0:12:31because we really need to make sure that we don't kill that queen.
0:12:31 > 0:12:33The queen is the absolute critical thing in this colony.
0:12:33 > 0:12:35We can get away with not bringing all the ants back,
0:12:35 > 0:12:39but if we don't have the Queen intact, then we're stuck.
0:12:44 > 0:12:47'Waiting at the nest site is Andrew Stevenson.'
0:12:47 > 0:12:48- All right, Andy? - All right?
0:12:48 > 0:12:50How's it going, good to see you.
0:12:50 > 0:12:51This is the nest?
0:12:51 > 0:12:52What do you think?
0:12:52 > 0:12:55'Digging up ants is Andy's speciality.
0:12:55 > 0:12:58'He provides leafcutter colonies to zoos, museums
0:12:58 > 0:13:01'and universities all across Europe.'
0:13:01 > 0:13:02I don't think it's too big for digging,
0:13:02 > 0:13:05but what we're going to do is we're going to start at the bottom
0:13:05 > 0:13:08with a trench, and then take sections as we go back through the
0:13:08 > 0:13:12bank, hopefully showing a lot of the architecture of the nest as we go.
0:13:13 > 0:13:16'At the moment, the only sign the leafcutters are even here
0:13:16 > 0:13:20'is this loose pile of earth produced by the ants
0:13:20 > 0:13:22'as they dig out their underground nest.
0:13:23 > 0:13:25'This is because in the wild,
0:13:25 > 0:13:28'our species of leafcutter tends to be nocturnal.'
0:13:30 > 0:13:32'So to get a sense of how big the nest really is,
0:13:32 > 0:13:34'we have to wait for night to fall.'
0:13:42 > 0:13:43So here are leafcutters on the trail,
0:13:43 > 0:13:46and you can really get a feel for their destructive power.
0:13:46 > 0:13:48This is a fruit tree,
0:13:48 > 0:13:51and the leaves are just pouring down out of the tree.
0:13:51 > 0:13:53All of these fragments have been cut up, they're in the canopy,
0:13:53 > 0:13:57and there are hundreds of ants passing every minute.
0:13:57 > 0:14:00Just conveying, like a conveyor belt of leaves from the top of the tree,
0:14:00 > 0:14:04all the way to the colony, which is about 100 metres away up the hill.
0:14:05 > 0:14:08'It's easy to see why farmers are no friends of leafcutters.
0:14:12 > 0:14:15'From the huge numbers of ants in the soil here,
0:14:15 > 0:14:18'we reckon this colony is at least a million strong,
0:14:18 > 0:14:21'so it's certainly on the scale that we need for the project.
0:14:25 > 0:14:28'And so many ants means a large, subterranean nest.
0:14:31 > 0:14:35'So to get a sense of how big a job we'll face on the dig tomorrow...'
0:14:35 > 0:14:37Adam, over here, we've got one.
0:14:37 > 0:14:40'..Andy and I are placing lights at each nest entrance we find.'
0:14:42 > 0:14:46'This should show us roughly how big the nest is beneath our feet.'
0:14:47 > 0:14:50What we've done is marked out what turned out to be
0:14:50 > 0:14:52more or less a circle of lights.
0:14:52 > 0:14:54It seems to show that most of the activity in this colony
0:14:54 > 0:14:55is focused on the bank here,
0:14:55 > 0:14:58where we're going to start doing our sectioning in the morning.
0:14:59 > 0:15:02It's good news, because it means that once we get stuck into
0:15:02 > 0:15:04that central part of the bank right in the middle of the lights,
0:15:04 > 0:15:07we should start hitting fungus chambers quite quickly,
0:15:07 > 0:15:11and with any luck, fingers crossed, we might even get the queen.
0:15:17 > 0:15:18'It's the day of the dig,
0:15:18 > 0:15:22'and time to see what the colony looks like underground.
0:15:22 > 0:15:26'But the ants aren't about to take our intrusion lightly.'
0:15:26 > 0:15:28This is pretty much the first blow of the spade,
0:15:28 > 0:15:30we've been digging for about a minute, and already,
0:15:30 > 0:15:32on the surface here, I can count
0:15:32 > 0:15:35at least 20 or 30 of these big soldiers.
0:15:35 > 0:15:37It's made our life a bit more difficult, in a way,
0:15:37 > 0:15:40because we're now going to be under attack digging this trench.
0:15:41 > 0:15:43'Undeterred by the threat of the soldiers,
0:15:43 > 0:15:45'Andy and his team continue with the dig.'
0:15:47 > 0:15:49Let's start taking about a foot at a time.
0:15:49 > 0:15:51We'll start taking a slice and we'll work our way back.
0:15:54 > 0:15:57'Before long, we've pushed back into the nest.
0:15:58 > 0:16:03'What we see is a maze of chambers, connected by a system of tunnels.
0:16:05 > 0:16:07'This natural architecture is what we've tried to
0:16:07 > 0:16:09'recreate in building our own ant nest,
0:16:11 > 0:16:15'with glass boxes and tubes replacing the chambers and tunnels.
0:16:16 > 0:16:18'By mimicking a real-world design,
0:16:18 > 0:16:22'we hope to encourage the ants to behave as they do in the wild.
0:16:29 > 0:16:32'And it's not just the ants we need to rescue from this nest.
0:16:34 > 0:16:38'The underground chambers are packed full of vital fungus.
0:16:40 > 0:16:43'We need to collect as much of this fungus as we can.'
0:16:43 > 0:16:46'Without it, the ants will quickly die.'
0:16:48 > 0:16:50We've got into quite a good rhythm, now, really.
0:16:50 > 0:16:52There's lots and lots of these fungus chambers
0:16:52 > 0:16:54going back into the bank.
0:16:54 > 0:16:56Every time you put the spade in and pull some soil off
0:16:56 > 0:16:58it exposes some more,
0:16:58 > 0:17:01so it's really just a case of methodically going through them,
0:17:01 > 0:17:03when they fall out, or when you pull them out,
0:17:03 > 0:17:07and making sure the queen's not there, so just keep cutting back,
0:17:07 > 0:17:09keep cutting back, trying to find that queen.
0:17:11 > 0:17:15'At the end of day one, we've recovered thousands of ants
0:17:15 > 0:17:17'and a large quantity of fungus,
0:17:17 > 0:17:21'but we've still to recover the most vital ant of all.'
0:17:21 > 0:17:22No, she's not here.
0:17:22 > 0:17:23'The queen.
0:17:25 > 0:17:28'Failure to find her means failure of the entire project.
0:17:41 > 0:17:44'Day two, and the hunt for the queen continues.
0:17:46 > 0:17:49'We're searching for something quite distinctive.'
0:17:50 > 0:17:53The queen is huge compared to other ants,
0:17:53 > 0:17:56and she'll be covered in smaller ants, who tend her.
0:18:00 > 0:18:02There's something really smart here.
0:18:03 > 0:18:04Oh, yeah?
0:18:04 > 0:18:05OK.
0:18:05 > 0:18:06Yeah, yeah.
0:18:06 > 0:18:09'This could be our needle in a haystack.'
0:18:09 > 0:18:11This looks very promising.
0:18:13 > 0:18:15So this could be the queen in the middle.
0:18:15 > 0:18:16I think we're in, here.
0:18:18 > 0:18:19Yes.
0:18:19 > 0:18:20There she is. The queen, excellent.
0:18:20 > 0:18:23One ant in two million, and we've found her.
0:18:23 > 0:18:24'Through tons of earth,
0:18:24 > 0:18:27'we managed to find the most important ant of all.
0:18:28 > 0:18:30'It's a great relief to the whole team,
0:18:30 > 0:18:33'and it means our project can go ahead.'
0:18:34 > 0:18:37So this is what we've been seeking in all our mining.
0:18:37 > 0:18:40This is the queen of the colony,
0:18:40 > 0:18:42and I'm going to very carefully pick her up.
0:18:42 > 0:18:45She is surrounded by a attendant workers who are biting me now - ow!
0:18:45 > 0:18:46But she's in there.
0:18:46 > 0:18:50That's the egg-laying machine that's at the heart of this colony.
0:18:50 > 0:18:53And there she is, ready to go on her...
0:18:53 > 0:18:57We're going to stick her onto a really nice use of fresh fungus,
0:18:57 > 0:19:01very carefully, very gingerly, just plonk her on the top, there.
0:19:01 > 0:19:02And that's..?
0:19:02 > 0:19:03That's us.
0:19:03 > 0:19:04That's us done. Good job.
0:19:08 > 0:19:10'The race against time begins now.'
0:19:11 > 0:19:16'We need to get the ants from here to the UK as quickly as possible.
0:19:24 > 0:19:27'After two flights and a transatlantic journey
0:19:27 > 0:19:28'of more than 4,000 miles,
0:19:28 > 0:19:31'the ants arrive at their final destination,
0:19:31 > 0:19:35'the Glasgow Science Centre, where their new home awaits.
0:19:46 > 0:19:51'We put the ants and some fresh soil onto the top of the nest.
0:19:51 > 0:19:52'This is our ground level.
0:19:54 > 0:19:58'From here, they make their way down into the nest boxes,
0:19:58 > 0:20:00'like the chambers we saw in the wild.
0:20:03 > 0:20:07'And it's with some relief that we come across an old friend,
0:20:07 > 0:20:08'the queen.'
0:20:08 > 0:20:09Excellent.
0:20:11 > 0:20:13'With the survival of the queen confirmed...'
0:20:13 > 0:20:16- Yep, she's in. - OK.
0:20:16 > 0:20:18'..and the ants exploring their new nest,
0:20:18 > 0:20:21'the signs are good that our colony has survived the journey.
0:20:23 > 0:20:25'Now we're hoping that they'll take over
0:20:25 > 0:20:28'and complete the building of their new world.'
0:20:43 > 0:20:47'We've given our ants time to settle into the main nest area.
0:20:49 > 0:20:50'Now we're ready to let them loose
0:20:50 > 0:20:53'on the wider world we've built for them.
0:20:55 > 0:20:58'It's our first chance to see how they organise
0:20:58 > 0:21:01'the great collective endeavour they're famous for.
0:21:01 > 0:21:02'Leaf cutting.'
0:21:05 > 0:21:09What we want to do now is to allow them to forage in a natural way,
0:21:09 > 0:21:12they would do in the real environment, and to do that,
0:21:12 > 0:21:17we need to join up the colony with the virgin foraging lands beyond.
0:21:21 > 0:21:25'For the ants, it's finally time to explore.'
0:21:26 > 0:21:31Well, we've only just put the bridge in, and already we've got workers
0:21:31 > 0:21:35swarming up as far as here, so I don't think it will take very long
0:21:35 > 0:21:38for them to find the other end of this bridge.
0:21:40 > 0:21:45'Tentatively, the ants start to make their way down the bridge,
0:21:45 > 0:21:48'although it's not exactly a massive trail yet.'
0:21:54 > 0:21:57In the wild, you see them foraging all over the ground,
0:21:57 > 0:22:00but how far will they forage from the main nest?
0:22:00 > 0:22:03Up to 100 metres, sometimes more, so you can follow these trails
0:22:03 > 0:22:06deep into the forest, and in fact, this colony was foraging deep into
0:22:06 > 0:22:10a citrus grove, and you could follow them back for 100 metres or more.
0:22:15 > 0:22:19'Our time-lapse cameras reveal that the trickle quickly becomes a flood.
0:22:20 > 0:22:25'More and more ants head out to explore the foraging areas beyond.
0:22:28 > 0:22:32'Now we'll have to wait to see how quickly they discover the plants
0:22:32 > 0:22:35'and get their leaf-cutting operation under way.
0:22:41 > 0:22:44'But there's one caste of ant we'll hardly ever see out here,
0:22:44 > 0:22:46'and that's the soldiers.
0:22:50 > 0:22:52'Unless they're responding to a threat,
0:22:52 > 0:22:55'they tend to stay hidden deep within the nest.'
0:22:58 > 0:23:01But we won't get a full picture of how our colony works
0:23:01 > 0:23:05unless we can discover what these mysterious ants are doing.
0:23:06 > 0:23:10So to find out, we've turned to technology.
0:23:12 > 0:23:14'We're going to use radio tracking devices
0:23:14 > 0:23:18'to follow individual soldiers 24 hours a day.
0:23:20 > 0:23:22'Joining us to help is Clare Asher
0:23:22 > 0:23:25'from the Zoological Society of London.'
0:23:27 > 0:23:30So, what we're going to do is we're going to glue some radio frequency
0:23:30 > 0:23:34tags onto their back, and Claire here is quite an expert at this.
0:23:34 > 0:23:36I'm keeping well out of it, because I'm getting glued up myself.
0:23:38 > 0:23:40So I just pop a little blob of glue.
0:23:40 > 0:23:41Yeah.
0:23:42 > 0:23:44On their back.
0:23:44 > 0:23:46How heavy are these tags?
0:23:46 > 0:23:50They hardly weigh anything at all, and to an ant like this,
0:23:50 > 0:23:52they won't even really notice it.
0:23:54 > 0:23:56There we go. It's fiddly work.
0:23:56 > 0:23:57It is. You just need to...
0:23:57 > 0:24:00And that should dry in a short time?
0:24:00 > 0:24:01Very quickly, yeah.
0:24:01 > 0:24:04I should point out that what we're doing isn't hurting
0:24:04 > 0:24:07the soldier ants at all.
0:24:07 > 0:24:10How long would they survive in the wild anyway?
0:24:10 > 0:24:12These sorts of ants would only live a couple of months, often.
0:24:12 > 0:24:13They're not long-lived.
0:24:15 > 0:24:16This is going to be great,
0:24:16 > 0:24:18because this is going to tell us what these soldiers
0:24:18 > 0:24:21are doing, which we don't have a chance of finding out.
0:24:21 > 0:24:22And where they are.
0:24:22 > 0:24:25Yeah, and how much they move around, what they're getting up to,
0:24:25 > 0:24:27which we know very little about, if anything, really.
0:24:27 > 0:24:29So it is original research, this?
0:24:29 > 0:24:30Yes.
0:24:37 > 0:24:42Every tagged ant will emit a unique radio signal.
0:24:42 > 0:24:44And to detect those signals,
0:24:44 > 0:24:47we've placed radio receivers all over the nest.
0:24:49 > 0:24:52This will allow us to track each individual ant
0:24:52 > 0:24:54and follow its every movement.
0:24:57 > 0:24:59We don't know what the ants are going to do,
0:24:59 > 0:25:03or even if this experiment will work, but we're hoping it will give us
0:25:03 > 0:25:07new insights into the role of the soldiers in the colony.
0:25:12 > 0:25:16'While we've been busy, so have the foraging ants.'
0:25:17 > 0:25:18Just look at that.
0:25:18 > 0:25:20That's barely three hours
0:25:20 > 0:25:23and already there's an incredibly well-established trail.
0:25:23 > 0:25:24Yeah, it's teeming with ants.
0:25:24 > 0:25:27We've got a really nice flow of ants going this way without leaves,
0:25:27 > 0:25:30and these leaf-carrying ants going back to that big fungus garden
0:25:30 > 0:25:32over there, so it's really, really nice.
0:25:32 > 0:25:35Now, it seems to me that a few of these are a bit confused,
0:25:35 > 0:25:37and some are going the wrong way.
0:25:37 > 0:25:39Yeah, I think we've got a little bit of a pinch point here.
0:25:39 > 0:25:42It's so busy going in this direction that I think some of these
0:25:42 > 0:25:45ants are getting turned around, but that will even itself out.
0:25:45 > 0:25:48Collectively, the ants carrying leaves are going in that direction,
0:25:48 > 0:25:51and the ants not carrying leaves are going in that direction,
0:25:51 > 0:25:53but there's always a few little errors.
0:25:53 > 0:25:57I feel I want to help the ones that are heading the wrong way and just
0:25:57 > 0:26:00go, "Come on," take you off and put you down there, bit of a head start.
0:26:07 > 0:26:10'These ants are finely-tuned leaf-cutting machines.
0:26:14 > 0:26:17'A large colony can consume the same weight of vegetation
0:26:17 > 0:26:19'per day as a cow.
0:26:22 > 0:26:25'And they're making short work of the plants we're giving them.'
0:26:31 > 0:26:35It's fantastic to watch them at work, because if you just look at it,
0:26:35 > 0:26:40glanced at it, it would just seem to be random, but it clearly isn't.
0:26:40 > 0:26:41I don't know if you can see up close, George,
0:26:41 > 0:26:44the way that they're actually cutting the leaf fragments.
0:26:44 > 0:26:47It's really interesting. It's not how you might expect them to do it.
0:26:47 > 0:26:49They're not using those mandibles like scissors.
0:26:49 > 0:26:52The right-hand jaw is anchoring the leaf,
0:26:52 > 0:26:55and the other one is a bit more like a guillotine.
0:26:55 > 0:26:57Yeah, more like a blade going through.
0:26:59 > 0:27:02'This method is incredibly powerful,
0:27:02 > 0:27:05'enabling the ant to slice through even the toughest of leaves.'
0:27:07 > 0:27:11Here we can see that same blade-like technique being used
0:27:11 > 0:27:13on a very thick banana leaf.
0:27:14 > 0:27:18They're anchoring themselves with the back feet, the back legs,
0:27:18 > 0:27:21so when they go around with this guillotine, they're describing
0:27:21 > 0:27:25an arc of a circle, and the bigger the ant, the bigger the arc.
0:27:25 > 0:27:26Absolutely.
0:27:26 > 0:27:28So you end up with a really nice mechanism to make sure that
0:27:28 > 0:27:30bigger ants carry bigger loads.
0:27:34 > 0:27:35Over the next few days,
0:27:35 > 0:27:40our ants establish the leaf-cutting operation on an impressive scale.
0:27:43 > 0:27:48A marching column across the ropes, over the foraging table
0:27:48 > 0:27:50and up the bridge.
0:27:53 > 0:27:56When they reach the top, the ants head down into the nest,
0:27:56 > 0:28:00making their way through the tubes towards the fungus gardens.
0:28:10 > 0:28:14There, smaller and smaller ants chop up the fragments
0:28:14 > 0:28:16until it's mashed into a kind of plant mulch.
0:28:21 > 0:28:26The tiniest ants of all then insert this mulch into the growing fungus.
0:28:29 > 0:28:32There's nothing haphazard about this process.
0:28:32 > 0:28:37The structure we see here is carefully built by the ants.
0:28:39 > 0:28:42The pattern of ridges and hollows allows them
0:28:42 > 0:28:46to fit more fungus into a confined space,
0:28:47 > 0:28:51and the hollows provide a safe place to nurture the brood.
0:28:54 > 0:28:57The whole process is like a massive production line.
0:29:01 > 0:29:06It just looks like a conveyor belt of green material just disappearing.
0:29:06 > 0:29:08It feels like the right sort of language to use.
0:29:08 > 0:29:10We've got an industrial cutting process going on here.
0:29:10 > 0:29:14We've got this conveyor belt going back to the processing, the factory,
0:29:14 > 0:29:17if you like, back at the nest, so it's a real machine at work.
0:29:21 > 0:29:25It's this kind of collective endeavour that has made ants
0:29:25 > 0:29:28so fascinating to us humans down the ages.
0:29:35 > 0:29:38During the Industrial Revolution, when factory life was
0:29:38 > 0:29:43transforming human society, the parallels were striking.
0:29:48 > 0:29:54Dr Charlotte Sleigh has studied how we viewed ants throughout history.
0:29:54 > 0:29:58I think the 18th century is a period when you start seeing some really
0:29:58 > 0:30:01sustained interest in ants and the way that they live, and a lot
0:30:01 > 0:30:05of those very earliest writers were coming from a theological tradition.
0:30:05 > 0:30:08Indeed, many of them were ordained clergyman.
0:30:08 > 0:30:11The qualities that the ants exhibited
0:30:11 > 0:30:13were considered to be really twofold.
0:30:13 > 0:30:17One of them was industriousness, they worked, really, really hard,
0:30:17 > 0:30:20and that's something everybody should do, and the other thing
0:30:20 > 0:30:24that they exhibited was what the Victorians called mutual aid.
0:30:24 > 0:30:28That is to say, they helped one another,
0:30:28 > 0:30:32and supported one another in the life of the nest.
0:30:35 > 0:30:39And as the Victorians travelled the world on the business of Empire,
0:30:39 > 0:30:42they encountered new and intriguing species of ant.
0:30:45 > 0:30:49One such traveller, an English engineer called Thomas Belt,
0:30:49 > 0:30:51particularly admired the leafcutters.
0:30:54 > 0:30:56Thomas Belt was a mining engineer,
0:30:56 > 0:31:00and when he went out to Nicaragua, around about 1870,
0:31:00 > 0:31:02he was not impressed with the native Nicaraguans,
0:31:02 > 0:31:05he was not impressed with the Hispanic colonists,
0:31:05 > 0:31:07he thought they had become sort of lazy and dependent
0:31:07 > 0:31:10on the native labour, but what he really rated
0:31:10 > 0:31:13were the leafcutter ants, and in particular,
0:31:13 > 0:31:17he was so tremendously impressed with the mining that they did,
0:31:17 > 0:31:20just like he was planning to, with the tunnels they constructed,
0:31:20 > 0:31:26it was as though he had found the English in Nicaragua in the ants.
0:31:33 > 0:31:35Watching our leafcutters at work,
0:31:35 > 0:31:38it's easy to see why Thomas Belt was so impressed.
0:31:41 > 0:31:44Their leaf cutting operation is a highly-sophisticated,
0:31:44 > 0:31:47highly-organised collective endeavour.
0:31:49 > 0:31:53This remarkable ability to cooperate isn't unique to the leafcutters.
0:31:56 > 0:31:59Adam's been investigating on another species of ant
0:31:59 > 0:32:03that takes the idea of cooperation to a whole new level.
0:32:10 > 0:32:13Floating on the Amazon River is a wonder of the animal world.
0:32:18 > 0:32:21It may look like a tangle of weeds, but up close,
0:32:21 > 0:32:23it's a seething mass of ants.
0:32:31 > 0:32:34This is Solenopsis invicta, the fire ant.
0:32:37 > 0:32:42To survive the regular floods of the Amazon, an entire ant colony
0:32:42 > 0:32:45can join together as one large raft, built from their own bodies.
0:32:51 > 0:32:54They can survive like this for months, waiting for dry land.
0:32:59 > 0:33:01So, how do the fire ants do it?
0:33:05 > 0:33:08'I've come to Georgia Institute of Technology in America, to meet
0:33:08 > 0:33:12'a scientist who's tried to discover the secrets of the fire ant raft.
0:33:13 > 0:33:16'It's my first chance to see these extraordinary
0:33:16 > 0:33:18'boat-builders up close.'
0:33:23 > 0:33:25One of the big questions people ask is
0:33:25 > 0:33:27what happens to the ants on the bottom.
0:33:27 > 0:33:30Do they drown, and the answer is no.
0:33:30 > 0:33:31They essentially remain dry,
0:33:31 > 0:33:35even those bands that break through the surface tension of the water
0:33:35 > 0:33:39and are fully submerged trap a layer of air around their bodies
0:33:39 > 0:33:40so they can still breathe.
0:33:40 > 0:33:43So there's an obvious thing for us to do now, which is to try
0:33:43 > 0:33:44and submerge them and see what happens.
0:33:44 > 0:33:46Can you push these down?
0:33:46 > 0:33:47When you push it under the water,
0:33:47 > 0:33:52they retain a pocket of air around their bodies.
0:33:52 > 0:33:55It's almost encapsulating them inside an air pocket.
0:33:55 > 0:33:56I can show you that here.
0:33:57 > 0:33:59They're very buoyant.
0:33:59 > 0:34:00- They are.- There we go.
0:34:00 > 0:34:02So there's a silvery sheen over the outside,
0:34:02 > 0:34:05which is all the air bubbles that have been trapped.
0:34:05 > 0:34:07That's the air-water interface line, there.
0:34:12 > 0:34:14Each ant is naturally water repellent.
0:34:19 > 0:34:21Droplets simply slide off them.
0:34:24 > 0:34:26And when thousands of ants combine,
0:34:26 > 0:34:30the result is a raft that is virtually unsinkable.
0:34:34 > 0:34:37When you do push them under the water, they pull themselves
0:34:37 > 0:34:41even tighter together, so that when the subjected to the high
0:34:41 > 0:34:44pressures underneath the water, it still keeps the water out.
0:34:50 > 0:34:52Magnified hundreds of times,
0:34:52 > 0:34:54the secrets of the fire ant raft are revealed.
0:34:57 > 0:35:00The mandibles are used to grab hold of a nest-mate's leg.
0:35:02 > 0:35:05At the end of each leg is an adhesive pad and a claw.
0:35:09 > 0:35:11This, like a sticky grappling hook, allows them
0:35:11 > 0:35:15to form further flexible connections with any nearby nest-mate.
0:35:19 > 0:35:23The ants' own bodies act as a set of interlocking units,
0:35:23 > 0:35:27so the entire colony can turn itself into a single structure.
0:35:35 > 0:35:38So this is really an unsinkable, self-healing lifeboat?
0:35:38 > 0:35:42It is. It is a force to be reckoned with, that's for sure.
0:35:47 > 0:35:51This remarkable ability allows the fire ants to survive
0:35:51 > 0:35:53the worst floods of the Amazon.
0:35:56 > 0:36:00Cooperation has made them an engineering marvel of the natural world.
0:36:01 > 0:36:04And one of the most successful and species on the planet.
0:36:14 > 0:36:19It's now been ten days since our ants were released from the nest.
0:36:19 > 0:36:22And I've come back to see how far the colony has come.
0:36:24 > 0:36:31And straightaway, I can see foraging trails now traverse environment from end to end.
0:36:34 > 0:36:37The fungal gardens I saw last time have grown,
0:36:37 > 0:36:40and I can see some new ones too.
0:36:47 > 0:36:51Since they arrived in their new home, the ants have made real
0:36:51 > 0:36:55progress towards getting their society up and running again.
0:36:59 > 0:37:03One of the best examples of this is at the very bottom of the nest.
0:37:08 > 0:37:10We're now in the bowels of the colony,
0:37:10 > 0:37:15right down below where all the ants have their nest chambers.
0:37:15 > 0:37:18And the reason we're down here is that there's a lot happening.
0:37:18 > 0:37:21The ants have a waste dump down here.
0:37:22 > 0:37:27All that leaf processing produces a lot of waste that needs to be dealt with.
0:37:29 > 0:37:32And ants cope with the trash burden in a similar way to us.
0:37:34 > 0:37:36This is an ant landfill.
0:37:38 > 0:37:42Now, what we've got here is a waste dump they've made
0:37:42 > 0:37:46actually in the trough that surrounds the whole colony.
0:37:46 > 0:37:50And that's a water-filled trough, which is designed to keep the ant in.
0:37:50 > 0:37:53What's happened is, the ants have built a waste dump.
0:37:53 > 0:37:57And because it's wet and the bacteria are building up in here,
0:37:58 > 0:38:04the smell of decaying ants and fungus is overpowering, it's disgusting.
0:38:06 > 0:38:10Normally, the dump is placed in chambers at the bottom of the colony
0:38:10 > 0:38:15where workers turn over the waste as a gardener does their flowerbeds.
0:38:17 > 0:38:21This speeds up the breakdown of potentially harmful substances.
0:38:23 > 0:38:26But the ants aren't just dumping their garbage down here,
0:38:26 > 0:38:29they are also disposing of dead bodies.
0:38:31 > 0:38:33Over on this side is the graveyard.
0:38:33 > 0:38:36Now, this is actually very interesting.
0:38:36 > 0:38:39The ants, of course, don't live for ever and when they die,
0:38:39 > 0:38:44their remains are taken down and dumped out of the colony.
0:38:44 > 0:38:50And that in my hand is just dead remains of literally hundreds and hundreds of ants,
0:38:50 > 0:38:55of all castes, small workers, large workers, soldiers.
0:38:55 > 0:38:58So, when the ants have no longer any function
0:38:58 > 0:39:02and when they die they are simply taken out and dumped.
0:39:04 > 0:39:09The main reason why ants have to keep the waste and the dead remains
0:39:09 > 0:39:12of ants out of the way of the colony is that when you're
0:39:12 > 0:39:16in such high abundances in the colony you don't want any diseases
0:39:16 > 0:39:20to spread so you have to maintain your environment, it has to be clean.
0:39:20 > 0:39:23So anything that could possibly rot is removed.
0:39:26 > 0:39:29Seeing the dump and the graveyard really brings it home to me
0:39:29 > 0:39:32just how sophisticated the ant colony is.
0:39:34 > 0:39:37It's easy to see why people have looked at the ants
0:39:37 > 0:39:40and thought they were seeing our own world reflected back.
0:39:42 > 0:39:48We've even used the language of our own social structures to describe ant society.
0:39:48 > 0:39:52Workers, soldiers, the Queen.
0:39:54 > 0:39:59But, is ant society really organised in this kind of hierarchy?
0:40:02 > 0:40:06To answer that question, we need to take a closer look
0:40:06 > 0:40:11at the roles of the different ants in our colony, especially the Queen.
0:40:11 > 0:40:15Tended round-the-clock by workers and fiercely protected
0:40:15 > 0:40:19by soldiers, she's the colony's most prized member.
0:40:19 > 0:40:22But does that mean she's in charge?
0:40:24 > 0:40:27I can't introduce you to our colony's Queen because she's deep in
0:40:27 > 0:40:32a chamber somewhere behind me, and I wouldn't want to disturb her anyway.
0:40:33 > 0:40:37But Adam has brought a Queen from a much smaller colony
0:40:37 > 0:40:40and we can take a closer look at her.
0:40:40 > 0:40:44So, what we've got here, George, is one I dug out the ground in Trinidad.
0:40:44 > 0:40:48- There's the Queen. - I've never seen the Queen before like that.
0:40:48 > 0:40:51She's an impressive creature, she's impressive in her own right,
0:40:51 > 0:40:56but when you see her next to the smaller ants it gives you an idea of how big she is.
0:40:56 > 0:41:00We can see the Queen's enormous body protruding from the fungus,
0:41:00 > 0:41:04with smaller ants attending her.
0:41:04 > 0:41:10Inside her large abdomen are the ovaries that allow her to lay up to 30,000 eggs a day!
0:41:12 > 0:41:16So, is the Queen in our colony roughly the same size?
0:41:16 > 0:41:19Yeah, the Queen in our colony will be exactly like this.
0:41:19 > 0:41:21This is the same species from the same place.
0:41:21 > 0:41:24- She's a beautiful sort of velvety-brown colour?- Yeah.
0:41:24 > 0:41:27- I just want to just touch her.- Yeah.
0:41:27 > 0:41:29She's beautiful.
0:41:36 > 0:41:40Our colony will only ever have one Queen in residence.
0:41:40 > 0:41:47But once a year, it will produce new queens who will leave the nest to start new colonies.
0:41:47 > 0:41:52This is also the only time the colony will produce males,
0:41:52 > 0:41:56and these males have one sole purpose - to mate.
0:42:00 > 0:42:04Leafcutters have never been observed mating in the wild,
0:42:04 > 0:42:09but we can see how much of a large-scale operation this is
0:42:09 > 0:42:12with the British species, the wood ant.
0:42:13 > 0:42:18In late summer, the colony produces hundreds of new queens and males.
0:42:20 > 0:42:25These ants have wings and they fly from the nest en masse to find a mate.
0:42:27 > 0:42:29This event is called the nuptial flight.
0:42:31 > 0:42:36These winged individuals are the females, the new queens, the males that they'll mate with.
0:42:36 > 0:42:40It is a very effective way of dispersing, not just mating
0:42:40 > 0:42:46with individuals from another colony, but also spreading out and spreading the colony far and wide.
0:42:50 > 0:42:53After the nuptial flight, the males simply die.
0:42:53 > 0:42:55The Queen will never mate again.
0:42:58 > 0:43:00She's now ready to start a new colony.
0:43:01 > 0:43:04From now on, her role is to lay eggs.
0:43:09 > 0:43:15It's a staggering thought that all the ants in our colony have the same mother.
0:43:17 > 0:43:21And as males are only produced for the brief mating period,
0:43:21 > 0:43:25all the ants we see here are female and they're all sisters.
0:43:31 > 0:43:35And there's something else that's intriguing here.
0:43:35 > 0:43:38All the eggs the Queen lays are essentially the same.
0:43:41 > 0:43:46So how can they become all the different kinds of ant that make up the colony?
0:43:47 > 0:43:49The workers are in control of what goes on.
0:43:49 > 0:43:52Because when the Queen lays eggs, she doesn't lay an egg
0:43:52 > 0:43:56for a minor worker, or a soldier, and an egg for a queen, she just lays an egg.
0:43:56 > 0:44:00So it's totally how that larva that hatches from the egg is
0:44:00 > 0:44:04nurtured, how much food it's given that determines what it turns into.
0:44:06 > 0:44:10So the workers who feed the larva they are actually controlling
0:44:10 > 0:44:14the number of soldiers and worker castes produced within the colony.
0:44:18 > 0:44:22They're really flexible and dynamic and can respond to what's going on in the environment.
0:44:22 > 0:44:26So if we start disturbing this colony, they'll start producing more soldiers.
0:44:26 > 0:44:28And it's happening right in here now?
0:44:28 > 0:44:33It's happening right here, all over these fungus gardens, they're rearing these workers up
0:44:33 > 0:44:38within these fungus gardens and they're responding to what's going on, responding to the lights,
0:44:38 > 0:44:43to heat, to food, responding to what the Queen's doing in terms of how many eggs she's laying.
0:44:43 > 0:44:48And that information is somehow integrated in the workers, it's all about the workers this colony,
0:44:48 > 0:44:51it's not really about the Queen, she's just popping out eggs.
0:44:52 > 0:44:58So the ant colony has a very particular form of social organisation.
0:44:59 > 0:45:03The Queen is the only ant who reproduces.
0:45:03 > 0:45:06Her eggs will become the workforce of the colony.
0:45:08 > 0:45:11Each generation raises the next, from egg to adult.
0:45:13 > 0:45:19This results in multiple generations working together for the good of the colony.
0:45:23 > 0:45:28And these attributes put our ants in a very special group of insects.
0:45:28 > 0:45:31The truly social or eusocial insects.
0:45:31 > 0:45:34Eusocial insects are phenomenally successful.
0:45:34 > 0:45:39Where as they only make up less than 5% of all insect species,
0:45:39 > 0:45:43they account for the majority of the insect biomass on Earth.
0:45:49 > 0:45:55Apart from ants, the major groups of eusocial insects are termites, wasps and bees.
0:45:55 > 0:45:57WINGS VIBRATE
0:46:00 > 0:46:04Together, these insects outnumber all the others on Earth combined.
0:46:05 > 0:46:08Being eusocial is one of the most important,
0:46:08 > 0:46:11evolutionary developments in the animal kingdom.
0:46:18 > 0:46:20It's such a significant step,
0:46:20 > 0:46:24that scientists are trying to discover when it first occurred.
0:46:24 > 0:46:29And what it is about being eusocial that gives these insects such an advantage.
0:46:33 > 0:46:40Dr David Grimaldi is the curator of fossil insects at the American Museum of Natural History.
0:46:41 > 0:46:48He's spent 25 years researching specimens of ants and other insects millions of years old.
0:46:49 > 0:46:52This sample is from the Cretaceous era.
0:46:52 > 0:46:56These early ants were wandering around at the time of the dinosaurs.
0:46:56 > 0:47:00Dinosaurs died out but the ants went on
0:47:00 > 0:47:03to become astonishingly abundant.
0:47:06 > 0:47:08These ants are a window into prehistory.
0:47:14 > 0:47:17The sap of ancient trees trapped them as they foraged and then
0:47:17 > 0:47:21hardened into amber, preserving them for millions of years.
0:47:29 > 0:47:33Now these remarkable specimens are helping scientists discover
0:47:33 > 0:47:37more about the origins of eusocial insects.
0:47:39 > 0:47:43There is one remarkable piece from the Cretaceous,
0:47:43 > 0:47:48probably the most important piece, a chunk of 100-million-year old amber,
0:47:48 > 0:47:52that contains ten individuals, almost certainly workers.
0:47:54 > 0:47:57The ants are so rare in Cretaceous amber,
0:47:57 > 0:48:01so the probability that you would get ten individuals preserved
0:48:01 > 0:48:07in one piece just based on chance alone is astronomically improbable.
0:48:07 > 0:48:09Unless of course, they were social.
0:48:12 > 0:48:16Other ancient samples revealed that being social didn't just
0:48:16 > 0:48:20affect the ants' behaviour, it also changed their anatomy.
0:48:22 > 0:48:26These ants have pouches to share food with their sisters.
0:48:31 > 0:48:37This feature of and anatomy is most clearly seen today in the Australian honeypot ant.
0:48:40 > 0:48:44These ants are so full of food, they can hardly move.
0:48:46 > 0:48:49They're like living larders, feeding their sisters.
0:48:51 > 0:48:56When you have many, many individuals that specialise in foraging
0:48:56 > 0:49:01and protection and nursing of the larva and in defence of the nest,
0:49:01 > 0:49:04you can be much, much more effective.
0:49:04 > 0:49:10So, being social is a tremendous adaptation,
0:49:10 > 0:49:16perhaps one of the most effective adaptation is in the animal kingdom,
0:49:16 > 0:49:21because we can see that when ants become highly, highly social,
0:49:21 > 0:49:26they become a very dominant life form.
0:49:31 > 0:49:35The advantages brought by eusociality have allowed these
0:49:35 > 0:49:37insects to dominate the globe.
0:49:39 > 0:49:43Ants have been called ecosystem engineers,
0:49:43 > 0:49:46as they can change the environment around them.
0:49:49 > 0:49:52Nutrients released from their underground nests fertilise
0:49:52 > 0:49:54the surrounding soil,
0:49:54 > 0:49:58which in turn promotes the growth of plant life on the surface.
0:50:00 > 0:50:04With more plants come more animals, and studies have shown that an
0:50:04 > 0:50:10ant colony can actually increase the diversity of animal life around it.
0:50:14 > 0:50:18Eusocial insects can even affect our lives.
0:50:19 > 0:50:22Without bees to pollinate our plants,
0:50:22 > 0:50:24we wouldn't be able to grow enough food crops.
0:50:25 > 0:50:29You might say it's eusociality that feeds our world.
0:50:41 > 0:50:43It's been 15 days
0:50:43 > 0:50:46since we began following the progress of our ant colony.
0:50:47 > 0:50:50In that time, they've been far from idle.
0:50:52 > 0:50:56They're now well-established in a nest we built for them.
0:50:59 > 0:51:04The most amazing change since the colony has really become
0:51:04 > 0:51:09established is the incredible growth of the fungus gardens.
0:51:09 > 0:51:14You can see the green leaf material where the fungus hasn't quite
0:51:14 > 0:51:18grown yet, so it's just becoming white from the base up.
0:51:18 > 0:51:21You can see at the very outside edge,
0:51:21 > 0:51:23you've got all the chewed, green material,
0:51:23 > 0:51:28the food for the fungus, and then the fungus moves up.
0:51:28 > 0:51:30It's fragile as anything.
0:51:30 > 0:51:31It's just...
0:51:33 > 0:51:36It's just a miracle of micro-engineering, this.
0:51:36 > 0:51:40And it's one of the most beautiful things I've ever seen.
0:51:42 > 0:51:46To see how much progress the ants have made re-growing
0:51:46 > 0:51:50their fungal gardens, we're going to open up a nest box again.
0:51:52 > 0:51:55- Look at that.- There we go. - They're not happy about this.
0:51:55 > 0:51:59You can really see the structure of the fungus garden.
0:51:59 > 0:52:02They are really... That whole thing is hollow
0:52:02 > 0:52:04and there is a soldier in there.
0:52:04 > 0:52:07This is their very reason for being, isn't it?
0:52:07 > 0:52:09That is the major resource.
0:52:09 > 0:52:12Yes, it's not like a mushroom or a toadstool. It's very fragile.
0:52:12 > 0:52:14It's more like a sponge.
0:52:14 > 0:52:17There's a huge surface area in here, so there's lots of little
0:52:17 > 0:52:20- chambers and cavities and places for them to feed.- That is unbelievable.
0:52:20 > 0:52:23- It's a really beautiful structure. - Really soft.- Yeah.
0:52:24 > 0:52:29It's these white tufts, produced by the fungus, that feed the colony.
0:52:32 > 0:52:35They contain just the right balance of nutrients to support
0:52:35 > 0:52:37the developing brood.
0:52:48 > 0:52:52This fungus garden alone, grown since the ants arrived,
0:52:52 > 0:52:55will feed thousands of new ants.
0:52:58 > 0:53:00It's the clearest indication yet
0:53:00 > 0:53:03that our leafcutter colony is thriving.
0:53:06 > 0:53:08Before we get completely inundated,
0:53:08 > 0:53:12I think we're going to have to put this back down very gently.
0:53:12 > 0:53:13Put that back.
0:53:13 > 0:53:16Ah, one's gone down my front. Ah-ah! Ouch!
0:53:16 > 0:53:18HE GASPS
0:53:18 > 0:53:20Ah, yep.
0:53:20 > 0:53:24See, they're incredibly good at defending. This is their colony.
0:53:24 > 0:53:28And we've broken into it. And that's the result.
0:53:28 > 0:53:31I don't think we'll be doing that again.
0:53:31 > 0:53:32I'm beginning to regret this now.
0:53:32 > 0:53:34We've had a good look at the fungus garden,
0:53:34 > 0:53:38and we've seen a great response, but yeah, perhaps not again.
0:53:44 > 0:53:48Away from the nest, there are more signs of progress.
0:53:50 > 0:53:54The ants are constantly monitoring their long foraging trails.
0:53:55 > 0:53:59If any blockages occur, workers swiftly clear them.
0:54:11 > 0:54:15What our colony is showing is organisation on a massive scale.
0:54:19 > 0:54:22And that begs an important question.
0:54:24 > 0:54:28How did they organise all this? How did they know what to do?
0:54:29 > 0:54:33Humans wouldn't be able to do this without some kind of hierarchy,
0:54:33 > 0:54:37without somebody taking responsibility, giving instructions.
0:54:41 > 0:54:43And, as we've seen, this is not the case with ants.
0:54:45 > 0:54:47There is no hierarchy.
0:54:47 > 0:54:52No central command or control from any individual or group of ants.
0:54:52 > 0:54:54Not even the queen.
0:54:57 > 0:54:58So how do the ants do it?
0:55:01 > 0:55:05To help answer that question, Adam's going to put them to the test.
0:55:06 > 0:55:10I've set the ants a problem. I've given them a Y-shaped trail.
0:55:10 > 0:55:13At one end of that Y is food and at the other end is nothing.
0:55:13 > 0:55:17And I've connected that trail up to the main trail,
0:55:17 > 0:55:20so they're pouring down out of the nest, coming onto this trial
0:55:20 > 0:55:22and are being faced with a choice.
0:55:22 > 0:55:24Do they go left or right?
0:55:27 > 0:55:30Our ants have a clear 50-50 choice between right and left.
0:55:33 > 0:55:35But after just 20 minutes,
0:55:35 > 0:55:39virtually all of them are heading down a path that leads to the food.
0:55:41 > 0:55:43So, how do they know where to go?
0:55:43 > 0:55:45At this distance, they can't see the food.
0:55:45 > 0:55:47Their eyesight isn't good enough.
0:55:50 > 0:55:55Instead, it's all down to be ingenious way the ants share
0:55:55 > 0:55:56information with each other,
0:55:56 > 0:55:59using their acute sense of smell.
0:56:03 > 0:56:06The ants moving down here are laying behind them
0:56:06 > 0:56:09a chemical pheromone trail that marks the way for other ants.
0:56:12 > 0:56:16They can detect tiny amounts of these pheromones
0:56:16 > 0:56:17using their antennae.
0:56:21 > 0:56:24When an ant goes out foraging, she leaves the pheromone trail
0:56:24 > 0:56:28on the ground behind her that her sisters are able to follow.
0:56:32 > 0:56:36If she finds food, she will then lay down even more pheromone on her
0:56:36 > 0:56:38way back to the nest,
0:56:38 > 0:56:40making the original trail even stronger.
0:56:42 > 0:56:46If she doesn't find food, she won't lay any more pheromone
0:56:46 > 0:56:49and the trail simply evaporates away.
0:56:52 > 0:56:54The stronger the pheromone trail,
0:56:54 > 0:56:57the more likely an ant is to follow it.
0:56:57 > 0:56:59And, in turn, add her own pheromone to the route.
0:57:04 > 0:57:07When this is applied to hundreds and thousands of ants,
0:57:07 > 0:57:11very strong trails are produced that link the nest directly to food
0:57:11 > 0:57:13sources in the environment.
0:57:19 > 0:57:21And what that means is that the branch that's got
0:57:21 > 0:57:24food at the end of it is much more concentrated in terms
0:57:24 > 0:57:26of pheromone than the branch that doesn't.
0:57:26 > 0:57:29So that when ants come to that fork and they have to make a decision,
0:57:29 > 0:57:33they follow the trail head that has the most amount of pheromone.
0:57:33 > 0:57:35So they're much more likely to go right than they are to go left.
0:57:35 > 0:57:37That means these ants can organise themselves.
0:57:37 > 0:57:41The queen's not in the colony going, "Turn right, turn left,
0:57:41 > 0:57:42"take the third exit."
0:57:42 > 0:57:45They follow the trail of pheromone to the food.
0:57:47 > 0:57:52So each individual ant is dealing with simple signals, simple rules.
0:57:53 > 0:57:56But collectively this system achieves complex results.
0:57:58 > 0:58:02It enables the colony to find new food sources, exploit them
0:58:02 > 0:58:05efficiently and react swiftly when they are depleted.
0:58:06 > 0:58:10This is what underpins the entire leafcutting operation.
0:58:16 > 0:58:20But pheromones aren't the only way leafcutters communicate.
0:58:21 > 0:58:24They're constantly exchanging information,
0:58:24 > 0:58:29and with the right technology, we can even listen in.
0:58:31 > 0:58:33Is it possible to actually hear?
0:58:33 > 0:58:36Yes, luckily, I'm festooned with gadgets,
0:58:36 > 0:58:37so we can actually...
0:58:37 > 0:58:39We can actually mic these up.
0:58:39 > 0:58:40Dr Gadget.
0:58:40 > 0:58:43Yes, we can get some sound out of these.
0:58:43 > 0:58:46They're very small animals and it must be a very faint noise.
0:58:46 > 0:58:49Yes, it's a very small noise and it's quite high-frequency,
0:58:49 > 0:58:51but if we just press that on to there...
0:58:56 > 0:59:00To human ears, the ants' world seems silent,
0:59:00 > 0:59:05but amplified by the microphones, the leaf comes alive with noise.
0:59:09 > 0:59:11'And there is one particular sound we're listening for.
0:59:14 > 0:59:17'In amongst the sound of leaves being cut
0:59:17 > 0:59:20'and ant footsteps is a high-pitched chirrup.'
0:59:20 > 0:59:22ANTS CHIRRUP
0:59:22 > 0:59:25'This is stridulation,
0:59:25 > 0:59:30'a sound the ants make by rubbing two sections of their abdomen together.'
0:59:32 > 0:59:36- That little chirrup?- Yeah. - There.- Yup.
0:59:38 > 0:59:42So they're making this sound but it's part of a group of sounds
0:59:42 > 0:59:44they make, these sounds.
0:59:47 > 0:59:51'That little chirruping noise is a recruitment signal.
0:59:51 > 0:59:56'The more nutritious a leaf is, the more the ant make this noise,
0:59:56 > 0:59:59'sending a cascade of vibrations through the plant.
1:00:05 > 1:00:09'And this draws other ants to the tastiest part of the plant,
1:00:09 > 1:00:12'which means the ants will tend to take the best leaves first.'
1:00:16 > 1:00:21But there's more to stridulation than simply leaf cutting.
1:00:21 > 1:00:23It can make the difference between life and death.
1:00:27 > 1:00:31As they build their underground network of tunnels and chambers,
1:00:31 > 1:00:35our ants, just like human miners, face an ever-present risk.
1:00:37 > 1:00:39A roof collapse could bury them alive.
1:00:41 > 1:00:45To discover how they respond, we're going to simulate this catastrophe.
1:00:48 > 1:00:50And time for another gadget.
1:00:50 > 1:00:52This is a plate microphone,
1:00:52 > 1:00:55so this is recording directly from what's on the surface.
1:00:55 > 1:00:59'We're going to put an ant on the surface of this microphone
1:00:59 > 1:01:03'and bury it with soil, just like a roof collapse in the nest.
1:01:04 > 1:01:06'And then, we listen.'
1:01:08 > 1:01:11- You put that on, and I'll... - I'll wrangle the ant,
1:01:11 > 1:01:14- you get some earth on there.- Ready?
1:01:16 > 1:01:18- There we go.- Buried alive.
1:01:20 > 1:01:22So this is going to be the sound of ant fear.
1:01:22 > 1:01:24This is an ant that has been trapped under the soil.
1:01:24 > 1:01:26It's calling its nest mates.
1:01:27 > 1:01:30ANT CHIRRUPS
1:01:30 > 1:01:33There's a bit of hiss there, but you can hear...
1:01:33 > 1:01:35That's the noise they're making
1:01:35 > 1:01:37by moving their abdomen backwards and forwards.
1:01:37 > 1:01:39That's very obvious, isn't it?
1:01:42 > 1:01:45It's a very clear signal that causes a very specific behaviour.
1:01:45 > 1:01:48"Come over here, dig me out."
1:01:54 > 1:01:57'What we're hearing is the ant's alarm call.
1:01:57 > 1:02:00'She is appealing to her nest mates for help.
1:02:01 > 1:02:03'With only a loose covering of soil, this ant
1:02:03 > 1:02:06'isn't in any real danger.
1:02:08 > 1:02:11'As she digs her way to the surface, the noise of panic stops
1:02:11 > 1:02:13'and she emerges.'
1:02:15 > 1:02:16- There we go.- She's free.
1:02:18 > 1:02:22You actually get a window into their world. It really is amazing.
1:02:22 > 1:02:25Because they're so small, we can't hear these sounds without
1:02:25 > 1:02:28fancy microphones and things, but once you start hearing them,
1:02:28 > 1:02:31you realise they are living in a very complicated world.
1:02:31 > 1:02:33They produce sounds, they've got chemicals.
1:02:33 > 1:02:35It's a very complex world they're in.
1:02:38 > 1:02:41So this is how the ants organise themselves.
1:02:42 > 1:02:47Each individual follows simple rules using communication tools
1:02:47 > 1:02:50like pheromones and stridulation.
1:02:50 > 1:02:53And applied to huge numbers of individuals,
1:02:53 > 1:02:58these simple rules allow the colony to solve complex problems.
1:02:58 > 1:03:01This is collective swarm intelligence.
1:03:06 > 1:03:10Ant species around the world use this ability to tackle
1:03:10 > 1:03:12problems that challenge even us humans.
1:03:19 > 1:03:23'I've come to Bristol to discover how one species of ant uses swarm
1:03:23 > 1:03:25'intelligence to make a vital decision.'
1:03:33 > 1:03:37These are Temnothorax albipennis, also known as the rock ant.
1:03:37 > 1:03:40They're absolutely tiny, only about two millimetres long.
1:03:40 > 1:03:44Don't let their size fool you, these tiny creatures are smart operators.
1:03:44 > 1:03:47They use an ingenious set of rules to make decisions that
1:03:47 > 1:03:50test us to the limits.
1:03:52 > 1:03:53'For instance, house-hunting.
1:03:58 > 1:04:00'We might find it stressful.
1:04:01 > 1:04:04'But to the rock ants, it's a matter of life and death.
1:04:07 > 1:04:10'Here, at the University of Bristol's ant lab,
1:04:10 > 1:04:12'Professor Nigel Franks
1:04:12 > 1:04:16'has spent the last decade studying the behaviour of these insects.'
1:04:18 > 1:04:20So this is a rock ant nest that you have set up in the lab,
1:04:20 > 1:04:25- pretty similar to what you would get in the wild?- In a sense, yes.
1:04:25 > 1:04:28In terms of the spatial scale, the spatial arrangement,
1:04:28 > 1:04:32the colonies normally live in very, very flat crevasses in rocks,
1:04:32 > 1:04:36with maybe a millimetre between the floor and ceiling,
1:04:36 > 1:04:39so we can keep them in these nice simple microscopes like this.
1:04:39 > 1:04:42As soon as they get them destroyed, particularly if they lose
1:04:42 > 1:04:46the roof of their nest, in the wild, they can't do anything about that.
1:04:46 > 1:04:51- They simply have to find a new nest site to live in.- OK, let's do it.
1:04:53 > 1:04:56'Removing the roof effectively destroys the nest.
1:04:56 > 1:05:00'In the wild, this would be a perilous situation for the colony.
1:05:02 > 1:05:05'It's time to find a new home as quickly as possible.
1:05:07 > 1:05:10'We've given them a range of options of varying suitability.'
1:05:15 > 1:05:18Right over here we've got a really poor nest.
1:05:18 > 1:05:21Too small and, in addition to that, it's got some dead bodies in there.
1:05:21 > 1:05:26It's an absolute slum. Over on this side we've got the absolute des res.
1:05:26 > 1:05:30We've got a nice big nest, hygienic, clean
1:05:30 > 1:05:32and it's made dark with a red filter.
1:05:32 > 1:05:36So we've got from really superb palatial accommodation
1:05:36 > 1:05:38right down to an absolute slum.
1:05:41 > 1:05:43'The ants go scouting for a new home.
1:05:45 > 1:05:50'Like a team of insect surveyors, they inspect each site,
1:05:50 > 1:05:53'checking factors like hygiene and light intensity.
1:05:54 > 1:05:58'It doesn't take them long to discover our des res.
1:05:59 > 1:06:03'It's clean, it's dark, but is it big enough?
1:06:04 > 1:06:08'This is where their ingenious system of rules is revealed.'
1:06:11 > 1:06:16They will go inside, they will actually pace the map in a way and
1:06:16 > 1:06:19work out the floor area to see if it is big enough for a whole colony.
1:06:22 > 1:06:24'When the ant encounters a potential new nest,
1:06:24 > 1:06:26'she criss-crosses it many times.
1:06:28 > 1:06:29'As she does so,
1:06:29 > 1:06:33'she leaves behind her on the ground a tangle of pheromone trail.
1:06:34 > 1:06:36'She will then leave the new nest,
1:06:36 > 1:06:38'but that's not the end of her assessment.
1:06:42 > 1:06:45'A short while later, she returns for a second inspection.'
1:06:48 > 1:06:51They then sort of smell the ground
1:06:51 > 1:06:54and every time they cross a previous path, they note it.
1:06:54 > 1:06:58And, essentially, if they were in a very large nest, the frequency
1:06:58 > 1:07:01with which they would cross a previous path would be very low.
1:07:01 > 1:07:04If they're in a very small nest, it would be very high.
1:07:08 > 1:07:11'So by counting the number of times she crosses her own path,
1:07:11 > 1:07:16'an ant is able to very accurately work out how big a new nest is.'
1:07:19 > 1:07:23So it's a beautiful example of the ants using an exquisitely simple
1:07:23 > 1:07:27rule to solve a very complicated problem.
1:07:29 > 1:07:31'But one ant's view isn't enough.
1:07:33 > 1:07:36'Like us, they need a second opinion. And quickly.
1:07:36 > 1:07:40'Because without a nest, the colony is in danger.'
1:07:42 > 1:07:46If she thinks a nest is suitable, she will return to the colony
1:07:46 > 1:07:51and she will attempt to recruit one other nest mate by a process
1:07:51 > 1:07:52we call tandem running.
1:07:54 > 1:07:57'To get that second opinion, the scouting ant
1:07:57 > 1:08:01'physically leads a nest mate to the new location on a tandem run.'
1:08:04 > 1:08:07'When the tandem runners arrive at the new nest,
1:08:07 > 1:08:11'the leader heads back to the colony to recruit another ant,
1:08:11 > 1:08:14'whilst the follower carries out her own survey.
1:08:16 > 1:08:19'If she thinks the new nest is a suitable new home,
1:08:19 > 1:08:23'she will also return to the colony and recruit yet another ant.'
1:08:25 > 1:08:30And so the numbers snowball slowly. One, two, four, eight, etc.
1:08:33 > 1:08:35'Because time is of the essence,
1:08:35 > 1:08:37'they can't wait for every ant to agree.
1:08:39 > 1:08:43'So, once a critical number of ants, which can be as few as ten,
1:08:43 > 1:08:46'are in favour of the new site, another rule kicks in.
1:08:48 > 1:08:51'Tandem running stops, and a moving behaviour begins.'
1:08:54 > 1:08:56They will run back to the old nest
1:08:56 > 1:08:59and start picking up their nest mates, whacking them
1:08:59 > 1:09:02over their shoulders, so to speak, and running them to the new nest.
1:09:02 > 1:09:05And they can run with an ant over their shoulder or a huge brood item
1:09:05 > 1:09:08in their mandibles at three times the speed
1:09:08 > 1:09:11that they can lead a tandem run. So it's like a gear change.
1:09:11 > 1:09:14It's like going from second gear to fifth gear, and - wallop!
1:09:14 > 1:09:17The colony commits and will rapidly emigrate to the nest
1:09:17 > 1:09:19they have chosen.
1:09:22 > 1:09:26The rock ants have used simple rules, applied one after the other,
1:09:26 > 1:09:31to find a swift, collective solution to a life-and-death situation.
1:09:35 > 1:09:38And this is just one species of ant with its own set of rules to
1:09:38 > 1:09:41solve its own unique set of problems.
1:09:47 > 1:09:48In the wild,
1:09:48 > 1:09:53driver ants create imposing trails guarded by huge soldiers to
1:09:53 > 1:09:56ensure the safe passage of the brood from one place to another.
1:10:01 > 1:10:04The Asian weaver ants build intricate nests
1:10:04 > 1:10:07using their own brood as glue guns.
1:10:11 > 1:10:13This is an insect using a tool.
1:10:17 > 1:10:21All of these behaviours, wonders of the natural world,
1:10:21 > 1:10:24owe their existence to simple rules followed by colony
1:10:24 > 1:10:28members in the same way over and over again.
1:10:42 > 1:10:44Back in our colony, we are approaching
1:10:44 > 1:10:47the end of our project to explore the world of the ants.
1:10:50 > 1:10:52But there's one cast of ant whose roles
1:10:52 > 1:10:56and behaviours remain more mysterious than any other.
1:10:56 > 1:10:58The soldiers.
1:10:58 > 1:11:03As we've seen, they tend to remain hidden deep within the nest.
1:11:03 > 1:11:06But we're about to discover some of their secrets.
1:11:11 > 1:11:13In our most ambitious experiment,
1:11:13 > 1:11:16we've used radio tracking technology to follow the movements
1:11:16 > 1:11:21of a group of soldiers day and night over a period of ten days.
1:11:27 > 1:11:31Now, the results are in. And Adam has been crunching the numbers.
1:11:33 > 1:11:36How difficult would this have been in the wild colony?
1:11:36 > 1:11:38This sort of thing would be impossible, because in the wild,
1:11:38 > 1:11:40we'd be underground right now.
1:11:40 > 1:11:42You know, you can't use this sort of technology
1:11:42 > 1:11:44deep in the ground in any sort of effective way.
1:11:44 > 1:11:47So we've got no insight about how these things happen
1:11:47 > 1:11:50in a natural nest. That's why this is such a nice opportunity.
1:11:50 > 1:11:54So now you've begun to analyse all the results from the tagging.
1:11:54 > 1:11:57What's beginning to emerge?
1:11:57 > 1:11:59Well, what's really interesting is that individual soldiers
1:11:59 > 1:12:02are behaving in quite a strange way. They're patrolling.
1:12:02 > 1:12:06So one, for example, goes from this box to this box to this box
1:12:06 > 1:12:09back again, back again, over about 20 hours.
1:12:09 > 1:12:11We have others doing exactly the same thing,
1:12:11 > 1:12:13oscillatory behaviour between boxes.
1:12:13 > 1:12:16So almost as if each of the soldiers has a sector
1:12:16 > 1:12:19of the nest they control.
1:12:23 > 1:12:28Our results reveal the soldiers as a highly organised security force.
1:12:33 > 1:12:37Every ant we tag has an oscillating patrolling behaviour,
1:12:37 > 1:12:39all of it focused around the fungus gardens.
1:12:42 > 1:12:45And we discovered there's more than one type of patrol.
1:12:48 > 1:12:52Some soldiers moved back and forth between just two nest boxes.
1:12:52 > 1:12:54Others have a much larger route,
1:12:54 > 1:12:58visiting five or more boxes over a period of days.
1:13:03 > 1:13:06This area here is a hotspot of activity,
1:13:06 > 1:13:10with a number of different patrols converging on one box.
1:13:10 > 1:13:13Due to the extra security presence,
1:13:13 > 1:13:17it's our suspicion that this area is the location of the queen.
1:13:20 > 1:13:25Overall, what we see is an organised security network, operating
1:13:25 > 1:13:29on a regular schedule, guarding the prized assets of the leafcutters -
1:13:29 > 1:13:30the queen...
1:13:32 > 1:13:34..the brood...
1:13:34 > 1:13:36and the fungus.
1:13:38 > 1:13:42That makes sense, because they are the high-value
1:13:42 > 1:13:45resource of the colony, and that's where the young are.
1:13:45 > 1:13:48Yes, so the soldiers seem to be kind of barracked into these
1:13:48 > 1:13:50areas where they've got something to defend.
1:13:54 > 1:13:59Our data indicate that the soldiers are hardwired to patrol the nest,
1:13:59 > 1:14:03poised and ready to repel anything that threatens the colony.
1:14:07 > 1:14:09To see that response,
1:14:09 > 1:14:13we can simulate an attack on the nest by pushing a camera down into it.
1:14:17 > 1:14:19To the ants, this appears to be a predator,
1:14:19 > 1:14:21and it triggers a call to arms.
1:14:25 > 1:14:30Ants near the camera release a pheromone that signals alarm.
1:14:31 > 1:14:34This pheromone attracts more ants onto the scene.
1:14:37 > 1:14:40Almost instantly, there is a whole swarm attacking the camera.
1:14:42 > 1:14:45Once again, they are following a simple rule.
1:14:45 > 1:14:48Defend the nest.
1:14:52 > 1:14:54But in the wild,
1:14:54 > 1:14:58following this rule is likely to cost some ants their life.
1:15:03 > 1:15:06This is a praying mantis feeding on driver ants.
1:15:09 > 1:15:12When the colony responds to the threat, one of the first
1:15:12 > 1:15:16ants on the scene throws herself into the jaws of the mantis.
1:15:19 > 1:15:22She stops the insect taking any more of her nest mates,
1:15:22 > 1:15:26but sacrifices her life in the process.
1:15:30 > 1:15:33And as more individuals arrive, the tables turn,
1:15:33 > 1:15:36and the predator literally loses its head.
1:15:44 > 1:15:47To achieve the collective goal of defending the nest,
1:15:47 > 1:15:50individual ant lives are expendable.
1:15:53 > 1:15:56And this is the darker side of the parallel that people have
1:15:56 > 1:15:59drawn between humans and ants.
1:16:03 > 1:16:08Instead of a model of industriousness, a world of mindless
1:16:08 > 1:16:13automatons, following rules, unable to control their destiny.
1:16:16 > 1:16:18There's a moment, I think in the 20th century,
1:16:18 > 1:16:22where certainly all those ideas of industriousness are gone,
1:16:22 > 1:16:24the ant becomes a very scary thing.
1:16:24 > 1:16:29Ant society becomes everything that humans want to avoid.
1:16:29 > 1:16:31I think there are a couple of things that add to that.
1:16:31 > 1:16:34The experience of the First World War,
1:16:34 > 1:16:38and the sense of soldiers being sent off anonymously to their death.
1:16:42 > 1:16:48Also, I think, the experience of mass life in factories.
1:16:48 > 1:16:49You know, think about Henry Ford,
1:16:49 > 1:16:52think about those cars rolling off the production line.
1:16:52 > 1:16:56That's really very much like our leafcutter ants,
1:16:56 > 1:16:59and their production line with the leaves.
1:16:59 > 1:17:03There's no room for individuality, it's pretty horrific.
1:17:04 > 1:17:07The ant is everything we don't want to become.
1:17:09 > 1:17:12It also find it's way into science fiction films.
1:17:12 > 1:17:16I mean, I remember a film called Them, where the
1:17:16 > 1:17:20Earth is being threatened by these giant ants.
1:17:20 > 1:17:23'There is no word to describe them.'
1:17:25 > 1:17:27SHE SCREAMS
1:17:27 > 1:17:31It's a classic Communist-era movie, in fact.
1:17:31 > 1:17:34The sort of, the unknowability of these ants,
1:17:34 > 1:17:37the sense that their operating under some system that's
1:17:37 > 1:17:41swayed by propaganda, that we can't even really comprehend.
1:17:41 > 1:17:45They are the classic Commie enemies.
1:17:45 > 1:17:47Is there any type of gas we could use?
1:17:47 > 1:17:49No, we can't take a chance, it might poison the whole city.
1:17:49 > 1:17:53So bringing things right up-to-date now, there has been
1:17:53 > 1:17:59a change of emphasis, the interest in what ants do is now altered a bit.
1:17:59 > 1:18:02That's right, we've become increasingly interested in them
1:18:02 > 1:18:07as technological systems, if you like. As natural computers.
1:18:07 > 1:18:11And we're interested in the way that they solve problems,
1:18:11 > 1:18:13and the way in which they, in particular,
1:18:13 > 1:18:16find the most efficient way of solving problems, the most efficient
1:18:16 > 1:18:21ways of foraging for food, bringing it back to the nest, and so on.
1:18:25 > 1:18:28It's a radical thought.
1:18:28 > 1:18:31It suggests we could see our ant colony as a giant,
1:18:31 > 1:18:35powerful computer, that can solve complex problems.
1:18:37 > 1:18:41Problems like finding sources of leaves, and delivering them
1:18:41 > 1:18:45efficiently to the parts of the nest where they are required.
1:18:51 > 1:18:55As we've seen, the colonies solve these problems using a logical
1:18:55 > 1:18:58system, based on pheromone trails.
1:19:00 > 1:19:03And this system is now inspiring new technologies,
1:19:03 > 1:19:07designed to solve some very large human problems.
1:19:20 > 1:19:25Here, in the Texan heat, a very cold industry is at work.
1:19:31 > 1:19:36This is Air Liquide, a company that supplies tanker loads of compressed
1:19:36 > 1:19:41gas to thousands of customers, from hospitals to oil refineries.
1:19:47 > 1:19:52I'm here to meet Charles Harper, to find out how insight from ants
1:19:52 > 1:19:56is helping the business solve a fiendishly-complicated problem.
1:19:59 > 1:20:03Here we monitor the supply of, and the production of all our gases
1:20:03 > 1:20:05and our liquids in the United States.
1:20:05 > 1:20:08We have about 10,000 customer sites to deliver to,
1:20:08 > 1:20:14we have 1,000 trucks and drivers to dispatch, so on any given day we
1:20:14 > 1:20:18have to know who needs a delivery, and where to source the liquid from.
1:20:21 > 1:20:24Finding the best routes to get the right truckloads to the right
1:20:24 > 1:20:29customers every day is a massive logistical challenge.
1:20:31 > 1:20:36And this challenge has a name - the travelling salesman problem.
1:20:40 > 1:20:44The task is to find the shortest route between a number of cities,
1:20:44 > 1:20:48visiting each only once before returning to the starting point.
1:20:52 > 1:20:55With five cities, there are only 12 possible delivery routes.
1:20:57 > 1:20:59But as more destinations are added,
1:20:59 > 1:21:03the number of potential routes skyrockets.
1:21:04 > 1:21:09A trip with just 15 cities has over 40 billion possible routes.
1:21:16 > 1:21:19Air Liquide faces a travelling salesman problem that has
1:21:19 > 1:21:23trillions of possible solutions.
1:21:23 > 1:21:26So for help, they turned to the ants.
1:21:28 > 1:21:32Inside this computer, there is a programme based on ant
1:21:32 > 1:21:39behaviour, it's called an ACO, or ant colony optimisation.
1:21:39 > 1:21:42So, you're running your delivery network very similar to
1:21:42 > 1:21:44an ant colony going out foraging,
1:21:44 > 1:21:47only instead of bringing food in, your looking to take goods out?
1:21:47 > 1:21:50Exactly. Just the reverse, and in our particular case,
1:21:50 > 1:21:52we're delivering food out to the customers,
1:21:52 > 1:21:55in this case it's liquid oxygen or nitrogen,
1:21:55 > 1:21:58but as an ant colony would bring food
1:21:58 > 1:22:03and supplies back to the mound, we use that ant motion, and ant
1:22:03 > 1:22:07reinforcement in the pheromone trail to simulate our routes.
1:22:11 > 1:22:14The programme sends out digital versions of ants
1:22:14 > 1:22:15to investigate potential routes.
1:22:17 > 1:22:18Just like our own leafcutters,
1:22:18 > 1:22:23the digital ants lay virtual pheromones as they go.
1:22:23 > 1:22:26Shorter routes become reinforced with pheromone, as more
1:22:26 > 1:22:28and more ants begin to follow them.
1:22:28 > 1:22:32While the longer roots begin to evaporate, and are ignored.
1:22:36 > 1:22:38It's the same technique our ants
1:22:38 > 1:22:41use to establish the quickest route to a food source.
1:22:43 > 1:22:47The digital ants quickly and efficiently identify the better
1:22:47 > 1:22:51options, so there's no need to calculate every possible route.
1:22:53 > 1:22:55And Air Liquide gets a highly-efficient way
1:22:55 > 1:22:57to run its complex operations.
1:23:08 > 1:23:11But solving complex delivery problems is just
1:23:11 > 1:23:14the beginning of what ant colony optimisations can do.
1:23:15 > 1:23:18Their ability to identify the best
1:23:18 > 1:23:22route from billions of options is now helping scientists reach
1:23:22 > 1:23:24far more ambitious destinations.
1:23:31 > 1:23:34Dr Max Vesile, from the University of Strathclyde's
1:23:34 > 1:23:38Advanced Space Concepts Laboratory, has studied how lessons
1:23:38 > 1:23:42from the ant colony can be applied to travelling through space itself.
1:23:46 > 1:23:50Well, one thing we decided to do some time ago was to try to use
1:23:50 > 1:23:56ants to try and plan a trajectory from one planet to another,
1:23:56 > 1:24:00passing by a number of intermediate planets, and exploiting
1:24:00 > 1:24:03their gravity to change the velocity of the satellite.
1:24:13 > 1:24:16If you send a spacecraft through the gravitational
1:24:16 > 1:24:19field of a planet at precisely the right angle,
1:24:19 > 1:24:21it acts like a catapult,
1:24:21 > 1:24:24propelling the spacecraft across the solar system.
1:24:25 > 1:24:28This is called a slingshot.
1:24:30 > 1:24:33By using more than one planet, it's possible to
1:24:33 > 1:24:38slingshot across the solar system, without the need for tons of fuel.
1:24:40 > 1:24:43But calculating the best combination of slingshots
1:24:43 > 1:24:45is extremely complicated.
1:24:49 > 1:24:51So, you need to go from one point to another,
1:24:51 > 1:24:54but you've got lots of points in between,
1:24:54 > 1:24:56that you need to pass to get that boost?
1:24:56 > 1:25:00Exactly, so what we asked the ants do, is to tell us
1:25:00 > 1:25:05the best possible sequence of planets to reach the destination.
1:25:05 > 1:25:09It's again similar to the travelling salesman problem,
1:25:09 > 1:25:13but in this case, these cities are moving, and we have the
1:25:13 > 1:25:18additional rule that we can visit multiple times the same city.
1:25:18 > 1:25:21And on top of that, basically the cost of going from one city to
1:25:21 > 1:25:25another, depends on the time in which we reach the city.
1:25:25 > 1:25:27So, this is a much more complex problem
1:25:27 > 1:25:30- than ants are solving on Earth? - Definitely, yes.
1:25:34 > 1:25:39This research work is still in its infancy, but Max has tested
1:25:39 > 1:25:43his galactic version of ant colony optimisation on the Cassini probe.
1:25:45 > 1:25:50Launched in 1997, it flew to Saturn, propelled there by slingshots,
1:25:50 > 1:25:52past Venus, the Earth, and Jupiter.
1:25:55 > 1:25:59The digital ants not only replicated this route, but also
1:25:59 > 1:26:03suggested two others that would have been quicker and more efficient.
1:26:07 > 1:26:10It's literally millions of miles away from leafcutting.
1:26:23 > 1:26:28We've reached the end of our project to explore the hidden world of ants.
1:26:29 > 1:26:33The past month has revealed the sheer scale
1:26:33 > 1:26:35of their organisational powers.
1:26:35 > 1:26:40Well, it's incredible to see how far the ants have come.
1:26:40 > 1:26:44We've uprooted them, and brought them halfway around the world.
1:26:44 > 1:26:47We've seen them rebuild their entire society
1:26:47 > 1:26:49in the space of just a few short weeks.
1:26:52 > 1:26:57They've now taken control of this new territory, from the outermost
1:26:57 > 1:27:01plants to the depths of the nest, and the colony is thriving.
1:27:03 > 1:27:08We hope it will continue to be the subject of scientific observation.
1:27:11 > 1:27:15But for me, the colony has already helped to show ants in a new light.
1:27:19 > 1:27:22Rather than a vast number of individuals, the colony is
1:27:22 > 1:27:28really a super-organism, functioning in a complex and sophisticated way.
1:27:28 > 1:27:31The different ants like cells and organs and animal,
1:27:31 > 1:27:35have different functions, but operate together as an ordered whole.
1:27:38 > 1:27:42Seen as a super-organism, the ant colony truly is one of the most
1:27:42 > 1:27:47impressive achievements in the evolution of life on our planet.
1:27:50 > 1:27:53And the more we come to understand it,
1:27:53 > 1:27:57the more we can harness the genius of the ants for our own benefit.
1:28:00 > 1:28:03We now have a better understanding of the parallels
1:28:03 > 1:28:05between ants and ourselves.
1:28:06 > 1:28:10But we're only just beginning to understand what they can teach us.
1:28:31 > 1:28:34Subtitles by Red Bee Media Ltd