06. Insects
Category
📺
TVTranscript
00:00There are more kinds of insects in the world than all other kinds of insects, and there
00:30kinds of animals put together. But because they are so small, we rarely see how extraordinary
00:36they are. Occasionally, they assemble in astonishing numbers. A billion monarch butterflies hibernate
00:48in the forests of Mexico.
00:59Vast clouds of mayflies emerge all at once to mate.
01:09Insects face endless challenges. They can transform their bodies to meet every purpose.
01:17Eyes grow on stalks. Bodies become chemical guns.
01:24To discover how and why they do such things, you have to enter their world.
01:55Patagonia, Chile. Home to one of the most extraordinary of beetles.
02:05There are many kinds of beetles in the world, but this one has some of the biggest jaws
02:10of all. He is Darwin's beetle.
02:18He's on his way to the forest to look for a mate. Whether he gets one or not will depend
02:25on his strength and on the size of his jaws.
02:32He starts his search. A female is likely to be on a tree trunk, but trees in this part
02:54of the world are very tall. His search could be a long one.
03:02Unfortunately for him, she is 25 metres above him, near the top.
03:19She has more normal-sized jaws, but then she only needs them for feeding. But he needs
03:27immense jaws for fighting, because there are other males around with the same mission.
03:48Sheer strength is not enough in these battles. The technique is to reach over your mate and
03:56your opponent's head, and hook your jaws under his wing covers. That's why his jaws
04:03are so long and have that odd shape. He's got the grip. Now he has to lift. And that
04:15needs strength.
04:23Another lift is needed.
04:39And that's that.
04:43Beetle armour is strong, so he bounces. The winner climbs on. There are more males ready
04:50to fight him up here.
05:21And here she is at last.
05:36But she doesn't seem to be in the mood.
05:51So now he has to use his great jaws as a restraining cage.
06:06Success at last.
06:14But the hurling habit dies hard.
06:25Insects' bodies have the capacity to take on an almost infinite variety of shapes. This
06:32is one of the keys to their success.
06:44This male moth doesn't go in search of females. He inflates a pair of scented plumes that
07:01protrude from the end of his abdomen. And they come to him.
07:14All insects have the same basic design. Six legs and an armour-covered body. But the different
07:22parts can become exaggerated to solve particular problems.
07:32This beetle has a giraffe's neck in order to fight.
07:39A praying mantis is disguised as a flower and waits in ambush.
07:49Another is almost invisible among dead leaves.
07:55Insect armour can carry colours that can camouflage or communicate.
08:10But the armour can also be converted into wings.
08:20And that makes insects a global force, enabling them to invade almost every habitat on earth.
08:40In southern France, one insect is starting on the most important day of its life.
08:58Dawn. And a newly hatched damselfly.
09:05She needs to mate and lay her eggs before sunset. Her adult life is so short, she may
09:12not get another chance.
09:19Her success will depend on these fragile wings.
09:26She faces many perils.
09:36Few insects can escape from a spider's web.
09:47But her wings are more powerful than they look.
09:57She wants to mate with the strongest male.
10:02However, the stream where she might find him is a battleground.
10:14She watches while dark-winged males compete for the best territories, flashing their wings
10:20at each other in threat, or trying to force their opponents into the water.
10:31Fighting finished, the female uses her wings to signal her presence to the winner.
10:46She won't be rushed, but if he doesn't grip her with his tail, a rival might steal her.
10:54As they mate, their linked bodies form the shape of a heart.
11:04But now she has the problem of laying her fertilized eggs, and that brings new hazards.
11:13Like any athlete, she must warm her muscles for optimum performance, and does so by using
11:23her wings as solar heating panels.
11:27She must fly dangerously low if she's to find the right place for her eggs.
11:42Only the quickest damselflies escape.
12:13Safely past the frogs, this female has reached a suitable plant on which to lay her eggs.
12:32But she has to place them underwater if they're to survive.
12:37For the first time, her wings seem to be a hindrance, but in fact they help her yet again
12:43by trapping a silvery layer of air which enables her to breathe.
12:52She cuts into a plant stem and deposits her eggs inside.
13:08Now her wings are going to be truly tested.
13:14If she can't break through the water surface, she will drown.
13:38Her day has been a complete success.
13:59Damselflies seldom venture beyond their home stream,
14:04but some insects fly huge distances.
14:09September, on the shores of Lake Erie in southern Canada.
14:14A monarch butterfly is fueling up on nectar.
14:26A chill gust of northerly air.
14:31It's time to leave.
14:36The coming winter will be so cold it would kill her.
14:48She has never flown more than a few hundred metres in her life.
14:54But now she is heading out over Lake Erie, which is a hundred miles across.
15:14This is just the first leg of one of the world's greatest animal migrations.
15:20She will continue south, using the sun as a compass, to cross America, a journey of 2,000 miles.
15:33Her destination is Mexico and one small and special group of trees.
15:39No one knows how she finds them in these great mountain forests.
15:46She joins other monarch butterflies that have travelled here from all over North America.
15:57Countless butterflies crowd these particular trees, hanging from every branch.
16:04They come here because although winter brings a chill to the air,
16:10there will not be a lethal freeze of the will in Canada.
16:16The conditions are perfect for hibernation.
16:23Hibernating butterflies are vulnerable to predators.
16:29But monarchs are poisonous.
16:33However, a few birds have learned to rip out the toxic parts and eat the rest.
16:39They kill hundreds of thousands of butterflies and dislodge many more.
16:46Those that fall must get back into the trees before nightfall brings another killer.
16:52They vibrate their wings to warm their flight muscles, but it's a race against time.
17:04Night brings a lethal ground frost.
17:10Night brings a lethal ground frost.
17:41Those that do survive sleep safely huddled together in the trees for four months.
17:55The warmth of spring wakes them from their hibernation.
18:11Night brings a lethal ground frost.
18:21Night brings a lethal ground frost.
18:31Night brings a lethal ground frost.
18:41Night brings a lethal ground frost.
18:51Night brings a lethal ground frost.
19:01Night brings a lethal ground frost.
19:11Night brings a lethal ground frost.
19:21The majority of the butterflies that flew here from Canada have survived.
19:27They take their first drink since their arrival last autumn.
19:34With increasing warmth, more and more butterflies awake.
19:52Soon they will all disperse northwards and tranquility will return to this forest
19:58until the great grandchildren of these butterflies return to escape the freezing northern winter.
20:29Some insects, however, have made a speciality of living in the most adverse conditions.
20:42Mono Lake is known as California's Dead Sea.
20:48It's twice as salty as the ocean and lethal to almost all life.
20:59Alkali flies are one of the few creatures able to tolerate these conditions.
21:06And since they have virtually no competitors, they swarm in their millions.
21:29Flies are one of the most successful of all insects.
21:39There are 85,000 different kinds and among them a perfect fly for almost every habitat, even this one.
21:59The alkali fly has special abilities that enable it to live on this lake.
22:09It can walk underwater to eat algae.
22:15Fine hairs trap air bubbles that prevent it from drowning.
22:21But most critically, the fly has a physiology that can neutralize the lethal levels of salt.
22:27The alkali fly's dominance of Mono Lake goes unchallenged, except for a few weeks of the year.
22:44A hundred thousand Wilson's panorope are migrating to South America.
22:50Mono Lake is their only stopover.
22:56It's an invaluable and irresistible feast.
23:06A fly has no defense except to fly and become lost in a vast swarm.
23:18It needs considerable skill to pluck an individual fly from the air.
23:27There are gulls here too.
23:33Though their fly-catching techniques are not so refined.
23:56In four weeks, the phalaropes double their weight.
24:10Then they set off again, heading south, leaving the gulls behind.
24:17The size of the fly population has scarcely been affected.
24:23For them, sheer abundance is defense enough.
24:30But for some insects, defense is a much more complicated affair.
24:36An ooghpster beetle in South Africa.
24:42He hunts ants.
24:49Eating ants may give him more than just nourishment.
24:55He may get something else from them that helps him fight his enemies.
25:02The ants launch a counter-attack and nip his ankles.
25:08But he simply kicks them out of the way.
25:14The valiant ants drive him away.
25:45Straight into real danger.
25:51A mongoose.
25:57It's inquisitive.
26:03But it's also wary of the ooghpster.
26:10The beetle takes aim.
26:16And fires formic acid straight at the mongoose's eyes and mouth.
26:25The beetle probably collected this acid from the ants.
26:31It certainly makes the beetle itself very distasteful.
26:37The acid carries the beetle's warning pattern.
26:43It also imitates the way the beetle runs.
26:49Not particularly well, it's true, but well enough to fool predators into thinking it just might be an acid-firing beetle.
27:07Different kinds of insects have developed chemical weapons.
27:14A pair of devilrider stick insects.
27:20They fire bitter-tasting oils, terpenes.
27:29European wood ants under attack from a hungry crow.
27:35It's an acid that gives nettles their sting, so this is like one of us falling into a nettle patch.
27:51But the master of chemical warfare is the bombardier beetle.
27:57It can create a chemical reaction within its body so violent that boiling caustic liquid explodes out of its abdomen.
28:14By pulsing the jet 500 times a second, it keeps its rear end just cool enough to prevent it being cooked.
28:28In the woodlands of Minnesota, there is an insect that has another chemical weapon.
28:47But this one fights as an army and can stand up to almost any predator.
28:58Bees collect nectar all day and transform it within their stomachs into one of nature's richest foods, honey.
29:16Hundreds of them are bringing their precious loads back to their colony in this hollow log.
29:28The honey in their cones provides food for their young and for the whole colony if the weather turns cold or there's a drought.
29:35But so much food attracts thieves.
29:44A black bear cub has a sweet tooth.
30:05But he's never come across bees before and he doesn't know that they will defend their honey to the death.
30:17Stinging is the ultimate self-sacrifice for a bee because it can't pull out its barbed sting.
30:27So its body is torn apart.
30:35The bee's attack was far too much for the cub.
30:49But a greater challenge is coming.
30:56The cub's mother.
31:04The bees fight so hard that she only has time to steal a single cone.
31:18While the family enjoy their honey at a safe distance, the bees appear to have been defeated.
31:25Their home has been destroyed and their young will inevitably die out in the open.
31:38Yet the colony is not doomed because the workers are now rescuing at least some of what really matters.
31:45Their honey.
31:51Each survivor is able to eat its own weight in honey, storing it in its stomach.
32:03They will have to abandon their dying young, but they will take much of their precious honey with them to sustain themselves while they build a new colony.
32:10Working together in such an organized society is the insect's great innovation.
32:21So how did it begin?
32:30It may have started in a place like this, the nest of the Japanese red bug.
32:40Parent insects don't usually care for their offspring, but this bug is different.
32:52The young feed on fallen fruit from just one kind of rare tree.
32:59They could never find it by themselves, so their mother collects it for them.
33:06She probes every fruit she finds to test its ripeness and rejects one after another.
33:12This can take hours.
33:43At last, a perfect fruit.
33:54A thief! It's easier to steal than find fruit for yourself.
34:02For both bugs, the outcome of this dispute will be life-changing.
34:09As the mother struggles to keep her prize, her young back in the nest are growing restless.
34:22The thief has won.
34:28The mother doesn't know that her hungry young are leaving their nest in search of a better provider.
34:39She returns to find that her nest is empty.
34:55Her young find the nest of the thief, who is herself a mother.
35:02She returns to find that she has twice as many mouths to feed.
35:13The loser has failed at her only chance of parenthood.
35:24For the thief, life has suddenly gotten much harder.
35:31A fruit won't now last as long as it did.
35:37The young clamber over her, demanding more.
35:43She returns with another fruit, but her enlarged and insatiable brood wants still more.
36:06So, she has to work non-stop, day after day.
36:14At last, the young become big enough to fend for themselves.
36:29But their success has come at a cost.
36:35The mother has worked herself to death.
36:41She has to feed her young a meal before they leave home.
36:47Looking after the young in such a way is thought to be the first step towards living in a community.
36:59But some insects benefit from doing the opposite of collaborating.
37:05They kill one another.
37:10This is the largest in the world.
37:15It nests in the baked soil of the Australian outback.
37:21Flowers are rare in this desert, so colonies of these bees are few and far between.
37:33The bees excavate tunnels for their young.
37:41The community is so harmonious that it's hard to believe that this place is also the setting for mass murder.
37:57Tempers do flare when a bee gets confused and goes down another's burrow.
38:03But these are minor disagreements.
38:09The colony is peaceful at the moment, because every bee here is a female.
38:15It's the males that are the killers, and they are all dead.
38:24Their story began two months earlier, before the appearance of the females.
38:32Male Dawson's bees.
38:40The females are only just emerging, burrowing their way one by one out of the tunnels where they hatched and grew up.
38:49And their scent inflames the males.
38:55They are huge and built for fighting.
39:01And each one wants to be in the best position to mate with a female.
39:10A female emerges, and immediately there's a brawl as every male tries to reach her.
39:26It's very rare for animals to kill their own kind in combat,
39:32but stinging and biting rivals to death is usually the only way these male bees get a female.
39:40A winner manages to claim a female, and the pair race for cover.
39:57Meanwhile, the female's lingering scent drives one unsuccessful male into a deadly frenzy.
40:04Another female, caught in the middle of another brawl, becomes an accidental casualty.
40:17By the time the last female has emerged, every male is dead.
40:23The battles have ensured that the strongest males will have mated with the most females.
40:33Two months later, and it's an all-female world with the next generation already developing underground.
41:04Insects have evolved sophisticated societies that, in complexity,
41:10are the closest thing in nature to our own cities.
41:25The insects that built this structure in Argentina dominate the surrounding grasslands
41:31thanks to skills that seem almost more human than insect.
41:41It's a metropolis, a home to millions of ants.
41:49The colony needs a huge supply of food.
41:53It's surrounded by grass, but the ants themselves can't digest a blade of it.
42:02Nonetheless, they collect it.
42:07Although they're all the same species, they exist in different shapes and sizes.
42:19The heads of these big-jawed individuals are not full of brain, but brawn.
42:25They give the species its name. They are grass cutters.
42:38They work all day, every day.
42:56The smaller ants, down on the ground, are porters,
43:02with the job of carrying the grass segments back to the colony.
43:09They have great strength. Their main problem is balance.
43:15The ants' main job is to transport the grass segments back to the colony.
43:45Columns of them carried the grass back to the nest along highways as straight as Roman
44:08roads.
44:15Different members of the colony specialise in particular tasks in much the same way as
44:20people do.
44:23But, as in human society, there can be problems.
44:29A hitchhiker makes one ant's job much harder.
44:35And this isn't even grass.
45:00A single colony harvests half a tonne of grass a year, more than any other animal on these
45:07plains.
45:08But since they themselves can't eat it, why do they do so?
45:18The answer lies underground.
45:21They have one of the most extraordinary survival strategies in the insect world.
45:28The ants have dug a network of tunnels that extend downwards for over seven metres.
45:40At the heart of the colony lies the key to their survival, a fungus.
45:45But this isn't sloppy housekeeping.
45:47This is a fungus that is found nowhere else on earth.
45:55The ants cultivate it assiduously.
45:59The big-jawed ants chop up the grass, covering it with an antibiotic saliva that kills every
46:05kind of fungus except this one.
46:12The ants are farmers.
46:15They feed the grass to the fungus and the fungus thrives.
46:24The ants cultivate dozens of these fungus gardens throughout the colony.
46:30This is what they eat.
46:34The system is so efficient that a single colony can have five million members.
46:42But the fungus is also dangerous.
46:48As it grows, it releases carbon dioxide that could asphyxiate the entire colony.
46:55The ants' way of dealing with this danger is ingenious.
47:01They construct their nest so that it has an automatic air conditioning system.
47:08The outer surface is so shaped that the slightest breeze sucks out stale air through these central
47:14vents.
47:16At the same time, fresh air is drawn down through the outer vents right into the heart
47:21of the nest.
47:29Our own societies have existed for thousands of years, but insect societies have lasted
47:35for millions.
47:46There may be 10 million different kinds of insects, and there are 200 million individuals
47:53for every one of us.
47:58The insects' flexible armor and their adaptability has made them the most abundant and the most
48:04diverse animal group in our planet's history.
48:31The Sierra Madre Mountains in Mexico are home to one of the greatest natural wonders.
48:40A billion bright orange butterflies offer the life team a wonderful filming challenge.
48:50The colonies are only found above 3,000 meters, and the team trek there slowly in the thin
48:57air.
49:10The monarch phenomenon was only discovered here around 30 years ago, and one man has
49:15been studying them every year since, Professor Lincoln Brouwer.
49:20His knowledge will be essential if the team are to achieve their goal of flying a camera
49:25among the butterflies.
49:28It's amazing that the butterflies only come to this area that's about 30 by 60 miles in
49:34extent.
49:36There are other areas that have high forests in different parts of Mexico, to the west
49:42of here, to the south of here.
49:45But as far as we know, this is the only place that monarchs are able to spend the winter.
49:51Butterflies are in such numbers that filming them the traditional way, from a camera on
49:56a tripod, is reasonably straightforward.
49:59But to get a butterfly's viewpoint by flying a camera amongst the swarms is going to be
50:05altogether more difficult.
50:09First, the team need a spot where butterflies gather in huge numbers.
50:18Luckily, Lincoln knows a place where thousands come down to drink every day.
50:25The crew spend the next three days preparing the equipment.
50:29A remote-controlled camera, a lot of cable, two bicycle wheels, a bag of rocks, and some
50:35muscle power.
50:40Now all they need to do is wait until the butterfly numbers reach truly impressive proportions.
50:51By midday, the butterflies are swarming, and it's time for the camera to glide with them
50:56through the air.
51:10That's it, stop that, that's it, stunning, we've got great numbers coming in, so let's
51:18keep going, and then we'll do a turnaround shot.
51:22A series of unique shots, flying with the butterflies.
51:28But that was the easy part.
51:37Now it's time to get the camera 50 metres up into the treetops.
51:44Filming the roosting butterflies is not going to be simple.
51:47The clusters are unstable.
51:51And they can suddenly disperse without warning, what Lincoln calls an explosion.
51:57Here's another explosion, wow, look at that.
52:00And they're going right over our head.
52:04Spectacular, no doubt, but a real problem for the climbing team, Jim Spickler and Tim
52:09Fogg.
52:10Would it be better for us to start now, we're going to be very careful not to disturb them
52:14or limit our disturbance, but if we do disturb them, right now it seems that they're warm
52:20enough that they could relocate to a cluster right adjacent to them, do you think that's
52:24true?
52:25Well, if you disturb them, they tend to fly away from the tree, 50 feet or so, so you'll
52:32lose those clusters, I think, if you disturb them.
52:35Do you think they'll cluster again, no, tomorrow night?
52:40I doubt it, I think they'll just move down.
52:45That's really hard stuff, you know, because I can't see how we can get up the trees and
52:51do what we have to up there, close to any clusters without them flying.
52:55I just don't know how I'm going to be able to get an arrow into the tree.
52:59If you picked your tree, you could put the arrow in it now.
53:04The prospect of rigging cables high in the canopy without disturbing the butterflies
53:10is a daunting one.
53:11They may only get one chance.
53:14One false move and they'll all be gone, and I sort of had the impression that they might
53:18come back again, but Lincoln says they just won't, they'll just move on to another tree,
53:22so we'll put all the rigging in, disturb them and then that's it.
53:28Deciding which trees to rig is a critical decision.
53:34Can you get right to the tree number six, do you think, or is that too far?
53:44They begin by firing a line over a suitably high branch.
53:59That'll work.
54:03Nobody, not even Lincoln, knows how the butterflies will react.
54:13Yeah, that's going to work perfect, I think.
54:15OK, great.
54:17I've got to do a change over here, so just give me a moment.
54:21There's an explosion.
54:29Thankfully, it's not in the trees that Jim and Tim are rigging with such care.
54:35I've got it too much. Can you just push it towards me a bit, in fact?
54:38Oh, ow.
54:39Am I OK?
54:40Yeah.
54:41OK, get your fingers out.
54:43OK, that's good.
54:47It takes another three days to get the aerial rig set up,
54:51and the butterflies are ready to go.
54:54They're ready to go.
54:57OK, that's good.
55:00It takes another three days to get the aerial rig set up,
55:04followed by many hours of fine-tuning.
55:07Can you just pan it so we don't see it in the monitor, please?
55:16Everything is finally set, and the butterflies are still there.
55:21One, two, three.
55:27Take one.
55:36Too slow.
55:38There was no load at the beginning, and suddenly it just completely stopped.
55:42Yeah.
55:47Take six.
55:49Keep going. Start to slow.
55:52Keep going, keep going, keep going.
55:56OK, Mike, hold it.
55:58Not far enough.
56:00If we've not got enough weight, then...
56:11Take nine.
56:13Go on, Mike. Go on, Mike.
56:16Getting close, Mike. Now start slowing.
56:18OK. So...
56:20It's still not right, and now time is running out.
56:24I think the light's going.
56:26Shall we do one last take?
56:28All right, because these ones here, they're losing the light on them.
56:33Try and get a shot that's going past here, if it's smooth.
56:37One, two, three, and we're away.
56:42Take 17.
56:49And it's looking good.
56:51OK, start slowing, Mike.
56:54OK, keep it going, keep it going.
56:58I can't see it.
57:00Success at last.
57:06With the technique now working, the crew rig more and more shots
57:10to give an aerial perspective on the monarch phenomenon.
57:21His work advising the crew over,
57:24Lincoln continues the observations he's been making
57:27for over a quarter of a century.
57:29Although the butterflies are still here in immense numbers,
57:32he's worried there is a threat to their survival.
57:36The big, huge influx,
57:39maybe sometimes as many as two billion butterflies,
57:42flying down into this tiny area of 30 by 60 miles,
57:47is thoroughly endangered by illegal logging.
57:51If the forest is not protected, the phenomenon will be lost.
58:07That would be a disaster.
58:09I mean, it would be like taking the Mona Lisa
58:12out of the Parisian Museum and burning it up.
58:42NASA Jet Propulsion Laboratory, California Institute of Technology