1 00:01:03,863 --> 00:01:07,355 North America the Mississippi river. 2 00:01:07,500 --> 00:01:11,436 Its July and the afternoon is still very hot. 3 00:01:12,272 --> 00:01:15,571 People here dread this kind of day at this time of year. 4 00:01:15,708 --> 00:01:17,699 They brace themselves. 5 00:01:19,779 --> 00:01:22,543 Because it is happening again. 6 00:01:25,085 --> 00:01:27,713 All afternoon they've risen out of the water 7 00:01:27,854 --> 00:01:33,417 mayflies invade the city in their millions in their billions. 8 00:01:40,200 --> 00:01:41,132 For the last year 9 00:01:41,267 --> 00:01:44,896 they existed ad grubs feeding in the mud at the bottom of the river 10 00:01:45,105 --> 00:01:48,268 building up energy for this one day. 11 00:01:49,209 --> 00:01:52,337 At dusk they take to the air. 12 00:02:00,553 --> 00:02:03,647 This is a dance of life and death 13 00:02:03,790 --> 00:02:06,623 there is only one reason to fly to mate. 14 00:02:06,759 --> 00:02:13,221 And this is their only chance tomorrow the will all be dead. 15 00:02:24,110 --> 00:02:25,907 They can't even eat 16 00:02:26,079 --> 00:02:28,741 adult mayflies have no mouthparts. 17 00:02:36,656 --> 00:02:39,557 With only enough energy to fly once and mate 18 00:02:39,692 --> 00:02:41,751 they crash onto the water surface 19 00:02:41,895 --> 00:02:45,058 pouring out their cargo of eggs as they die. 20 00:02:53,873 --> 00:02:59,209 From this final act comes a stream of new life a continuing story 21 00:02:59,345 --> 00:03:03,805 unbroken for nearly four hundred million years. 22 00:03:09,222 --> 00:03:11,656 And in that four hundred million years 23 00:03:11,791 --> 00:03:15,557 the biggest problem mayflies have face is a recent one. 24 00:03:15,695 --> 00:03:19,096 Humans have built cities on their river. 25 00:03:26,306 --> 00:03:29,673 Cities with bright lights that draw them away from the dance 26 00:03:29,809 --> 00:03:33,142 so that they die without ever laying their eggs. 27 00:03:54,567 --> 00:03:57,661 The night leaves a scene of devastation 28 00:04:01,374 --> 00:04:03,001 their bodies litter the roads 29 00:04:03,142 --> 00:04:06,407 and bridges and clog up machinery. 30 00:04:07,247 --> 00:04:09,738 Less than a day after they emerged from the river 31 00:04:09,882 --> 00:04:12,510 every single mayfly is dead. 32 00:04:12,652 --> 00:04:16,588 They had only one reason for living and may of them failed. 33 00:04:18,057 --> 00:04:20,890 It all seems so printless even tragic 34 00:04:21,060 --> 00:04:24,359 but each mayfly was just an insect being an insect 35 00:04:24,497 --> 00:04:27,625 its only purpose in life to make more insects. 36 00:04:27,767 --> 00:04:30,497 More and more 37 00:04:31,337 --> 00:04:36,604 And all insects are as dedicated to this cause as mayflies. 38 00:04:39,345 --> 00:04:41,438 This is a moth. 39 00:04:42,615 --> 00:04:44,708 At least mayflies get to fly 40 00:04:44,851 --> 00:04:48,548 but a female vapourer moth doesn't even have wings 41 00:04:48,855 --> 00:04:51,119 she's just a bag of eggs. 42 00:04:54,961 --> 00:04:57,759 She mated once with a passing winged male 43 00:04:57,897 --> 00:05:01,025 who then flew away leaving her to spend her whole adult life 44 00:05:01,167 --> 00:05:04,500 in an area not much bigger than a postage stamp. 45 00:05:16,082 --> 00:05:20,883 Most insects lay hundreds of eggs in the hope that a few will survive. 46 00:05:22,922 --> 00:05:27,325 Every egg has its own fleeting moment maternal care and attention 47 00:05:27,460 --> 00:05:29,223 but once in place the eggs 48 00:05:29,362 --> 00:05:32,820 are left to hatch or not by themselves. 49 00:06:00,526 --> 00:06:03,359 But even though their mother is probably dead by now 50 00:06:03,496 --> 00:06:06,260 she has given them the best start she could 51 00:06:06,399 --> 00:06:09,800 each egg is a microscopic survival capsule. 52 00:06:17,643 --> 00:06:22,080 Most are smaller than a pinhead yet every different kind of insect egg 53 00:06:22,215 --> 00:06:25,309 is a unique an intricate sculpture. 54 00:06:39,832 --> 00:06:43,529 Vast numbers of eggs are an insurance against disaster 55 00:06:43,669 --> 00:06:48,038 but if it weren't for these disasters insects would overwhelm the planet. 56 00:06:50,309 --> 00:06:53,301 Flies for example breed every few week 57 00:06:53,446 --> 00:06:54,743 if this pair were to breed 58 00:06:54,881 --> 00:06:58,078 and all their descendents survived and bred for a year 59 00:06:58,217 --> 00:07:02,210 the resulting ball of maggots would be as big as the Earth. 60 00:07:03,556 --> 00:07:07,014 more than enough bait for a whole nation of fishermen. 61 00:07:07,660 --> 00:07:10,629 But nature has a way of keeping things in check 62 00:07:10,763 --> 00:07:14,324 predators competitors disease 63 00:07:14,467 --> 00:07:17,402 flies die like flies. 64 00:07:17,637 --> 00:07:19,832 Its only when human meddle with nature 65 00:07:20,039 --> 00:07:25,067 that they unleash the real power of insects to make more insects. 66 00:07:25,778 --> 00:07:27,541 If a fisherman say 67 00:07:27,680 --> 00:07:31,172 put a tray of maggot in a fridge expecting the cold 68 00:07:31,317 --> 00:07:35,310 to keep them subdued until he got back from holiday 69 00:07:37,623 --> 00:07:42,390 and if just after he left for the airport a fuse blew. 70 00:07:45,932 --> 00:07:48,264 the fridge would warm up nicely 71 00:07:48,401 --> 00:07:50,926 and there would be nothing to stop all the maggots 72 00:07:51,070 --> 00:07:53,538 turning into blue bottle flies. 73 00:07:55,908 --> 00:07:58,706 In a matter of days each one of these 74 00:07:58,845 --> 00:08:04,147 will produce a thousand new maggots an unpleasant welcome home 75 00:08:04,417 --> 00:08:07,818 with such huge numbers mayflies and bluebottle flies 76 00:08:08,020 --> 00:08:12,980 have no problem finding a mate but its now that simple for everyone. 77 00:08:15,061 --> 00:08:20,727 A derelict warehouse in north America is a huge three dimensional space 78 00:08:20,867 --> 00:08:25,065 so how can a lone silk moth hope to find a mate here? 79 00:08:28,040 --> 00:08:31,806 Silk moths have been introduced from the rainforest of Asia 80 00:08:31,944 --> 00:08:34,538 a place just as big and complicated. 81 00:08:35,314 --> 00:08:37,009 And there they developed a system 82 00:08:37,116 --> 00:08:40,085 that works however complex the surroundings. 83 00:08:43,055 --> 00:08:46,024 She advertises herself with scent 84 00:08:46,158 --> 00:08:47,284 a special chemical 85 00:08:47,426 --> 00:08:51,089 a pheromone released from a gland on her abdomen. 86 00:08:57,270 --> 00:09:01,434 The scent consists of long molecules with a particular shape. 87 00:09:01,574 --> 00:09:05,305 These are only recognized by this kind of moth. 88 00:09:06,379 --> 00:09:10,713 They fit like a key in a lock into special receptors 89 00:09:10,850 --> 00:09:13,148 on the male moth's antennae. 90 00:09:26,599 --> 00:09:28,999 His antennae are so sensitive 91 00:09:29,101 --> 00:09:32,070 it only takes a dozen molecules to excite him 92 00:09:32,204 --> 00:09:34,832 he could detect her a mile away. 93 00:09:41,280 --> 00:09:44,738 By flying upwind and tacking across the waves of scent 94 00:09:44,884 --> 00:09:47,580 he moves in her general direction. 95 00:10:04,537 --> 00:10:06,095 As he gets closer 96 00:10:06,238 --> 00:10:07,796 the scent gets stronger 97 00:10:07,940 --> 00:10:10,704 and the waves turn into a flood. 98 00:10:16,816 --> 00:10:19,148 She could be anywhere here 99 00:10:19,285 --> 00:10:22,049 it seems like she is everywhere. 100 00:10:37,436 --> 00:10:39,233 He's overwhelmed 101 00:10:39,372 --> 00:10:44,537 he knows he is very close but he has to find her as best he can. 102 00:10:59,191 --> 00:11:04,823 The do finally get to mate but scent is most effective over long distances. 103 00:11:04,964 --> 00:11:07,489 At short ranges it can be confusing 104 00:11:07,633 --> 00:11:11,660 which is why this polka dot moth in the deep south of the USA 105 00:11:11,804 --> 00:11:14,830 has developed a separate short range system as well. 106 00:11:15,875 --> 00:11:19,470 A male moth homes in on a female's scent 107 00:11:29,088 --> 00:11:31,454 She avoids any last minute confusion 108 00:11:31,590 --> 00:11:36,186 by switching to a finer signal a beam of sound. 109 00:11:37,263 --> 00:11:40,096 Not that humans would recognize it as sound 110 00:11:40,232 --> 00:11:42,462 the moth's music is pitched seven octaves 111 00:11:42,601 --> 00:11:47,265 above human hearing moths hear in ultrasound. 112 00:11:58,551 --> 00:12:03,648 She gives him precise directions with a medley of ultrasonic clicks. 113 00:12:07,259 --> 00:12:10,820 As he closes in he clicks back 114 00:12:15,868 --> 00:12:18,530 The problem with broadcasting sound though 115 00:12:18,671 --> 00:12:21,606 is that some predators can also tune in. 116 00:12:25,077 --> 00:12:28,046 These brightly coloured moths are very poisonous 117 00:12:28,147 --> 00:12:31,139 they don't care who else hears their broadcast. 118 00:12:32,518 --> 00:12:36,420 But more appetizing insects need a secure channel. 119 00:12:46,532 --> 00:12:48,864 Leaf hopper are not poisonous 120 00:12:49,001 --> 00:12:50,366 so when they use sound 121 00:12:50,503 --> 00:12:53,063 it has to be as private as a phone call. 122 00:12:56,275 --> 00:13:00,109 They transmit vibrations through their legs to the plant stems 123 00:13:00,246 --> 00:13:04,376 and the sound is received by touch. 124 00:13:05,050 --> 00:13:08,816 In other words leafhoppers hear with their feet. 125 00:13:10,956 --> 00:13:13,550 The males move from plant to plant calling 126 00:13:13,692 --> 00:13:16,661 and listening for females of their own kind. 127 00:13:29,508 --> 00:13:32,443 They've not distracted by sounds in the human world 128 00:13:32,578 --> 00:13:34,341 and humans are completely unaware 129 00:13:34,480 --> 00:13:38,382 that their garden plants are alive with secret music. 130 00:13:57,102 --> 00:13:59,400 Some insects are not as shy 131 00:13:59,538 --> 00:14:04,168 they've songs are so amplified that humans cannot fail to hear them. 132 00:14:14,119 --> 00:14:18,317 The world's loudest singers live in Australia. 133 00:14:20,926 --> 00:14:25,158 Distant relatives of leafhoppers cicadas. 134 00:14:33,239 --> 00:14:38,643 A cicada sings by clicking membranes in his absomen back and forth. 135 00:14:38,777 --> 00:14:42,042 His song can be heard half a mile away. 136 00:14:45,284 --> 00:14:47,752 But to a predator wanting to hunt him down 137 00:14:47,887 --> 00:14:50,651 his song seems to come from a different bush. 138 00:14:50,789 --> 00:14:54,122 Hes not only loud he's a ventriloquist. 139 00:14:55,628 --> 00:15:00,258 Once they get going some cicadas can sing at 120 decibels 140 00:15:00,399 --> 00:15:03,368 enough to drown out a pneumatic drill. 141 00:15:32,431 --> 00:15:36,424 Double drummer cicadas are the loudest insects in the world 142 00:15:36,568 --> 00:15:39,036 but not far behind are "greengrocers" 143 00:15:39,138 --> 00:15:43,234 "yellow Mondays" "black princes" "cherry noses". 144 00:15:43,375 --> 00:15:45,707 And they all live in Sydney. 145 00:15:46,278 --> 00:15:50,772 No wonder that in the din of summer many people move away for the season. 146 00:15:56,522 --> 00:16:02,722 Some insects use vision to find a mate they've attracted by simple good looks. 147 00:16:04,029 --> 00:16:08,432 A female jewel beetles flaunts her golden dimpled wing casing 148 00:16:08,567 --> 00:16:11,161 which is irresistible to a male. 149 00:16:19,411 --> 00:16:23,677 It's also big with him is beautiful 150 00:16:38,163 --> 00:16:39,357 But in recent years 151 00:16:39,498 --> 00:16:42,626 males have discovered other distractions. 152 00:16:56,081 --> 00:16:59,073 For a male jewel beetle it's the simple things 153 00:16:59,218 --> 00:17:02,415 that are exciting if its orange and dimpled 154 00:17:02,554 --> 00:17:04,715 then its just what he is looking for. 155 00:17:08,260 --> 00:17:12,128 And enormous this must be a super female 156 00:17:12,264 --> 00:17:14,391 a jewel beetle goddess. 157 00:17:16,335 --> 00:17:21,363 Certain beer bottles have just the right colour and texture 158 00:17:23,409 --> 00:17:26,867 all the males in the area are besotted. 159 00:17:45,798 --> 00:17:48,767 The real females are ignored. 160 00:17:51,170 --> 00:17:55,800 With so many males on the bottle the beetles were in danger of extinction 161 00:17:55,941 --> 00:17:58,739 until the breweries began redesigning their bottles 162 00:17:58,877 --> 00:18:02,244 hoping the males would spend some time with their females. 163 00:18:04,650 --> 00:18:08,643 A male walnut fly also has a simple goal in life. 164 00:18:11,023 --> 00:18:14,982 He has to hay claim to a blemish on the surface of a walnut. 165 00:18:15,094 --> 00:18:18,325 Its not easy other males will challenge him. 166 00:18:23,602 --> 00:18:29,063 Every male knows that a female fly needs to lay her eggs inside the hard shell 167 00:18:29,208 --> 00:18:33,235 but she can only pierce the casing through a soft blemish. 168 00:18:34,947 --> 00:18:38,075 The male that controls the blemish will be guaranteed a visit 169 00:18:38,217 --> 00:18:42,813 from a female sooner or later there is no room for a rival. 170 00:18:50,762 --> 00:18:53,287 These two males could just fight it out 171 00:18:53,432 --> 00:18:55,297 but the bigger one would win. 172 00:18:55,434 --> 00:18:57,334 So why not just take each other's measure 173 00:18:57,469 --> 00:18:58,629 decide who's bigger 174 00:18:58,770 --> 00:19:02,672 who would lose and avoid the intervening violence? 175 00:19:08,046 --> 00:19:11,573 This dispute is settled and no-one gets hurt. 176 00:19:17,623 --> 00:19:21,650 Real males in the insect world do resort to combat 177 00:19:21,793 --> 00:19:25,559 and evolve nasty weapons just for fighting duels. 178 00:19:27,366 --> 00:19:32,360 Outside a temple in Thailand deer horn stag beetles clash head on 179 00:19:32,504 --> 00:19:35,098 for the honour of claiming a female 180 00:19:35,240 --> 00:19:37,140 but the fight isn't just a brawl 181 00:19:37,276 --> 00:19:41,872 it's a ritual every bit as formal as anything inside a temple. 182 00:19:45,450 --> 00:19:47,384 There are rules to follow 183 00:19:47,519 --> 00:19:51,011 The first to destroy the component is the winner 184 00:20:22,588 --> 00:20:24,852 This fight is a female 185 00:20:24,990 --> 00:20:28,790 and she gets to mate with the champion. 186 00:20:28,927 --> 00:20:32,328 Females never have time for losers. 187 00:20:44,109 --> 00:20:46,304 For most insects choosing the strongest male 188 00:20:46,411 --> 00:20:51,007 and laying vast numbers of eggs is enough to win the game of survival 189 00:20:53,552 --> 00:20:56,885 but some are much more inventive than that. 190 00:20:58,624 --> 00:20:59,750 To an insect 191 00:20:59,891 --> 00:21:04,794 even a computer is just somewhere warm and safe a carpet beetles grub 192 00:21:04,930 --> 00:21:09,526 or woolly bear lives a peaceful life feeding on dust particles 193 00:21:09,901 --> 00:21:12,369 but there is something else here as well. 194 00:21:16,808 --> 00:21:20,437 This wasp has plans for the woolly bear. 195 00:21:41,233 --> 00:21:44,066 It can run but it cant hide. 196 00:21:45,103 --> 00:21:49,767 The wasp stings the woolly bear not to kill it but to stun it. 197 00:21:54,880 --> 00:22:00,011 Once its paralysed she drags her still living trophy to a safe hideaway. 198 00:22:23,308 --> 00:22:26,800 This wasp is a more caring mother than most insects 199 00:22:26,945 --> 00:22:32,110 she lays one egg on the helpless body and leaves it to hatch. 200 00:22:41,393 --> 00:22:44,954 Wasps have turned exploitation into a fine art 201 00:22:45,097 --> 00:22:49,158 they nourish their young at someone else's expense. 202 00:22:55,140 --> 00:22:58,075 This hawk moth caterpillar doesn't know it yet 203 00:22:58,210 --> 00:23:01,805 but its about to become a walking incubator. 204 00:23:06,418 --> 00:23:12,721 The females wasp hijacks the caterpillar resistance is useless 205 00:23:12,858 --> 00:23:15,088 as soon as she finds somewhere soft enough 206 00:23:15,227 --> 00:23:17,388 she will inject her precious eggs. 207 00:23:22,601 --> 00:23:25,229 The inside of the caterpillar is mostly liquid 208 00:23:25,370 --> 00:23:28,806 so her eggs will be cushioned and safe from the outside world. 209 00:23:50,662 --> 00:23:55,463 She can leave them the caterpillar will take care of them from now on. 210 00:24:01,706 --> 00:24:02,798 It gorges itself 211 00:24:02,941 --> 00:24:04,841 trying to stockpile food reserves 212 00:24:05,043 --> 00:24:06,806 for the time when it becomes a moth 213 00:24:06,945 --> 00:24:09,004 but the wasp eggs have hatched into grubs 214 00:24:09,147 --> 00:24:12,913 and they absorb all the nourishment the caterpillar can provide. 215 00:24:18,223 --> 00:24:20,589 As fast as the caterpillar lays down fat 216 00:24:20,725 --> 00:24:25,025 around its gut the wasp grubs devour it. 217 00:24:27,065 --> 00:24:31,024 From then they take control they release a chemical 218 00:24:31,169 --> 00:24:35,105 that imitates one of the caterpillars own hormones one that stops it 219 00:24:35,240 --> 00:24:38,141 from beginning its transformation into a moth. 220 00:24:39,077 --> 00:24:44,606 Instead, it keeps on eating and growing until it turns into a supergiant 221 00:24:44,749 --> 00:24:48,185 a huge eating machine that just manages to keep up 222 00:24:48,320 --> 00:24:52,654 with the ravenous appetites of the parasite inside. 223 00:25:05,937 --> 00:25:08,405 Eventually when they've taken all they need 224 00:25:08,540 --> 00:25:12,567 from the caterpillar they release chemicals to paralyse it 225 00:25:12,711 --> 00:25:14,872 and they wriggle through the body wall. 226 00:25:25,724 --> 00:25:27,316 Their first task in the outside world 227 00:25:27,459 --> 00:25:32,920 is to spin their silken cocoons to begin their transformations into wasps. 228 00:25:39,471 --> 00:25:43,032 The caterpillar will never complete its own transformation 229 00:25:43,174 --> 00:25:48,510 but from one caterpillar's body hundreds of wasps have been given life. 230 00:26:47,072 --> 00:26:52,374 Insects may be small and each individual seems vulnerable on its own 231 00:26:52,510 --> 00:26:55,308 but they have one thing going for them. 232 00:26:58,483 --> 00:27:02,283 Numbers Sheer quantity. 233 00:27:05,023 --> 00:27:08,754 There are simply so many insects. 234 00:27:18,269 --> 00:27:23,070 As each insect's purpose in life is to produce even more 235 00:27:23,208 --> 00:27:25,438 whatever happens to the rest of the world 236 00:27:25,577 --> 00:27:28,546 insects are here to stay. 237 00:27:33,818 --> 00:27:39,450 There will always be lots of insects making more insects 238 00:27:39,591 --> 00:27:45,188 making more insects...