1 00:00:01,840 --> 00:00:07,520 Speaker 1: Welcome to Brainstuf, a production of iHeartRadio, Hey brain Stuff 2 00:00:07,560 --> 00:00:12,640 Speaker 1: Lauren volebamb Here. Plants that eat animals may sound like 3 00:00:12,680 --> 00:00:16,160 Speaker 1: the premis for a horror story, but there's nothing supernatural 4 00:00:16,200 --> 00:00:19,960 Speaker 1: about it. Carnivorous plants have existed on this planet for 5 00:00:20,079 --> 00:00:23,760 Speaker 1: millions of years. There are more than five hundred different 6 00:00:23,840 --> 00:00:28,120 Speaker 1: kinds with appetites, ranging from single celled organisms to insects 7 00:00:28,200 --> 00:00:32,560 Speaker 1: to spiders. Today, let's talk about one of the most famous, 8 00:00:32,960 --> 00:00:38,800 Speaker 1: the venus flytrap. The venus flytrap grows roots, stems, leaves, flowers, 9 00:00:38,800 --> 00:00:42,320 Speaker 1: and seeds just like most plants, but it also grows 10 00:00:42,479 --> 00:00:45,599 Speaker 1: two specialized lobes on the end of each leaf that 11 00:00:45,760 --> 00:00:50,760 Speaker 1: form a hinged trap. Those lobes are distinctively green on 12 00:00:50,800 --> 00:00:53,840 Speaker 1: the outside and reddish pink on the inside, with small 13 00:00:53,880 --> 00:00:57,560 Speaker 1: bristles along the edges. But when they're open, they look 14 00:00:57,640 --> 00:01:01,720 Speaker 1: like toothy little mouths calling for a snap. And when 15 00:01:01,720 --> 00:01:05,319 Speaker 1: an insect or a racknid crawls across that pinkish inner surface, 16 00:01:05,600 --> 00:01:09,240 Speaker 1: the trap slams shut and the plant digests its prey. 17 00:01:09,920 --> 00:01:13,680 Speaker 1: It's a mouth and stomach in one. Although the venus 18 00:01:13,680 --> 00:01:17,560 Speaker 1: flytrap has captivated people across the world. Wild populations of 19 00:01:17,600 --> 00:01:21,199 Speaker 1: these plants actually grow in an incredibly small geographic area, 20 00:01:21,680 --> 00:01:24,320 Speaker 1: a region along the coasts of North and South Carolina, 21 00:01:24,600 --> 00:01:27,440 Speaker 1: only some seventy five square miles in area, that's about 22 00:01:27,440 --> 00:01:31,720 Speaker 1: two hundred square kilometers. Their native areas are bogs and 23 00:01:31,760 --> 00:01:36,120 Speaker 1: wetlands that are humid and sunny. They're so scarce that 24 00:01:36,160 --> 00:01:39,560 Speaker 1: some early botanists doubted their existence despite all the stories 25 00:01:39,600 --> 00:01:44,280 Speaker 1: spread about a flesh eating plant. But okay, if other 26 00:01:44,360 --> 00:01:48,160 Speaker 1: plants can thrive on nothing but water, air, nutrients in 27 00:01:48,200 --> 00:01:52,640 Speaker 1: the soil, and some sunshine, why do venus flytraps eat insects? 28 00:01:54,400 --> 00:01:57,280 Speaker 1: Flytraps actually get a good deal of their sustenance just 29 00:01:57,360 --> 00:02:01,280 Speaker 1: like other plants do. During photosynthesis, plants use the energy 30 00:02:01,320 --> 00:02:03,840 Speaker 1: of the sun to drive a reaction that converts carbon 31 00:02:03,880 --> 00:02:08,280 Speaker 1: dioxide and water into sugar and oxygen. The sugar produced 32 00:02:08,320 --> 00:02:10,520 Speaker 1: is then converted to energy that the plant cells can 33 00:02:10,639 --> 00:02:15,359 Speaker 1: use a molecule called adenosine triphosphate or ATP. ATP is 34 00:02:15,400 --> 00:02:18,720 Speaker 1: what our cells used to get stuff done too. However, 35 00:02:18,919 --> 00:02:22,800 Speaker 1: in addition to sugar, plants also need to make amino acids, vitamins, 36 00:02:22,880 --> 00:02:27,120 Speaker 1: and other cellular components to survive in the coastal bogs 37 00:02:27,160 --> 00:02:30,880 Speaker 1: where venus flytraps live, the soil is acidic and minerals 38 00:02:30,880 --> 00:02:34,760 Speaker 1: and other nutrients are scarce. Most plants can't survive in 39 00:02:34,800 --> 00:02:37,239 Speaker 1: this environment because they can't make enough of the building 40 00:02:37,280 --> 00:02:41,919 Speaker 1: blocks necessary for growth. The venus flytrap evolved an alternate 41 00:02:42,040 --> 00:02:46,040 Speaker 1: means of getting those key nutrients. Living creatures like insects 42 00:02:46,080 --> 00:02:48,120 Speaker 1: provide a good source of the stuff that's missing from 43 00:02:48,160 --> 00:02:53,360 Speaker 1: the soil, plus additional carbohydrates so that covers the y. 44 00:02:53,720 --> 00:02:57,240 Speaker 1: But how do these plants catch and eat prey. A 45 00:02:57,280 --> 00:02:59,960 Speaker 1: plant doesn't have a brain or even a nervous system 46 00:03:00,120 --> 00:03:04,480 Speaker 1: to coordinate their functions and movements, nor do they have bones, tendons, 47 00:03:04,480 --> 00:03:09,720 Speaker 1: and muscles to coordinate. But most plants do have some 48 00:03:09,880 --> 00:03:13,280 Speaker 1: way of attracting animals or insects, regardless of whether they're 49 00:03:13,360 --> 00:03:17,720 Speaker 1: going to eat them. Lots of flowering plants have evolved colors, scents, 50 00:03:17,760 --> 00:03:21,840 Speaker 1: and sugary nectar to attract bees, butterflies, and other pollinators. 51 00:03:22,840 --> 00:03:25,840 Speaker 1: In those cases, the animals get a snack, and they 52 00:03:25,919 --> 00:03:29,520 Speaker 1: unwittingly ferry the plant's pollen to neighbors of the same species, 53 00:03:29,800 --> 00:03:35,080 Speaker 1: thus fertilizing them. Hopefully. Similarly, fruits evolved to be sweet 54 00:03:35,120 --> 00:03:38,040 Speaker 1: and tasty because if a bird or other animal eats 55 00:03:38,080 --> 00:03:41,760 Speaker 1: them and later poops the seeds elsewhere unharmed, a new 56 00:03:41,760 --> 00:03:45,360 Speaker 1: plant can grow. In the case of the venus flytrap, 57 00:03:45,560 --> 00:03:49,080 Speaker 1: the inner surface of those specialized lobes secretes a sweet 58 00:03:49,080 --> 00:03:53,480 Speaker 1: nectar that draws in insects searching for food. But the 59 00:03:53,520 --> 00:03:57,240 Speaker 1: inner surfaces of the lobes also sport short, stiff, hair 60 00:03:57,400 --> 00:03:59,800 Speaker 1: like structures that serve as a sort of motion to 61 00:04:01,520 --> 00:04:05,000 Speaker 1: When a creepy crawley crawls across the surface and brushes 62 00:04:05,120 --> 00:04:09,040 Speaker 1: two hairs in close succession or one twice, the lobes 63 00:04:09,080 --> 00:04:12,240 Speaker 1: close down in as little as half a second, trapping 64 00:04:12,240 --> 00:04:17,480 Speaker 1: the creature inside a fun fact or black thereof No 65 00:04:17,480 --> 00:04:21,599 Speaker 1: one knows exactly how this works, ever since Charles Darwin 66 00:04:21,680 --> 00:04:25,040 Speaker 1: described the species in eighteen seventy five, and he called 67 00:04:25,080 --> 00:04:28,560 Speaker 1: it the most wonderful plant by the way. Ever since then, 68 00:04:28,800 --> 00:04:31,159 Speaker 1: researchers have been trying to get to the bottom of 69 00:04:31,200 --> 00:04:35,320 Speaker 1: this trapping mechanism, but it's difficult to observe what's going 70 00:04:35,360 --> 00:04:38,599 Speaker 1: on inside a living plant during half a second of action. 71 00:04:39,960 --> 00:04:43,800 Speaker 1: The prevailing hypothesis goes that a venus fly trap accomplishes 72 00:04:43,839 --> 00:04:47,640 Speaker 1: this feat by rapidly changing the geometry of those specialized 73 00:04:47,680 --> 00:04:52,440 Speaker 1: lobes via water transfer within the lobes upon stimulus. Let 74 00:04:52,480 --> 00:04:56,919 Speaker 1: me break that down, Okay. Each lobe or half of 75 00:04:56,920 --> 00:05:01,680 Speaker 1: a venus flytrap's trap seems to have two functional layers inside, 76 00:05:02,120 --> 00:05:05,240 Speaker 1: an upper layer up against the pinkish interior surface of 77 00:05:05,279 --> 00:05:08,560 Speaker 1: the trap and a lower layer up against the green 78 00:05:08,640 --> 00:05:13,280 Speaker 1: outer surface of the trap. Cells within the layers contain water. 79 00:05:13,839 --> 00:05:17,960 Speaker 1: That's not unusual. Cells generally do contain water, but the 80 00:05:18,080 --> 00:05:21,200 Speaker 1: upper and lower layers are each capable of holding onto 81 00:05:21,320 --> 00:05:25,960 Speaker 1: water and of transferring it quickly to each other. When 82 00:05:25,960 --> 00:05:28,960 Speaker 1: the trap is open. That's actually a tense state for 83 00:05:29,000 --> 00:05:31,839 Speaker 1: the lobes of the leaf, wherein more water is being 84 00:05:31,880 --> 00:05:37,119 Speaker 1: held by the upper interior layer of cells. This makes 85 00:05:37,160 --> 00:05:41,960 Speaker 1: each lobes slightly convex and holds the trap open. But 86 00:05:42,240 --> 00:05:46,640 Speaker 1: when something triggers those motion detector hairs that somehow tells 87 00:05:46,680 --> 00:05:49,760 Speaker 1: the plant to open up pores between the upper and 88 00:05:49,839 --> 00:05:54,719 Speaker 1: lower layers, water quickly moves into the lower outer layer, 89 00:05:55,120 --> 00:05:59,359 Speaker 1: making each lobes lightly concave, curling in around its prey. 90 00:05:59,520 --> 00:06:03,719 Speaker 1: In a fraction of a second, this closed state is 91 00:06:03,880 --> 00:06:07,280 Speaker 1: relaxed for the lobes of the leaf. They open back 92 00:06:07,360 --> 00:06:10,800 Speaker 1: up again by slowly transferring water back to the upper 93 00:06:10,880 --> 00:06:15,720 Speaker 1: interior layer, but it takes a while. Again, no one 94 00:06:15,880 --> 00:06:18,760 Speaker 1: entirely understands how all this works, though there is some 95 00:06:18,880 --> 00:06:22,880 Speaker 1: interesting research into all the biochemical details. But for our 96 00:06:22,920 --> 00:06:26,320 Speaker 1: purposes today, let's focus in on what happens when that 97 00:06:26,440 --> 00:06:30,960 Speaker 1: trap does close on some tasty prey. The lobes of 98 00:06:30,960 --> 00:06:34,200 Speaker 1: the leaf form an airtight seal so that digestive fluids 99 00:06:34,200 --> 00:06:37,560 Speaker 1: and insect parts are kept inside the trap, and so 100 00:06:37,640 --> 00:06:42,159 Speaker 1: that bacteria and molds can't get in. Those toothy looking 101 00:06:42,200 --> 00:06:44,760 Speaker 1: spines on the outer edges of the trap laced together 102 00:06:45,000 --> 00:06:48,520 Speaker 1: and latch the trap shut. There is an upper limit 103 00:06:48,560 --> 00:06:50,919 Speaker 1: to the size of insect that a trap can accommodate. 104 00:06:51,560 --> 00:06:53,920 Speaker 1: The traps will grow up to around an inch long 105 00:06:54,120 --> 00:06:56,320 Speaker 1: or about two and a half centimeters, and in order 106 00:06:56,360 --> 00:06:59,039 Speaker 1: to close tightly, an insect that catches can only be 107 00:06:59,160 --> 00:07:02,159 Speaker 1: about a third of that size. If an insect is 108 00:07:02,200 --> 00:07:05,120 Speaker 1: too large, the trap can't form a seal against microbes, 109 00:07:05,200 --> 00:07:08,440 Speaker 1: which will move in and eat the decomposing insect and 110 00:07:08,600 --> 00:07:12,040 Speaker 1: the trap itself too. The trap will turn black and 111 00:07:12,160 --> 00:07:17,000 Speaker 1: drop off of the plant, but back to dinner. Once 112 00:07:17,040 --> 00:07:20,120 Speaker 1: an insect or a rapnet is firmly ensconced in the trap, 113 00:07:20,480 --> 00:07:24,640 Speaker 1: the process of digestion can begin. The trap now serves 114 00:07:24,640 --> 00:07:28,160 Speaker 1: as a miniature stomach, just like our stomachs. The trap 115 00:07:28,160 --> 00:07:32,600 Speaker 1: secrete acidic digestive juices that do three things. They dissolve 116 00:07:32,640 --> 00:07:35,400 Speaker 1: the soft tissues and sell membranes of the food. They 117 00:07:35,480 --> 00:07:38,280 Speaker 1: serve as an antiseptic to kill any microbes that got 118 00:07:38,280 --> 00:07:41,800 Speaker 1: in with the food, and they break down various proteins 119 00:07:41,840 --> 00:07:44,760 Speaker 1: and other molecules into small pieces that the plant can 120 00:07:44,760 --> 00:07:48,520 Speaker 1: take in. It takes some five to twelve days for 121 00:07:48,600 --> 00:07:51,600 Speaker 1: a trapped digest prey, depending on the size of the prey, 122 00:07:51,800 --> 00:07:55,480 Speaker 1: the age of the trap, and the ambient temperature. Older 123 00:07:55,480 --> 00:08:00,640 Speaker 1: traps and colder temperatures make digestions slower. The process continues 124 00:08:00,720 --> 00:08:03,080 Speaker 1: until all that's left of the insect is its herd 125 00:08:03,120 --> 00:08:08,520 Speaker 1: exoskeleton and its bath of digestive juices. The plant reabsorbs 126 00:08:08,560 --> 00:08:12,080 Speaker 1: the fluids and the trap slowly reopens, after which the 127 00:08:12,120 --> 00:08:14,760 Speaker 1: praise remains are usually either washed away in the rain 128 00:08:15,040 --> 00:08:18,480 Speaker 1: or blown away by the wind. A venus fly trap 129 00:08:18,520 --> 00:08:20,800 Speaker 1: can tell the difference between living prey and a dead 130 00:08:20,880 --> 00:08:25,200 Speaker 1: exoskeleton or other non edible debris that might fall in. 131 00:08:25,200 --> 00:08:28,559 Speaker 1: Inanimate objects that trigger the trap's motion sensitive hairs won't 132 00:08:28,680 --> 00:08:32,480 Speaker 1: keep moving once it slams shut. If there's no further 133 00:08:32,520 --> 00:08:35,920 Speaker 1: stimulation of the hairs, the trap won't seal up, but 134 00:08:36,000 --> 00:08:38,880 Speaker 1: it will be stuck in partially shut state until tension 135 00:08:38,920 --> 00:08:41,080 Speaker 1: can be re established in the lobes of the trap. 136 00:08:42,360 --> 00:08:45,240 Speaker 1: This process takes about twelve hours, at which point the 137 00:08:45,360 --> 00:08:50,120 Speaker 1: unwonted object falls out. This selection process is pretty good, 138 00:08:50,240 --> 00:08:53,240 Speaker 1: but not perfect. While the trap is out of commission, 139 00:08:53,480 --> 00:08:56,720 Speaker 1: real food may be crawling all around the plant. Imagine 140 00:08:56,760 --> 00:08:58,360 Speaker 1: if you had to sit with a chicken bone or 141 00:08:58,400 --> 00:09:00,840 Speaker 1: peach pit in your mouth for twelve hours while the 142 00:09:00,840 --> 00:09:02,640 Speaker 1: rest of your dinner sat on the table in front 143 00:09:02,640 --> 00:09:06,240 Speaker 1: of you. Of course, the venus fly trap doesn't feel 144 00:09:06,280 --> 00:09:09,280 Speaker 1: any kind of way about it. It's a passive participant 145 00:09:09,280 --> 00:09:13,600 Speaker 1: in the process of eating dinner. Any given trap won't 146 00:09:13,679 --> 00:09:18,000 Speaker 1: last the full lifetime of the plant. After about ten 147 00:09:18,040 --> 00:09:21,480 Speaker 1: to twelve closures, either partial or complete, the trap will 148 00:09:21,520 --> 00:09:26,240 Speaker 1: stop trapping and remain partially open. It'll devote its remaining 149 00:09:26,280 --> 00:09:29,840 Speaker 1: time to photosynthesis, usually for around two to three months, 150 00:09:31,040 --> 00:09:35,720 Speaker 1: while our imaginations dream up people eating killer plants. In reality, 151 00:09:36,000 --> 00:09:38,839 Speaker 1: we're the threat to venus fly traps and other carnivorous 152 00:09:38,880 --> 00:09:42,880 Speaker 1: plants in the wild. Venus fly traps today only cover 153 00:09:43,000 --> 00:09:46,600 Speaker 1: about a third of their historic range. In the nineteen seventies, 154 00:09:46,640 --> 00:09:49,480 Speaker 1: there were around four million of them. That's down to 155 00:09:49,559 --> 00:09:52,360 Speaker 1: just over three hundred thousand as of twenty twenty due 156 00:09:52,400 --> 00:09:55,640 Speaker 1: to over collection by humans and the draining and destruction 157 00:09:55,760 --> 00:09:59,400 Speaker 1: of the natural wetlands where they grow. There's a hefty 158 00:09:59,440 --> 00:10:02,959 Speaker 1: fine North Carolina felony charge for removing them from the wild, 159 00:10:03,360 --> 00:10:07,040 Speaker 1: but lots of reputable plant nurseres propagate and sell them legally. 160 00:10:08,280 --> 00:10:10,320 Speaker 1: If you grow one at home, you'll be looking to 161 00:10:10,360 --> 00:10:15,439 Speaker 1: replicate its boggy, bright homeland with specialized soil and humid conditions. 162 00:10:15,720 --> 00:10:19,520 Speaker 1: A terrarium can help. Check growing guides online or talk 163 00:10:19,559 --> 00:10:23,200 Speaker 1: to your local garden center. A venus flytrap will grow 164 00:10:23,240 --> 00:10:26,720 Speaker 1: to about five inches or thirteen centimeters tall, with about 165 00:10:26,720 --> 00:10:30,120 Speaker 1: four to eight traps per plant. You'll want to provide 166 00:10:30,120 --> 00:10:32,680 Speaker 1: it with two or three small flying insects like a 167 00:10:32,679 --> 00:10:36,400 Speaker 1: house fly every month. A far cry from the feed 168 00:10:36,440 --> 00:10:39,800 Speaker 1: me seemore eating habits of carnivorous plants in science fiction. 169 00:10:44,640 --> 00:10:47,520 Speaker 1: Today's episode is based on the article how Venus flytraps 170 00:10:47,559 --> 00:10:50,719 Speaker 1: work on HowStuffWorks dot Com, written by Anne Mieker O'Connell. 171 00:10:51,600 --> 00:10:54,559 Speaker 1: Brain Stuff is production of iHeartRadio in partnership with HowStuffWorks 172 00:10:54,600 --> 00:10:57,400 Speaker 1: dot Com and is produced by Tyler Klain. Four more 173 00:10:57,440 --> 00:11:01,160 Speaker 1: podcasts my heart Radio, visit the iHeartRadio app, Apple Podcasts, 174 00:11:01,280 --> 00:11:03,160 Speaker 1: or wherever you listen to your favorite shows.