1 00:00:00,000 --> 00:00:05,000 Hello, my name's Lindsay Turnbull and I'm an associate professor in the Department of Plant Sciences 2 00:00:05,000 --> 00:00:10,000 at the University of Oxford, and we're right in the middle of this very serious corona virus crisis right 3 00:00:10,000 --> 00:00:15,000 now. And my students are all stuck at home and we want to keep them in touch with biology 4 00:00:15,000 --> 00:00:21,000 and keep in touch with us. And so we're going to make a new series of videos and they're going to be called back garden 5 00:00:21,000 --> 00:00:46,000 biology. 6 00:00:46,000 --> 00:00:51,000 Welcome to my second episode. I'm going to look at a particular plant this time 7 00:00:51,000 --> 00:00:56,000 and it's pollinators and I'm starting in my front garden, not with my focal plant, 8 00:00:56,000 --> 00:01:02,000 but just to show you some general principles. This is Rosemary. We grow that as a herb 9 00:01:02,000 --> 00:01:07,000 humans. And if I touch her and if I bruise the leaves, I got a really wonderful smell. 10 00:01:07,000 --> 00:01:12,000 Now, on this, Rosemary, every time I come out here, I can see bees visiting it. They're 11 00:01:12,000 --> 00:01:18,000 not interested in its culinary properties. They are interested in its flowers. But you probably 12 00:01:18,000 --> 00:01:23,000 know that not all flowers are the same. Some flowers are really attractive to bees and others are not. 13 00:01:23,000 --> 00:01:28,000 And bees are interested in two things that flowers produce. They're interested in nectar, which 14 00:01:28,000 --> 00:01:33,000 is a sugary liquid, very high and energy. Bees are flying and burning energy, 15 00:01:33,000 --> 00:01:39,000 so they need that nectar. The other thing they are interested in is pollen. 16 00:01:39,000 --> 00:01:44,000 The plants, of course, want them to pick up pollen and transfer it around between flowers. 17 00:01:44,000 --> 00:01:50,000 But the bees will take some of that pollen as well and take that home to feed their larvae. 18 00:01:50,000 --> 00:01:55,000 Poland has a lot of protein in it. It's not just sugar. So it's not just empty 19 00:01:55,000 --> 00:02:00,000 calories. It's actually got good stuff in it to feed growing bee larvae. 20 00:02:00,000 --> 00:02:06,000 Now, if you want to really attract bees, you've got to have enough flowers. And so this rosemary plant 21 00:02:06,000 --> 00:02:11,000 is attracting a lot of bees, partly just because it's huge. And if that's of a second one growing near 22 00:02:11,000 --> 00:02:16,000 it and that kind of a parent's seed to insects is really important. And 23 00:02:16,000 --> 00:02:21,000 that's what we're going to look at in the back garden. It can go and look at another plant, which has got a few 24 00:02:21,000 --> 00:02:26,000 clever tricks to try to persuade bees that there's perhaps more on offer 25 00:02:26,000 --> 00:02:32,000 than there actually is. So around in the back garden now and crouching next to the focal plant, 26 00:02:32,000 --> 00:02:37,000 it's been a bit of a gap between me shooting that first sequence in the front garden and coming to do this, because 27 00:02:37,000 --> 00:02:42,000 unfortunately, I've had this cold 19 virus, or at least I think I've had it. And I was in bed 28 00:02:42,000 --> 00:02:47,000 for about eight days and I was very lucky that I didn't have any of the really serious symptoms that some 29 00:02:47,000 --> 00:02:53,000 people have had. But it is a reminder that we're all vulnerable to it and we must follow 30 00:02:53,000 --> 00:02:58,000 the advice as closely as we possibly can. We certainly don't want to have it. It wasn't very nice experience. 31 00:02:58,000 --> 00:03:04,000 OK, well, here is my fear. Plant is quite attractive. Not a real showstopper, but nice 32 00:03:04,000 --> 00:03:09,000 if you come up close to it. I am told you what it is here. And the reason for that is I want 33 00:03:09,000 --> 00:03:14,000 you to have a guess and I'm going to cut off one of its leaves and show it to you. I'm going to have to wear a 34 00:03:14,000 --> 00:03:19,000 glove because I am quite allergic to this plant. And if I touch it, I tend to find that I react 35 00:03:19,000 --> 00:03:24,000 to it. So let's chop off a leaf and have a look at it. I'm also going to ask 36 00:03:24,000 --> 00:03:29,000 you, is body part. Does it remind you of any guesses? 37 00:03:29,000 --> 00:03:34,000 Well, it's supposed to look like a disease lung. And the reason for that 38 00:03:34,000 --> 00:03:40,000 or the explanation, I should say, for why and that's important 39 00:03:40,000 --> 00:03:45,000 in its name is that in mediaeval times, a herbalism was a big thing. And of 40 00:03:45,000 --> 00:03:50,000 course, today, a lot of our medicines do come from plants. Plants produce an incredible 41 00:03:50,000 --> 00:03:55,000 array of chemicals. They are the sort of natural pharmacy. But we didn't know in mediaeval 42 00:03:55,000 --> 00:04:00,000 times what plants were they supposed to use for different ailments and may develop something 43 00:04:00,000 --> 00:04:05,000 called the doctrine of signatures. May decided that obviously God wanted people 44 00:04:05,000 --> 00:04:10,000 to heal themselves. And so he would give signs on various plants as to what they should be used 45 00:04:10,000 --> 00:04:16,000 for. And because that leaf looks like a disease lung. They thought that clearly this plant 46 00:04:16,000 --> 00:04:21,000 must be used to treat lung conditions. Now, it's probably all a bit backwards. And I think this 47 00:04:21,000 --> 00:04:26,000 plant was used to treat lung conditions before the adoption of signatures ever emerged, probably. 48 00:04:26,000 --> 00:04:31,000 So a lot of it was a bit, you know, being kind of deciding after the fact. Yes, Ash, those leaves do 49 00:04:31,000 --> 00:04:36,000 look a bit like a disease lung. But anyway, this is called Longworth's. And I certainly don't 50 00:04:36,000 --> 00:04:42,000 advise, no matter how bad your coffee is, that you start grinding the leaves of this plant and treating yourself. It has 51 00:04:42,000 --> 00:04:47,000 got some very toxic compounds in it. And I don't know whether there's any scientific evidence to show that any 52 00:04:47,000 --> 00:04:52,000 medicine derived from this plant could actually help you if you had a cough. And you certainly 53 00:04:52,000 --> 00:04:58,000 shouldn't try to harvest things yourself because plants can vary a lot and some leaves will have a 54 00:04:58,000 --> 00:05:03,000 lot of compounding and some will have a lot less. Now, the reason I'm interested in it, we were talking 55 00:05:03,000 --> 00:05:08,000 about pollinators. And if you look closely, we just zoom in on this plant for a minute. We can see 56 00:05:08,000 --> 00:05:13,000 something a little bit unusual. So the flowers are very different colours and that is 57 00:05:13,000 --> 00:05:18,000 very unusual. And if we look here, this is a newly opened flower. It's just starting 58 00:05:18,000 --> 00:05:24,000 to open and it's got a lovely pink colour. And as the flowers get a bit older, 59 00:05:24,000 --> 00:05:29,000 here's one that's a little bit older and you can see it starts to get suffused with power poles. You can see 60 00:05:29,000 --> 00:05:34,000 sort of pink and purple together. And that flower is the oldest one. And it's really 61 00:05:34,000 --> 00:05:39,000 very blue. Okay, so why is it doing that? 62 00:05:39,000 --> 00:05:45,000 Well, that's something that I want to take a look at in more detail, and it's to. With its pollinators. 63 00:05:45,000 --> 00:05:50,000 That's why that plant is changing. Kind of like that. And scientists have come up with explanations as to why 64 00:05:50,000 --> 00:05:56,000 this happens. It's quite a rare phenomenon. And actually, the biggest mystery is why 65 00:05:56,000 --> 00:06:01,000 more plants don't actually do it. But before we look at what what the explanations are for 66 00:06:01,000 --> 00:06:07,000 this colour change, we need to have a closer look at its main pollinators. 67 00:06:07,000 --> 00:06:12,000 The small gingery bee visiting this long word is a male of the hairy footed 68 00:06:12,000 --> 00:06:17,000 flower bee. And that's a very common early bumblebee in British gardens. This 69 00:06:17,000 --> 00:06:23,000 little black bee is the female of the same species. And we can see that she 70 00:06:23,000 --> 00:06:28,000 has these little orange blobs on her legs. And those are pollen sacs. So she's not just taking 71 00:06:28,000 --> 00:06:34,000 nectar. She's gathering pollen to take back and feed her brood of bee larvae. 72 00:06:34,000 --> 00:06:39,000 And both of those bees you can see really target the pink flowers. If they land on a blue 73 00:06:39,000 --> 00:06:44,000 on, it's not for long. Mostly, they seem to be able to aim straight for the pink ones. 74 00:06:44,000 --> 00:06:49,000 Now, there are also other insects that visit Longworth's. I wasn't able to film it on long word, but this 75 00:06:49,000 --> 00:06:55,000 is a bee fly. You can see it's a fly because it's such an amazing flyer 76 00:06:55,000 --> 00:07:00,000 able to bullseye those tiny little forget-me-not flowers without even landing on 77 00:07:00,000 --> 00:07:05,000 the flowers, just hovering above them. Only a fly can do that. When the bee 78 00:07:05,000 --> 00:07:10,000 fly lands and sits down, you can really tell it's a bee fly. See how its tongue is sticking out. 79 00:07:10,000 --> 00:07:16,000 A bee tucks its tongue underneath its body. The fly. Wow. But embarrassing, really. 80 00:07:16,000 --> 00:07:22,000 Okay, so we've just been having a look at some of the pollinators of loanwords. Is that the most common one is the hairy forces 81 00:07:22,000 --> 00:07:27,000 flower bee. So how did interactions to plants and the pollinator drive 82 00:07:27,000 --> 00:07:32,000 the evolution of that floral colour change that we can see? In other words, maybe 83 00:07:32,000 --> 00:07:37,000 glad to know I've got my pleader. I'm going to try and show you how it works. So let's have a 84 00:07:37,000 --> 00:07:42,000 closer look. I've got three potential lungworm plants here. This 85 00:07:42,000 --> 00:07:47,000 especially be the leaf. And here's the stamp on which the flowers are going to appear. And this plant is going to be 86 00:07:47,000 --> 00:07:52,000 what's called the ancestral plant. I'm going to imagine this is how long it started and it produced 87 00:07:52,000 --> 00:07:57,000 pink flowers. And every day I'm going to assume that the plant produces another flower. So it's 88 00:07:57,000 --> 00:08:03,000 day one, day to day three. But the flowers only last for three days. 89 00:08:03,000 --> 00:08:08,000 So on day four, when that flower appears, is going to disappear. 90 00:08:08,000 --> 00:08:14,000 And on day five, when this new flower appears, that one's going to disappear. And on day six 91 00:08:14,000 --> 00:08:20,000 and the final one appears that's going to disappear. So the most flowers it's ever going to have is three. 92 00:08:20,000 --> 00:08:25,000 It's going to be from over there for a second. Make this a bit easier. Now, what if there's 93 00:08:25,000 --> 00:08:30,000 a mutant plant that's doing something a bit different? So it opens a flower on 94 00:08:30,000 --> 00:08:35,000 day one, flower on day two and a flower on day three. But on day four, 95 00:08:35,000 --> 00:08:41,000 when this flower opens, it decides to hold onto that flower. It's not producing actual pollen 96 00:08:41,000 --> 00:08:46,000 anymore. So it's not really costing the plant anything, but it just decides to let that flower, 97 00:08:46,000 --> 00:08:51,000 that the old flower hang on in there on day five. It's still going to let that one 98 00:08:51,000 --> 00:08:56,000 hang on there. And on day six, it's going to do the same. So on average, these flowers last for six days, 99 00:08:56,000 --> 00:09:02,000 but only for three of them when they're in the first three days of actually producing pollen 100 00:09:02,000 --> 00:09:07,000 and nectar. That's valuable for bees. And these three are bit on rubbish. And the question is 101 00:09:07,000 --> 00:09:12,000 if will this plant do better than this one? Well, I think the answer is in the short term, yes, it 102 00:09:12,000 --> 00:09:18,000 would, because it looks much more attractive to the bees. And so they might go to this plant 103 00:09:18,000 --> 00:09:23,000 in preference to that one. So this plant will be more successful and we might end up with a 104 00:09:23,000 --> 00:09:28,000 lungworm population that looks like this. Okay. So that's all well and good. 105 00:09:28,000 --> 00:09:33,000 But now the bees are coming to the lungworm plans. And if they arrive first at one of these 106 00:09:33,000 --> 00:09:38,000 flowers, the old ones, because they can't tell the difference, then they're going to be really disappointed 107 00:09:38,000 --> 00:09:43,000 because there isn't any pollen or nectar there. And they might choose to just fly off again. And so 108 00:09:43,000 --> 00:09:49,000 the lungworm might start to suffer as the bees start to realise that this is not a plant to be trusted. 109 00:09:49,000 --> 00:09:54,000 It's not sending what we call honest signals. And so a second thing 110 00:09:54,000 --> 00:09:59,000 might happen where Longworth's charvat a new kind of change occurs. 111 00:09:59,000 --> 00:10:04,000 So here's what might happen now. This plant opens a pink flower on day one, 112 00:10:04,000 --> 00:10:09,000 a new pink flower on day two and a new pink flower on day three. But then on day 113 00:10:09,000 --> 00:10:15,000 four, when it opens a new pink flower, it changes the colour of the old 114 00:10:15,000 --> 00:10:20,000 one. OK. And then on day five, when yet another new one, pink one 115 00:10:20,000 --> 00:10:25,000 opens, it changes the colour, the old one. And finally, on day six, when the last 116 00:10:25,000 --> 00:10:31,000 new one opens, it changes the colour again. I'm going to shove that along and show the radial flower 117 00:10:31,000 --> 00:10:36,000 as being really blue purple. And the question we have to ask now, will that be more successful 118 00:10:36,000 --> 00:10:41,000 than that? And I think this will be more successful. And the reason is that bees 119 00:10:41,000 --> 00:10:47,000 is still a lots of flower. To attract him, the bees will come there. But they are targeted 120 00:10:47,000 --> 00:10:52,000 at the flowers with the high reward so they won't leave quickly feeling disappointed. 121 00:10:52,000 --> 00:10:57,000 Instead, they will stay and they will visit the flowers with the pollen in 122 00:10:57,000 --> 00:11:02,000 the nectar. Okay, so it seems that the Longworth has come up 123 00:11:02,000 --> 00:11:07,000 with a really great strategy, and I can imagine it evolving like that as a two step process. 124 00:11:07,000 --> 00:11:12,000 First, to retain the old flowers, but then as pollinators learnt, perhaps 125 00:11:12,000 --> 00:11:17,000 Lungworm is cheating on it to develop the systems, change the colour of them 126 00:11:17,000 --> 00:11:23,000 so that pollinators wouldn't be cheated. And that's an example of cocoa evolution, 127 00:11:23,000 --> 00:11:29,000 where the plant and its pollinator are influencing each other and the way 128 00:11:29,000 --> 00:11:34,000 that they evolve. So we're going to end where we began again with back at the patch of Longworth's. 129 00:11:34,000 --> 00:11:39,000 And in fact, I can see a male hairy fossil flower bee sting right now as we speak. This 130 00:11:39,000 --> 00:11:44,000 patch of Ludwig is in the shadiest coolest part of the garden and it's still going strong. Some of the other 131 00:11:44,000 --> 00:11:49,000 parts where it's been sunny are finishing. Lungworm is one of the first plants to flower 132 00:11:49,000 --> 00:11:55,000 in the year. And that's why it's so important for these very early pollinators. And studies 133 00:11:55,000 --> 00:12:00,000 have been done that show that the plant is also highly dependent on that hairy footed flower 134 00:12:00,000 --> 00:12:06,000 bee. If it's not allowed access to the flowers. Then you get very poor seeds that 135 00:12:06,000 --> 00:12:11,000 actually the lungworm by the primrose have back pain from mating system. So it requires 136 00:12:11,000 --> 00:12:17,000 pollinators to come and transfer pollen amongst plants in order that it can set seed. 137 00:12:17,000 --> 00:12:22,000 And we live. It's got this very clever trick of hanging onto the old flowers in order to look 138 00:12:22,000 --> 00:12:27,000 like there's more normal for him. There actually is. But when the bees arrive, they didn't feel cheated 139 00:12:27,000 --> 00:12:32,000 because they know exactly which flowers are offering the best rewards. Now, the pink ones, not 140 00:12:32,000 --> 00:12:37,000 the blue ones, and the bees seem to know that. And they focus in on those pink ones and spend more time visiting 141 00:12:37,000 --> 00:12:43,000 them. And that's also been shown. And if you have some of this club home and you want to have a go, 142 00:12:43,000 --> 00:12:48,000 you could film on your phone very easily and then watch and see whether they do seem to target 143 00:12:48,000 --> 00:12:53,000 the pink ones. When I've done that, I feel like they really do do that, but I haven't really quantified that properly 144 00:12:53,000 --> 00:12:58,000 or anything. If you want to grow long and you haven't got it in your garden, it's really, really easy 145 00:12:58,000 --> 00:13:03,000 to grab it from seed. And once you've got it spreads very easily and you can move it around your 146 00:13:03,000 --> 00:13:08,000 garden, you can move the seedlings around as tough as old boots or grab anywhere. And it's particularly good for 147 00:13:08,000 --> 00:13:14,000 growing in what's called dry shade underneath trees. It's specialised on doing that 148 00:13:14,000 --> 00:13:19,000 at the moment. It can grow under trees because most of the trees haven't really leafed out yet properly. 149 00:13:19,000 --> 00:13:24,000 And once the trees leaf out, they take all the light, they suck up all the water and they make life very difficult 150 00:13:24,000 --> 00:13:30,000 for anything growing underneath. Anyway, that's the end of today's or 151 00:13:30,000 --> 00:13:35,000 this this week show. And hopefully we'll be back again next week and hopefully we'll all be recovered in this 152 00:13:35,000 --> 00:13:51,600 household anyway from this horrible virus. I hope you're staying safe at home as well.