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 --> 00:00:45,000 biology. 6 00:00:45,000 --> 00:00:51,000 Well, welcome to this episode. Back in biology, I'm going to look at the plant today that most 7 00:00:51,000 --> 00:00:56,000 gardeners, I think, would be pretty confident to just cool of weed and they wouldn't allow it to grow in their gardens. 8 00:00:56,000 --> 00:01:01,000 So some of the plants we've looked at so far are like primroses and the flotilla arrays and 9 00:01:01,000 --> 00:01:07,000 the Longuet are native plants or close to native plants. The flotilla was probably brought 10 00:01:07,000 --> 00:01:12,000 to Britain in around the 15 hundreds. It has naturalised itself very well and it's certainly native 11 00:01:12,000 --> 00:01:17,000 to northern Europe. But most gardeners are happy to have these things in their garden going 12 00:01:17,000 --> 00:01:22,000 as far as actually buying them and garden centres and deliberately planting them. But this plant 13 00:01:22,000 --> 00:01:27,000 is not something I've deliberately planted, but I'm allowing it to grow in my garden. And if you just pan 14 00:01:27,000 --> 00:01:32,000 left, we can see that there is quite a stand of it here, growing in my garden 15 00:01:32,000 --> 00:01:38,000 and in the back corner where it's not doing any harm to anyone. And I quite like kids. And its 16 00:01:38,000 --> 00:01:43,000 name is Garlic Mustard and its common name when one of its common names 17 00:01:43,000 --> 00:01:48,000 is Jack by the hedge amounts, because it always grows in this where you see these stands 18 00:01:48,000 --> 00:01:53,000 of it just growing the long side hedges. It can't invade grassland, it seems, 19 00:01:53,000 --> 00:01:58,000 and it rarely invades the woodland itself. So there's just this narrow strip of habitat where it 20 00:01:58,000 --> 00:02:04,000 can grow extremely well and you can find a lot of it. Now, if we just zoom in a bit more 21 00:02:04,000 --> 00:02:09,000 closely and see what it looks like, you can see these are obviously 22 00:02:09,000 --> 00:02:14,000 flowering. You can see the small white flowers appearing at the top of the plants. They just have four 23 00:02:14,000 --> 00:02:19,000 petals. And those little four petals, flowers are typical of the 24 00:02:19,000 --> 00:02:24,000 brassica family. So this belongs in the brassica family. And that's the 25 00:02:24,000 --> 00:02:29,000 cabbage family. Right. So we eat lots of brassicas. And if that this is edible, 26 00:02:29,000 --> 00:02:35,000 I don't personally. But it is edible. And if I take a leaf, Marbury's it. Then I get an amazing 27 00:02:35,000 --> 00:02:40,000 smell of garlic. Right. So it's not a typical brassica smell. It's got 28 00:02:40,000 --> 00:02:45,000 a very strong smell of garlic and garlic. Of course, we associate with a completely different plant family. 29 00:02:45,000 --> 00:02:50,000 The alliums, the onion family, they are famous for producing garlic compounds. 30 00:02:50,000 --> 00:02:55,000 But this brassica can do that as well, as well as having the sort of mustardy 31 00:02:55,000 --> 00:03:00,000 flavour of of some of the brassicas because mustard that you actually eat in a jar, that they are 32 00:03:00,000 --> 00:03:07,000 the seeds of a mustard plant farmed. So it's related to this also in the in the cabbage family. 33 00:03:07,000 --> 00:03:12,000 It used to be widely eaten. It was a very popular thing. And for that reason, 34 00:03:12,000 --> 00:03:17,000 it was taken from Europe to North America by settlers who wanted to 35 00:03:17,000 --> 00:03:22,000 have this plan, which they considered to be valuable for food and for various medicines. They took it 36 00:03:22,000 --> 00:03:27,000 with them. And that has created an enormous problem in North America. And 37 00:03:27,000 --> 00:03:33,000 this is not the only plants we've done that. So when many plants from Europe, which appeared to be quite 38 00:03:33,000 --> 00:03:38,000 well behaved here, didn't really cause a problem, are taken to other parts of the world, 39 00:03:38,000 --> 00:03:43,000 they can suddenly cause very big problems indeed. 40 00:03:43,000 --> 00:03:48,000 So I brought in a piece of the garlic mustard. I just cut it off and placed it on this tray so we can look at it 41 00:03:48,000 --> 00:03:53,000 a bit more closely. You can see it has quite large leaves with a 42 00:03:53,000 --> 00:03:59,000 sort of a little bit of a heart shaped base and then there to around the edge. This 43 00:03:59,000 --> 00:04:04,000 is a two year old plant. I know that for sure, because garlic must that is what we call a biennial. 44 00:04:04,000 --> 00:04:10,000 That means in the first year, it just forms a rosette that doesn't flower. In the second year, it flowers 45 00:04:10,000 --> 00:04:15,000 and dies. So it never last very long. So it has these large, quite soft, 46 00:04:15,000 --> 00:04:20,000 thin leaves. And you can see they've already suffered quite a lot of damage. You can see little holes 47 00:04:20,000 --> 00:04:25,000 in them or they've been nibbled away at. And if I move up a bit further, we can see 48 00:04:25,000 --> 00:04:30,000 even more holes here. So things are eating this plant. And if we move up to the 49 00:04:30,000 --> 00:04:36,000 top, we can see the sort of business end of the plant and a bug just ran out at me. This 50 00:04:36,000 --> 00:04:41,000 is the flowering part. And a lots of the insects I've been seeing on here are concentrated on this. 51 00:04:41,000 --> 00:04:47,000 And you can see the little white flowers with their four petals. 52 00:04:47,000 --> 00:04:52,000 And in here you see the developing seed pod. So they're just starting to develop 53 00:04:52,000 --> 00:04:57,000 now. Must hold it against the white background. You can see they are going to be long, thin, upright seed 54 00:04:57,000 --> 00:05:02,000 pods. And inside there's the seeds will develop. What's interesting about 55 00:05:02,000 --> 00:05:08,000 here, I'm going to show some little bits of clips that I've taken. I've been monitoring the plants for the last week 56 00:05:08,000 --> 00:05:13,000 or two while I've been flowering and just trying to take pictures of all the things I see on there. And 57 00:05:13,000 --> 00:05:18,000 they're covered in insects all the time. In fact, this plant in its European native 58 00:05:18,000 --> 00:05:23,000 range has sixty nine different inset herbivores that eat it. None 59 00:05:23,000 --> 00:05:28,000 of them look massively impressive. Perhaps you don't even realise that they are having an impact 60 00:05:28,000 --> 00:05:34,000 on the plant. They are. They are things like tiny little weevils, tiny little pollen 61 00:05:34,000 --> 00:05:39,000 beetles and all those things that eating the business end of the plant. They are reducing 62 00:05:39,000 --> 00:05:44,000 its fitness and taking away its pollen, which means it can't so successfully pollinate. The plants, 63 00:05:44,000 --> 00:05:49,000 they're eating, the seed pods themselves. And one of our most charismatic insects that we're most 64 00:05:49,000 --> 00:05:54,000 interested in having perhaps in our garden, the butterflies and the orange tip butterfly, which 65 00:05:54,000 --> 00:05:59,000 is a very attractive butterfly that you might see flying around your garden at the moment, is white with orange tips 66 00:05:59,000 --> 00:06:05,000 to the four wings. The females lay their eggs on this plant. And when they emerge, 67 00:06:05,000 --> 00:06:10,000 they eat those developing seed pods. And all those things take a toll on the plant 68 00:06:10,000 --> 00:06:15,000 and probably help to prevent it from being too successful. And that's 69 00:06:15,000 --> 00:06:20,000 one of the problems when we take a plant somewhere else and when we take this plant to America, it may 70 00:06:20,000 --> 00:06:25,000 well be that people just took the seeds and therefore all the insect passengers didn't go 71 00:06:25,000 --> 00:06:30,000 with it. And what happens in the States is you don't find all these insects on the plants at all. 72 00:06:30,000 --> 00:06:36,000 That was virtually nothing. They're eating it because they're insects are not adapted to this 73 00:06:36,000 --> 00:06:41,000 plant and it's unique chemistry. All plants have a unique chemistry and insects have to be coevolved 74 00:06:41,000 --> 00:06:46,000 with their host plants. And that is probably contributing to 75 00:06:46,000 --> 00:06:52,000 the problem in the States. And they've been doing some trials with some of the weevils 76 00:06:52,000 --> 00:06:57,000 that we have here that eat garlic mustard to see whether an introduction might be possible. 77 00:06:57,000 --> 00:07:02,000 People are very reluctant to introduce yet more things even as biological 78 00:07:02,000 --> 00:07:08,000 control agents, because what we know is that although they're supposed to only garlic mustard, 79 00:07:08,000 --> 00:07:13,000 you know, this is a brassica brassicas are a commercial crop. And if those weevils turn 80 00:07:13,000 --> 00:07:18,000 their attentions to broccoli or cabbage, you'd suddenly have a new pest species to deal 81 00:07:18,000 --> 00:07:24,000 with. And so perhaps that's why that permission has not been given. 82 00:07:24,000 --> 00:07:29,000 If you're not sure how to identify Weevil, but you're interested in what it looks like, a weevil is a little beetle with a 83 00:07:29,000 --> 00:07:34,000 very distinctive head into the straw one for you now. So the head 84 00:07:34,000 --> 00:07:39,000 looks like this had me either down here and they have this amazing 85 00:07:39,000 --> 00:07:44,000 rostrum. My antennae normally come off around here. And on the end of this rostrum 86 00:07:44,000 --> 00:07:49,000 are the mouthparts. Most weevils eat plants and they use the mouthparts on the end to often 87 00:07:49,000 --> 00:07:55,000 chomp into the plants and then lay their eggs inside them. Some of them live below ground 88 00:07:55,000 --> 00:08:00,000 on the roots and some of them live above ground on the leaves. And a little grey weevils are the ones 89 00:08:00,000 --> 00:08:05,000 we've seen on the garlic mustard. So what exactly have we seen on the garlic mustard? 90 00:08:05,000 --> 00:08:10,000 Well, here you see the sort of inset falls that constantly hangs around these plants, tiny 91 00:08:10,000 --> 00:08:15,000 little midges or parasitic wasps that we can't even see properly. Close up here, 92 00:08:15,000 --> 00:08:20,000 the little pollen beetle, a shiny little guy who lives on the flowers. I'm walking 93 00:08:20,000 --> 00:08:25,000 up and down the stems. Here are two of those little grey weevils. I managed to catch 94 00:08:25,000 --> 00:08:30,000 one in my hand and here he is and freeze frame. And we can see that tiny little rostrum 95 00:08:30,000 --> 00:08:36,000 there, almost like a little elephant's trunk. When we took that plant out of the tray, there was this bug 96 00:08:36,000 --> 00:08:41,000 running around wildly. Again, I'm really not sure what species that is, but where there are 97 00:08:41,000 --> 00:08:46,000 prey, there are predators. And this is the rather handsome 14 spot Lady Bird who is crawling 98 00:08:46,000 --> 00:08:51,000 around the plants and also things coming to the flowers. This an early hover fly. 99 00:08:51,000 --> 00:08:57,000 And, of course, the pest resistance, the orange tip butterfly itself didn't manage to get it on the garlic 100 00:08:57,000 --> 00:09:02,000 mustard, but here it is, having a rest on a daisy and the more. So I want to finish 101 00:09:02,000 --> 00:09:07,000 this piece, not back exactly where I started, but on the other side of the garden where there's something 102 00:09:07,000 --> 00:09:12,000 that gardeners will be a lot more comfortable with. This is Camastra. This is a North 103 00:09:12,000 --> 00:09:17,000 American plant. It's been brought here and it's grown very widely in gardens 104 00:09:17,000 --> 00:09:22,000 and plants like this sometimes. Give me pause for thought. It grows very well. It 105 00:09:22,000 --> 00:09:28,000 forms very large clumps. We know that in its native North America, it can form 106 00:09:28,000 --> 00:09:33,000 very dense patches in wet meadows. And you start to wonder, well, 107 00:09:33,000 --> 00:09:38,000 what if this plant escaped from my garden and started to establish in the U.K.? 108 00:09:38,000 --> 00:09:43,000 Could it become a difficult, invasive one that we would then have to spend a lot of money 109 00:09:43,000 --> 00:09:49,000 getting rid of? Like Japanese knotweed and we just don't know. Gardens are harbouring 110 00:09:49,000 --> 00:09:54,000 hundreds of plants that have been brought to Britain from all over the world. And rather looking 111 00:09:54,000 --> 00:10:00,000 thought, frankly, puts into wondering which ones of them will become problematical 112 00:10:00,000 --> 00:10:05,000 and which ones are bad ways. We know that most don't because that they have to be cossetted and 113 00:10:05,000 --> 00:10:10,000 gardens gardeners have to work really hard to grow them. But you certainly don't have to work hard for this thing. It's 114 00:10:10,000 --> 00:10:15,000 very easy to grow. It thickens up and grows very well. And what you can say 115 00:10:15,000 --> 00:10:20,000 is, unlike the garlic mustard, I can see virtually no insects on it. You know, it's advertised 116 00:10:20,000 --> 00:10:26,000 as being pest free, disease free, trouble free. What that means is that none of our native 117 00:10:26,000 --> 00:10:31,000 herbivores actually eat it. And that could mean that something like this in 118 00:10:31,000 --> 00:10:37,000 50 years time, rather than admiring it, we might be seeing this as a brand new villain of the piece. 119 00:10:37,000 --> 00:10:43,000 So what can you do in your garden this week? Well, have a look around. What native plants. 120 00:10:43,000 --> 00:10:48,000 Have you got. Popping up in your flower beds that perhaps weren't invited, but perhaps. Are there any 121 00:10:48,000 --> 00:10:53,000 way. And can you see those tiny little bugs and insects? They're little 122 00:10:53,000 --> 00:10:58,000 aphids. The little weevils that little pollen beetles. All those things that we saw 123 00:10:58,000 --> 00:11:03,000 on the garlic mustard. And remember, all those things are playing their part. They're stopping 124 00:11:03,000 --> 00:11:09,000 those plants from becoming too invasive and dominating everywhere. And they're also food 125 00:11:09,000 --> 00:11:14,000 for the things we like best. I see all those little birds that are foraging around your garden, 126 00:11:14,000 --> 00:11:30,520 too, till next time. Have a great week.