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Slime Mould - Sarah Lloyd
36 Plays4 years ago
Sarah Lloyd is a Naturalist, photographer and author of 'Where The Slime Mould Creeps'. Host Mykal Hoare dives into the enchanting microscopic world of Myxomycete Slime Moulds.
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Transcript
Introduction and Podcast Context
00:00:03
Speaker
Growing Media is a proudly independent podcast produced by me, Michael Hall, with zero corporate or network interference in our content. But this means we are running on the smell of an oily rag over here. So if you like the show and would like to make a small contribution, you could head over to our Patreon. You can find the link in our show notes.
00:00:28
Speaker
The producers of growing media recognise the traditional owners of the land on which this podcast is recorded and pay respects to Aboriginal elders past, present and those emerging.
00:00:43
Speaker
G'day, I'm Michael Haw and welcome to Growing Media.
Slime Molds Introduction and Sarah Lloyd
00:00:47
Speaker
Now, as you know, not everything that glitters is gold. Look under your feet. It just might be slime mould. Wait, what's slime mould? Well, I didn't know either until stumbling across the book, Where the Slime Mould Creeps by Sarah Lloyd.
00:01:06
Speaker
Now, slime molds are a complex subject, not widely known outside the scientific community. They are small creatures that live in our soil. They come together to creep the forest floors in search of food, then create enchanting-looking fruiting bodies.
00:01:23
Speaker
As I said, they are very complex and I would encourage you to have a look at the link in the description for this episode. That will take you to an Instagram post where you will see some macro photography of the fruiting bodies as well as a diagram of their life cycle for future reference throughout the episode.
00:01:42
Speaker
Now, Sarah Lloyd. She's a naturalist, photographer, author and slime mould expert, having discovered several species new to science. Sarah can often be found face down in the forest floor looking for these little creatures. And I mean, look, who can blame her? They are magical. Hey, Sarah, how are you doing? Hi, man. Hi, very well, thank you.
00:02:07
Speaker
Now, you live in Tasmania. Why don't you tell us a little bit about yourself and how you got so interested in the forests around your local area? Well, I've lived in Tasmania pretty well all my life. I grew up mainly in Hobart, but I have spent the last 30 or so years at a place called Burle and particularly at Black Sugarloaf, which is the name of the small mountain on which we live. And my partner and I bought 60
00:02:37
Speaker
acres of forested land 30 years ago. We've actually since put a bit more forested land adjacent to the first block. You've expanded. We've expanded mainly, well, you know, if you start seeing pink tapes going up around the bush in Tasmania, it usually means somebody's tying it off to log it. So we...
00:02:58
Speaker
and it was pretty well adjoining our forested land, so we bought that as well. So now I've got even more areas to search for slime molds. So when did you actually get interested in slime molds?
Slime Molds' Scientific Classification
00:03:11
Speaker
Well, probably about, I think it's about 11 or 12 years ago now. My interest in natural history really started with a love of birds, but then that turned into getting
00:03:25
Speaker
meeting a local field naturalist, getting involved in a local field naturalist group that led on to an interest in plants and fungi, mainly got interested in fungi through the Fungi Map Project, which you may have heard about. And then through that, I was pretty much introduced to slime molds through the Fungi Map Project, even though slime molds are not fungi. I suppose that brings us to the question, well, what is a slime mold?
00:03:51
Speaker
Yeah, well, that is a good question. Slime mold. Well, they're currently classified as protists or protoc-tisters. So that's the kingdom they're in and it's mainly a kingdom that excludes anything that's not a plant, animal or fungus. So it's a bit of a place to put things that can't easily be classified, but they're based on their
00:04:18
Speaker
single cell stage which lives in the soil, which is basically amoeba. Yeah, they're classified as amoeba zones in that kingdom protestor. So with the taxonomy, I believe initially they were classified as fungi. Yeah, so way back when Swedish botanist known as the father of taxonomy Carl Linnaeus was devising his system of classification, he settled on two kingdoms, plants and animals.
00:04:46
Speaker
And at the time, there wasn't much interest in fungi. And so they went into the plant kingdom. And slime molds were thought to be fungi, so they also went into the plant kingdom. But then a bit later on, people realized that fungi were completely different to plants. They don't have green photosynthesizing cells, and their structure is very different. So the fungi kingdom was added, and slime molds went into the fungi kingdom.
00:05:13
Speaker
But then they have this plasmodial stage, which is the moving feeding stage, which a lot of people might know about. It's often referred to as the blob. And based on the fact that it moved about and fed, it was placed in the animal kingdom. But then based on the amoeboid stage that was observed later on,
00:05:35
Speaker
they have been placed in this kingdom protista or protocpista. So they've moved around quite a bit then. They have been in practically every kingdom you could be in. Now, what do they look like exactly? What should we be looking out for? Well, if you're looking for the plasmodial stage, it's quite a structured organism. It tends to be yellow. They don't actually often appear on the surface.
00:06:00
Speaker
of substrate. So if you're looking for the fruiting body stage, which is the stage that I'm studying, I suppose they probably average about two millimetres in size, two millimetres high, the ones that I'm studying. You do get much smaller ones and there are some larger ones. I suppose the most well-known would be a fully ghostceptica that has that wonderful
00:06:26
Speaker
common name of dogs vomit dogs vomit yeah so that can get quite large you know that could get oh they can get 10 20 centimeter 20 centimeters across wow very very fragile though okay they look that's interesting because if people post photos on sites like iNaturalist you often see this this little mark where you can tell somebody's touched it
00:06:49
Speaker
You can't get away with that with slime molds there. So you've just got to leave them alone if you want to get that perfect picture. That's right, yes. A lot of the other ones I'm studying, the ones I mainly collect are about two millimeters high and they range from, well they have quite a lot of different sort of shapes. A lot of them are simply balls on stalks essentially but they're very exquisite in the way they're arranged. Some of them have this beautiful
00:07:16
Speaker
what's called a peridial net. So it's a network of threads that surround the spore mass. And a lot of them are iridescent, which is quite spectacular for something so small. Yeah, very beautiful. Yeah, they almost glitter and shine in... They do. Yeah, they're definitely iridescent. So they've got the same sort of structural element in the membrane. You see in a CD, you know,
00:07:44
Speaker
If you sort of move CDs you get that rainbow effect. That kind of like holographic-y type thing. That's right, yeah. That's the same thing with this iridescent slime
Slime Molds' Groups and Characteristics
00:07:55
Speaker
moulds. So there's two different kind of groups of slime moulds. There's a group which is just one large single cell organism and then there's another group which is a collection of single cell organisms that come together. So it is a bit confusing because there are these two
00:08:14
Speaker
completely different groups of organisms that are both called slime molds. So it does make it very confusing. So there's one group that are called Dictyostelids. And they're the cellular slime molds. So they have amoeba in the soil. And the amoeba feed until they run out of food. And they send out an attractant, which attracts the other cells in the area.
00:08:42
Speaker
combined to form a multicellular organism. And that's very tiny. You don't actually see them in nature unless you've got a microscope. They're pretty well soil-dwelling. The ones that I study are called the mixomycetes. And they also have this amoeba, amoeboid stage in the soil. But the amoeba multiplied by cellular division.
00:09:09
Speaker
And so they divide, they multiply, they do mate in the usual mating way. And they eventually form a plasmodium. And the plasmodium is essentially one large cell with multiple nuclei. So they don't have cell walls within this large structure.
00:09:33
Speaker
They're acelial slime molds, yeah, yeah. And from one large cell, they form the fruiting bodies. Do they only do this during food scarcity? It's really hard to know what triggers their formation of fruiting bodies. So this year, it's been quite a wet year in Tasmania. And over the last couple of months, I've been watching a particular species on a log in the field. So it's a species that does, the Plasmodium does,
00:10:01
Speaker
feed on the surface of the log, often on fungus. So there's this white, what they call a paint splash fungus that covers the log and the plasmodium of this species will move about and it will feed on this white fungus. And then, depending on, we don't quite know what, it will start forming fruiting bodies.
00:10:25
Speaker
And so along with particular log at the moment, I think there might be five or six different little groups of fruiting bodies. So the plasmodium at one stage is broken up into different little patches and gone off on its own and form fruiting bodies in different parts of the log. So the fruiting bodies hold the spores, which enable it to spread itself far and wide.
00:10:51
Speaker
How do they disperse the spores? So the spores are mainly wind dispersed, so the plasmodium forms the spaw-bearing fruiting bodies and they just sit there until something probably ruptures the outer membrane that protects the spore mass and then the spores are dispersed often by wind. There are
00:11:14
Speaker
There are actually quite a lot of beetles that feed on the spores and they would, and actually a lot of other invertebrate feed on the spores. So yeah, they'd be spreading spores most inadvertently, just as they're sort of passing by. So that's the purpose of the fruiting body. What are some of the animals that feed on them? Well, there's a group of animals called springtails. Calembla is the more scientific name.
00:11:40
Speaker
And there's a few genera of springtails that feed exclusively on developing fruiting bodies. So they're getting nutrients from developing fruiting bodies. And they'll be feeding on the plasmodium as well. But I tend to see them when they're feeding on the developing sidewall fruiting bodies because that's when they're more conspicuous. Because a lot of the plasmodia
00:12:05
Speaker
You don't see them because they function within the substrate. So they'll be in the soil or in old rotting logs or even in some quite recently fallen logs. It can be extremely hard but there are some families that have very fine plasmodial threads and they can find their way through really dense wood. How do they move? Well it's a process called shuttle streaming. So this is the plasmodial
00:12:35
Speaker
stage and it's known as shuttle streaming or cytoplasmic streaming. They move forward for about a minute and then they'll stop through a bit and then they'll move backwards for a bit and then ultimately they move forward again. But it's contraction of the veins in the plasmodium that constrict and then
00:13:02
Speaker
expand. Probably one thing I should say about the plasmodial stages, it's almost like they're two completely different organisms because there are some people that only study the plasmodial stage of a slime mold. They probably wouldn't even know that they have fruiting bodies of such variety and beauty. And one of the reasons they study them is because they are essentially a giant cell with these multiple nuclei that can move all over the place.
00:13:30
Speaker
So it's like they're a model organism. And so there are lots of experiments being done on the plasmodial stage of myxomyc.
Slime Molds' Problem-Solving Abilities
00:13:39
Speaker
During my research, I saw some wild experiments conducted with slime molds. Some where they were feeding them oats and they placed an oat, like a rolled oat, on the capital cities of Japan or of Tokyo, major kind of transport hubs of Tokyo.
00:13:58
Speaker
And then the slime mold creeped out, fanned out, found and locked onto that and then reduced itself back creating the pretty much exact line of the most effective route to get to the city, i.e. the food source.
00:14:20
Speaker
And when you put a map of Tokyo over the top of that, the lines basically follow the metro lines in Tokyo. You know, engineers have taken years and years and years to work this out, to kind of work out the most effective and fast route to the city, but the slime molds seem to have done it incredibly quickly. That's right, yes. So they are very efficient at finding food.
00:14:48
Speaker
And when people, I mean, there's a lot, quite a few stories come up, you know, they come up periodically, probably a couple of times a year, when people send the links to these stories. And these, you know, slow molds have been around probably for 600 million years.
00:15:05
Speaker
possibly for longer. So it's hardly surprising. They're pretty good at finding food. Yeah. Well, I suppose we've had a long time to train for that one. So it's actually pretty remarkable how they can move and search for food being that they are kind of without a brain or without a nervous system. And they seem to have an intelligence that we don't really understand yet.
00:15:30
Speaker
That's right. Yes, we have no idea how they do
Slime Molds' Global Presence
00:15:33
Speaker
it. No. Some sensory thing there somewhere that's... I was thinking like a hive mind, hive mentality kind of thing. Yeah, well, if you listen to ABC Off Track, spoke to Dr Tanya Lattie, and she studies the plasmodial stage of slime molds. And one of her interests is how colonial organisms work. So ants and bees.
00:16:00
Speaker
have these, you know, massive colonies with numerous individuals. And she sees analogies, excuse me, with fine-melled plasmodia. So you'd have to ask her about that one. Okay, I will see. Are they found across the entire Earth? They are. They're very, very common.
00:16:24
Speaker
I think they're much more common than anyone really thought until people started really looking closely for them. And not, you know, within the last 10 years, the interest's really taken off. So they seem to be most, reach their peak of diversity in the temperate forests of the world. But they're also found in tropical forests, they're found in deserts. There's a particular group called Snowbank species.
00:16:54
Speaker
found at the edge of melting snow in spring. There are a lot of species in the northern hemisphere where they have larger areas of snow than in Australia, but there are snow bank species in Australia. Even in sub-antarctic islands, anywhere there's vegetation they're found. How do people search for them? The main way people search for slime molds is to collect substrate and take it back to the laboratory.
00:17:23
Speaker
Because they're so unpredictable as to when they're going to appear, so you never quite know if they're going to be any in the field or not, so it's hard for people to plan trips to a particular location to coincide with the fruiting time. So what they do is they go into the field, collect any fruiting bodies that might be there, but they also collect substrate, so leaves, bark, bits of wood, any organic material.
00:17:51
Speaker
I'll take it back to the laboratory and put it in petri dishes, keep it moist, actually on paper towel, and then just keep checking it over days, months, and to see what comes up. Sounds like that's accessible for almost anybody.
Engaging with Slime Molds
00:18:07
Speaker
Anyone can do it, yeah. There's a teacher in Melbourne who's not only getting her primary school students looking for slime rods in the field, but she's also got lots of petri dishes full of
00:18:20
Speaker
substrate and the children are really keen on. Oh, how fantastic. Yeah, that's great. Yeah, that is great. Now you have actually found four species of slime mold yourself that are new to science? That's correct. Yes. Can you tell us a little bit about those species? Yeah, well, the first one that I collected that was new to science, I misidentified as a species that only found in the tropics. Okay. Because it's a really distinctive looking species, which is quite unusual for slime mold.
00:18:51
Speaker
a lot of them superficially look similar and you have to do a lot of microscopy to actually identify them. This one looked similar to a species from the tropics. I wrote an article about it for the Fungi Map newsletter and a researcher from the US, Dr. Steve Stevenson, I think he saw the article
00:19:13
Speaker
He accessed my collection and one of his students was working on the particular group at the time and based on the morphology, it looked different to what I had misidentified it as and some DNA research, yeah, they decided it was a new species. And what's it called?
00:19:31
Speaker
with the Eloidae, so they named it in my honour. How great! I found it, I sent it to them and they did all the work and so they named it in my honour. How good, that's actually kind of a dream isn't it? Well actually I thought the next step was more exciting where I was the lead author in the paper about the three other new species I found, the three species of tubifera. So that was
00:19:59
Speaker
I think probably more interesting than having a name, species named after me. Yeah, fair enough. Yeah, that is pretty good. And what do they look like? The Chibifera. Yeah. They're more blobby than, they're a bit more like a smaller version of the fully goseptic at the dogs vomit, although much smaller. And they're actually called Chibifera because they're a whole series of little miniature tubes that coalesce.
00:20:28
Speaker
And so some of them, one particular one was very different from anything I'd seen in the books. And a couple of the others were, they were a bit different looking, although one actually looked very similar to a northern hemisphere species. I just wrote, I wrote a post on my website about them and sent the link to a person in Ukraine, Dr. Dimitri Theontov.
00:20:57
Speaker
who studies this particular family of organisms and he was very interested. I ended up sending him material and he did the DNA and they turned out to be new to science. Based on the DNA, sometimes it's really hard to look just at the morphology, even the spores that a thousand times magnification can look almost identical to
00:21:24
Speaker
to other species but yeah the DNA settled that one. So they've really got to kind of narrow it down to the DNA and not just sort of take it on face value I suppose. Yeah well it's getting more and more the case that they're doing DNA but they're still, there's another species, another couple of species that I've found that are almost certainly new to science. In fact it's probably even the new genus.
00:21:49
Speaker
Yeah, that was pretty exciting. It was one of the first species I ever found and I didn't know what it was and hardly surprising because it's not only probably a new species but a new genus. So that's pretty exciting. I've just sent the material once again off to this person in Ukraine who's very keen to figure out what it is. It doesn't really fit into any
00:22:15
Speaker
known genus at the moment. That is crazy. Do we think then that there's going to be more of these throughout Australia or Tasmania, I suppose? It's pretty unusual to find a new genus. I don't know when the last one was added. The likelihood of finding new species is pretty high.
00:22:39
Speaker
Yeah, he doesn't do a lot of work. Yes. Such a wealth of knowledge needed to know whether you've got something special on your head. Well, that's right. And that's, that's, that's a difficult path. Yeah. So there are a few that are a couple of others I thought might be new species and they've turned out not to be. Um, one was actually, yeah, it was, it was thought to be a subspecies of another species when it turned out to be a species in its own right.
00:23:07
Speaker
OK. But that was described only a couple of years ago in New Zealand. So that was from a New Zealand collection. That was quite interesting because I thought that mine was something unusual and it turned out to be, well, beautiful, but already described. Already described. Yeah. What does your collection look like? Do you have some in your home? Well, I've got some metal drawers and
00:23:35
Speaker
They're a bit like miniature filing cabinets. And I think I've got over 2,000. So they're really very convenient to store because they're so small and you can fit them in matchboxes. So when I collect them in the field, I mount them on sort of thick cardboard. I just mount them on with a bit of glue and then put them in a matchbox and label them. So they're all labeled with my name, date, location,
00:24:03
Speaker
latitude, longitude, substrate. And yeah, where I collected it. So all that information. Best time of day to find a slime
Discovering and Documenting Slime Molds
00:24:14
Speaker
mold. Fresh ones tend to appear either overnight or in the early morning. And when they're fresh, they're often really brightly coloured. So you see white ones, hot pink, hot orange. And so they can be conspicuous. But then as the spores mature, most of the spores are quite dark in
00:24:33
Speaker
in the fruiting bodies. They'll go dark and would be really difficult to see. So when I'm searching for them in the forest, I generally use a very strong life, like it's just a head lamp or a torch. And I have always had my 10 times magnifying glass or a jewelers loop with me, so I can see. And I generally check big old logs, those really big old moss and liverwort logs around here.
00:25:02
Speaker
They're really good at certain times. Any dead organic material, standing dead trees, logs on the ground, leaves on the ground, yeah, anything. You just got to look very closely. Other than being a naturalist and a writer, you're actually a photographer as well. I imagine here we're talking about macro photography. I suppose, I don't know. I call myself a photographer because I take a lot of photos.
00:25:30
Speaker
You know, when I see some people's photos on Instagram, they're really our photographers. I don't know though, I've looked through your Instagram and there is some absolutely stunning pictures on there. Yeah, some of them are okay. You're too modest, they're fantastic. Yeah, well, I take them for, you know, for my own record. I take a lot of photos in the field, which I really like doing, although it's pretty hard on the body.
00:25:59
Speaker
But I've got a number of cameras that I use on my microscopes as well. And I have recently bought an extreme macro lens, so you get really close ups with quality. Have you found a slime mold yet? I haven't, no. I'm in the Blue Mountains and I'm very excited to go out and have a look for some actually. Can you go walking in the bush? Yeah, yeah, absolutely.
00:26:28
Speaker
Not in the Blue Mountains. I know there are a few photographers up there that are interested and take the old photo of slime molds, but I don't think anyone, there's only a few people in Australia actually doing like collecting and depositing. So I suppose the one thing I didn't say is a lot of the, most of my collections I sent to, well a lot of collections I sent to the herbarium in Melbourne. And there aren't many people, there's only a handful of people in Australia doing that sort of work.
00:26:57
Speaker
but there are a lot more people getting into just photography and yeah. Do you think we need more people getting out there and sending samples into the herbarium? Yeah, I mean it's always good to have as many records as possible and you get much more sense of what's where. But the other thing that people can do is take photos and put their photos on platforms like iNaturalist and then they get recorded scientifically. I mean the problem with
00:27:27
Speaker
Instagram is... people post fantastic photos, but they're not scientifically recorded anywhere. Whereas if they posted the same photos on iNaturalist, they'd be recorded as occurring in Australia and, you know... And where and kind of what time of year. That is where we will leave it for today. Thank you so much for your time. No worries. Thanks for your interest.
Engagement and Feedback
00:27:53
Speaker
You can find Sarah on Instagram at sarah.loyd.tasmania to check out those amazing slime mould photos. Also grab a copy of her book Where the Slime Mould Creeps to deep dive into this microscopic world, all will be linked in the show notes.
00:28:11
Speaker
Thank you so much for listening to this episode of Growing Media. I am so glad we could catch up again. You can find us on Instagram at GrowingMediaOz. I am Michael Haw, M-Y-K-A-L-H-O-A-R-E. Please don't forget to rate, review, and subscribe to the show. It would mean the absolute world to me. Hooroo! See you in a fortnight!