Spider facts

RB: Welcome to the Museum Revealed podcast brought to you by the Queensland Museum. Join me, Dr Rob Bell (RB), as we chat to the people that make museums so fascinating, from curators to scientists and researchers. It’s a deep dive into conversations with these storytellers that inspire us to be curious about our past, make sense of the present. And help us consider the future. And right now, I’m joined by Dr. Robert Raven (RR). So it’s a sort of a Rob and Rob show, I guess, in a little way. And you’re probably best known for all of your work with spiders. So tell me, what’s your official title here at the museum?

RR: Oh, I think I’m somewhere between Spider Man, chief of head of biodiversity, terrestrial biodiversity and principal scientist in arachnology. But I’m basically the arachnologist, one of the archaeologists here is about six of us.

RB: And arachnids are not just spiders, are they? Although they’re probably what my associate.

RR: They’re eight legged creatures. So everything from that little mite that’s feeding on the fat at the base of your hair follicles. Right up to the big tarantulas and feed on bats as they fly past them on the trees.

RB: And it’s an area that I think a lot of people find fascinating. A lot of people don’t like spiders for one reason or another. They’re obviously a pretty crucial part of our world, our biodiversity. And you have a somewhat peculiar relationship as far as well. You’re obviously fascinated by them. You’ve studied them for quite a while.RR: Yeah. I mean, the thing was that I was associated with some friends who were very, very good bird watchers. They were in the Six Hundred Club, which is getting to the maximum number birds you can get in Australia. And I learnt that I’d seen a bird, but I couldn’t replace remember what it was. And I thought, you have to figure out something to help you get through the university courses, which are boring me desperately. And I thought about it and I thought, you have an irrational fear of a spider being on your arm. Spiders are all around us. Not that particular one. Perhaps there’s spiders all around us. So. And it was quite interesting because, you know, after I’d studied them for a while and tried to command this fear, I discovered from time to time that I still have it. It’s just when the guards down, you know, I’d be walking around with, like a honey jar full of alcohol in my hand at night with with a couple of trapdoors and a funnel web or two in the jar. And the next minute, this is in swimming in 70 percent alcohol. Next minute, the funnel web climbed out of the jar onto my hand. I could feel this wet thing and I just flung my hand to kingdom come drop the jar and sat down and counted my pulse for a while. But it was just very interesting because I realised then subsequently I’ve had similar sort of event in the desert, you know, collecting all day and night and then get into the tent and your find it’s great place to find a spider within a mere centimetre or two of your face. And it’s the sort of thing that causes death, deaths on roads, you know, that kind of things, when you flip down the visor. So, yeah, the fear is still there. I know when I’ve when I’ve got a cold or something, then I’m a bit under the weather that I can’t deal with it. And also, I was lying in bed the other night, looked up and saw Huntsman said, no, sorry, you can’t stay here while I go to sleep. That’s not going to work. So I had to get up and get it down, which takes a little bit of power. The shield goes up and it works out. So it’s facing my fears. And as I try to point out to a lot of people, there aren’t many capital cities in the world that I haven’t been to as part of my work. Now, there’s a cross benefit to facing your fears. You know, I’ve been to most of these places because there are Australian spiders or something important in those places. So. And I’ve been funded by federal governments to do this kind of thing. So it’s been great.

RB: I think I think that’s amazing. And certainly something for aspiring scientists and arachnologists out there to keep in mind the amount of places that you can get to go to. So I’d like to talk about a few different spiders, probably will focus on some of the Australian ones. A little bit about the funnel web you mentioned is probably one of Australia’s more famous or feared spiders for want of a better way to put it. It’s always a bit of a competition. If you Google these days, there’s always lists of, you know, the most venomous, it’s the most dangerous. That is the funnel web, the most venomous. I guess it’s got the most toxic venom. Is that the best way to put it?

RR: It has that we had a situation a few years back where Guinness Book of Records had something else down, a Brazilian Wandering Spider. And I double checked my information and then I wrote to them. I said, you know, however dangerous the venom may be by micro drop or whatever. It certainly hasn’t matched the actual fatality rate. So they changed that to the you know, they pharmaceutically most active venom. So the Australian funnel webs are documented to have killed 13 people. And the same with the Redbacks. Different, different reasons.

RB: Most people would think those numbers are low. I mean, they I hear funnel web and this they’re deadly? They kill people, but it’s actually very, very low.

RR: Yeah. Yeah. Very low. And it hasn’t. Nothing. On the funnel web side, nothing has happened since 1960, I think, or 1980, when they came up through the venom of the redback was the 60s. So, yeah, people have been treated and successfully come through.

RB: So you’ve got the Guinness Book of World Records to change their records?

RR: Yeah, I told him the fact you showed that. And I assume that they would respond accordingly. And they did.

RB: Yeah. Excellent. So, Howard, how is it then that they measure it on that number call and L.D. 50, is that what they use to measure the toxicity or is that where it gets a little bit?

RR: Yeah, well, L.D. 50 is the lethal dose through required to kill half of the animals injected. So. And the thing is that, you know, we are quite big, handsome organisms. Right. But if you get a funnel web to bite a mouse, nothing happens to it. Cats and dogs play with them and have no reaction at all. So it’s just primates. Those of us with opposable thumbs that have lost some sort of ability to metabolise the venom. The funnel web venom was developed many millions of years ago to deal with a completely innocuous vegetarian called a millipede. And what it does to the millipede is it stops it spraying out this high like cyanide, like toxin, which would kill the funnel web. So it’s got to paralyse the millipede. And to us, it does the exact opposite. It causes fibrillation, trembling of the heart and lung and all of the organs. And we simply drown in our own fluid.

RB: So it’s a danger to us as essentially kind of just a weird quirk of evolution that we just happen to fit into this profile.

RR: Many primates were around when it evolved. It’s just purely accident. There’s a beautiful big things called Len Mullet’s these Lizards. And we’ve got photographs of these things, hunting male funnel webs, which is the most dangerous sex. So we know that they are completely harmless to those things and they eat them and so on. So it’s, you know, dogs, cats. So the LD 50 then. Can’t be tested except on primates.

RB: So tell me, when they make the antivenom you mentioned the antivenom for these sort of things. Is that where they use? Is that the horses that they used or some sort of large creature that they have.

RR: They have used horses. That was the redback. Yeah. We’re using horses for. But the problem is that tetanus was also the injection we get for tetanus was also extracted from horses. So there’s already horse protein in the system. When we get a second hit from the redback, for example. Then the first thing that hospitals have to do when they before they do that is they put you in intensive care in case you have anaphylactic shock to the double hit of horse serum. So, you know, it’s a delicate process. And so they switch to sheep, I think, with the redbacks now.

RB: So they’re effectively using their immune response to help us. Is that how it works?

RR: Yes. Well, it’s a very low dose. Yeah.. But things like the odd thing with the redback is that it’ll affect just about anything, you know, forget how it came from toads right through to horses. It’s just the horse is a big animal and it doesn’t have such an effect. Well, they just turn the dose down for the Redbacks. For the for the sheep.

RB: Now there’s something else. And I still get asked this quite a bit. So let’s see if we can confirm or deny the myth when we’re talking about Venom. Daddy Long Legs venomous or not venomous.

RR: Well, most spiders are venomous. I find that there’s almost no doubt that all spiders are venomous. But the thing is, most of the venoms are not particularly harmful to us. And in many, many, many cases, spiders simply don’t bite. Now, if you if I had a funnel web on the table, just a little tap on the table and this thing would rear up into the attack position. It’s a crazy animal. And there was a couple of them like that. So that these things have A an interest in biting and B, the venom to do it. They don’t know that, you know, in many other cases with these guys, with the funnel webs, when they actually rear their front up their eyes on the top of the head. So they’re looking away from the source. See, what they’re doing is reacting to vibration attack. So that’s the thing about the that the daddy long legs. It’s one I think one of the great American presidents said that the truth is barely out of the barn before the rumour has got around the world. Yes. And I believe it was a Boy Scout leader in Cairns on one April Fool’s Day. Let the joke go. And he couldn’t bring it back. It was gone. So they when Europe gets locked down like this or they get into winter, they get totally bored and they have to do as much as they can in the labs. And so they’ve studied the animals that live around them to death. And one of the ones was Daddy Long Legs. They just they’ve actually they’ve actually frozen male and female daddy long legs and copulate to see how everything work so intensely studied. The venom came at totally boring. Nothing to it. To us at all. Totally harmless.

RB: Do they have sufficient fangs to actually they you know, pierce the skin?

RR: But the problem is that they have an unusual fang arrangement where they have a tooth up opposite the fang so it can actually open as wide as we would think. They think we have got instances of reports, of claims, of a bite from them. And there are some really big daddy long legs, certainly in the West. Not an Australian one, but. And I know. But again, the issue is, how did you get them to bite? I mean, you know, you have to really ram your finger in there.

RB: Look, I’ve picked them up lots of time and all they try and do is get away from you, which is understandable as half the legs of the first creature. So what is their prey? What do they go after?

RR: Well, they’ll take just about anything. I mean, they’re after a little crickets and ants and beetles and sorts of things. I mean, spiders include a group of animals which are amazing and they can take on something is basically hard boned as an ant and extract the goodness out of the little bits that are still in there. Suck the inside. They basically, vomit into the animal and then liquefy the contents and then suck that all back out. They have a beard in front of their mouth, bit like a bikie’s beard to take out the bigger particles because they can’t swallow bigger particles.

RB: So sort of a strategist strained the ant suit that they’ve just created.

RR: We don’t want any of those funny legs and sharp points going down. It’s a liquid stomach.

RB: But this is all fascinating stuff. Join us shortly as we get more about spiders from their web to some of the stranger sexual habits. Welcome back to Museum Revealed, a podcast, we are chatting to Dr Robert Raven and we are talking about spiders. His favourite subject, because he is the director of a arachnology here, which is sort of spiders and other eight legged creatures. I want to talk now a little bit about spider webs. There’s not a person out there, I imagine, that hasn’t walked through one at some point. And I’m guessing they’re there for the spider to catch their prey. Now, not all spiders make webs, is that correct?

RR: They all have the ability to make silk of some kind. And some of them don’t actually use the web to catch with. Some of them just use them as a space to live in. So trapdoor the funnel webs, often they most of the space that they live in is down under the ground, but they have thread lines coming out at the top which gives them some degree of sort of increases their sensory area where they detect foreign animals coming through. So but most of them have web web was the function that they they developed. It makes them spiders.

RB: Okay. Very interesting. Now, spider silk is not all the same either. It is. So people think of a typical spider web, for example, sitting up a tree, maybe the dewdrop sitting on it. There’s two different sorts of silk, maybe more. But I know I’ve been told that this is the answer to why spiders don’t get stuck in their own webs. Is that some of it stickier and some is not? Is that correct or is that an oversimplification?

RR: That is an oversimplification. I mean, the ones that build a circular web, what they do is that they have some web, which is some silk, which is structural, but not sticky. And then after they’ve built that structural thing and then they put the sticky spiral in after it.

RB: The guidelines, the ones that go into the trees, tend not to be as sticky. The jury’s still out on why they don’t stick to their own market. Why?

RR: What we do know is that if you put you on my web, then you get stuck. Even if it’s the same species. So it’s it might be a geography kind of thing. They know where the structures are and so on. But, yeah, there I mean, there are different kinds of silk. I mean, the ones that we see this bird spectacular are the silk that they used to wrap the egg sacs in. Some of them come up a mottel colour, you know, and should be all the same silk. But there are different kinds of silk that are feeding out for these sorts of things. So quite a few different kinds of silk. And one of the things that we’ve been hearing about a lot is that, you know, people have been trying to genetically engineer it. It’s a very difficult process because the thing is that when silk is extruded, it comes out as a liquid and it goes through a very, very, very, very tiny pore. Well the spinnerets are the big bits, there are tiny pore ons that. And when they pull on that liquid, it turns into a strand. It’s under pressure that the actually becomes silk. And there are many pieces to it. You know, it’s amazing to see some of the garden orbs. And you take one and hang her against a light. You’ll see this billow of silk coming out of her. So that they’re absolutely amazing with the amount that they produce in them that they can produce. So very interesting kind of thing. One of the things that they did discover not that long ago was that I always thought that when at the end of the day, when the spiders finished with well into the morning, into the night, when she’s finished with the web, she pulls it down and that’s process. She should get all the little insects and things that she wouldn’t deal with one by one. And, you know, she’ll get a bit of pollen as well. And that that was go it goes without saying. But the other thing which we didn’t know was that they were actually digesting the silk, but not actually doing anything to it. They radioactively tagged it and found that that silk was coming out. It’s been around in within 20 minutes. Well, wow. How does that work? And must be some amazing kind of shunt that’s taking this special molecule and passing it.

RB: So they are using it as a food source. They’re actually recycling.

RR: So once it’s made, it’s highly advantages to keep it, you know, going through that big energy cycle. It would save them an enormous amount of energy. Somehow they I don’t vouch for the science, but I believe it’s good.

RB: So there you. No, that that’s that’s incredible. Now, I guess we should probably mention and people might have already sort of guessed, but the reason that people are trying so hard to genetically engineer spider silk is not because they want to make massive spider webs, but it’s got some pretty incredible properties, I suppose. And that’s what we want to try and replicate.

RR: It makes fantastic dresses.

RB: I have I have seen a photo of one where it was made from golden orbs or Madagascan golden eggs or something like that, thousands of thousands.

RR: I think the big thing that they wanted to try and do is to make it as a replacement for fabrics like Kevlar are so strong but flexible. Yes. And one of the things that we heard about for a long time was that the military, U.S. military was involved in interested in trying to do this. And they got to some degree along the way. One of the things that most housewives have probably figured out already is a solution to this. And the word is solution. That’s when you get the red back spider building in those lovely little cane chairs, getting in is just about impossible to clean them out. So you just take a light bleach solution and spray it through. And the silk will disappear. Even the silk around the egg sac will dissolve and allow the ants to get in and spiders will dry up. So all you would need to if you had a beautiful spider silk vest to protect you, what you’d need is a cap of bleach and that would protect you.

And that would be it. Dissolved away. It’s no good. Sorry.

RB: I mean, I’ve seen a spider web, too. I’ve noticed what looks to me at least like multiple spiders. Sometimes the big maybe the golden orb sitting in the middle somewhere. But other spiders might be occupying what looks like the same webs. Does that happen?

RR: Sometimes they can be a number of things. I mean, she makes a fantastic big structure, strong. And what you’ll get in the situation is one of the things you get is that there’ll be little males around the system. But what people often misinterpret as males as little parasites, little silver dew drop spiders, which are a totally different family. In fact, closely related to redbacks. And these guys feed on the little bits of particles that she won’t take down. See the golden orb, doesn’t take a web down like a normal garden orb, they serve or once they leave them up there for day in, day out. But you also get other spiders using the superstructure of the web to build their webs against and sort of make a bigger colony. But the Golden Orbs. I saw a wonderful situation driving up to be number one stage. Just a whole corridor above the road was just solid golden orbs. They were just using each other to bolster the structures. And they can be very strong.

RB: Now, something I’ve often wondered and I don’t know whether people have thought it through themselves, but you see a spider web in a particularly interesting spot, perhaps strung between two trees or between two things, a long way apart. And you think that spider is really small. How does it manage to get the lines strung across there? So how do they go about doing that? Did they don’t, I imagine, throw it with a grappling hook across to the other trees? How do they get the web across such a big span?

RR: Diverting momentarily. One of them the only occasion which Darwin talked about spiders when the ship was 2000 miles from the nearest land and the entire rigging was covered with spider webs. They were ballooning. They were they were leading. They’re carrying themselves on this on the air. And this is a function of the same process when the little spiders sit there. They pull the thread out and it’s got a little sticky drop on the end, they pull it out until finally the wind lifts it and then the wind will carry it to a point. And the thing is that spiders got to find corridors where insects will go through. So it won’t be a tangle of trees. It’s got to be an opening up of the best places about head height usually. So the so that she puts the web out and it sticks. And I’ve seen situations out near Mt Isa And there’s no trees, but there’s a golden orb. And I thought, how did she do that looked. And it’s like 40 metres to the nearest tree.

RB: So they’ve just ballooned out the way that they put the web out until it’s finally got that. We just carried it and finally and then she sticks.

RR: And then that she reinforces that one makes a little triangle, which you’ve got like bell dropping to the ground and then that’s it, she’s away. Then she’s got the she sets the radials and does the circles and so on. So it’s an amazing engineer. Yeah. They they’re very capable of taking advantage of all available space, that’s for sure.

RB: Fascinating. Now let’s go, I guess, slightly sideways now into the world of spider reproduction, because there are some very strange and odd ways that spiders reproduce and some of them probably normally and regularly. But in the spider world, the female is normally bigger than them all. Is that correct or is that just some species normally heavier built?

RR: I guess she’s more sedentary, tends to be more functional. His process. Once he becomes he doesn’t become adult until the end of his life. So he’s got the last moult and then he goes looking for a female. Usually hunting by scent pheromones. And he can make a mistake, a serious mistake, a deadly one. You know, wrong. Wrong. Female. And you’re dead. So then he’s got to go through a process of encouraging her to understand that he’s not food. You know, that’s a tricky process with spiders because they really have a discriminating interest in eating all the time. And once he’s settled that, you know, big golden orb has a tiny little male and she or he almost wraps like a nuptial fail around her to try and reassure her that she’s like that to her and then goes in. But, you know, take the world. I mean, the scientific name for a red back is murderous widow. You know, she bites and kills the male and she actually bites him. He has to mate twice because he’s got to P.T. pulps that reproductive structure. It puts one in. He flips over and puts his body into her waiting catholicity the jaws. She chews on him and he goes away at the end of that one, narrows his body up a bit to facilitate, cleans himself up, come back and mates a second time. She actually kills him. And in most cases, actually eats him. So we had we had an ABC crew here some years ago. You know, they wanted to film it and they said nothing happened as it will. That said, there were five dead males hanging like trophies in the way at the end of the night.

RB: So so, in fact, the males that death is necessary for reproduction to occur?

RR: Not necessary, but he definitely gets into a very nasty situation. And with the funnel webs. The female goes into the what we call the attack position. Head up, things open and he goes in underneath. So he has different mechanisms, hooks on the legs and so forth, and crosses his hands over his head and then goes into to try and keep those fangs close while he goes deep underneath. And does the mating. I’ve actually seen you know, I was watching one in a vial until time wasn’t the final wave was a curtain web spider. And I got so excited or shook. That was it. She just went straight through and ate him, no second thoughts.

RB: So a precarious life. The adult male spider you said only sort of go through that right at the end.

RR: Yes, Generally. I mean, some of them managed to make more than once. The tarantulas, I think, do mate more than once. But it’s a precarious process, whatever happens.

RB: Well, it’s amazing stuff. We could we could talk forever. And I think, you know, we have to have you back sometime because if somebody spidery facts that we haven’t gone through. But thanks, Dr. Rob Raven, for joining us so much on the Museum Revealed podcast. I certainly learnt a whole lot more that I didn’t know before. Hopefully went out there, did as well. And if you’re just into learning even more than that. Well, follow the Queensland Museum on social media at @qldmuseum or head to our website at qm.qld.gov.au today and while you’re there, sign up for the e-news list to stay updated on absolutely everything. There will be show notes to go along with this as well. So you can find out a whole bunch of more information about the things that we’re actually talking about today. And until next time, of course, stay curious.