What are the symptoms and treatments for spider bites? Is our fear of spiders evolutionary or cultural? Can Arachnophobia be cured?
In this episode of AM Live, join our panel of experts featuring Sophie Li, Clinical Psychologist; Nicole Wright, Pharmacist and Specialist in Poisons Information; and Lachlan Manning, Naturalist and Live Exhibits Officer at the Australian Museum as they examined the dangers – real and imagined – which underpin our society’s persistent fear of spiders.
Tanya Goldberg: Good evening everyone, hello. Good evening and welcome to the Australian Museum. My name is Tanya Goldberg and I'm a creative producer here. I'm really glad to see you all here tonight and I commend you also making it, swimming here through the rain, well done. Before we go any further and on behalf of everyone present I would like to acknowledge and pay respect to the traditional owners of the land on which we meet tonight, the Gadigal people of the Eora Nation. It's upon their ancestral lands that the Australian Museum stands.
Tonight I'm really excited to offer you a night talk that explores the intriguing intersection between scientific knowledge and human psychology. We have a range of great programs that have accompanied our awesomeSpiders: Alive and Deadlyexhibition. Following tonight's talks, the next thing is an arachnophobia treatment workshop this Saturday morning for those who are seriously keen to change the way they feel about spiders. There are only two places left in that workshop, so if you do feel that you need some help in that area I encourage you to hop online as soon as you get home and book yourself in. And if you still really feel like you need it you can keep your eye out for a second workshop in May that will be running because it's proving so popular.
But tonight we are here to understand arachnophobia from a range of perspectives in an effort to eliminate what has been a persistent fear for humans over centuries. We have a fantastic panel for you featuring Australian Museum's live exhibits officer Lachlan Manning, and clinical psychologist Sophie Li.
But to start off, I'd like to introduce Nicole Wright who is deputy manager of the New South Wales Poisons Information Centre, a registered pharmacist and specialist in poisons information. Previously Nicole has been a medicines information pharmacist as well as working as a clinical educator in the faculty of pharmacy of Sydney University, as a mental health pharmacist at the RPA, and in community pharmacy practice.
Nicole's role as a specialist in poisons information involves teasing apart complex polypharmacy overdoses to inform toxicological diagnoses. Tonight she is going to discuss phobia and spider mythology within the context of recent literature and tell us about calls received by the New South Wales Poisons Information Centre, as well as clinical symptoms and first aid. So please welcome Nicole Wright.
Nicole Wright: Thank you Tanya and thank you everyone for coming along tonight. I hope that I have something interesting to share with you this evening. Basically what we were going to start off with was looking at some of the mythology surrounding spiders and how that relates to some of the calls that we take at the Poisons Information Centre, particularly relating to whitetail spider bites and whether they cause necrotic ulcers. And then we will progress and talk about funnel web spider symptoms and also the treatment and also redbacks, and then we will sum it all up.
Okay, so I thought this would be an interesting email to start with. This email did the rounds in New South Wales Health twice over the last eight years, and it reads, 'Watch out for this spider. This is a new known spider, so please take note. He's been found all over eastern Australia and heading to WA. Looks similar to a huntsman. The spider is in all states so watch out. Not a good look. Please take note of the spider, it's very dangerous. Please warn kids and send this to everyone you know to alert them as well. This spider is breeding at a rate of speed and is found in more and more houses. Please ensure the family takes a good look at this spider. Maybe some should not look at the photos of this person who got bitten on the thumb and the end result. Please take note of what the spider looks like.'
And this is apparently the progression of symptoms over a course of 10 days following this really nasty spider bite. What was interesting which followed this was the following; people have now attributed the same massive thumb injury as a brown recluse spider in three countries and in the US seven American states, a hobo spider in Canada, a solpugid spider in Iraq, an African spider bite from an infestation in Belgium where the bite victim has only 14 minutes to get to a hospital, and 88% of the victims will lose a limb. And in reality there is [no] proof that this thumb injury is even related to spider bite in the first place. So I thought we'd start with that.
In addition to that…that's not particularly clear for you guys, but basically to put things in perspective, this email highlights yet another myth or sensation which has done the rounds, and it also points out…and the comment is from one of our clinical toxicologists at the Poisons Information Centre, that: 'You have more chance of dying in a car accident than you do of dying of a spider bite. So if you're worried about this email and you believe the contents of it, hand in your licence, pull over your car and don't get back on the road.'
So some people have decided that they're going to make a little bit of a career out of spider bites. This gentleman, Rod Crawford, works in the United States and he has an entire website dedicated to myths associated with spider bites. And one of those is that doctors can ID spider bites from symptoms, which we all know is not true.
So I thought I'd talk a little bit about spider phobia and spider mythology. Spiders have been a source of intrigue and fear for a very long time, and I think our clinical psychologist is probably going to talk about that in a little bit more detail. In one of the studies I read, the fear of spiders is common. In a study of 261 people, 32% of women and 18% of men reported that spiders made them feel anxious, nervous or very frightened.
And in the context of this, many myths have developed about spiders, the effects of their bites and also their toxins. Some of these myths include that daddy longlegs are the most venomous spider, or the Tarantism Dance which evolved in Europe. So there are several theories as to why spiders have such an influence on individuals and also on society. And one of the models that helps to explain the fear of spiders, which also explains the high prevalence of spider mythology, is the association of spider phobia with disgust sensitivity.
So putting aside our emotion and our dislike of these creatures and basing our judgement on a rational assessment of the risk that spider bite poses, is this fear or concern really rational?
So some of you may have attended the exhibition earlier and there was a video to the side that talked about whitetail spiders in Australia and the potential for them to cause necrotic ulcers. And the belief or the fear and uncertainty about chronic necrotic ulcers has focused on attention of spider bites as a putative cause because these are really difficult to diagnose, necrotic ulcers, and spider bite was something that practitioners could pin as a cause for the symptoms.
The current myth is that many types of spiders, particularly the whitetail spider in Australia, are responsible for necrotic ulcers. The diagnosis of spider bite is based mainly on suspicion and also on fear of spiders, the diagnosis of a chronic ulcer is really only based on stories of suspected spider bites causing devastating necrotic fasciitis. So let's delve into this in a little bit more detail. It was first assumed that whitetail spiders were associated with necrotic arachnidism in 1982 in Australia.
However, no patients who developed necrotic ulcers were actually seen to be bitten by the spider. As whitetail spiders are ubiquitous and found in almost every home in Australia, it's not surprising that they were found in the environment within a couple of days of the spider bite.
In 1987 there was a case report of probable necrotic arachnidism in a patient who developed severe skin necrosis and also systemic effects, which means whole-body poisoning. Again, no spider was seen and the diagnosis was one of exclusion. They try to identify the chronic lesion as a cancer or a diabetic ulcer, but when they were unable to and it became too difficult, they decided that spider bite was, of course, the most logical situation.
Despite further cases of whitetail spider bites being published in Australia, again, none of these have been linked with a definite spider bite where the spider has actually been seen or captured at the time of the bite and then expertly identified by an arachnologist. However, on the flip side there have been eight definite whitetail spider bites causing only mild effects, and a large number of definite whitetail spider bites with no major effect being noted.
So we have a widespread modern plague of necrotic arachnidism and we'll believe in Australia that necrotic ulcers are due to whitetail spider bites, yet the evidence that we have doesn't really seem to support this. In addition there have been no prior reports in the last 200 years leading up to the 1980s when this sensation took off, but the myth continued to strengthen, and it has become ingrained in our society that whitetail spider bites are clearly associated with necrotic ulcers. And this is reflected in the calls that we take at the Poison Centre every year which range from anywhere between 600 calls a year to 1,000 calls a year from panicked people who are very concerned about the fact they've been bitten by a whitetail spider.
So we are setting out to I guess dispel that myth and educate the public a little bit more.
Necrotic arachnidism, or more commonly in Australia the whitetail spider bite, has become an entrenched diagnosis, despite the lack of evidence that spider bites actually cause necrosis or ulcers in Australia. There are similar species of spiders overseas which have been shown to cause necrotic effects, but again, when they delved down into the literature and the evidence behind it they found that most likely these were being misdiagnosed as spider bites when they also had an alternate cause or diagnosis.
So a gentleman called Geoff Isbister who is one of our clinical toxicologists at the Poison Centre set out to conduct a study of 130 definite bites by whitetail spiders because he believed that the only way to prove this was to study people who had been bitten by a whitetail, saw the whitetail, have it identified by an arachnologist, and then look at whether those people developed a nasty lesion or not. And two, look at the people who were presenting with a nasty ulcer and seeing whether there was a history of a spider bite or not and whether an alternative diagnosis could be made for those symptoms.
And what he found was that bites by the whitetail spider caused only mild effects in most cases, with sometimes persistent painful red lesions, but that they were very unlikely to cause necrotic ulcers, and none of the patients in this study, so that's 131, actually developed necrosis from a whitetail spider bite.
For the patients who did present with necrotic ulcers, the clinicians who were looking after the patients actually investigated for alternate causes, and in the majority of cases did find that the spider bite [ulcer] was caused by a diabetic ulcer or an inflammatory condition or an infective cause such as MRSA.
So I guess this study was the first one which really showed in Australia that whitetail spiders are not associated with necrosis.
So current evidence suggests that spider bites in Australia are very unlikely to cause necrotic lesions, and if I'd like anything it's for you to go home and share with your family and friends tonight who think that they've been bitten by a whitetail or someone else was bitten by a whitetail 20 years, 40 years ago, 60 years ago, that it is very unlikely, unless the spider was seen, that has caused those symptoms.
What became problematic was that the doctors actually believed in this myth as well, and so when doctors were seeing patients with an ulcerating lesion, they weren't investigating the patients thoroughly to see what was going on. And as a consequence of that, a lot of these patients developed cancers or other conditions which went untreated for a long period of time. But I think that has probably contributed to the number of people out there who know somebody who has been bitten by a whitetail spider and developed a necrotic lesion.
Okay, and maybe all this hype is because nobody cares about spider bites that do nothing. We only want to hear about spider bites that do something or that are nasty, and that will never make for good news if they do nothing.
So when we look at the science, most spider bites do not pose any sort of a medical risk, and even spiders that do cause clinically significant human envenomation cause very little mortality and/or severe morbidity. But spider bites are common and we take hundreds of calls at the Poisons Information Centre every year relating to spider bites and trying to put worried callers' minds at ease. So what I've shown you there is just some data that we collected, the phone calls have been taken by the New South Wales Poison Centre, which takes calls for New South Wales, Tasmania and the ACT, and that was over a ten-year span. But you can see that we are taking roughly 600 redback spider bite calls a year, in addition to about 50 funnel web spider bites.
So, moderate to severe envenoming resulted almost exclusively when it has occurred in Australia from redback spiders and rarely from funnel web spiders. In Australia the only spiders that have definitely caused death are the redback spider with 13 cases, and the Sydney funnel web spider, also with 13 cases. Deaths associated with the redback spiders, when the clinicians delved a little bit deeper, are not actually an effect of the primary venom, and a lot of the cases were patients who suffered from other medical conditions that could have increased their risk or somehow played into the systemic effects and the symptoms that the patients developed. We haven't had any deaths from redback spider since the advent of antivenom in 1956.
Funnel web spiders are obviously much more dangerous, and we did have lots of people die up to the 1970s. But again, since the advent of funnel web spider antivenom in 1981, there has not been anyone who has died from funnel web spider bite in Australia. So this is good news. Maybe that fear of spiders is irrational after all.
So when we talk about the treatment of Australian spider bites, we usually consider spider bites in three medically relevant groups. The first is big black spiders, and we treat any larger black-looking spider as if it could be a funnel web because mouse spiders and trapdoor spiders are often quite difficult to identify from funnel web spiders, particularly to a panicked person who has just been bitten and to the untrained eye.
Redback spiders do not cause a rapidly developing or life-threatening effects, but many do cause substantial pain and they can cause a range of other whole-body effects, which I'll talk about in a moment.
And then any other spider is basically lumped into the 'all other Australian spiders' category, and they cause minor effects and the patient can be reassured. That's not to say that they won't cause pain or a puncture mark or a little bit of bleeding, particularly for a large spider, but the management just focuses on an ice pack and some Panadol or Nurofen, there's nothing to worry about. So we spend a lot of our time reassuring people about this.
So funnel web spiders are the most dangerous spiders in Australia. They can cause severe life-threatening envenomation, but this is rare. And there's usually only 5 to 10 cases a year of patients who require antivenom. So it's not as common as you might think for a spider which we take so many calls about. I think when I looked at the data we take about 50 calls a year, and of those we have 5 to 10 requiring antivenom, so roughly 10% to 20%.
Severe envenoming from funnel web spiders has ranged from southern New South Wales to Southern Queensland, and involved six species, including the Sydney funnel web, the southern tree funnel web and the northern tree funnel web. Funnel web bites cause significant local pain. They tend to latch on when they bite you, and you really have to do progressively shake the spider off. Quite often patients will have bleeding, they'll have two definite puncture marks, and they do become unwell very quickly if they are going to.
In some cases patients can be mildly envenomed. So I had a patient the other day who felt quite nauseated, she was complaining of some palpitations, but none of the significant effects that we would give antivenom for.
So patients with a funnel web spider bite, even in the absence of symptoms, we will observe in hospital for four hours and we will also observe patients who have been bitten by a big black spider, for the reason I discussed before, they are very difficult to identify from funnel web spiders.
So, a painful bite by a big black spider with abrupt onset of sweating, agitation, piloerection (which means goose bumps), coma and fasciculation. Fasciculation is unusual muscle twitching, and quite often this affects the tongue. And I probably should have included a video, but patients' tongues just undergo these really crazy muscle spasms and it's really interesting to see.
So basically in a patient who is severely envenomed we would expect that all their glands that produce secretions will turn on, they will become sweaty, they'll start to salivate, they'll start to cry in some cases. They will develop piloerection, so goose bumps, hypertension which is high blood pressure, their heart rate can go up and down.
The first thing that people usually report is that they've got like a numbness and a tingling around the outside of their mouth, and then the tongue starts doing unusual flicky things, and that's almost a tell-tale sign that someone has been bitten or envenomed by a funnel web.
Sometimes at the bite site the local muscles in the area will also be doing the funny twitching. The main concern is that it causes shortness of breath and difficulty breathing, and the fluid moves from the body into the lungs and that can obviously be fatal in some cases. But antivenom works really effectively to reverse that. Sometimes we do need to use additional treatments in combination with it but we have a good antidote that works quite well.
So in terms of first aid for funnel web spiders, it's the same as for a snakebite. So basically funnel web spiders will bite you and you are likely to develop symptoms within 20 minutes but generally within an hour, and always within four hours. So you get pretty sick, pretty quick. So in terms of applying a pressure bandage, the most important thing to remember is to stay still, and the reason for that is the venom from a funnel web spider or a snakebite moves through the lymphatic system, and you want to prevent the venom from moving through the lymphatics and getting into the circulation or the bloodstream.
And there are two techniques that we use to do that, and this technique was actually discovered by an Australian guy. I don't know how much it is used in other parts of the world, but certainly it's written about quite a lot. And with the correct application of a pressure bandage, even in the absence of getting a patient to hospital or to help, they are able to sit under a tree for possibly one or two days and they will be okay, whereas as soon as if you get up and run to the house, the venom spreads, you can become very sick very quickly.
So the two main components are a compression bandage, so a nice tight bandage starting over the bite site and wrapping all the way up the arm, the same kind of tightness that you would use for a sprained ankle or a sprained wrist. And that prevents the lymphatics from spreading the venom. And then a splint, so whatever you can find, a piece of wood, anything that's firm, a tree branch, and then you would bandage a second time and that prevents the muscles around the arm from moving and pushing on the lymphatics. And with an appropriately applied pressure bandage, as I said, your outcome is quite good and you can sit there for a long time while you're waiting for help to arrive. You should call 000 before you start to apply the pressure bandage, but the most important thing is to stay still, not move around, and await transport to hospital.
So the pressure bandage stays on until patients get to hospital, and we don't stock funnel web spider antivenom in every hospital in Australia. We do have a register which shows which hospitals stock funnel web spider antivenom. Obviously it's only along the east coast because funnel webs aren't found in Western Australia, and also you need the patient to be in an area where if they do deteriorate quickly once the pressure bandage comes off, the clinicians are able to intervene and to treat any symptoms which develop, and give the antivenom.
And antivenom being made from equine products, so horses and things like that, can cause an allergic reaction, so that's not uncommon and you need to have the facilities and the drugs to be able to resuscitate someone should that happen.
So we would usually observe for 2 to 4 hours in a patient after the bandage had been taken down and if they are well they can go home at that stage. If the patient does require antivenom usually you're looking at 12 to 24 hours in hospital, and that would be to treat some of the other effects, like a little bit of fluid in the lungs as well with additional medications and drugs.
This is really good. When I dug up some of the funnel web spider case reports from the 1970s which showed that patients were in hospital for 13 to 26 days on average, so we've cut that right back to 1 to 2 days in patients who are envenomed, which is quite good.
The dose is two vials, the vials are $1,200 each, so not cheap, but we have a great healthcare system that covers those, so that's good. And generally patients don't require more than two vials. However, I'm sure some of you have heard about the case report in the literature or on the news a couple of weeks ago about the little boy who had 12 to 14 vials of the funnel web spider antivenom. So it does happen from time to time. You can just imagine the costs that those sort of things are associated with.
So I'll move on to redbacks. These are the most common cause of significant envenoming in Australia, with 5,000 to 10,000 case reports per year. Clinical features are distressing. Redback spiders hurt. They don't hurt when they bite, but quite often you develop significant pain, burning in your feet, sweating, over a period of one to two days following the bite.
So it's a slow-moving venom. It's not particularly large, and it does take a number of days for the effects to really climax. Severe and persistent pain occurs in the half to two-thirds of patients, although the bite itself might not be felt, as I just discussed. It's quite often likened to a pinprick. Progression to systemic or whole-body symptoms occurs in about one-fifth of patients and the effects develop over hours. The most severe effects usually dissipate or start to dissipate within 72 hours, but some patients do have really residual pain or symptoms lasting for up to a week.
And if a redback spider bite was left untreated, then usually the symptoms and signs will decrease over several days but up to a week, and that's what we tend to see because a lot of the pain relief that we have is not really adequate in treating patients' level of pain, to none. So basically it will reduce their pain level or their pain score but is not going to eliminate the pain.
So redback spider bites are characterised by a triad of local pain, sweating and piloerection. And piloerection is just the word for goosebumps. And usually that happens over the bite site within about an hour of being bitten, but sometimes it can take a little bit longer. And then the pain will start to spread up the arm or up the leg to the lymph nodes in the armpit or the groin, and that will radiate to the abdomen. So patients will have abdominal pain, back pain, headache. Quite often they will feel nauseous and have some vomiting.
It also causes really unusual sweating patterns. So it's almost tell-tale sign that if a patient presents and they are sweaty below the knees and they are not sweaty anywhere else, regardless of where they've been bitten, on the back, on the shoulder, on the arm, they are sweaty below the knees and they will have a burning type pain in their feet. And it's thought that the redback then actually has a higher affinity for the different types of sweat gland receptors that I found in the lower leg. Which is quite interesting.
Less commonly they are associated with a wheel or fanned marks, those sorts of symptoms. So they are incredibly uncomfortable, and the bites of widow spiders or redback spiders cause this spectrum of effects which are known as latrodectism, which essentially refers to radiating pain, sweating, and then little bit of nausea, vomiting, headache, the non-specific things I spoke about before.
Interestingly in children they quite often develop erection, and that doesn't seem to happen in adults, so I don't know whether it's at the end of the spectrum, but young children will quite often be inconsolable, crying, they'll have the sweatiness below the legs and they'll have an erection, which I'll find is very interesting. I can't account for why that happens.
So in terms of redback spider treatment, first aid just focuses on application of an ice pack for symptomatic relief. You shouldn't use a pressure bandage because that concentrates the venom at the site and it causes a substantial amount of pain for the patient. So ice pack and then standard pain relief. If someone rings up with a redback spider bite we don't actually send them to hospital anymore, we let them know that symptoms might worsen over 12 to 24 hours, and to treat the pain with some paracetamol and some Nurofen and an ice pack. And only if the pain is unable to be managed at home or if they are sweating profusely would we send them into hospital for antivenom. And I'll go into that in a moment. Which is quite different to the approach that we had years ago because we did send all patients to a hospital 10 years ago.
So we've discovered a lot about redback spider antivenom and whether it's useful for treating the symptoms caused by redback spider bite. And there's controversy surrounding the route of administration, who do we treat, or whether we even treat at all.
So for years we were using intramuscular antivenom, but we've now done a study which shows that intravenous antivenom is much more effective, so into the vein. So that approach has kind of gone out the window. The dose, again, is two vials administered by slow infusion over 20 minutes. And unlike funnel webs where sometimes additional doses are necessary, it is not necessary for redbacks.
There is some controversy over whether you can use antivenom in a delayed fashion, so at 48 hours, but it does tend to work for some patients. And I had a lady who became incredibly sweaty following a redback spider bite and she was in hospital for a couple of days and she actually needed 4 litres of fluid to replace what she was losing through sweating. So she was a candidate for antivenom.
Redback spider bite antivenom is generally recommended for severe local or radiating pain, or patients who don't respond appropriately to pain relief, or for those, like I mentioned, who have excessive sweating or other symptoms like that.
So we did another study, again Geoff Isbister, he's published a lot, he is very well known in the toxicology world. He performed a randomised controlled trial of 224 patients looking at patients who received antivenom and patients who received standard analgesia. The people who got the antivenom also got standard pain relief. And what they found was the patients who received antivenom didn't actually fare any better on the pain score or the reduction of sweating or the reduction of blood pressure than patients who just got the standard pain relief. So we are starting to see a shift or a trend away from antivenom, and part of that is related to the fact that antivenom, as I mentioned before, can cause allergic reactions. That happens in 4% to 5% of patients. So when we were using a lot of the antivenom it was affecting a substantial proportion of people. But also the results of this study show that for the most part pain relief is as effective as giving people antivenom plus pain relief.
So I guess I just wanted to leave you with the fact that most spiders do not pose any sort of medical risk, as we've discussed. For the funnel web spider, which is a problem, we have an effective antivenom and appropriate first aid. So no one has died since 1980 from funnel web spider bite.
Redback spider bites are not life threatening. Whitetail spiders do not cause necrotic ulcers. So maybe we do have a little bit of an irrational fear of spiders. And I just couldn't help myself with this. You think your fear of spiders is completely irrational, then a friend tells you about her fear of chickens. And I wanted to leave you with that. Thanks guys.
Tanya Goldberg: I'd like to introduce Lachlan Manning. Lachlan is a naturalist and a self-described arthropod obsessive who you may have seen earlier in the exhibition milking spiders for venom extraction. As a live exhibits officer here at the Australian Museum, its Lachlan's duty to ensure the care and welfare of live animals exhibited here is at its absolute best. For our Spiders: Alive and Deadlyexhibition that routine involves feeding spiders, cleaning up after them, setting up enclosures that meet their needs, collecting venom samples and sharing his fascination with them with others and all of you. Tonight Lachlan will explore our topic from the perspective of arachnology.
Lachlan Manning: So as you've seen I'm here to answer the question; should we fear spiders? No. Well, thanks for being…no, all right. Okay, let's go back in time a little bit to 360 million years ago where the first spider arrived.
So our first spider, we have the segmented spider. A little bit after that we have funnel webs, then orb weavers. We then go into trapdoors. And about this time we've reached so far 6- to maybe 8 million years ago the first ape men I guess, the proto-humans have started arriving, so have the huntsman, the jumping spiders, the crab spiders, all the hunting spiders. Then lastly we have the comb footed spiders. So basically we have coevolved, we have…our evolutionary history has been with spiders. We have been with spiders our entire history.
So does this mean potentially that we have evolved to be afraid of spiders? Say, a Homo Neanderthal has experienced a spider bite and has been envenomed, it was a rather tragic experience for him, he shared it with all his other friends in his mammoth skin tepee and he was, like, look, avoid these spiders, they're dangerous and they're going to hurt me. And they've passed it on to their children and their children until it becomes a genetically inbuilt fear of spiders or some sort of survival technique going, 'Yep, avoid spiders.' I don't think genes actually work that way. However, we have seen captive bred monkeys being exposed to rubber snakes. These captive bred monkeys have never seen a snake, they have had no reason to fear a snake, the yet they've seen a rubber snake presented to them by the keeper and they have screamed, they have gone ape.
So we have Joshua New and Tamsin German who have looked into this potential theory and exposed a random group of students to these images we see here. If you want to go into more detail, simply look up that title in Google Scholar. But he exposed these students in an indirect attention, so he had them focus elsewhere while he threw these spiders…threw these images in the corner of their eye.
But people actually recognised a lot of these images to be spiders, even the ones that look like flowers we have across there which people recognised to be a spider. We have something that looks sort of like a hypodermic needle. A lot of them ignored that. Remember, this is happening in the corner of their eye, this is in direct attention, and a lot of them went, yes, I saw a few spiders. Now, these weren't arachnophobes, they were just a random group of students. So maybe, just maybe we have evolved a survival technique to avoid these potentially dangerous spiders so we can get on with life.
However, we have five out of 40,000 species of spider in the world that are potentially dangerous, even potentially. So this is literally a handful of species. Is it really a survival technique that we see a spider that's probably not going to do us any harm and just sit still, maybe weep in the corner. I don't mean to belittle your fear if you do have that, but is it really a survival technique?
Well, let's look further into our cultural history perhaps. So we have spiders depicted in many major civilisations and minor civilisations, spiders are everywhere, except for the polar cap. So it makes sense that some cultures depict them in their artworks, in their stories, in their fables. We have some artwork depicted here. I really like the ancient Chinese…well, it's actually a modern one but it is representing an ancient Chinese pendant which pictures a ximu, I think that's pronounced…so that is actually seen as a symbol of luck, or the name ximuactually means the 'happy insect'. Other cultures depict them as deities, as totems. Others go a more negative connotation. The Greek goddess Athena was challenged by this woman named Arachne.
Arachne was just a mortal woman who weaved, and she thought she spun tapestries and silks a lot better than the goddess Athena and she challenged her to a weaving duel basically. She was punished, Arachne, for being so boastful, and transformed into a spider.
We have other cultures depicting spiders as tricksters. I can't remember which culture it was but one depicted a spider as a guardian of the passageway to the underworld, which sort of reminds me of Tolkien's Shelob in The Lord of the Rings, guarding the tunnels into Mordor. If you haven't seen that, Mordor is sort of an allegory to hell. So we have some positive and negative connotations in culture. However, none of them actually represented them as fearful, or at least nothing I could find. There was definitely a respect for them sort of as a deity or the way you would respect your mum, but no fear.
Then we come to today where the fear of spiders somehow has become one of the most common fears. We have good cultural representations of spiders, we have Spiderman, Charlotte's Web, Charlotte helped the pig, that was great, Charlotte was a spider, by the way. But then we have really, really terrible connotations. That is a scary image, I will pass on from that.
But really are spiders that scary? Let's compare them to a bus. So buses are great for the environment, they transport people around from A to B. Spiders are great for the environment, they remove pests such as cockroaches, slaters, crickets, other things that could affect our crops or our homes. Buses, they have the potential to kill humans. Some spiders I guess, yes, they do have the potential. Children need to be educated to stay off the road, stay away from buses, wait until they've come to a stop. Children need to be educated about spiders as well. You know, they're great, feel free to observe them but don't touch them. We need to learn proper first aid to deal with someone that has been hit by a bus. We need to learn proper first aid to deal with someone who has been bitten by a spider.
Despite all these similarities, people seem to connotate spiders with the word 'danger'. Our language today seems to put everything into danger or unsafe, and we have dangerous spiders, but we have buses which…no one says dangerous buses, it just doesn't happen. So why doesn't it happen for spiders?
Well, we have taken all these cultural links of them maybe being tricksters, maybe there's a little bit of a survival technique developed from a proto-human stage in our evolutionary history. We have pop culture referring to spiders as really bad, evil things, but they are really not that great, and we have somehow developed all these myths around spiders.
You Nicole actually mentioned something about the daddy longlegs. There's a myth about the daddy longlegs. We are getting into the fun part now, busting some myths. I love that show. So, daddy longlegs, there's a myth that daddy longlegs is the most venomous spider in the world, yet its fangs are too short or too weak to penetrate human skin. Right, busted on two levels right there. So the venom has been looked into. It has been tested on mice. There seems to be no or little effect from the venom. It probably started when people saw daddy longlegs catching redbacks, a really dangerous spider whose toxin is quite toxic, and snakes, again, very toxic, and they thought, well, an animal that can kill these toxic animals must be even more toxic. Not the case at all, they're tricky web…their web is just so sticky, so complex, a lot of things get tangled up in it, as well as the daddy longlegs' long legs, they throw silk over their prey, or anything that becomes entangled in their web. So that's how they catch their prey. It's nothing to do with venom.
And their fangs (here's the second level), they can actually penetrate our skin. Adam Savage, if you like the Mythbustersshow, aggravated a colony of daddy longlegs spiders and claims that he actually did get bitten but it was nothing but a fleeting nip.
Next myth, myth number two. Wherever you go in Australia there is a redback in your toilet seat. Yes, there is a song, and there is actually several cases of redback spiders biting people in some private areas, which is not so fun but it does happen, and thanks to great medical care it has all been solved. But nonetheless they are not in every toilet seat. If you go out to the back of the bush there is a long-drop non-flushing type dunny arrangement…yeah, check it, but a lot of the cases toilet bowls are smooth, they are flushing, it's too wet, it's too slippery, redback spiders can't get a grip on such a small surface, their legs have too large tarsal claws or tow hooks I like to call them, they can't grip on a smooth surface, and it's just too damp. Redback spiders like a really dry environment. So that myth is well and truly busted. I really wanted the Mythbusters'Myth Busted!' thing but apparently it was copyrighted.
So funnel web spiders, I've heard funnel web spiders can jump, they can run up walls. Busted right there. So funnel web spiders, they are a really primitive spider. As I said, they were one of the second families to evolve in evolutionary history. They are burrowers, they are pretty much limited to the ground. Some funnel webs managed to burrow into tree trunks but that's all they can do. They managed to climb up tree trunks using these tarsal hooks I referred to before which can cling into the rough bark and climb up that.
However, they are pretty weak, they can't cling onto plaster or tiles or any other smooth surface, they just can't grip it, so there's no way they can do that. As for jumping, their legs don't work like that, they are spread out, they are not underneath the spider, they can't really push blood into them fast enough to launch the spider into the air, they are too heavy, it doesn't work. So, well and truly out.
Thanks to Nicole for this one because whitetail spider bites can cause flesh rotting wounds. As you said, Isbister and Gray knocked this one straight out of the park, so let's not spend any more time on that.
This is a weird one. So I've heard people saying they've heard of stories of people being bitten and then the spider has laid eggs under the skin. What? No. Just no. They don't work like that. So the mouth and the egg laying area of the spider, the genital opening are two completely different ends. Even if the spider were to make a nip then turn around, they don't have a little straw-like tube which some crickets and some flies do. There's is called an ovipositor, it's like a soft hypodermic needle these crickets have to lay eggs. This is usually used to lay eggs in sand. Spiders don't have this at all, they just have a genital opening used to release their eggs into usually a silk sac, and they wrap that silk sac up and they sit there and guard that. Eggs under skin would just be too warm, too moist, too easily squashed. All it takes is a pat. They definitely don't want to do that.
There are some insects that do something similar, they take the other flies or other crickets or other spiders even and this fly will inject eggs into this fly or cricket or spider and the egg will hatch inside and eat the animal inside out. I have not heard of this being done on people though, and definitely not by spiders. So, busted.
Spiders are unpredictable. I actually have a diagram and a robot there predicting walking movements of spiders. Well, technically the first diagram there is a scorpion but it's still an arachnid, it's all very similar. It's right leg, left leg, right leg, left leg, rather much like us, just times four. So, totally predictable. In fact, as Tanya said, I am the live exhibits officer, my job here is to care for spiders. This involves catching spiders up, examining their medical condition, and setting up environments suitable for them. So basically it's my job to predict what spiders do, and I can show you what a spider will do.
So, Harry, is your name? Yeah. So I'm going to pretend to be a spider. Do you want to pretend to be a bushwalker for me? And when I say go, you will walk up to me. So this is our bush, this is my tree, I'm a huntsman spider. You're going to walk past me and I'll show you how I predict what this huntsman, me, will do. So ready? You're a bushwalker, what are you going to do? Walk, yeah, cool. Let's go.
Yep, cool. So I did nothing. So if you were casually walking past a spider, most spiders are just going to sit there, they're going to rely on their camouflage, their ability to blend in with their environment, to stay still. A lot of spiders aren't particularly fast. They don't produce a lot of then, so their best favour is to stand still. But what if you went a little further and you tried to catch me. Do you want try to catch me this time? All right, let's go.
Run!! Okay, so I admit there's a little unpredictability. I can't tell which way the spider is going to run but it will run. It's not going to turn and bite. It's in its best interest to get out of this dangerous situation. He is 10 times the size of me, I'm not going to deal with that. So are spiders unpredictable? No, they're totally predictable. Next.
Last myth. So the female spider eats its male after mating. So this one is kind of true. So some spiders do this, the redbacks in particular. Once finished the little male will get eaten by the larger female. But only some spiders. A lot of spiders are the same size and the male is slightly smaller. This is just too much of a challenge for the female to try to eat him. The female is only going to be interested in maybe eating the spider if the male spider is just too much of a nuisance, it's not leaving home, it's not doing the chores around the place and it's just being a real pain, he has overstayed his time or he's just not really a compatible mate and he's just continually trying. Usually the male just runs straight out of there as soon as he knows business is not going ahead, but only if he doesn't do that will he get bitten. But that's only that.
Now, we've just seen seven myths and misconceptions. I want to replace these with alternative facts, and we will be quick-fire with these. And when I say alternative facts I don't mean alternative facts, I mean the true kind. So, first, spiders can touch, they can hear, they can smell, they can even taste with specialised hairs and pits in their legs. That's like me shaking a leg and going, oh, it tastes great, feels great, let's go. And there's a fabulous diagram that shows all the different organelles in a spider's leg. They are really super spiders.
Next one, okay, so spiders can survive under water up to hours, some of them even prefer to live in the water. So we have the water spider or the fishing spider or raft spider who does a really great impression of the Christian Lord and Saviour and walks out onto water and he can walk on it, swim on it no problem. He can even dive in it if he wanted to using waterproof hairs, trapping a bubble of oxygen underneath him or even right around him to put all the water away and keep him safe.
A lot of other spiders, even if they aren't specialised for swimming, say the funnel web, can live under water for a little bit. They won't thrive but unless they were left there until the oxygen is depleted you see the hairs around them aren't as specialised as a water spider but still have a tight hydrophobic water repelling property, so they can live under water for a few hours.
All right. Spiders have a built-in suit, so this is probably like something that everyone knows rather than a skeleton. Spiders have an exoskeleton, they have a hard cuticle skin that protects all their organs inside, but what you might not know is that they even have inbuilt night goggles. So they've got a suit of armour and night-vision goggles, some of them. So the net casting spider actually has an F-number. So the F-number is a camera word for saying how much light we can pick up in an aperture. So the net casting spider can have an F-number of 0.59…no, not impressed? Fine. They can see better than a cat, dog, a camera or us. Even an owl. They can see better at night than any of them.
A lot of spiders are caring mothers, so a lot of spiders protect their eggs in an egg sac, as I mentioned, all of these spiders will make sure this egg sac is the right temperature, the right humidity. They will even stand there guarding this egg sac, making sure none of these parasitic flies are laying their eggs in it, making sure nothing takes off and eats it, making sure it is constantly the right temperature, the right humidity. To even go about guarding this egg sac properly they will not eat, they will starve themselves, they will reject any food, just because they are focusing on this egg sac. This could be anywhere from a month to 9 months in some species. Imagine not eating your entire pregnancy. Yes, they do often leave the egg sac after they've hatched and the young go off on their own, but they've just gone without food for nine months. You wouldn't be blamed for doing that either.
So spider silk could be used for fashion and pharmaceuticals. So here we have a lovely cake, I think it's on display in a museum in France. This is made entirely of silk of the Madagascan orb weaving spider. So that golden sheen is all given off by the silk. We have other…I've seen tapestries and a few shawls made from a similar silk. We also have the silk of the golden orb weaving spider being used to reconnect severed nerves or severed tendons. You see, they connect the nerve to the broken ends of the nerves and the tendons. The regrowing tissue seem to grow along the silk and reconnect, and then the silk eventually deteriorates since it is mostly water anyway. So far they haven't found a great synthetic material that does the same property. So we are really relying on spiders to help us with this one.
A few more, so last one, I think second last one. Yes, second last one.
So spider venom is being used in agriculture and in pharmaceuticals. So if you missed my presentation earlier, I extracted venom from a spider, this venom will go on to the University of Queensland. They're using it to look into ways of reproducing this as a painkiller medicine mostly, as it's a really great neurotoxin that travels along the nerves. Let's make these painkillers travel along those nerves as great as these do. And they are also using them as pesticides because spiders are really great at catching insects.
Last one. Now, if we have any arachnophobes, I will put a spider up on the screen in one moment. They can dance. This is a male peacock spider, and to lure his female he will actually do a great dance involving the waving of the hands and fanning of his abdomen, much like a peacock spider saying, 'Hey baby, look at me, I'm great, you're my ragtime gal, c'mon.'
Now, if you are an arachnophobe, I just have one reference besides the paper I mentioned before, Learning to Love Spidersby Lynne Kelly. Lynne Kelly was actually a woman who was terrified of spiders and as she grew up she only became more terrified. She ended up wanting to conquer this fear and just gave spiders around her place names and characters and personalities. And she will come up and see a black house spider in the corner of the window and say, 'Oh hello Tabitha, how are you doing?' And she eventually got over it using similar techniques like that. However, I'll leave that to Sophie to really get into that.
And lastly just thank you for being here, thank you to Jürgen Otto who was taking the photo of that fabulous spider, as well as many other peacock spiders. Thanks to Joshua New for supplying me with this paper, and thank you to Helen Smith who was actually going to be your presenter tonight until she unfortunately injured herself, so you got stuck with me. So thanks for doing it with me, and have a great night.
Tanya Goldberg: Finally please welcome Dr Sophie Li, clinical psychologist and postdoctoral research at the University of New South Wales. Sophie has completed both her PhD in behavioural neuroscience and masters in clinical psychology at UNSW, and her current research in the translational neuroscience lab at UNSW aims to determine the neural, behavioural and cognitive mechanisms that underlie anxiety disorders in order to improve treatments for them. She specialises in the treatment of anxiety disorders, and has extensive experience in delivering exposure based treatments to people with arachnophobia. You can of course experience more of Sophie's expertise during our arachnophobia treatment workshops. But tonight, to discuss the psychological dimensions of arachnophobia, please welcome Dr Sophie Li.
Sophie Li: Thanks. So I'll be talking about the psychology of phobias and whether or not they can help us understand why so many people do fear spiders and whether or not we should fear spiders. So, first just to talk a little bit about phobias and what phobias are. So arachnophobia or, as it is often referred to, spider phobia, is classified as a specific phobia. What a specific phobia is is an excessive and persistent fear of an object or a situation that results in avoidance or the individual will remain in the situation but experience quite marked distress and anxiety. And that distress and anxiety or even that avoidance results in a significant disruption in their day-to-day living. It is the most prevalent anxiety disorder, with a prevalence of around 12%. So, more than one in 10 people will have this excessive persistent fear of an object or situation.
You can develop a phobia of just about anything. So to give you some examples of some more unusual phobias that I've heard of, one that's been apparently documented for centuries is a phobia of teenagers which…I don't know, maybe that's not so irrational. Another is a severe fear of beards, which might be quite debilitating in this day and age of the hipster. So you can pretty much develop a phobia of just about anything. But the more common phobias that you would have heard of are generally animal phobias, especially spider phobias, one of the most prevalent, but also snake phobias, phobias of dogs. Also heights, flying, blood and injections are also very common, as are phobias of small enclosed spaces. So you probably all would have heard of claustrophobia.
So why do we develop phobias? We've heard a bit about the evolutionary and even cultural or social processes that might contribute to the development of phobias. One theory that Lachlan didn't mention that psychologists refer to quite often in the treatment of phobias is that we may develop an excessive fear of something because of a previous a bad experience we've had with that thing. And the bad experience doesn't have to be our own bad experience, it can be the bad experience of someone close to us or even we've observed someone else having a bad experience with the object or the situation. And we do hear quite frequently in arachnophobia that a person with arachnophobia will have a parent or a grandparent or a sibling that has the same sort of a fear. So we can learn from the people around us to fear things as well.
So many people have a fear of spiders. It's not unusual to be a bit trepidatious, I suppose, about spiders. But only a small portion of those people would be classified as having a diagnosis of arachnophobia, and that's around a prevalence of about 5%, so that's still incredibly common, for 5% of the population to have an excessive and persistent fear of spiders. It's usually developed quite early in childhood. So most people can't remember a time when they weren't afraid of spiders. And there's even one study where research has interviewed the parents of five-year-old arachnophobics and their parents couldn't identify a particular situation that had occurred to cause the fear, they were just fearful upon first seeing a spider.
It usually has a pretty static course, and what I mean by that is if you have the phobia, have arachnophobia as a child, if it's not treated it tends to be maintained into adulthood and beyond.
I am often asked how debilitating can arachnophobia be, and the best way I find in answering this is to give some examples. So I've met people who have travelled to Europe every Australian summer to avoid spiders. They come back in winter because the spiders…I don't know, Lachlan probably knows where they go, but they are not around as much.
A really common example that I hear is when a person sees a spider in a room in their house, they can't return to that room for several days or weeks, and definitely not if they aren't absolutely certain that someone has taken care of the spider and removed it. And that's particularly debilitating if it's somewhere like the bathroom. So I've had people avoid bathrooms for a year. I've had people who can't go to…hopefully they've got a second bathroom, otherwise it might be quite tricky.
People who have avoided it who haven't gone to really good friends' weddings because the ceremonies have taken place under trees. So it can have quite a significant impact on a person's life and be quite debilitating.
So why do some people develop phobias and some people don't? Most people's perceptions of spiders are not really consistent with reality, and we've kind of heard that from Nicole and Lachlan already. But just to demonstrate my point, I want everyone to close their eyes and conjure up the image of a spider and just take note of its colour, of its size and of its features, so its eyes, its level of hairiness. And just keep that image in your mind and open your eyes and compare that image with the Hawaiian smiling spider. Or with the tiny jumping spider. Or with the peacock spider. So for most people, the spider in your mind's eye probably didn't look like one of these spiders.
So the real difference between a person who has a fear of spiders and a person who has a spider phobia is that people with spider phobia are convinced that something quite catastrophic is going to happen when they are close to a spider or when they come into close contact with a spider. In terms of what these catastrophic beliefs can be, they vary between different people and between the kinds of experiences that they have. But again, some common examples are that a spider's movements are really unpredictable, they jump, they are motivated to pounce on you. And so the fear is that a spider will move unpredictably, be unavoidable, will get on a person's body and bite them and cause ill effects. So that's probably the most common belief.
But other beliefs that are perhaps a bit less usual are that the spider will crawl on them, burrow under their skin and lay eggs and spiderlings will hatch some time later, that spiders are actually coated in toxin, and it touching the skin will cause really awful rashes and illness. And I guess other thoughts of beliefs about the toxicity of spiders. So often when I ask the people when they come in for treatment how many deadly spiders do you think there are in Australia, if there are around 5,000 types of spider in Australia, the common answer is somewhere between 1,000 and 2,000, when the reality is that there is two. So these common misperceptions persist.
So why are these beliefs maintained over time? Why aren't they corrected? When we get this good information from people who know about spiders, how come people don't just adjust their beliefs according to this information? And to understand why I need to explain to you how psychologists understand how a person's thoughts, emotions and behaviours are all connected. So this is called the cognitive behavioural model, and this is the model that we base our treatment on.
When an arachnophobic person sees a spider, so there's a spider, it triggers their catastrophic belief about what is going to happen, which might be something like the spider is going to jump, is going to get on me, it is going to crawl all over me, bite me and cause me significant harm. That results in an anxiety response or a fear response which is often panicky-like symptoms, like a racing heart, sweaty, tense. With spiders, and I haven't written it on the slide, but very commonly also a disgust response, so feeling quite nauseous and sick in the stomach, almost like a stomach flu kind of feeling is also present when they see a spider.
And these thoughts and these feelings result in the person running away basically, escaping the situation, removing themselves from the threat, and avoiding all future potential situations where they might see a spider.
The good thing about escaping and leaving a spider situation is that that person's fear response, their anxiety is immediately alleviated, and for them that's really nice because it's not nice to feel anxious. The not so good thing about avoiding spider situations is you don't get the opportunity to see that the catastrophe you think is going to happen doesn't actually occur. You don't get the chance to see that what actually happens is the huntsman does stay sitting on the tree trunk just watching you walk past and doesn't actually jump on you.
The other thing that people with spider phobia do that perpetuates their belief that something catastrophic will happen is they engage in things…what we call safety behaviours. Safety behaviours are little actions that a person does to prevent coming in contact with spiders that's not over-avoidance. So it can be things like pre-emptively spraying bug spray in their bedroom before they go to bed. I can see some people who have offered me those examples in treatment before. Closing windows before they go to bed. Having a person walk in front of them when they are walking through bushes. Sticking to footpaths when they are walking through grassy areas. What safety behaviours do is a person might walk through a bushy area with a person in front of them and they think, well, the only reason a spider didn't jump and pounce on me is because it jumped and pounced on the person in front of me. And instead of realising that that probably wouldn't have happened even if the person wasn't walking in front of them. So again, it prevents them from seeing what actually does happen when they are in a spider situation if they don't engage in the safety behaviours.
So, to summarise that little bit, escape and avoidance of spiders and safety behaviours result in a lack of knowledge, a lack of factual information about what spiders do, how they behave and the level of toxicity, and I guess overall the level of threat they pose to us. And it also results in a lack of skills. So as psychologists we call this skills deficits, so not having the confidence to know what to actually do when you are in a spider situation, so knowing how to effectively use a cup and a postcard to catch a spider, remove it and take it outside.
So how do we treat people with arachnophobia? What we are aiming to do with our treatments is to actually change a person's beliefs about spiders, and we do this through cognitive behavioural therapy and exposure therapy. And our goal, as I said, is to gather factual information about spiders but also show the person that they can cope in a spider situation.
So to explain what we do in exposure therapy, this is the anxiety graph. So on the Y axis you've got anxiety. 100 refers to the worst ever anxiety you've experienced when being in a spider situation. And along with the X axis you've got time. So what normally happens when an arachnophobic person is confronted by a spider is their anxiety level goes up. And then they escape, and their anxiety levels come immediately back down. But as I said before, the issue with escape is that that person never gets to really test out whether or not what they think is going to happen actually does happen. So what exposure therapy does is it requires a person to stay in the situation and to see what happens. So we are kind of testing out whether one of two things happened. So one, does your anxiety level go up, keep going up past 100, past the worst anxiety you've ever experienced and the catastrophe does occur?
Or, alternatively, does your anxiety go up, peak, plateau, start to come down, and what you think is going to happen doesn't actually occur? So exposure therapy is about setting up lots of little experiments to test out your beliefs about what's going to happen and to see whether they happen or not.
Does it work? Exposure based therapies are very effective. Some studies show that up to 90% of people who engage in exposure therapy show clinically significant benefits, meaning that they no longer meet diagnostic criteria for spider phobia. And these positive effects are maintained for up to one year, which is when they did the follow-up test.
So if there is a really effective treatment, why do people still have arachnophobia? And I think there's several reasons for this. One is that many people are unaware that there is a really effective treatment, so they just don't know that this treatment is available. Another is that they can be unaware that there is a problem. Because the fear develops at such an early age, people become very, very good at adjusting their lives in a way to accommodate their fears. So they become very good at doing those little safety behaviours, so good that it becomes a habit and they no longer notice that they are doing it, so they no longer know that actually this fear is causing them to have to change their behaviours in some ways.
Another reason is that treatments may not be readily available. As a psychologist, when treating arachnophobia ideally what we want is to have live spider specimens. That's the best way to show a person how a spider behaves and what a spider does. It's not always really easy to get spiders. I know my weekends now are usually…it consists of me walking through bushes with my children and takeaway containers looking for spiders. Not every psychologist has the time or inclination to do that.
And there's a prevalence of 5%, so a lot of psychologists probably have a little bit of a fear of spiders themselves and they probably should come and do my workshop as well. Then if a person is aware of treatment, they are aware of the problem and there are treatments available, very often what happens, this is probably the main barrier to treatment, is people are just too fearful to seek treatment. They understand that treatment involves exposure to the thing that they fear, and it takes quite a bit of courage and determination, and usually when people seek treatment it's for a particular purpose, there's a reason, something has happened in their lives where they think 'I no longer can go on living with a spider phobia disrupting my life in this way'.
So, in conclusion, arachnophobia is one of the most common anxiety disorders, but it's really the primary reason a person will seek treatment. This is despite it being a very treatable condition and there being very effective treatments for arachnophobia. And the treatments are based around correcting a person's beliefs about spiders. So a huge component of the treatments is actually gathering information about spiders, hearing from toxicologists, and naturalists who are expert in spiders to gather that factual information and correct those unhelpful and catastrophic beliefs that we might have about spiders. So if anyone thinks that maybe they are ready to confront their fears of spiders and would like to do that, we will be running the workshop on Saturday and another one mid May. You're very welcome to come.