Spider attack or a web of lies?

One of the more common types of public enquiry I get as a natural history curator is about spiders. Every year in September people start reporting large spiders that they don’t recognise and which therefore *must* be invasive species or tropical escapees from packets of bananas. Every year I either reassure (or disappoint) those people by explaining that the spider they have discovered is a common species in its fully-grown adult stage, sometimes looking a bit on the bloated side because it’s full of eggs.

Araneus_diadematus_comparison

Garden Spider (Araneus diadematus) full of eggs. Inset: comparison against non-gravid Garden Spider abdomen – note the characteristic cross pattern.

This year has been a bit more active on the spider enquiry front, because there has been a lot of scaremongering about spiders in the tabloid press. Beyond the usual September influx of sightings when adult male spiders become more active as they seek females to mate with, there has also been an increase in the number of requests for identification throughout the year, with people unnecessarily concerned about the Noble False Widow (Steatoda nobilis) spreading steadily northward as the global climate warms.

Male Giant House Spider (Eratigena atrica) on the lookout for females. Inset: note the 'boxing glove' pedipalps that show this is a male

Male Giant House Spider (Eratigena atrica) on the lookout for females. Inset: note the ‘boxing glove’ shaped pedipalps that show that this is a male

With all this frenetic arachnological activity I thought it might be time to lay to rest some common misconceptions about spider bites and offer a reality check to counter some of the over-hyped reports of injuries blamed on spiders.

Spider bites

Spiders in Britain are pretty harmless critters. So far there have not been any reported deaths in the UK from spider bites ever. You are literally more likely to be killed by being struck by lightning.

This is partly because spiders very rarely bite people, despite what you might be told by the press. The UK is full of things that do bite however, such as mosquitoes, midges, horseflies, ticks, bed bugs and fleas. All of these unpleasant beasties have a reason for biting – they are after your blood. Spiders are not. They will generally only bite when they feel very threatened.

Another reason why spiders in the UK are not life-threatening is simply that their venom doesn’t pack enough punch. The most venomous spider living in the UK is the Noble False Widow, which can give a painful bite, similar in intensity to the sting of the Common Wasp (Vespula vulgaris).

NobleFalseWidow

Noble False Widow spider – a little visitor in my kitchen

Keep in mind that a Common Wasp is far more likely to sting you than a Noble False Widow is to bite you, since the spiders are not aggressive – they largely keep to themselves and they don’t try to mug you for whatever sugary food or drink you have available.

A few other spiders in the UK can also bite, sometimes painfully, but again their venom is meant for subduing small invertebrates rather than humans, so although you may get some pain and perhaps swelling some time after being bitten, that may persist for a few days, it shouldn’t cause you any serious problems unless it gets infected.

Spider bite or MRSA?

Now this is where it gets interesting. Cellulitis caused by bacteria like Staphylococcus aureus (or ‘staph’ for short) can commonly be mistaken for spider bites. Any bites, stings, scrapes, cuts or even hair follicles in the skin can open the underlying tissue to infection, leading to necrosis of the skin, similar to that caused by the bite of certain spider species – in particular the Brown Recluse (Loxosceles reclusa), which it’s worth noting does not occur in the UK.

Cellulitis - not a spider bite! Image by James Heilman, MD

Cellulitis – not a spider bite. Image by James Heilman, MD

In areas of the USA where the Brown Recluse is also not present, it still gets blamed for a large number of injuries that are actually caused by staph bacteria that are resistant to Methicillin antibiotics (this is the strain of bacterium more commonly known as MRSA). In one study assessing the possibility that MRSA had become established in a prison community, half of the study group incorrectly assumed that the symptoms of their MRSA infection were symptoms of having been bitten by a spider.

In fact, it seems that spiders regularly get blamed for injuries that they don’t cause. One American study reported 216 medical diagnoses of Recluse bites in Western states in 41 months, despite the fact that the spiders don’t naturally occur in those areas. In fact there had only ever been 35 confirmed sightings of Recluse spiders in the regions studied, which really doesn’t add up: how can non-existent spiders be biting people?

Why blame spiders?

It seems that there are a few factors at play here, not least irrational arachnophobia fuelled by irresponsible reporting in the press. People are told about ‘deadly’ spiders and then when they get an infection they assume that it’s actually a reaction to a spider bite. They then tell the media they’ve been bitten by a spider and the vicious circle is complete.

People also assume that a bite has been caused by a spider because they have seen a spider nearby. However, that spider is probably an innocent bystander that’s more interested in eating the bloodsucking pest that actually caused the bite – assuming that it’s a bite at all and not cellulitis caused by something else.

Cellar Spider (Pholcus phalangioides) feeding on a different spider species

A Cellar Spider (Pholcus phalangioides) intent on feeding on a another spider species and not remotely interested in biting humans

Finally, the effects of spider venoms are often very poorly understood, because they are so frequently conflated with a variety of other dermatological problems and the rarity of confirmed bites means that little research has ever been carried out. That means medical staff are operating from a poor information base and may rely on poor information when making a diagnosis. The danger here is that significant medical issues (such as the spread of MRSA) may be overlooked because spiders are being unfairly blamed.

So if you read a case in the media about some horrible ‘spider bite’ it’s sensible to remain a bit sceptical. If the spider wasn’t seen actually doing the biting, the chances are the injury wasn’t actually caused by a spider at all. More likely it’s an infected wound, maybe following a bite or sting from something else with a taste for human blood or the sweet things we eat ourselves.

Coming up in July and August

I don’t normally use my blog to publicise the event that I have coming up, because quite frankly I’m not usually that organised.

Doing a theatrical turn for the Enlightenment Cafe. Photo by Liz Lutgendorff 2012

Nonetheless, if you have the strange compunction to hear me speak, or to attend something I’ve helped organise, here are some gigs that are coming up soon (click the links for details):

July

  • 12th July 2014 (09:00 – 18:00): Tetrapod Zoology Conference (London Wetlands Centre) – I’ll be talking about my research on mermaids at 11ish during this exciting all-day conference.

Tetrapod Zoology

  • 16th July (18:30 for 19:30 start): Science in the Pub (Old King’s Head, London Bridge) – The monthly science talk I host every 3rd Wednesday of the month, with Dr Erica McAlister from the NHM talking about science and museums
  • 18th July 2014 (09:30 for 10:00 start): Taxidermy: Creativity, Curation, Context & Care (Chandler House, Bloomsbuy, London) – I’ll be chairing this one day conference, which should be brilliant as the line-up of speakers is looking great!

Image by Sean Dooley

  • 25th – 27th July 2014 (17:00 on 27th): Winchester Science Festival (Discovery Centre, Winchester) – I’ll be talking about the evolution and adaptations of the skull in vertebrates.

August

  • 20th August 2014 (18:30 for 19:30 start): Science in the Pub (Old King’s Head, London Bridge) –  TBC

That’ll do for now as details get more fuzzy as we look further into the future, but there are more talks coming up in in September, which I’ll add at a later date. Now I’d better think about getting some of these talks prepared!

Geekwars?

After a weekend of discussion about the hashtag #bonegeeks for a crowd-sourced, social media based resource for images of bones, I have come to the conclusion that you can’t please all of the people all of the time.

The nub of the discussion centres on the word ‘geek’, which is a term that some people dislike and don’t identify with. This is fair enough – how one identifies with and adopts labels for themselves is a personal thing, a point that Alice Roberts made earlier in the year.

Language evolves and so terms take on new meanings to reflect common usage. To my mind this means that the term ‘geek’ has taken on a new and (to my mind) positive meaning as “someone who is interested in a subject (usually intellectual or complex) for its own sake“, so I am happy with that description for myself – but I can understand that others feel differently.

In order to try to come up with a better hastag for a bony resource I made a poll that included a range of suggestions, the most popular of which can be seen below:

poll

Now obviously #bonegeeks comes out on top – presumably due to input from other people who self-identify as geeks, but there are enough people voting for alternatives to raise a warning flag that several people may feel actively excluded by use of term ‘geek’. In light of this I am unwilling to stick with #bonegeeks, but the general lack of consensus on alternative names leads me to reject the other options.

Where to go from here? The obvious answer is to go back to what we are trying to achieve and to think of a hashtag that is descriptive of the outcome rather than the contributors, so I suggest we use #bonepics so that both #bonegeeks and every other brand of osteology enthusiast who doesn’t consider themselves a geek can get on with making something rather awesome…

What’s in a name?

On Friday there was a lighthearted discussion about a hashtag that could be used to compile images of bones on twitter as an identification resource. It’s always a struggle to find the bones you’re after on an image search and #bonegeeks (as it is currently called) will hopefully help to remedy that problem.

bonegeeks_header

The hashtag used will be the one mechanism by which this resource will be readily found in order to be further curated, so it is important to use something short, memorable, descriptive and – importantly – something that isn’t already in use (which is why #boners was decided against). It should also be a term that people feel some sort of affiliation with – and it certainly shouldn’t put people off (another reason why #boners was perhaps unsuitable).

However, this last point raises an issue, since some people clearly were put off – and when I say ‘some people’ I mean a person whose opinion I respect.

 

Earlier this year Alice made an explicit statement about the use of the term ‘geek’, which puts her comment in context:

“There’s been a movement towards reclaiming the word ‘geek’ but I’d rather get away from it entirely”…”If you say: ‘It’s cool to be a geek,” where does that leave people who don’t consider themselves to be geeks? Aren’t they allowed to be interested in science? Science is for everyone.”

As someone who self-identifies as a bit of a geek (and borderline nerd) I’ve already done my bit of reclaiming and I’m comfortable with it, but Alice’s point is still valid – not everyone who might want to get involved identifies as a geek.

It’s still early days, so if any changes to the hastag are to be made, they need to be made as soon as possible in order to stop the proliferation of hashtags and increase the difficulty of finding information. Perhaps the best idea if to make a poll of unused hashtag suggestions and allow people to vote on their favourite option. Here is such a poll, with any suggestions that have been made included, unless the hashtag is already in use on Twitter.

If you have any other suggestions please add them (on the poll or in the comments) – hopefully we may be able to find a decent hashtag amongst them, that people are happy to use.

#bonegeeks

There are some great resources online for finding images of comparative material for skulls, but the postcranial skeleton tends to be quite badly represented online even for common species. I’d love to change that, but it’s a big challenge for one person.

Paramastoid process of Pig (Sus scrofa)

Paramastoid process of Pig (Sus scrofa)

That’s why I’d like to set up #bonegeeks on Twitter (and maybe on other social media as well). The way I see it, people who have access to skeletal material could easily take snaps of bits of postcrania from known species (preferably with something for scale) using their phone and share the image to Twitter, Tumblr or Facebook with the name of the species and the bone (and perhaps where the specimen is held).

With the #bonegeeks tag it should be easy to collate images and hopefully start building up a comparative collection of images to make identifications easier.

It could start with a bone of the week to get the seldom depicted bones better represented and I’m sure #bonegeeks would be willing to respond to requests if there were particular bones that someone wanted to see.

I wonder if this could work… shall we give it a go and find out? Please add your thoughts on this idea in the comments section below or on Twitter using the #bonegeeks hashtag.

Oh and here’s how the idea got started: [View the story “#bonegeeks” on Storify]

Apes are monkeys – deal with it

Are apes monkeys?

Martin Robbins wrote a fun piece in The Lay Scientist the other day on the incorrect use of the term monkeys to describe apes (triggered by an article by Graham Smith for the Daily Mail). In Martin’s words:

A great crime against pedantry is in progress and it’s time for someone to draw a line

So as a pedant with a professional interest in this issue I am taking my stand, to help ensure that a miscarriage of pedantic justice doesn’t occur.

Nested hierarchies

Apes are monkeys in the same way that monkeys are primates, humans are apes and I am a human – it’s called a nested hierarchy.

This means that all apes are monkeys, but not all monkeys are apes. Just as all humans are apes, but not all apes are human. By the same token, humans are all ape, contrary to the title of the otherwise rather good book 99% Ape: How Evolution Adds Up.

This nested hierarchical system is the mainstay of biological taxonomy – each individual fits in its species (with the possible exception of hybrids), each species in its genus, each genus in its family and so on. It’s how Linnaeus organised things back in the 1750’s and it works remarkably well. [EDIT it’s actually a bit more complex than that]

Why do nested hierarchies work in biology?

Linnaeus’ system works well in biology because species share varying degrees of similarity depending on when they branched off from a common ancestor. The groups with most shared characteristics can be clumped together. That’s a bit tricky to explain in a few words, so here’s a simple diagram:

Primate phylogeny adapted to show clades. Image adapted from handout used by Mr. Krauz (click image for link to source)

The groups that form after a branching event are called ‘clades’ and the members of the group can correctly be referred to by the name of any of the clades that they are part of. This is known as monophyly (which means one leaf).

If a name is given to a group of species that are not all related in this way it will either be a polyphyletic group (many leaves) or a paraphyletic group (excluding leaves). Again, this can be confusing to describe, so here’s another diagram:

Monophyly, paraphyly and polyphyly in the vertebrates - from Wikipedia (click image for source)

Polyphyletic and paraphyletic groups are not particularly scientifically informative, since they include or exclude members of clades with no evolutionary justification. This means that scientists prefer to base names for groups on clear monophyletic clades.

That’s a scientific argument for considering apes to be monkeys.

But ‘Monkey’ isn’t a scientific term

Aha! I must make it clear that I have been using the term monkey as a direct match for the term Simiiformes (which includes the Old and New World monkeys, the lesser apes and the great apes) in the discussion above, but is that valid?

Obviously I argue that it is, since I’ve been using it – the question should be why wouldn’t it be valid? The only logically robust answer (that I can think of) is that it wouldn’t be valid if people don’t commonly use the two terms to refer to the same things. So do people use the term monkey to refer to the apes?

The simple fact is that this whole discussion has been raised because Graham Smith published an article in which he refer to apes as monkeys, which demonstrates that monkey is indeed used as a generic term to refer to apes.

Another example is Terry Pratchett’s Discworld, where the Librarian (who happens to be an Orang-utan) dislikes being referred to as a monkey, which happens regularly – it may be fiction, but it seems reasonable to suggest that it reflects the use of terminology of real people.

In addition, I would suggest that it’s helpful for common terms for biological groups to directly reflect the scientific terminology as much as possible, since this improves the ability of scientists to communicate with a non-specialist audience. So even if monkey didn’t mean the same as Simiiformes (which it seems to) it probably should. Otherwise monkey has no scientifically meaningful analogue, since it would refer to a paraphyletic (and therefore arbitrary) grouping.

Case closed?

I think that my argument is pretty robust and I’ll stand by it until I hear something convincing enough to change my mind.

That said, I will add an important caveat – monkey is a generic term and when referring to Chimpanzees, Gorillas, Gibbons, Orang-utans and Humans the more specific term of ape should be used for clarity. After all, you don’t refer to your pet cat as a pet carnivore, or a budgie as a theropod, because generic terms omit a lot of additional information.

So although apes are monkeys, they are still apes – and that means something.

[N.B. this discourse continues in more detail here]

Quite Interesting…

I’m rather excited that this Friday a new series of QI will be starting, with the theme of ‘H’. Apparently one of the questions in the first show is one that I helped the QI elves research – so I can’t wait to see if it catches anyone out on a General Ignorance forfeit.

The elves were in with me again today to get a bit more information, which hopefully will be used on a website that will accompany the new series – although it’s still a bit early to be sure it will work out as planned. I’ll keep you informed…