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Can wasps smell fear?

bridgy

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A friend of mine claimed this the other day (while we were sitting outside being constantly bothered by wasps of course!)

I've done a google search and found various references to it, but all anecdotal and nothing I would class as authoritative. My freind claimed she'd heard it discussed on the radio and that a couple of scientific studies had confirmed it was the case, and that this is why wasps always seem to be attracted to those who least like them (although I suspect this could be expalined simply by the additional fuss those peolpe make, which makes it more noticeable).

So, is this really the case, or a popular myth?

If it is the case, what are the evolutionary benefits to the wasp, or does fear just smell sweet?!

Many thanks
 
AFAIK, what wasps actually do, assuming you are talking about species of social wasps and not about species of solitary wasps, is exude a pheronome on a target for the hive's wrath; the more upset the wasps are, the more pheronome they attach to the target, the more wasps attack the target and the more trenchently they attack. This is what social bees do, and I believe social wasps are the same.

It would look to a victim like "smelling fear", but it's really the wasps smelling a signal laid by other wasps to "Attack! Attack!".

That being said, bees and wasps do smell various things, or better said sense what we call smell, so I'm not sure if they can perceive human pheronomal-like exudates.
 
I have no idea but it certainly seems that way. Anything I can give is going to be anecdotal too, but as a hater of wasps, I can tell you an example which would seem to suggest it isn't all about waving your arms around and making a fuss.

When I was sitting at a table just recently, there was a lot of wasps about. I decided I was going to sit completely still, and try to ignore them. However, they'd fly right up to me and just hang around me, almost landing on me for ages until I'd finally get up and move away.

They didn't seem to go near my friend, and he didn't care.

I dunno, though. It seems feasible.
 
More anecdotes!!

When I wear highly-perfumed hairspray, wasps can't keep away.

A few years ago I was convinced that wasps were more attracted to me when I wore certain colours of clothing (purple, for example), but I'm not sure how much sense that makes. I was thinking bright clothes = flowers.
 
Do humans in fact give on a "smell of fear"? As in a pheremone that indicates distress or fear?

Its the assumption that this all hinges on so I'm simply curious if anyone has ever specifically confirmed this.

On one hand, it seems a rather strange adaptation as why would one want to indicate fear to a potential predator. On the other hand, the pheremone for fear is perhaps intended for other members of the same species as a form of non-verbal communication of danger perhaps.

I've always found that wasps tend to be attracted towards people most when there is food about. Sit out on the deck and read and you're not likely to be bothered. Sit out on the deck with breakfast, and you'll likely be very popular.

Again I can't see any potential advantage for a wasp to be attracted to the scent of "fear". Unless they miscontrue it as something else.
 
voidx said:
Unless they miscontrue it as something else.
Click to expand...

That would seem much more likely.

voidx said:
On one hand, it seems a rather strange adaptation as why would one want to indicate fear to a potential predator.
Click to expand...

It might not be an adaptation. Maybe it's just a byproduct of something else going on in the body.
 
The theory I'm most convinced by is that wasps, and other nasty stingy things, are more likely to sting you if they're upset, and scared people are more likely to upset them. Someone who doesn't care about them will just sit there and not react (or hit them with something heavy), while a scared person will usually try to brush them away or flail around wildly, or even just flinch when they come near. Since wasps don't like being flailed at, they flail back.
 
I have no idea about the validity of the science behind it, but someone else one said that flailing the arms causes a vacuum of air that sucks the wasp towards you.

Is this nonsense? It certainly sounds it.
 
Humphreys said:
I have no idea about the validity of the science behind it, but someone else one said that flailing the arms causes a vacuum of air that sucks the wasp towards you.

Is this nonsense? It certainly sounds it.
Click to expand...

Nope, that's sort of true. When anything moves (in air), air takes time to move into the space that the object used to occupy, meaning there is a reduced pressure that will suck air, and any object in it, towards the object's wake. It's the same effect that you can use to save fuel by driving in the slipstream of a lorry, and if you've ever had a lorry drive past when cycling you would know how strong the suck can be.

However, it is only sort of true because there is never actually a vacuum formed. There is certainly reduced pressure, but even large aicraft going faster than sound don't produce a vacuum behind them, the air just flows in much too fast.
 
Cuddles said:
Nope, that's sort of true. When anything moves (in air), air takes time to move into the space that the object used to occupy, meaning there is a reduced pressure that will suck air, and any object in it, towards the object's wake. It's the same effect that you can use to save fuel by driving in the slipstream of a lorry, and if you've ever had a lorry drive past when cycling you would know how strong the suck can be.

However, it is only sort of true because there is never actually a vacuum formed. There is certainly reduced pressure, but even large aicraft going faster than sound don't produce a vacuum behind them, the air just flows in much too fast.
Click to expand...

Ah, well, maybe this can be another reason why wasps seem to be attracted to people who start flailing their arms.
 
Watching someone flail at a wasp always reminds me of Jim Furyk taking a golf swing.
 
I've always wondered if dogs can smell fear. I used to have a dog that appeared to enjoy "messing" with guests who were afraid of him. (He would sit right in fromt of them and give them...well...dirty looks.)
That could have been based on a 'social cue' thing, though. Or maybe we were all just imagining it.
 
Cuddles said:
Nope, that's sort of true. When anything moves (in air), air takes time to move into the space that the object used to occupy, meaning there is a reduced pressure that will suck air, and any object in it, towards the object's wake. It's the same effect that you can use to save fuel by driving in the slipstream of a lorry, and if you've ever had a lorry drive past when cycling you would know how strong the suck can be.

However, it is only sort of true because there is never actually a vacuum formed. There is certainly reduced pressure, but even large aicraft going faster than sound don't produce a vacuum behind them, the air just flows in much too fast.
Click to expand...

...and total your car and head when the lorry brakes a bit sharpish.
 
Thanks for all the enjoyable anecdotes guys - but I'm still none the wiser! And all the anecdotes have just made me even more curious about the facts of the matter!

Thinking about it, isn't there an insect expert on the forum here somewhere? Sorry I can't remember their name...but I'm sure there was a thread recently about insects where they were displaying their expertise....
 
When humans are afraid, part of the adrenaline/fightorflight response is to sweat. Wasps can detect the scent - although whether it irritates them is open to question (it does irritate honey bees).

Also, your behavior when you're scared of a wasp can provoke them. Most people, when they see a wasp, turn toward it quickly so they can watch it (and avoid it/swat it). The wasp sees this as a small object becoming much bigger very quickly, which can be interpreted as threatening.
 
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