# Scorpion stinger at 370x magnification - photograph



## ScorpDude (Jan 18, 2012)

Thought this might be of interest to some people 

Scorpion stinger of a Babycurus jacksoni taken at 370x magnification on a scanning electron microscope. This photo won me £200 in a photography competition at uni 







Can anybody offer any insight in to what those little bumps and nodules might be? I was half wondering if they were sensory, or if they were pores to allow air in to aid shedding (ie to avoid suction problems etc, allow the scorpion to become free of its old skin).

Thoughts folks?


----------



## Michiel (Jan 18, 2012)

Nice pic...the pits could have a sensory function...I don't see any setae or trichobothria protrubing from them. The bumps I can seem dust or other dirtparticles...

Verstuurd van mijn GT-I9001 met Tapatalk


----------



## Stan Schultz (Jan 18, 2012)

ScorpDude said:


> Thought this might be of interest to some people
> 
> Scorpion stinger of a Babycurus jacksoni taken at 370x magnification on a scanning electron microscope. This photo won me £200 in a photography competition at uni
> 
> ...


I can't answer your question, but I'm particularly fascinated by the twin venom ducts. Any idea at what point they merge? Or, are they parallel channels all the way to the glands? If so, are the glands separate and paired as well?


----------



## xhexdx (Jan 18, 2012)

Pikaia said:


> I can't answer your question, but I'm particularly fascinated by the twin venom ducts. Any idea at what point they merge? Or, are they parallel channels all the way to the glands? If so, are the glands separate and paired as well?


I was wondering this as well.

I was also curious if there were two more ducts on the other side of the stinger, or if there were only two.


----------



## snippy (Jan 18, 2012)

Yes, there are two venom glands in a scorpions versicle, arranged in a paired position!

Very nice picture, highly interesting!

Regards
Finn


----------



## pavel (Jan 18, 2012)

xhexdx said:


> I was wondering this as well.
> 
> I was also curious if there were two more ducts on the other side of the stinger, or if there were only two.


Add me to the list of conjecturers.

Nice shot, btw.


----------



## Ludedor24 (Jan 18, 2012)

some super shots


----------



## Galapoheros (Jan 19, 2012)

Wow, great pic!  There should be no duct on the other side imo.  I've thought about this design, the ducts seem to always be on the outside of the curve near the tip, and not on the inside of the curve.  It is the same with the fangs on snakes with hollow fangs, spider fangs, tarantulas, centipedes, they all have the duct on the outside of the curve from what I can tell, go ahead and look at them all if you have a scope.  It was kind of interesting to realize.  This is by my own amateur, hobby research out of curiosity btw, there may be exceptions out there but I haven't found any.  I haven't read anything about it but it might be out there.  My thought is that the ducts are on the outside of the fang curve because the aculeus flexed, or the fang is retracted/folded in such a way that it creates negative pressure on the outside curve of the fang, so that venom flows in more easily.


----------



## snippy (Jan 19, 2012)

Galapoheros said:


> My thought is that the ducts are on the outside of the fang curve because the aculeus flexed, or the fang is retracted/folded in such a way that it creates negative pressure on the outside curve of the fang, so that venom flows in more easily.


That would be a good explanation! I would think so too. There surely is negative pressure with ducts on the inner side, too, but I would think not as much (with ducts of similar shape and size compared).
Furthermore, 2 additional ducts on the concave side of the aculeus would simply not be possible in case of the picture because there is no space for it (when upholding some structural integrity at least). Maybe there would be space for one, but that would be somewhat asymmetrical and therefore not likely 

Any chance on a higher magnification of those indentations? As Michael said, there seem to be no sensory hairs, but it seems as if there where some structures in them, perhaps mechanoreceptors just for the use of sensing the pressure or even friction to determine whether and to which extent the aculeus has been inserted into the prey item.
This would make sense, because the surface seems smooth behind the ducts.

Regards
Finn


----------



## Michiel (Jan 19, 2012)

the whole metasomal action (i.e. raising the metasoma and arching the vesicle forwards) causes a certain "hydraulical pressure", I compare it with hydraulics, the pressure makes the venom glands contort or extend and this pushes the venom out.....If there was not a hydraulic kind of system, how would certain Parabuthus species be able to drip venom from their aculeus, without any prey or predator in the vicinity....

Also movement of certain body parts in some animals (whip spiders) is controlled by fluctuating blood pressures.......Hydraulics people.....

Reactions: Like 1


----------



## Yubz (Jan 19, 2012)

Awesome picture!


----------



## snippy (Jan 19, 2012)

Nobody denied that, Michiel. The position might be beneficial to venom flow, that's all that has been said.

Regards
Finn


----------



## Malhavoc's (Jan 19, 2012)

nature likes symmetry, the pivits and dents on the telson do not appear to be symmetrical making me lean toward damage, perhaps from being pushed through the carapace of prey items?


----------



## snippy (Jan 19, 2012)

For that to be true, they are much too regular. There seem to be four on each side for each duct. That cannot be coincidence  Apart from that if they where produced by stinging the prey, there would be marks behind the ducts, too - and I can see none.

Regards
Finn


----------



## Galapoheros (Jan 19, 2012)

snippy said:


> Nobody denied that, Michiel. The position might be beneficial to venom flow, that's all that has been said.
> 
> Regards
> Finn


Yes, I wasn't discounting that at all, in fact I have personally seen P. transvallicus spray well over 30cm, if angle were perfect, it could go much further.


----------



## Michiel (Jan 19, 2012)

snippy said:


> Nobody denied that, Michiel. The position might be beneficial to venom flow, that's all that has been said.
> 
> Regards
> Finn


I didn't mean anything by what I said, I emphasized what has been said, and gave a little extra explanation. At least, that was the aim

Verstuurd van mijn GT-I9001 met Tapatalk


----------



## snippy (Jan 19, 2012)

Ah okey, no worries then 

Regards
Finn


----------



## Vlad Tepes (Jan 20, 2012)

I can't comment on any of the questions but this photograph is fantastic!


----------



## Stan Schultz (Jan 21, 2012)

Galapoheros said:


> Wow, great pic!  There should be no duct on the other side imo.  I've thought about this design, the ducts seem to always be on the outside of the curve near the tip, and not on the inside of the curve.  It is the same with the fangs on snakes with hollow fangs, spider fangs, tarantulas, centipedes, they all have the duct on the outside of the curve from what I can tell, go ahead and look at them all if you have a scope.  It was kind of interesting to realize.  This is by my own amateur, hobby research out of curiosity btw, there may be exceptions out there but I haven't found any.  I haven't read anything about it but it might be out there.  My thought is that the ducts are on the outside of the fang curve because the aculeus flexed, or the fang is retracted/folded in such a way that it creates negative pressure on the outside curve of the fang, so that venom flows in more easily.


Physiologists have fretted over this topic as well. Their official opinion doesn't involve pressure per se because the venom glands are swathed in muscle tissue that is presumably strong enough to overcome any back pressure.

The "official" opinion is that the venom ducts are on the outside of the curve to help prevent clogging. Think about airflow around the curve of an aircraft wing's surfaces. The airflow is either relatively unaffected, or is actually compressed on the bottom surface of the wing, especially if it is cupped a little. (I recently had an opportunity to examine the wing of a small, two seater plane and the undersides of the wings were indeed slightly concave.) But, the airflow over the bulge on top is decompressed, producing a vacuum that lifts the plane. As a fang is forced into the flesh of the victim, that flesh that is inside the curve would tend to be compressed, forcing it into any openings and clogging them. That flesh on the outside of the curve would be stretched slightly as it passed around the bend, and the added tension would help it to not be forced into the openings and clogging them. That, of course, would expedite venom flow even though the forward pressure of the advancing fang or sting would tend to retard it.

For comparison, here is an SEM of the fangs of a baby _Brachypelma albopilosum_ showing the curve and the venom pore, also as _Galapoheros_ stated, on the outside of the curve.



(Uploaded with ImageShack.us)

And the little pores along the scorpion sting's length? Baroreceptors so the scorpion can monitor how much pressure it's using and tell it when to stop? Or how deeply the sting has penetrated?

I am also impressed that there is a limit to the "sharpness" of the sting and fangs. They don't go down to the molecular level, but are actually slightly rounded at the tips. Just sharp enough to penetrate the connective tissues and cell walls of the prey/victim, but no excessive effort wasted in over-engineering?


----------



## VickyChaiTea (Jan 21, 2012)

This thread is awesome. I never even thought about how much the position of the ducts would affect everything! That photo is really awesome.


----------



## Galapoheros (Jan 21, 2012)

Pikaia said:


> Physiologists have fretted over this topic as well. Their official opinion doesn't involve pressure per se because the venom glands are swathed in muscle tissue that is presumably strong enough to overcome any back pressure.
> 
> The "official" opinion is that the venom ducts are on the outside of the curve to help prevent clogging. Think about airflow around the curve of an aircraft wing's surfaces. The airflow is either relatively unaffected, or is actually compressed on the bottom surface of the wing, especially if it is cupped a little. (I recently had an opportunity to examine the wing of a small, two seater plane and the undersides of the wings were indeed slightly concave.) But, the airflow over the bulge on top is decompressed, producing a vacuum that lifts the plane. As a fang is forced into the flesh of the victim, that flesh that is inside the curve would tend to be compressed, forcing it into any openings and clogging them. That flesh on the outside of the curve would be stretched slightly as it passed around the bend, and the added tension would help it to not be forced into the openings and clogging them. That, of course, would expedite venom flow even though the forward pressure of the advancing fang or sting would tend to retard it.
> 
> ...


That was interesting, it basically fits the why I was thinking about it, compression and decompression is the act of pressure being applied.  A tarantala fang is inserted and is folded back in, which would create a decompressed area(neg pressure? I'm not sure if that's the right terminology) on the outside of the curve.  On an airplane wing though, it has to do with the speed of the wing through the air, I don't see the physics as being the same there.  It's the folding of the fang or pivoting angle of the aculeus that creates the pos pressure on the inside of the curve and neg pressure on the outside of the curve, as I see it anyway.  Yes I considered the "clogging" thing also.  I'm having a hard time choosing the best words for my thoughts.  But that "official" opinion happened to be mine also.  It also comes to mind that the feature(forgot the name) just below the aculeus, but just above the vesicle in scopions like Diplocentrus, might facilitate proper pressure on the inside of the aculeus, acting something like a depth gauge or governor.  Haha, but again, I see it in my head but I can't pick the best words to describe what's in my head.  Sharp objects appear dull at that mag, even sewing needle.
I have been thinking something I bet others might be thinking, "but scorpions don't have a folding aculeus, it doesn't fold like a spider fang(chelicera) or snake fang."  To me, after looking at scorpion stingers, they are put into motion on an axis but the curve of the aculeus is not true to the axis, the curve is wider, so that would cause pressure(compression) on the inside of the curve and neg pressure(decompression) on the outside of the curve also.  OK, I just now see now as I typed that that it fits Pikaia wing analogy better.


----------



## Michiel (Jan 22, 2012)

The aculeus is very hard, containing up to 25% of metals....

Verstuurd van mijn GT-I9001 met Tapatalk


----------



## Nomadinexile (Jan 25, 2012)

Pikaia, I agree that finite tapering is less wasteful, but I also believe at some point an ultra thin appendage becomes dangerous to itself, because of possible breaking and leaving dangerous open wound.  It may be strong, but some will encounter bone surely when stinging.   

Great thread all!


----------



## Stan Schultz (Jan 25, 2012)

Michiel said:


> The aculeus is very hard, containing up to 25% of metals....
> 
> Verstuurd van mijn GT-I9001 met Tapatalk


Do you have a reference for this, somewhere where it was reported in the literature?

What metals? In what form or tied into what chemical compounds?


----------



## 2nscorpx (Jan 25, 2012)

Pikaia said:


> Do you have a reference for this, somewhere where it was reported in the literature?
> 
> What metals? In what form or tied into what chemical compounds?


I was wondering the same thing...


----------

