Resistance to mycosis in AFS vs others

[CRX]

Curious about this. As much I dont want to admit it, it looks I may have some mildew or some kind of fungi growing on my AFS hide above its burrow. The springtails are still thriving, they walk around and among the white stuff and the grey stuff, and the scorp sits next to it every night not bothered. Is it possible tropical scorps that get flooded alot have a higher resistance to mycosis than desert ones? Has this ever been looked into?

 

[Tbone192]

I'd be very interested in a study relating to mycosis resistance in various genera of scorpion. I may attempt a very basic test using Paruroctonus boreus as a control, Centruroides margaritatus, and Javanimetrus cyaneus as test groups. Anyone should feel free to add their data. The more documentation the better.

 

[MorbidArachnid]

Heavily depends on what actually causes mycosis, people don't agree between infected soil, low ventilation, high humidity, or some combination of those (or some combinations of those combined with stress). Asian forest scorpions do appear to have more resistance because there's much less reported cases, but mild mycosis just looks like discoloration and on a dark scorpion it would be hard to tell unless it gets severe enough to attack the cuticle. Even in those cases, a missing tarsi is much more likely to be blamed on just a random injury. To be fair, injuries and punctures into the cuticle also darken, so it can also be difficult to diagnose.

I have multiple thoughts about mycosis, there's a lot of unknowns.

For one, we don't even know if it's one disease or many, there might be multiple fungi that can attack a scorpions cuticle. I've heard of mycosis talked about in centipedes too, but aside from similar presentation we don't know if these are similar strands of fungi. Tbh I'm not even sure how we know it's a fungi.

We also don't know a lot about the progression of the disease. I think mycosis is one of those things that's used to explain any random death where some spotting was also seen on a scorpion. Minor spotting on a tarsi or the edge of the pectins does not seem to be that detrimental, and scorpions do occasionally get these in the wild. Scorpions can deal very well with missing limbs, and if it's localized they can live normal lives with some mycosis.

That being said, we aren't sure what severe cases are doing. I've heard anecdotes of it spreading to other areas, presumably because it gets in the hemolymph as spreads internally, but I don't think we have autopsies to show what it's actually doing that is killing these animals. If it moves to attack internal organs that changes how it would be treated, if it's just external and the reports of it spreading are just because those people continue to keep their scorpion in poor conditions, then maybe a topical solution would work.

As mentioned, because injuries also darken and can be mistaken for mycosis, it's hard to separate what is actually mycosis and a death from mycosis, and what is misdiagnosed or a death from other external factors. A WC scorpion imported from overseas might have mycosis because of poor conditions during shipping, and might die shortly after. But is this death from the mycosis or just from shipping stress, dehydration, or some other unrelated disease? Again I'd be interested in an autopsy of a scorpion with mycosis.

As far as Asian Forest Scorpions being more resistant, wild Heterometrus seem to really like burrowing in moist clay, and a lot of wild caught specimens have clay caked onto their bodies. This seems like it would be the perfect environment to breed a fungal infection but mycosis is not often reported in Heterometrus. Hard to tell if it's from resistance though or if there is mycosis, the infection never spreads to the point where it's noticeable and would be diagnosed.

Fungal infections I believe present in tarantulas differently, I've never heard of mycosis in tarantulas (I don't know much about tarantulas so input on this is welcome) do they not get it? Or is it diagnosed as something else?

Also, and this is just personal thoughts from what I've seen, if your scorpion has minor mycosis spotting on it's tarsi and you intensely dry it out suddenly and then it dies, I wouldn't blame that on the mycosis. I think deaths from mycosis are over diagnosed in that way (similar to everyone blaming every random death on nematodes, bacterial infection, or "pesticide exposure" despite having little to no evidence any of these things happened).

 

[CRX]

I meant to post on scorpions lmao my bad

 

[MorbidArachnid]

Alright so these have been my observations so far on the subject.


This is my worst case of mycosis right now, top is when I got her on January 12, bottom is a pic I took yesterday. WC adult female Paruroctonus silvestrii, she has a constant water dish and I spray a corner of her enclosure frequently, 2-3 times a week. I've been monitoring it to see if it's gotten any worse, and I haven't noticed any spread. The one around her coxa is the one I'm most concerned about, but again I haven't noticed any spread or ill effects.


AF WC Smeringurus mesaensis, top pic was taken in November but I've had her since October, bottom pic was taken in July but she looks the same currently. I don't give her nearly as much water as my other scorpions, she gets a water dish and a light misting about once a month.






An extremely interesting case, AF WC Anuroctonus phaiodactylus. She was in long term captive care before coming to me, I believe her previous owner had her for at least 6 months. Top pic is from when I got her on Dec 8th, there were multiple tarsi that were completely caked in what was probably a clay/soil mixture. I'm not sure if this was from the substrate she was found in or was from the substrate the previous owner was using. I soaked it off, bottom pics are from today. There's mycosis on one limb, interestingly enough the other limbs are undamaged. I'm still inclined to believe wet substrate caked onto tarsi causes mycosis, but depending on how long the soil was on her this does indicate that there's some evidence against that. She's also one of my most water hungry scorpions, she has a constant water dish and gets a corner misted 2-3 times a week, I very frequently see her drinking and she loves standing in the water dish.

I don't have any examples of extremely xeric scorpions, both the silvestrii and phaiodactylus were collected in Southern California, so the moister conditions might lend more resistance than a true sand dweller would have. That's also why the mesaensis gets significantly less water. Does provide some interesting points about how it spreads and kills though, and is one of the main reasons I don't really believe mycosis is to blame for deaths in cases were there's some indication of it on a tarsi and the scorpion dies a week later. Again, more information is greatly appreciated tho, there's a lot we don't know and these are just my personal observations on a select few scorpions.

 

[The Snark]

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