Pandinus imperator died

[Veno Manus]

Do we have any evidence of what their burrow temps have been? I mean I understand ambient temp but burrow temps have to be colder in relation to depth and substrate.

Stop keeping tropical arthropods at room temps i digress, I've had this conversation before in the tarantula chat. Def think the two main deficits of care with scorpions is temps and water though, and it seems to be the underlying issue with a lot of help threads I see. I can't say for sure what temperatures are technically fine, but in Southern Thailand and Malaysia they rarely if ever experience temps below 24C, and summer temps get a lot higher than that.

 

[MorbidArachnid]

Do we have any evidence of what their burrow temps have been? I mean I understand ambient temp but burrow temps have to be colder in relation to depth and substrate.

Not specifically for scorpion burrows from what I've seen (outside of the Hadrurus arizonensis study I've talked about before), but from Properties and Management of Soils in the Tropics (Sanchez, 2019):

"Soil temperatures in the tropics, as defined in the Soil Taxonomy system, fall in the “iso” temperature regimes, that is, those with “less than 6C difference between the average soil temperature of June, July and August and the average soil temperature of December, January and February at 50 cm depth or to a dense, lithic or paralithic contact” (Soil Survey Staff 1999, 2014). Soil temperatures can be estimated from air-temperature records by adding 2C to mean annual air temperatures in the lowland tropics (Murtha and Williams 1986). Table 1.2 presents the soil temperature regimes as defined by the Soil Taxonomy system along with their corresponding approximate equivalents of mean annual air temperature at the soil surface and elevation at the equator, using a change of 6C for each 1000 m increase in elevation. The above definition excludes soil temperature variation
in the topsoil. This is illustrated in Table 1.3, where the monthly air and soil temperature variations are shown for a soil in Indonesia. Very high soil temperatures have been registered on the surface of bare soils during dry periods.
Mohr et al. (1972) reported a record of 86 C at the surface of a bare soil in Congo. At a depth of 10 cm, the same bare soil had a nearly normal temperature of 30C. At the same site, the surface soil temperature was 34C under grassland and 25C under forest. Unless exposed, soil temperatures even at the surface do not seriously exceed air temperatures. This buffering is due partly to the relatively low heat capacity of soils, about one-fifth of the heat capacity of water. Any excess heat is reradiated to the atmosphere. This is the reason why one cannot fry an egg even on the hottest soil, whereas it is possible to do so on asphalt because it has higher heat capacity."



In a later section he says " Soil temperature is seldom considered a serious limiting factor in the tropics. As mentioned in Chapter 1, soil temperatures approximate air temperatures at about 50 cm depth, and are usually adequate for most tropical crops. There are two instances, however, in which soil temperatures can be limiting. These are excessively high temperatures in certain sandy topsoils and low temperatures in the tropical highlands."

Obviously we can only loosely apply this to scorpion burrow temperatures, scorpions do not typically burrow in open soils for one. The takeaway I got from this is where as in desert regions, or regions exposed to direct sunlight particularly with sandy topsoil, the soil retains a lot of heat from accumulated thermal energy from the sun. This is why surface temperatures in the desert are so much higher than air temperatures, and why surface temperatures on exposed soil in the tropics can be hotter than air temperature. The shaded area in the tropics is not necessarily cooler than air temperature though, as anyone who's ever tried to escape the heat in the shade in Florida would know. Humid air retains a lot more thermal energy than dry air would, and that seems to still be diffused fairly evenly throughout the first layer of soil. The soil in the shade doesn't seem to be particularly *hotter* than air temperature as it would in the desert or in open sun, but it doesn't appear to be significantly *cooler* than air temperature either.

I also found this paper here which measured temperatures in burrows for African rodents. The closest approximation that they use to Heterometrus species would probably be mesic tropical, of which there was very little difference between the air and soil (and burrow) temperature. Even the Xeric tropical burrows had a temperature of around 30C, but the measurements were done in July and August. Once again not doing these studies in the winter limits their usage with captivity. This paper has localities too which would make it more interesting for Pandinus keepers, def seems that there would be more seasonal variation in the savannah where most hobby emps come from.

 

[Veno Manus]

That's what I call facts good info thanks for the details!

Not specifically for scorpion burrows from what I've seen (outside of the Hadrurus arizonensis study I've talked about before), but from Properties and Management of Soils in the Tropics (Sanchez, 2019):

"Soil temperatures in the tropics, as defined in the Soil Taxonomy system, fall in the “iso” temperature regimes, that is, those with “less than 6C difference between the average soil temperature of June, July and August and the average soil temperature of December, January and February at 50 cm depth or to a dense, lithic or paralithic contact” (Soil Survey Staff 1999, 2014). Soil temperatures can be estimated from air-temperature records by adding 2C to mean annual air temperatures in the lowland tropics (Murtha and Williams 1986). Table 1.2 presents the soil temperature regimes as defined by the Soil Taxonomy system along with their corresponding approximate equivalents of mean annual air temperature at the soil surface and elevation at the equator, using a change of 6C for each 1000 m increase in elevation. The above definition excludes soil temperature variation
in the topsoil. This is illustrated in Table 1.3, where the monthly air and soil temperature variations are shown for a soil in Indonesia. Very high soil temperatures have been registered on the surface of bare soils during dry periods.
Mohr et al. (1972) reported a record of 86 C at the surface of a bare soil in Congo. At a depth of 10 cm, the same bare soil had a nearly normal temperature of 30C. At the same site, the surface soil temperature was 34C under grassland and 25C under forest. Unless exposed, soil temperatures even at the surface do not seriously exceed air temperatures. This buffering is due partly to the relatively low heat capacity of soils, about one-fifth of the heat capacity of water. Any excess heat is reradiated to the atmosphere. This is the reason why one cannot fry an egg even on the hottest soil, whereas it is possible to do so on asphalt because it has higher heat capacity."

View attachment 486377

In a later section he says " Soil temperature is seldom considered a serious limiting factor in the tropics. As mentioned in Chapter 1, soil temperatures approximate air temperatures at about 50 cm depth, and are usually adequate for most tropical crops. There are two instances, however, in which soil temperatures can be limiting. These are excessively high temperatures in certain sandy topsoils and low temperatures in the tropical highlands."

Obviously we can only loosely apply this to scorpion burrow temperatures, scorpions do not typically burrow in open soils for one. The takeaway I got from this is where as in desert regions, or regions exposed to direct sunlight particularly with sandy topsoil, the soil retains a lot of heat from accumulated thermal energy from the sun. This is why surface temperatures in the desert are so much higher than air temperatures, and why surface temperatures on exposed soil in the tropics can be hotter than air temperature. The shaded area in the tropics is not necessarily cooler than air temperature though, as anyone who's ever tried to escape the heat in the shade in Florida would know. Humid air retains a lot more thermal energy than dry air would, and that seems to still be diffused fairly evenly throughout the first layer of soil. The soil in the shade doesn't seem to be particularly *hotter* than air temperature as it would in the desert or in open sun, but it doesn't appear to be significantly *cooler* than air temperature either.

I also found this paper here which measured temperatures in burrows for African rodents. The closest approximation that they use to Heterometrus species would probably be mesic tropical, of which there was very little difference between the air and soil (and burrow) temperature. Even the Xeric tropical burrows had a temperature of around 30C, but the measurements were done in July and August. Once again not doing these studies in the winter limits their usage with captivity. This paper has localities too which would make it more interesting for Pandinus keepers, def seems that there would be more seasonal variation in the savannah where most hobby emps come from.

View attachment 486378

 

[MorbidArachnid]

Also as an aside I'm not sure where the sentiment that burrows are generally cooler than the surrounding air (particularly in the desert) turned into "65F year round is fine". Generally cooler but it still gets to 110F in the summer in Arizona and its like 80-90F in the tropics so while the soil is probably cooler I don't think its a full 20-30 degrees cooler (or more if you're talking desert temps) ya know.

 

[Wolfram1]

Also as an aside I'm not sure where the sentiment that burrows are generally cooler than the surrounding air (particularly in the desert) turned into "65F year round is fine". Generally cooler but it still gets to 110F in the summer in Arizona and its like 80-90F in the tropics so while the soil is probably cooler I don't think its a full 20-30 degrees cooler (or more if you're talking desert temps) ya know.

well this is not what i said at all, i have other reasons to regard them as adequate, and its not year round, i find it a bit sad that you admit not knowing what the lower threshhold is and yet boldly claim that its detrimental to the animals.

And considering the build of Pandinus imperator or any Heterometrus sp. in no way are they desert scorpions. At least in case of Heterometrus they are almost cosmopolitan, but still adapted to forested areas. Forests will reduce the temperature below on the forest floor by a few degrees at a minimum and as far as i can tell their range is not restricted to lowland forests either.

I simply consider these temperatures as part of their natural temperature range, but i agree with you that it can bring problems with it if you are not careful or have a bad setup. Indigestion beeing the biggest threat, hence feeding less and smaller prey during that time.


On a seperste note at least with Scolopendra dehaani i have been advised to keep it below 22°C if possible and the ones with a friend that had been kept exactly the same except with 24-28°C over the summer have died in his care while i put mine into the cellar to escape the heat and they are all alive and well.
I know different animal and all that but they share habitat with heterometrus so i decided to give it a try. Exept i will allow them to experience the natural summer temperatures up to 28°C

It probably doesn't add much to the discussion here but feel free to PM me anytime if you want to discuss this topic with me. I just wanted to clarify i don't consider keeping them "at 65°F year round as fine".

 

[MorbidArachnid]

yea to be clear that specific part wasnt directed at you, that was referencing the other thread i talked about this on with regards to aphonopelma care. and yeah, i dont have bonefide scientific evidence that keeping them a few degrees below their natural temperatures are harmful to their health. I also dont do winter temperature drops so obviously it would be hypocritical of me to advocate for temperatures that match their native range.

also to be clear temps in their native range in no way match temps in captivity, we simply arent capable of closely mimicking the variety of microclimates and natural depths and topographic variation that an animal would experience in the wild. I've always been extremely skeptical of using air temps as the temps you should provide an animal in captivity, for example even in winter time animals can experience much warmer temperatures than the air due to insulation and natural heat given off from decaying leaves and wood. (There's a really good paper on microclimates experienced on an incline in an alpine forest, even in winter microclimates could reach 40C because sunlight still transfers thermal energy into leaves, wood, and air gaps underneath that and because these materials are very insulating they can retain some of that heat overnight, only to be warmed up even more the next day. ill link it in the next post when i find it). Similarly, obviously burrows in the desert do insulate desert animals, and shaded areas can be markedly cooler than air temperatures or surface temperatures in open soil. If the scolopendra is not able to escape 28C temperatures where it would normally in the wild, then obviously it would have health issues. (That being said, in the other discussion I had on this in regards to Hadrurus they still had burrow temps of around 35C, while the soil surface reached 64C, link here. I do not know if this applies to scolopendra generally, I don't know anything about centipedes and have never claimed to.)

And finally an anecdote, knew someone who claimed to have a Graemeloweus glimmei, it was a very small scorpion and when I asked how they ID'd it they said they knew it was a Graemeloweus because they've had it for over 2 years and it had never molted. It was not that though, it was what appeared to be a 4i Uroctonus mordax, ID'd by the Y shaped split in the median carinae on the 5th metasomal segment. I asked about temps, and they said they kept it at room temperature in a room that fluctuates between 65F in the winter and 80F in the summer, but that they didn't particularly keep track of it.

This was interesting to me because being temperate and montane scorpions, this is probably within their native (air) temperature range. It was interesting that it had taken so long to molt, obviously there's a lot of other factors you could take into account, such as feeding schedule and humidity, and obviously this might be within range for growth rates of Uroctonus mordax, but it does seem like a heck of a long time and I do think that the room temp is fine attitude leads to people also not checking their temps at all. Especially in a house without central heating and cooling, your house is also full of microclimates. They could have been going off the house temperature but the actual space where they were keeping the scorpion was much cooler. I currently have different temperature gages in different areas of my house (because I also dont have Central heat/AC) to demonstrate this point, which I'll have more to talk about with that once I get through a full year.

Generally my personal opinion on it, which is not backed by anything at all except my own experience and observations, is that scorpions seem to seek out and utilize heat when it's provided. I don't have any direct evidence that the mantra of room temps or not monitoring your temps is harmful, but I do have conformation biased observations that when people come and complain about their scorps not eating, being lethargic, or acting weird its usually a temperature issue. I also think that from what I've seen about soil temperatures, their burrows, and microclimates, they would still only experience such cold temperatures seasonally and being that we are talking about scorpions in the desert or in the tropics they wouldn't experience those cold temperatures year round. I think you should seasonally heat them up if you are going to be adamant about room temps. (I'm using "you" in a generalized sense to talk about the people who are against supplementary heating as a whole, not you specifically.)

I also think that a lot of a scorpions function and health is tied to external temperature, you mentioned impaction, I think it's likely it affects their immune system as well. Some insects exhibit behavioral fever induction and seek out hotter temperatures when infected with certain bacterial infections, which is interesting to say the least. And of course, tropical animals are not desert animals and have different adaptations, but if anything this would mean they're less equipped to handle colder temperatures because there's so little seasonal variation near the equator. Desert animals at least do experience significant temperature swings summer to winter and day to night.

Generally my opinion on it is we don't have enough information to make hardline limits, and at the end of the day care is largely about what you personally find important to replicate. I've already said I generally don't do winter temperature drops nor am I matching an animals native air temperatures. I just think some extra heat is beneficial. I wish the person who measured Hadrurus burrows did the experiment in the winter too, when surely they would experience much cooler temps. I desperately need people to stick temperature and RH probes into burrows in the wild. But for right now I'm just trying to piece it together off of proxy models and geology textbooks. I've unfortunately had to read a lot of really boring papers about soil composition when researching Hadrurus. So this is just my piece.

 

[MorbidArachnid]

https://link.springer.com/article/10.1007/BF01555192

Here is the microclimate paper

Edit: also im sorry if that wall of text isnt very approachable or comes of as confrontational. ive gotten that feedback a few times. i cannot stress enough that i have the disease that this is how i talk irl

 

[Wolfram1]

thanks for the link & mb i thought it was a jab at me initially, but its so very easy to misunderstand messages, thanks for taking the time and effort to clarify and expand your message

this will be helpful to us all, i think

I don't have any direct evidence that the mantra of room temps or not monitoring your temps is harmful, but I do have conformation biased observations that when people come and complain about their scorps not eating, being lethargic, or acting weird its usually a temperature issue.

it also wasn't my intention to disregard your experiences, i am way too inexperienced with scorpions care in general, only having started keeping 2 Heterometrus scorplings (H. silenus & very likely H. laoticus) in March this year.

In my observations they seem to be doing fine, hiding during the day and sometimes venturing out of their hide at night, very reactive to any light too, feeding well etc.
So far no observable reduction in activity.

but again i haven't had them for years so its hard to judge if i am missing something or if there will be signs after a prolonged period at ~20°C, (its only been 2 months) the cycle will be about 6 months total at 20°C, then slowly rising to about 28-30°C on hot summer days with night time reductions (if there is a prolonged heat period i would protect them further, but they did well this summer) and then slowly going back down in autumn until we reach the next winter cycle.

It's not an accurate recreation of their natural temperature range, but it should be within an acceptable range (in my opinion) and if so saves me a lot of trouble heating the scorplings.

I also think that a lot of a scorpions function and health is tied to external temperature, you mentioned impaction, I think it's likely it affects their immune system as well. Some insects exhibit behavioral fever induction and seek out hotter temperatures when infected with certain bacterial infections, which is interesting to say the least. And of course, tropical animals are not desert animals and have different adaptations, but if anything this would mean they're less equipped to handle colder temperatures because there's so little seasonal variation near the equator. Desert animals at least do experience significant temperature swings summer to winter and day to night.

that is a good point, and since bacterial infections are not a given it is hard to quantify how vital the heat really is, a scorpion could do very well at a given temperature one year and die the next because it happened to have an infection and no way to seek out extra heat

if a heat source is not an option for whatever reason, small rearing container, etc, all you can do to prevent it/minimize the risk of infection itself is having healthy soil, good ventilation, clean water as well as healthy feeders to reduce the risk of infection to a minimum

in the end those should be a given anyway, but it doesn't hurt to be extra vigilant.

It's too easy to temporarily forget about them since the care is so simple and their dietary needs so low.

 

[CRX]

I just wanted to add since maybe relevant, I've kept my little AFS at around 77-78 (maybe up to 80 occasionally) in the summer and the area of the house gets as low as 73-74~ in the winter.

I have had him since 2021, and while he is still small, he eats hungrily and he molts, he recently molted 2 weeks ago.

edit: i also have a hermit crab heater on the side of his tank (lol not rly a tank just a critterr keeper), but I think I may be due to get a new one cuz ive had that one for years and I worry it might not heat up like it needs to

 

[darkness975]

74 F in winter. You're lucky.

 

[CRX]

74 F in winter. You're lucky.

I've had him since 2021. But like I said, he does have a heater. Probably will get a new heater soon. 74 is the absolute lowest (in the room) and its higher in his enclosure.

 

[darkness975]

I've had him since 2021. But like I said, he does have a heater. Probably will get a new heater soon. 74 is the absolute lowest (in the room) and its higher in his enclosure.

I wish I could afford to keep my place at 74 in winter. That would be paradise.

 

[CRX]

I wish I could afford to keep my place at 74 in winter. That would be paradise.

The rest of the house gets colder, I think the temperature in my room is higher because of all the tanks and humidity

 

[darkness975]

The rest of the house gets colder, I think the temperature in my room is higher because of all the tanks and humidity

I would never leave the room! LoL

I had the same thing when I lived in one room years ago.

 

[CRX]

I would never leave the room! LoL

I had the same thing when I lived in one room years ago.

Hahah I try not to