Moisture discussion....

[jrh3]

So on facebook, I was talking to a guy that was basically saying all Tarantulas can be kept on dry substrate as long as there is a water dish. Even species as C. Lividus and O. Violaceopes. Stating that all tarantulas can survive in dry substrate as long as they can drink, that this is the only moisture they need. How much truth is it to this statement? It goes against what I have learned about moisture dependent species but he was a moderator on one of the groups so you would think he had some knowledge.

 

[Cemykay]

Most adult tarantulas can be kept dry with a waterdish, but it really depends on the origin of the species. If it originates from a rainforest there should be a moist corner or more of the substrate in the enclosure. Species like the Theraphosa blondi need a moist (but not swampy) substrate. Tarantula slings need some moist substrate to the additional waterdish to keep the moisture inside their body.

 

[jrh3]

Most adult tarantulas can be kept dry with a waterdish, but it really depends on the origin of the species. If it originates from a rainforest there should be a moist corner or more of the substrate in the enclosure. Species like the Theraphosa blondi need a moist (but not swampy) substrate. Tarantula slings need some moist substrate to the additional waterdish to keep the moisture inside their body.

Yes this is what i was explaining to him. But he insisted the opposite, so why do they need moist substrate? I keep species that require moisture and have no issues, Im just wondering if there is any truth to his statement.

So basically moisture dependent species on dry substrate, will cause the moisture to be wicked away from their body and a water dish alone cannot keep them hydrated enough?

 

[Venom1080]

Certainly a more maintenance heavy way to do things.. I cant see moisture reliant species being very comfortable in such an environment. Having to hover near the water dish constantly.


Probably one of those things you can do, but shouldnt bother.

 

[Cemykay]

Yes this is what i was explaining to him. But he insisted the opposite, so why do they need moist substrate? I keep species that require moisture and have no issues, Im just wondering if there is any truth to his statement.

So basically moisture dependent species on dry substrate, will cause the moisture to be wicked away from their body and a water dish alone cannot keep them hydrated enough?

Slings need moist substrate because because they lack the coating which prevents dehydration of their exoskeletons. Some moisture dependent species like Theraposas seem to have molting issues when kept too dry. Otherwise i don't know why or if every species can be kept dry..

 

[jrh3]

Slings need moist substrate because because they lack the coating which prevents dehydration of their exoskeletons. Some moisture dependent species like Theraposas seem to have molting issues when kept too dry. Otherwise i don't know why or if every species can be kept dry..

Good point with the slings lacking the coating.

 

[Feral]

Thank you for trying to talk the other person out of his misinformed opinion. Any actions he takes based on the opinion, or any advice he gives to others based on that option, could be dangerous to some spiders. So thank you.

Short answer, I can't say that most moisture-dependent inverts would have success with that person's "method" in most situations for any length of time. So if that guy actually is legitimately having success using that "method" with moisture-dependent species for an extended time, the only explanation I can see is that his air is already adequately humid from some other source. Like from a general humid climate in his geographical location. Or maybe some heavy use of a room humidifier near his enclosure or something. I don't know. But it certainly doesn't seem like something that is viable for at least most situations with moisture-reliant species.

Yes this is what i was explaining to him. But he insisted the opposite, so why do they need moist substrate? I keep species that require moisture and have no issues, Im just wondering if there is any truth to his statement.

So basically moisture dependent species on dry substrate, will cause the moisture to be wicked away from their body and a water dish alone cannot keep them hydrated enough?

Some species need/benefit from moist substrate because moist substrate creates a microenvironment of increased relative humidity (by way of the water in the substrate evaporating into the air). But hobbyists can't effectively measure or adjust humidity, so we say to instead focus on what we can control, which is substrate moisture.

Substrate moisture/humidity affects different species differently under different conditions and at different stages of life. In particular, some species aren't as good as preventing moisture loss through their cuticle as other species due to their evolution in a particular climate with higher humidity, so they dehydrate more quickly in dry conditions than other spiders do.

Water dishes are excellent, and also required, but some species just can't take in enough fluids orally to compensate for evaporative water loss through their cuticle in environments that are too dry for them, especially over time. The longer this state lasts, the more their moisture deficit adds up (i.e. the more dehydrated they become) until it kills them. Whatever the time frame... Their death could be direct in the form of primary dehydration, or result from a bad molt that is secondary to (caused by) primary dehydration, or result from being immunocompromised due to primary dehydration.

So yes, substrate moisture creates humidity and humidity is important to the health of arachnids but, since we hobbyists can't effectively measure or adjust relative humidity, we just say to instead focus on what we can control, which is the substrate moisture.

 

[Smotzer]

Slings need moist substrate because because they lack the coating which prevents dehydration of their exoskeletons. Some moisture dependent species like Theraposas seem to have molting issues when kept too dry. Otherwise i don't know why or if every species can be kept dry..

But then you have slings like Chromatopelma cyaneopubescens and Caribena versicolor that the substrate has to be kept dry with only a water dish. It’s a little confusing sometimes with moisture

 

[jrh3]

But then you have slings like Chromatopelma cyaneopubescens and Caribena versicolor that the substrate has to be kept dry with only a water dish. It’s a little confusing sometimes with moisture

I never overthink it. I have had good luck with eyeballing coco fiber for moisture levels.

 

[Smotzer]

I never overthink it. I have had good luck with eyeballing coco fiber for moisture levels.

not saying over think it just that a lot of people say "all" slings need moist sub. but thats not true

 

[boina]

In particular, some species aren't as good as preventing moisture loss through their cuticle as other species due to their evolution in a particular climate with higher humidity

You still insist that moisture loss through the spiracles isn't important even though the lowest number for that was ever measured was 60% loss through spiracles, 40% through cuticle? And in other invertebrates than a desert spider that water loss through the spiracles was several times as much as through the cuticle? You can never ever admit you might not be 100% right at all times.

The second fallacy is to think that the environment an animal evolved in is optimal. It isn't. Actually it never is. Adaption means nothing more than an animal can survive in an environment, not that it is optimal. Where an animal can survive depends on a combination of things, including pathogen pressure, population pressure, interspecies competition, predation, and so on. Humidity is one single factor in a huge number of factors and it may not be optimal for the species. There are many examples for survival in obviously subobtimal environments - nearly every desert animal does much better with more access to water, for example.

You don't know if an animal from the rain forrest really needs humidity or just tolerates it until you try. Most arboreals can actually be kept completely dry (unless you live in a desert and average humidity is extremely low) and so on. Higher humidity invariably comes with an increase in bacterial load - and if there are opportunistic pathogens among them they may very well kill your spider. For me that's a good reason to keep your spiders as dry as they can tolerate. More humidity doesn't mean better survival - see Avics, for example.

 

[Colorado Ts]

So on facebook, I was talking to a guy that was basically saying all Tarantulas can be kept on dry substrate as long as there is a water dish. Even species as C. Lividus and O. Violaceopes. Stating that all tarantulas can survive in dry substrate as long as they can drink, that this is the only moisture they need. How much truth is it to this statement? It goes against what I have learned about moisture dependent species but he was a moderator on one of the groups so you would think he had some knowledge.

I have a pair of female Aphonopelma hentzi, that come from a very dry climate. I tend to keep them in a dry enclosure, but during winter, when they go into torpor...I do wet the substrate in a corner or overflow the water dish every couple of weeks. They'll stay in torpor for months at a time...so yeah, I'll provide moisture when they are underground.

 

[Smotzer]

I have a pair of female Aphonopelma hentzi, that come from a very dry climate. I tend to keep them in a dry enclosure, but during winter, when they go into torpor...I do wet the substrate in a corner or overflow the water dish every couple of weeks. They'll stay in torpor for months at a time...so yeah, I'll provide moisture when they are underground.

Thanks for this little tip because I plan on getting one in a few months!

 

[cold blood]

Well, there are many species that require damp sub specifically to keep their book lungs working properly.

There are many species, or genera for that matter, that I just wouldn't want to keep constantly dry...These are ts known to be intolerant of such dryness....like Theraphosa, Xenesthis, or most Asians....IME violaceopes in particular are a bad choice to experiment with dry enclosures for very long. For periods, sure, but not constantly. But sure, enclosures, even for slings, can dry out for periods of time. Slings might be fine for days, an adult may be fine for weeks, perhaps months....but it will eventually catch up to you.
I did have a juvie O. violaceopes die on me due to an enclosure that inadvertently dried out for too long while I was away, and that t most certainly had a water dish (with water...just to be clear)

But with most species, I will periodically dry enclosures for a time....helps keep the little unwanted irritants at bay, but permanently, I would never consider that or be willing to subject my ts to such an unnecessary experiment.

 

[The Grym Reaper]

But then you have slings like Chromatopelma cyaneopubescens and Caribena versicolor that the substrate has to be kept dry with only a water dish.

C. cyaneopubescens have the same care as any other NW terrestrial sling (slightly moist sub until 1.5" to 2"), I'm not sure when exactly this "keep them bone dry right off the bat" thing started but it was within the last 2 years, I've also noticed that since this started there have been more posts about dead/dying GBB slings.

Aviculariinae can be kept on slightly moist sub (just overflow the dish every now & again to moisten about 1/3 of the sub and don't mist) provided your enclosures have suitable ventilation to prevent stagnant conditions, since what constitutes "suitable ventilation" seems to vary quite wildly depending on who you ask it's just easier to tell newbies to keep them dry.

As far as I'm aware, the only species that don't do well with moisture at all and need dry sub right off the bat are Baboons.

 

[viper69]

Tarantulas can be kept on dry substrate as long as there is a water dish

FALSE- Avics don't always drink from dishes, Some do, and yet later on they stop.

O. Violaceopes

False, a little moisture is better than not IME.


Lastly, some species require a bit of humidity for breeding, or so I've read.

 

[Smotzer]

C. cyaneopubescens have the same care as any other NW terrestrial sling (slightly moist sub until 1.5" to 2"), I'm not sure when exactly this "keep them bone dry right off the bat" thing started but it was within the last 2 years, I've also noticed that since this started there have been more posts about dead/dying GBB slings.

Aviculariinae can be kept on slightly moist sub (just overflow the dish every now & again to moisten about 1/3 of the sub and don't mist) provided your enclosures have suitable ventilation to prevent stagnant conditions, since what constitutes "suitable ventilation" seems to vary quite wildly depending on who you ask it's just easier to tell newbies to keep them dry.

As far as I'm aware, the only species that don't do well with moisture at all and need dry sub right off the bat are Baboons.

Thanks for the clarification! I don't know everyone on here says to keep GBB slings dry right off the bat, ill adjust my set up.

 

[Colorado Ts]

I had my Chromatopelma cyaneopubescens in enclosures on moist substrate, all 5 slings. They refused to eat, they became lethargic, they quit webbing. This went on for weeks. The slings would climb the sides of the enclosure and sit by the vent holes....nothing else. Not good.

I reached out to several people about what I was experiencing with my GBB slings. Everyone of them said the same thing....”dry out the enclosures, add a water dish”.

I moved spiders around and ran every enclosure through a food dehydrator until they were bone dry.

Problem solved...Within a week, they began eating, OMG they can web up an enclosure, and they began exploring the substrate...GBBs do not like moist substrate.

In fact...There was a time, when the GBBs first entered the hobby; they very quickly developed a reputation for being a difficult, sensitive species. Then someone figured out to put them on dry substrate....now they are a hobby staple, and actually considered a beginners spider.

 

[Smotzer]

I had my Chromatopelma cyaneopubescens in enclosures on moist substrate, all 5 slings. They refused to eat, they became lethargic, they quit webbing. This went on for weeks. The slings would climb the sides of the enclosure and sit by the vent holes....nothing else. Not good.

I reached out to several people about what I was experiencing with my GBB slings. Everyone of them said the same thing....”dry out the enclosures, add a water dish”.

I moved spiders around and ran every enclosure through a food dehydrator until they were bone dry.

Problem solved...Within a week, they began eating, OMG they can web up an enclosure, and they began exploring the substrate...GBBs do not like moist substrate.

In fact...There was a time, when the GBBs first entered the hobby; they very quickly developed a reputation for being a difficult, sensitive species. Then someone figured out to put them on dry substrate....now they are a hobby staple, and actually considered a beginners spider.

This is what I have been led to believe and am currently doing, and mine eats like a champ and has started webbing

 

[Colorado Ts]

Then you are fine.

I got mine 3/4” to 1” in size. They've moulted twice since I got them, and that last moult was astounding. OMG, 3 of the 5 have doubled in size...amazing.

Of the other 2 slings...one is just a problem child, finicky eater, almost no feeding response. So it is maybe an 1 1/8 in size.

The last one is just a slower grower and sitting at a solid 1 1/4 size.

I’m looking to get another group of slings and a couple adult females in the next few months.

...and a few D diamentinensis, they look like baby GBBs, but with after-burners.