HCA: Hermit Crab Association

HI everyone,

There is a bit of a debate going on about Eco Earth being a safe substrate due to it's acidity levels.

View debate here: viewtopic.php?p=733413#733413

For those of you that live in areas where hermit crabs are native- could you possibly do a PH test of their natural substrate in the wild and let us know your findings?

We want to find out if certain species of hermit crabs have a higher acidity tolerance in regards to their environment and the substrate found in it.

If you are willing to do the test please state:

Location
Type of Substrate(s) tested
Hermit crabs typically found in that area
Ph level of the substrate(s)

Thanks!

Edit:
Just wanted to post this here, kgbenson made a great point:
tigermoon89 wrote:

I would not make this assumption about pH. After all, there are many organisms that cannot tolerate a pH of 7 for very long.

Whether or not people agree on a number is not relevant.

Keith

The pH of coir is well-known since it's been used as seed starter for years. It has a pH between 5.5 and 6.8.

http://www.finegardening.com/how-to/art ... atter.aspx

A pH of 5.5 is what most humans are - our skin, saliva, urine, etc. It's also the pH of most hand soaps. (I actually tested that one out a while back because I was curious.) So it's really not that acidic by comparison.



Straight silica sand (playsand) should have a neutral pH of 7. Aragonite sand should be higher at 8.2.

In comparison, most freshwater fish live in a neutral pH between 6.0 and 7.6. Most salt-water is between 8.2 and 8.4. 7.0 is neutral. 5.5 is what the pH of rainwater should be - though depending on your area and pollution rainwater varies a lot now.




Finding out info about the soil composition of the tropics isn't that hard since there's a ton of farming going on down there. It's extremely acidic soil for crops and it's hard to get things like bananas to grow. I googed information about the soils of Puerto Rico since English articles are more likely since it's part of the U.S. and it's also part of Clypeatus native range,

On the third page down:
http://www.fs.fed.us/global/iitf/pubs/g ... 201997.pdf

It gives a chart of native soil pH for grassland, forest, grass-vine-fern, and shrub-small tree areas. The pH varies between 4.7 and 5.1.

The natural soil of Puerto Rico is much more acidic than the cocofiber we use.

Granted, this is just one place in one species habitat. However, they used to have a thriving population of Purple Pinchers before humans came along.

The other question that needs to be asked is where to hermit crabs actually bury themselves to molt? Do they do it back in the forest canopy? Between where the forest meets the beach? Does anyone know for sure? They can range very far inland so there should be no doubt that they would live on normal soils as opposed to just beach sand, but will they then migrate to a different location when it comes time to molt?

Edited to get rid of double link.

Wow! Wodesorel, you are a researcher extraordinaire!

Thanks. Mom and Dad are both geologists, so I was raised knowing way too much about this stuff.


I found some more info, and wanted to post it.

The location of the study in my previous post was at - Sabana (18”18’N, 65’5O’W) in the northeastern Luquillo Mountains of Puerto Rico.

There's another paper by the same people who list the location of this test in Puerto Rico as

The study was conducted at El Verde (18°19’N, 65°49’W) in the Luquillo LongTerm Ecological Research (LTER) site, within the subtropical wet forest life zone.

The pH there ranges between 4.7 to 5.9.
http://academic.uprm.edu/publications/c ... 93-100.pdf


Another study, located again in Puerto Rico

The RGA watershed is located in the north-central part of Puerto Rico

Soil pH ranged between 4.5 to 5.3
http://etmd.nal.usda.gov/bitstream/1011 ... 855930.pdf



This one is for the Caribbean side of Cost Rica:

This study was conducted at EARTH University at the confluence of Parismina and Destierro rivers, in the Caribbean lowlands of Limon Province, Costa Rica

pH range of 3.7 to 4.8
http://www.bio-nica.info/biblioteca/Jim ... taRica.pdf



And finally from the Caribbean cost of Columbia:

The region known as Cienaga Grande de Santa Marta is part of the exterior delta of the Magdalena River and is the largest Estuarine lagoonal complex in Colombia.

pH range of 5.8 to 6.85
http://www.uprm.edu/biology/profs/chine ... _e1998.pdf


The low pH of some of these places really shocked me. Sphagnum peat moss has a pH of around 4.5, so that would be very close to some of these soils.

However, I've been looking into Emperor Scorpion care since I saw one in person and thought it would be coolest pet ever. (Like a giant jet-black shell-less hermit crab! ) Imagine my surprise when I learned that this tropical exo-skeletoned arthropod that molts is recommended to be kept on sphagnum peat moss. My initial reaction from having hermits was complete terror, thinking about all the warnings I had heard about pitted exos and bad molts. Yet expert caretakers have been keeping them this way for decades with no exo problems, and the scorpions live out full life-spans of around 8 years. Since their native soil is acidic rainforest, they're already adapted to the low pH. Also, the acidic soil is a bonus in captivity as it prevents the growth of harmful microorganisms.

Great Work! I'm really impressed!!!

Would you know anything about the Ph in Florida where the hermit crabs are found?

Thanks for doing this!

I know next to nothing about Florida geography. The tropical islands and coastline are easy as it all falls into the clypeatus range. Florida - not so much!

For locations within the US (including Puerto Rico and Guam), you can use this site here for soil reports:

http://ssldata.nrcs.usda.gov/querypage.asp

If someone can give me a list of COUNTIES where hermit crabs are known to reside then I'll run the reports and list the info here.

general geological info is all well and good, and valuable, but what really matters can be summed up in a single concept:

microhabitat.

That is what counts.

Now - anyone got any data?

Keith

I've read before (and I can't find it, it's not in my books or the greenaway papers, it might have been from coenobita research or some other members) that in the wild, inland crabs (PPs, etc) don't always bury under substrate to molt. Rather, they simply bury under decomposing leaf litter, or otherwise hide under rotting logs or other forest litter.

So surface molts themselves may not really be that unnatural for hermit crabs.

This info here would explain the reasoning why some of our members (I know myself and Wodesorel) have had moss pit molts. Possibly the crabs think that the moss is the same thing as leaf litter?

JediMasterThrash wrote: Rather, they simply bury under decomposing leaf litter, or otherwise hide under rotting logs or other forest litter.

So surface molts themselves may not really be that unnatural for hermit crabs.

I think these two statements are largely at odd with one another.

Keith

samurai_crab wrote:This info here would explain the reasoning why some of our members (I know myself and Wodesorel) have had moss pit molts. Possibly the crabs think that the moss is the same thing as leaf litter?

Or, simply that space satisfies that crab most at that time. It might be perfect, or simply the best he/she is aware of within the area he/she can get to for any number of reasons.

Keith

wodesorel wrote: Imagine my surprise when I learned that this tropical exo-skeletoned arthropod that molts is recommended to be kept on sphagnum peat moss. My initial reaction from having hermits was complete terror, thinking about all the warnings I had heard about pitted exos and bad molts.

A) scorpions are not hermit crabs.
B) I don't know what to make of the poor molting stuff either, or the pitting of exoskeletons. I do know that acid substrates seem to dull shells more quickly and that makes sense given that dilute vinegar does the same thing that gastropod shell materials are definitely subject to degradation by acidic media, but exoskeletons are another matter and their ability to resist damage chemical, traumatic etc, varies between species.
Yep, for this species of scorpion, it works. It might work for land crabs but I would caution people about thinking that just because some species of scorpion do well when treated this way (and not all will, emperors are forest critters, not all scorpions are) that LHC will also. Apples and oranges.

Whoa there sonny, acid inhibits the growth of many harmful organisms (particularly with reference to many organisms with respect to human food born illness) but I think the statement above is entirely too broad. For that matter - what organisms are disease causing species for hermit crabs?

There are many acid tolerant organisms that can be harmful. Many.

Also, let us not equate rain forest floors with single agent finely ground materials like Coir. They are certainly not equivalent. Rainforest floors are very complex substrates with a large number of microclimates and so forth.

Keith

I have to add that surface molts are not common maybe here on the HCA but I do not find them to be common. I find them to be a problem. Its very hard on a crab. I would say if your having surface molts look at your tank and try to find out why. I have had one surface molt and it was the same day i brought an adopted crab into my tank, i would say that he never had time to dig down. He was in bad shape when i brought him into my home. I would look at your substrate, humidity and temp of the tank if you are having surface molts..

Keith - I only meant that the scorpions have adapted to molting in the soil in which they are found, which happens to be acidic. I wasn't referring to hermits, and I apologize if it came across that way. The largest reason I've heard to not use acidic substrate is because the crabs have an exoskeleton - however the scorpions prove that just because an animal has an exo doesn't mean it will dissolve in something acidic. If hermit crabs' native soil is acidic, then they should have adapted to it as well. The question is how often are they found in this type of substrate.

The Caribbean Islands are a mix of both volcanic islands (very acidic) and coral-based sand islands (basic). Hermits are found on all of these islands, regardless of geological make-up. Add in tropical decaying plants (again acidic), and hermit would have had to adapt to survive at both extremes. It would take someone actually going down there and observing where hermit crabs are molting and then taking samples to be completely certain, but the literature is out there to make some very educated theories as to what the soil composition is like.

Also, I don't think the shell argument is valid. Shells are composed primarily of aragonite (calcium carbonate). Hermit crab exo is mainly chitin (closely related to glucose, a sugar). Comparing the two is like comparing apples and oranges. Just because a shell dissolves doesn't mean that a hermit crab will. How about this one - in my freshwater tanks, seashells dissolve quickly, yet I had ghost shrimp stay alive for over almost two years without melting. Going by the theory that since the shell dissolves so should the crustacean, then the shrimp should have been dead a whole lot sooner.

wodesorel wrote:Also, I don't think the shell argument is valid. Shells are composed primarily of aragonite (calcium carbonate). Hermit crab exo is mainly chitin (closely related to glucose, a sugar). Comparing the two is like comparing apples and oranges. Just because a shell dissolves doesn't mean that a hermit crab will.

This explains a lot for those of us who use 100% coco fiber as substrate and have very healthy crabs. For over three years now I've used coco fiber exclusively and in that time I've never had a single surface molt and my crabs' exoskeletons are not at all damaged.