Is there a Biological Explanation of Molting

[Pennywise]

process anywhere. What I mean is the reason for refusal of food and why
and what effects it has on the spider. As to the complete process, what triggers
each phase of the molting process and the Biological reason for
each phase including what purpose it serves up to and including the actual
molt itself and the post molt process also. :?

 

[becca81]

Well, the purpose of molting itself is so that the tarantulas can grow. Due to its hard exoskeleton, it can't grow the same way that (for example) humans can. It has to grow a new (wrinkled up) skin underneath the old one in order to gain size. The stretching process after a molt is part of the increase in size - the exoskeleton isn't hardened yet as it allows the spider to completely "stretch out" its new skin before hardening and being ready to serve as a shield.

Molting can also serve the pupose of repairing any injuries so that the spider has a better chance of survival.

 

[MindUtopia]

As far as not eating, I think it has something to do with the fact that the lining of the mouth also sheds, so being free of food and the process of eating for several weeks allows that part of body to prep for molt as well. Though I'm sure there are other explanations, such as a slowing of metabolism as well.

 

[Mushroom Spore]

reason for refusal of food and why

I always thought it was because they just didn't have any more room inside their old skin. If you were eating a ton of food in tight pants, you might decide to stop eating too.

 

[Scolopeon]

As far as not eating, I think it has something to do with the fact that the lining of the mouth also sheds, so being free of food and the process of eating for several weeks allows that part of body to prep for molt as well. Though I'm sure there are other explanations, such as a slowing of metabolism as well.

Actually what she said was right, its the lining of the mouth. When they moult it becomes so soft and has to harden before they can feed again.
I agree with the first statement also.

 

[edesign]

It softens before the molt occurs? I am not overly familiar with T mouths myself...but from my understanding of the rest of the molt process things only need to harden after the molt occurs. However, since the mouth is partially internal I figured it was already soft all the time and that the fangs were what needed to harden before it could eat again.

So you're saying that the internals of the mouth become softer-than-usual/sensitive before a molt? :? Between what MindUtopia said and that, it would make sense...i think 2/3 of my T's are in premolt right now so I've cut way back on cricket purchases lately

 

[Pennywise]

Answers are good

but not exactly what I was looking for. This may not be at all correct but
here goes. The spider will refuse to eat for from a few days to several weeks
when the entire processes of pre molt, molt and then post molt are complete.
This is triggered by the fact that it's new exoskeleton has completely formed
underneath its existing outer shell. The new and old exoskeletons are separated
by a layer of fluid. The spider will molt when the outer shell
has sufficiently softened and weakened and the new shell has hardened
enough that the old shell may be split and shed during the forthcoming
molting process. Prior to the molt the spider will spin a "Hammock Web"
which will protect it and cushion it as it molts etc. :?

I had to guess what triggers the pre molt process being the new shell is fully formed
underneath the outer shell. It seems logical though doesn't it?

 

[Whiskeypunk]

but not exactly what I was looking for. This may not be at all correct but
here goes. The spider will refuse to eat for from a few days to several weeks
when the entire processes of pre molt, molt and then post molt are complete.
This is triggered by the fact that it's new exoskeleton has completely formed
underneath its existing outer shell. The new and old exoskeletons are separated
by a layer of fluid. The spider will molt when the outer shell
has sufficiently softened and weakened and the new shell has hardened
enough that the old shell may be split and shed during the forthcoming
molting process. Prior to the molt the spider will spin a "Hammock Web"
which will protect it and cushion it as it molts etc. :?

I had to guess what triggers the pre molt process being the new shell is fully formed
underneath the outer shell. It seems logical though doesn't it?

The Tarantula Keepers Guide has a good chapter on this process. I don't want to go into it here, cause I'm busy today and it's long.

 

[becca81]

I had to guess what triggers the pre molt process being the new shell is fully formed
underneath the outer shell. It seems logical though doesn't it?

From my understanding (and I could be mistaken), during pre-molt is when the "new" exoskeleton is being formed underneath the old exoskeleton, not prior to pre-molt.

Also, I'm not sure if the old skin actually softens or not, but I doubt it. The exuvial fluid allows for the old skin to "slide off" and the new skin is wrinkled up underneath.

 

[lucanidae]

moulting

Moulting is incredibly dangerous, the process itself and the time afterward. However, it's worth the risk because it allows for the protection of an exoskelton and the healing properties of a moult. Insects are the best moulters of all and they certainly are doing very well. The moult is triggered by many different hormones. The new exoskeleton is forming prior to pre molt and during premolt. The reason spiders don't eat is because they molt the structure that supports the sucking stomach, so the stomach needs to be empty. I've never heard of softening prior to molting.

 

[Pennywise]

I felt that I know so little about the molting process

which is something I have observed frequently and taken for granted.
For example, a spider needs to grow, it has an exoskeleton instead of
an endoskeleton. We observe the cycle and its general course, but the
truly intimate details of exactly what happens and what precipitates it
is something I would find fascinating to study. Yes hormones probably
would be the internal triggers of an internal biological clock or that
part of the spider's brain monitors the different phases of the molt cycle
and cause the release of hormones which start the next phase etc.etc.
I'll buy the lubrication too, the layer of fluid between the inner and outer
skin yes.
Dangerous yes that is a factor, I lost an H. Lividium that way and feel
quite lucky that my T. Blondi survived it's latest molt, in fact over a week
after molting it is still in post molt.

Softening of exoskeleton well like other parts of my example I invented that
and I am glad that I was corrected on this also.

 

[Prometheusmum]

Wouldnt they stop eating so the fleshy part of the body could seperate from the old skin so there is a new spider to come out? Just a thought...

 

[Kid Dragon]

Molt inhibiting hormone decreases to begin the pre-molt process. This triggers all the pre-molt behavior you have learned to recognize. In response to the decrease in molt inhibiting hormone, there is an increase in molting hormone which causes the old exoskeleton to thin. During molt the T breaks out of its old exoskeleton, and the cuticle of the new skeleton is still thin (soft). During the post-molt the new exoskeleton thickens (hardens) and the T has past the most vulnerable part of its life cycle. After this "rebirth" the T will soon be ready to :}

 

[Kid Dragon]

Wouldnt they stop eating so the fleshy part of the body could seperate from the old skin so there is a new spider to come out? Just a thought...

Molting takes so much energy the digestive system stops in response to hormonal activity. In humans, when adrenalin is released digestion stops as well.

Compared to what any human goes through with changes in hormone level, its a walk in the park compared to what a T has to go through to molt. In pre-molt and post-molt they most likely don't feel like eating. Men might not understand that as well as the women.

During molt they physically can't eat. I think it is very possible they can't physically eat during the later stages of pre-molt and the early stages of post-molt, but I don't know if anyone really knows this for sure.

 

[Pennywise]

I have heard claims of Ts eating right up

to the time they molt. I have only been doing this for 7 months and have
not witnessed anything like this. I had a B. Boehmei eat a cricket after
it started pre molt though. It was about a week or more after it quit eating.
I dropped the cricket in the wrong enclosure and realized it right away but
the cricket ran right into the spiders fangs and the tried to jump. The Boehmei
seemed to act mostly on reflex but he actually did eat the cricket anyway.
He didn't actually molt until another 2 weeks had passed.

 

[Whiskeypunk]

to the time they molt. I have only been doing this for 7 months and have
not witnessed anything like this. I had a B. Boehmei eat a cricket after
it started pre molt though. It was about a week or more after it quit eating.
I dropped the cricket in the wrong enclosure and realized it right away but
the cricket ran right into the spiders fangs and the tried to jump. The Boehmei
seemed to act mostly on reflex but he actually did eat the cricket anyway.
He didn't actually molt until another 2 weeks had passed.

My T. Blondi ate a cricket on a sunday night and molted tuesday night, so they can eat.

 

[Pennywise]

Well that shoots that theory

It would seem that if the fangs are still hard and can inject venom,
that the T can get nourishment if it is low on energy. Which means
it may be less vulnerable than one might think during pre molt.
It looks like during molting and also the post molt period while its
exo and fangs are still hardening is it's main period of vulnerability.

 

[David_F]

There's an article at the T Store forum that explains the molting process pretty well. Here it is.

I'd also recommend trying to get a copy of Biology of Spiders by Rainer Foelix. Good stuff about spiders in there.

 

[Nike]

Was just about to recommend the same book; it`s worth getting if you want to understand how the arachnids are put together and what makes them tick. It goes quite deep into technical stuff,but is written in a way that makes it understandable to a common mortal, too...

 

[Pennywise]

Great Link!

This is what I was looking for in my original post. I thank everyone who posted replies to my question for contributing. I think the link is in terms we can all understand, I know it sheds new light on the subject for me. Special thanks to David F for giving us the link!