Magnificent...

My thoughts were also with adult spiders.

do you put the spiders into a completely new and clean tank

I do. I have only transferred webbing from a female enclosure to a male enclosure to induce sperm web production, and it often works well. When I re house adults, I have never thought of transferring "old furniture" as such.

Yes they will react to negative stimuli

Can such reaction be a moult perhaps?

Ok, I call it stress for lack of a better term for being uncomfortable and insecure.

Try to feed a T' right after it made a run out of an enclosure and has been caught again. Or even right after rehousing it. Most likely it won't touch anything for a while.

Look at the posture of an "unhappy" T', how scrunched up or huddled they are.

By the way, I haven't even had the incidence of T's moulting out of their time after rehousing them. But then again, I try to do it as rarely as possible. And then I try to do it after their moult if at all possible. If a T' goes into premoult I routinely up the humidity in their enclosures somewhat and keep it at this level until the spider moults. So humidity will most likely play a role to a degree, as Duke and others conclude.

Scarab wrote:

Yes they will react to negative stimuli

Can such reaction be a moult perhaps?

I was thinking more in terms of the spider sitting huddled up in it's new enclosure making itself small or sitting on the side of the tank up off new substrate. Moulting uses up energy and resources whilst leaving the spider vulnerable during and after a moult so it would serve no purpose to the spider to moult as a reaction to negative stimuli.

Marula wrote:

Ok, I call it stress for lack of a better term for being uncomfortable and insecure.

But again these are both emotions.

Marula wrote:

Try to feed a T' right after it made a run out of an enclosure and has been caught again. Or even right after rehousing it. Most likely it won't touch anything for a while.

Yes but it is still in fight or flight mode at this point which over rides any feeding instinct. Leave it a couple of hours and throw a cricket in and you will probably find it takes it. This is certainly the case with most spiders that i receive in the mail and rehouse.

Marula wrote:

Look at the posture of an "unhappy" T', how scrunched up or huddled they are.

It is just a natural survival instinct for an exposed creature to try and make itself look small.

I'm fresh out of ideas then. Would love to know the reasons behind the phenomenon. Whatever it is, there is no doubt it happens, perhaps less so with dropping an egg case.

If any thoughts on the matter pop up, please share.

So then...

What is the difference between male webbing (spider silk) and that of females, if any?

Male tarantulas have special spinnerets surrounding the genital opening. Silk for the sperm web of the tarantula is exuded from these special spinnerets.
So I would say yes the final layer would be different.
Also interesting to note is the discovery of silk-producing organs on the feet of the Aphonopelma seemani.

Awesome...

Why does the male react the way he does when he comes into contact with female silk (or gets close to her nest)?