Molting Signs - A Public Service Announcement

[ph0bia]

It's seems that, recently, there have been a number of horribly misinformed people when it comes to signs indicating premolt. I'd just really like to set the record straight here. Also, I'd like to point out this wouldn't annoy me nearly as much if these signs weren't portrayed as 'set in stone rules'. I hate the word 'sign' here as this suggests fact, ie "a sign of premolt" would suggest that if the 'sign' is present, it IS in premolt whereas 'indicates' merely suggests that it 'could be'. All of the methods we have (besides the bald patch, which is a sign) are indications only.

Remember, the guy in front of you in traffic may be indicating left, but this doesn't mean he actually will. He may just not have realised his indicator is still on.


"The tarantula is fat, this means it will molt soon."

I'm confused where this one came from. Perhaps someone is suggesting that the extra layer of skin underneath makes the spider fatter? Or maybe it's because if you overfeed your tarantula it usually speeds up growth and lowers the time between molts. Either way, a fat tarantula is more unhealthy than a thin one (as long as there's water), and this is not a sign of premolt at all.
As a case in point, my Brachypelma auratum molted last month, yet she's already quite fat. She won't molt for about another year.


"Look for a bald patch, if you see one, it's in premolt."

This statement is obviously stemming from someone who didn't listen/read properly first time. A tarantula with a bald spot means it has kicked urticating hairs, meaning something has stressed it out, or it's been webbing it's burrow (they often shed hairs into burrow webbing) or it's just lost some by brushing against things.
I've seen people try to argue this point ("Mine has a bald patch and she's never kicked hairs!") and it really doesn't work. Firstly, you'd have to watch your T 24/7 to know that she's never kicked hairs, she may have done it when you're not watching, secondly, the fact is, that bald patch is from losing urticating hairs, not from premolt.
Now, the reason that I stated that this must stem from someone not paying attention is as follows:

A bald patch can be used to indicate premolt, but the presence of the bald patch itself is not an indication!

Tarantula innards are a tan brown colour and their skin is colourless. Brush away the urticating setae of a newly molted tarantula, and you will see a patch of skin that is sandy tan in colour. This is because you can see the haemolymph through the colourless skin.
As the spider enters premolt, the new skin is growing beneath the old one, hairs included. This means that the bald patch darkens, instead of looking into the innards and haemolymph, when looking through the colourless outer skin, you are now seeing the new skin beneath and the darker hairs.

To summarise, if the bald patch is tan, no molt soon! If the bald patch is a greyish colour, expect an imminent molt. The presence of a bald patch alone is NOT an indication of molt in itself!


"The tarantula is webbing, this means a molt is due."

Not strictly true, but closer to the mark than the two above "methods". A good indication of the onset of premolt it the tarantula entering its burrow and webbing it closed (though some do this nightly - see if they come out again the next night) or a tarantula laying down a silk 'mat' outside or inside of the burrow.
This silk mat is used like a cushion when the spider rolls over and molts. However, I have witnessed spiders web themselves in or create a so-called molt mat, then not actually molt for a few months after. It's a good indication, but nothing definite.


"It stopped eating? It's in premolt!"

Again, this statement is taking a possible clue and turning it into a positive identification. This is akin to saying that "that car's stopped at the side of the road because it's out of petrol". There are so many other possible reasons! It could be a mechanical failure, maybe someone in the car is having a problem, it could even be that they've pulled over for a picnic.
My point is, tarantulas stop eating if they're full. They also refuse food sometimes for no reason (I used to feed all of mine locusts, then some stopped feeding. Without molting, three of them fed again as soon as I switched to crickets) and sometimes they're in a self-enacted winter (especially Grammostola rosea). Yes, this can be an indication of a molt, but it's an indicator of many other things too; just as a wet patch on the floor may indicate a leak, it may also indicate someone spilled their drink or that the dog needs house training.


I hope this can clear up some problems!

[atum]

Nice little bit of help

[My plague]

That's ace!
looks like a sticky to me
be a shame to lose that
it's good

[jartok]

This is very true - p.s its americans who spell it molt - we spell it moult

[garlicpickle]

Originally Posted by jartok

its americans who spell it molt - we spell it moult

Thank goodness I'm not the only old-fashioned one here

[ph0bia]

Blach, I just get caught in the habits of the texts... MOULT!!!

Sticky please!

[davieboi]

my simple one is its stopped eating its webbing alot and the SKIN has turned black

[forever_20one]

Just out of interest... My first large spider is in pre moult (I hope, don't dash me!), it's abdomen has turned completely black. This happened 5 days ago - just wondering how long - average - before it sheds?

[Danhalen]

Originally Posted by forever_20one

Just out of interest... My first large spider is in pre moult (I hope, don't dash me!), it's abdomen has turned completely black. This happened 5 days ago - just wondering how long - average - before it sheds?

It's entirely dependent on the species. Which one are we talking about?

[garlicpickle]

Originally Posted by forever_20one

Just out of interest... My first large spider is in pre moult (I hope, don't dash me!), it's abdomen has turned completely black. This happened 5 days ago - just wondering how long - average - before it sheds?

sometime within the next few weeks can't really be any more precise than that. My genic is sub adult and on the 2 occasions she has moulted with me, she has turned completely black about 2 weeks before the actual moult. If you should see yours scratching off hairs and laying down a web mat, that means it's actually getting ready and will start moulting very soon. But they don't always even lay a mat, so it really is a case of just wait and see.