Barometric moulting

[Nitibus]

I have come to a possible conclusion and I was wondering if it is just a coincidence, or if other have made the same observation. I have been trying to keep detailed stats on T moults. One thing that I have noticed; T's seem to moult when the barometric pressure is decreasing. It seems everytime I have a rain storm, a T moults.

Could the lower pressure play a roll in helping the T pop its carapace ?

Has anyone else made this observation ?

 

[Talkenlate04]

Yes, Dan from Tarantulas.com brought it up to me about 6 months back, and ever since then I went back and looked at weather data in my area the dates I had molts and egg sacs and his theory is holding up pretty well, very well actually. Every molt I have had has occured when a front was coming through and the pressure decreasing. I had three molts yesterday, and in Oregon we had high pressure move away to the east starting mid morning yesterday.
I think it's pretty interesting. I am going to continue with trying to check on how much of a pressure drop there is to see if that makes any difference. The cool part is all this data is recorded by someone else so if you miss a day you can find it somewhere.

 

[138]

we had a storm come in from the gulf this past friday and my p. platy, c. gracile and l. violaceopes all molted that night.

 

[cacoseraph]

hmm... the molting process is very long and complex. i have doubts that the correlation would stand up to actual analysis beyond eyeball. the reason being that a front only drops pressure for a couple few days before it arrives and keeps it depressed for as long as it is around... but the molting process, especially in adults can take over a year

it is possible to my understanding of things that maybe a low pressure system could rush the last few days or something...

if anyone wants to give me their molt dates and baro data i can do things to it for them

 

[Talkenlate04]

I am only speaking of the molt itself not the "premolt" before hand.

 

[cacoseraph]

I am only speaking of the molt itself not the "premolt" before hand.

er... the whole process is ongoing and continuous, to my understanding. it can't exactly be split up like i think you are doing.

like... certain conditions must be fulfilled before a tarantula can experience ecdysis, that is, the actual crawling out of its skin. i.e. it must have a new exoskeleton ready, it must seperate from its old exo, and it must(sort of) reabsorb all available nutrients from the old exo.

so what i am saying is that once all these things are accomplished and the spider is primed for molting *then* and only then could some outside stimulus have genuine affect on the actual ecdysis timing.

of course, one of those preconditions (forming new exo) we definitely know how to manipulate... heat and feed

like i said, i would be happy to process any data anyone wants to give me. i love playing with numbers

edit: and bugs

 

[Talkenlate04]

I do see what you are getting at. I am just focusing on when they molt and when sacs are dropped. I realize I have nothing solid till I widen the data I am collecting. And I know that I am just focusing on the end result.
But I do think its interesting that they seem to wait till a low front comes through the area to molt. I had three small pokies in heavy heavy premolt. So dark and colorless and lethargic, but there was a ridge of high pressure in the area for the last 6 days. But when it moved out molt molt molt. I just think its interesting.
Do you have a suggestion on how to gauge different stages of the molt process then?

 

[cacoseraph]

Do you have a suggestion on how to gauge different stages of the molt process then?

nope =P

nothing worthwhile, at any rate. if you had the actual molt date that is really the only solid data produceable that i can see. you might be able to work something with when they last fed, but that is too fuzzy, as many variables are involved there.

 

[Talkenlate04]

Ya I kind of figured it would be harder to include some other aspect. Last day of feeding could be one. But every other aspect is hard to prove. Ahh well maybe over the long term I can prove a certain pressure has to be present for a molt to take place.

 

[Slash]

I was always under the impression that once the tarantulas body tell them its time to molt...its time to molt...no mater what the conditions are. But then again, many animals have amazing meteorological sencing abilities.

 

[Talkenlate04]

Hey now that I think about it this may explain some Ts molting while being shipped. They are being exposed to varying levels of pressure going up and down in a plane. Maybe that triggers a molt in a T that's waiting for a pressure change.

 

[cacoseraph]

Hey now that I think about it this may explain some Ts molting while being shipped. They are being exposed to varying levels of pressure going up and down in a plane. Maybe that triggers a molt in a T that's waiting for a pressure change.

i "noticed" that too, but when i tried to figure out if a disproportionate amount molted in shipping the theory started to fall apart. i mean, i've had hundreds of taras and what not shipped to me... and something like 3-5 have molted in transit. when you figure in the # of days in transit/in the shipping container versus the number of days in a year versus the chances of just randomly molting on any given day their seemed to be very weak or no correlation... but it's not like i ran numbers... i just did guestimating in my head, like

one problem about observations that aren't carefully controlled... humans tend to see what they expect, where they expect it, when they expect it and sort of filter out everything else. it is one of the prices we pay for our like, heuristical logical units in our brain that speed us up. (my opinion of course)

but i would love to run someones data (HINT HINT!!!!) hehehe

 

[Taceas]

Interesting, and I don't think its entirely out of the question, either.

I know snakes aren't tarantulas, but I notice most of the sheds occur when storm fronts move through. Matings also have a higher likelihood of taking place during stormy periods as well.

 

[Talkenlate04]

Problem is other then checking to see if there was a change in pressure I have not been recording squat :wall: . Like yesterday, I know the high pressure moved out of my area and was replaced with a low, but I don’t know what kind of pressure drop took place. Now that we have chatted I have started to think of ways to start a long term study with a spreadsheet.

As for the shipping thing, maybe the low number of molts has to do with where in the premolt process the T was when it was sent. I'd wager that most Ts are not shipped close to a molt. Heck there are a zillion variables.

 

[Talkenlate04]

Interesting, and I don't think its entirely out of the question, either.

I know snakes aren't tarantulas, but I notice most of the sheds occur when storm fronts move through. Matings also have a higher likelihood of taking place during stormy periods as well.

What about egg laying?

 

[cacoseraph]

Heck there are a zillion variables.

yeah

doing anything "real" is a gigantic pain the ass, usually. fun... but only in a somewhat masochistic sense. heh.

much respect for true scientists

 

[Talkenlate04]

So if I track the actual drop in pressure that takes place with each front, and add in when molts take place, maybe I can narrow down an ideal pressure that molts take place.........

Or have a ton of cool but mostly useless data.

 

[cacoseraph]

So if I track the actual drop in pressure that takes place with each front, and add in when molts take place, maybe I can narrow down an ideal pressure that molts take place.........

Or have a ton of cool but mostly useless data.

well... i can really only do corellations not causations. experiments are more the realm of causations, i think.

 

[Talkenlate04]

well... i can really only do corellations not causations. experiments are more the realm of causations, i think.

But if through my study I can say 90% of molts take place at this pressure, is that data a corellation or a causation? I would think its a direct corellation.

 

[cacoseraph]

But if through my study I can say 90% of molts take place at this pressure, is that data a corellation or a causation? I would think its a direct corellation.

it's just corellation. corellation is not causation. you pretty much have to do experiments to isolate variables to attempt to prove causation.