What factors initiate moulting? Specifically can damage to a given area bring on premoult?

Janie

Arachnopeon
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Aug 7, 2016
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Hello I have been thinking about the hormonal initiation of moulting ecdysis.

In crayfish when the animal outgrows its shell it leads to disruption of the area responsible for hormone production region in the eyes and moulting is initiated. If the eyes become damaged by trauma moulting is also initiated. Is this similar for tarantulas?

Can rough handling in the postal system lead to an initiation of moulting?
 

shining

Arachnodemon
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Jul 15, 2011
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Yes, they share that trait. I think all arthropods do.

If packaged correctly such an injury wouldn't be an issue.
 

viper69

ArachnoGod
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Shining may be right. Some people have speculated that a T may molt sooner if there is injury. I'm not sure if it's a scientific fact or observational from keepers.

Others, including myself, speculate the local weather, such as rain storms may stimulate molting as well. But that's not injury.
 

mmfh

Arachnobaron
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Jun 14, 2010
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I had a G. pulchripes that was due for a molt. Then she cast off a damaged leg. She molted the next day and I'm assuming that some type of healing or exoskeleton growth must have to occur between the casting off and a molting because she "bleed out" quickly and died. So I guess to cause a molt with physical damage you would have to know the molt cycle.
 

AphonopelmaTX

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Hello I have been thinking about the hormonal initiation of moulting ecdysis.

In crayfish when the animal outgrows its shell it leads to disruption of the area responsible for hormone production region in the eyes and moulting is initiated. If the eyes become damaged by trauma moulting is also initiated. Is this similar for tarantulas?

Can rough handling in the postal system lead to an initiation of moulting?
Do you happen to know of any research papers or books that describe how it came to be known that eye damage initiates ecdysis in crayfish? I would like to read the methodology used in experiments that led to that conclusion. I've been trying to find the answer to this very same question for a long time and can't come up with anything on ecdysis being initiated by trauma in spiders. If this definitely occurs in other arthropods, like crustaceans, I would like to know more about it. Maybe by reading how this works in other arthropods there could be some clues as to if it is possible in spiders.
 

AphonopelmaTX

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Others, including myself, speculate the local weather, such as rain storms may stimulate molting as well. But that's not injury.
Add me to that list too. Biorhythms along with nutritional well being I would say definitely have a role in the regular molting. Fortunately for me, I can study this a bit using two adult female Texas tarantula species: Aphonopelma anax and A. hentzi which are both wild caught. Since I live in a poorly insulated building in Texas, their biorhythms are in synch with wild ones and get to experience all of the seasons, well, the two in Texas hot and very hot. Every year in the month of June and July these two tarantulas in my collection molt like clockwork, but the exotics in my collection from both the northern and southern hemisphere don't. I also try to mimic Texas' rainy seasons too. Easy enough as when it rains regularly, I just add water to the substrate. I'm not sure that has any effect though, but I do it anyway.
 

Janie

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The original information came from a comparative biology paper I took ages ago, it ended with a story about fishermen trying to get larger crayfish by removing the eyes of undersized crayfish and wondering why their catch was not improving... Blind crayfish cannot see predators.

I found this book. https://books.google.com.au/books?i...s release hormone controlling ecdysis&f=false

And then googled corpora cardacia function. Apparently in spiders it sits in the ventral brainstem so pretty central.

I also found an article describing the hormone secreting cells as lying along the trachotheca (spelling?) I cannot find it just now and am worried about timing out so will look later. I wish there was more easily available information out there.

Thanks for the replies.
 

Janie

Arachnopeon
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Aug 7, 2016
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Add me to that list too. Biorhythms along with nutritional well being I would say definitely have a role in the regular molting. Fortunately for me, I can study this a bit using two adult female Texas tarantula species: Aphonopelma anax and A. hentzi which are both wild caught. Since I live in a poorly insulated building in Texas, their biorhythms are in synch with wild ones and get to experience all of the seasons, well, the two in Texas hot and very hot. Every year in the month of June and July these two tarantulas in my collection molt like clockwork, but the exotics in my collection from both the northern and southern hemisphere don't. I also try to mimic Texas' rainy seasons too. Easy enough as when it rains regularly, I just add water to the substrate. I'm not sure that has any effect though, but I do it anyway.
Really interesting, and it sounds as though there could be a link between environmental rhythms/conditions and moulting. I searched a veterinary scientific article data base I have access to and found nothing! The articles I did find were parasite control. Aargh. Google seems better.
 

viper69

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Add me to that list too. Biorhythms along with nutritional well being I would say definitely have a role in the regular molting. Fortunately for me, I can study this a bit using two adult female Texas tarantula species: Aphonopelma anax and A. hentzi which are both wild caught. Since I live in a poorly insulated building in Texas, their biorhythms are in synch with wild ones and get to experience all of the seasons, well, the two in Texas hot and very hot. Every year in the month of June and July these two tarantulas in my collection molt like clockwork, but the exotics in my collection from both the northern and southern hemisphere don't. I also try to mimic Texas' rainy seasons too. Easy enough as when it rains regularly, I just add water to the substrate. I'm not sure that has any effect though, but I do it anyway.
Glad you chimed in Apho. I have long believed they were tied to weather. I know many other animals are for breeding, such as frogs. But for molting I haven't come across this myself in literature (haven't looked across arthropods minds you).

I also think the exotics from the Southern Hemisphere are expecting a spring/summer during our fall/winter. I can't imagine why they wouldn't to be honest despite local cues, if any sensed, from living in the North. Hemisphere
 

viper69

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Really interesting, and it sounds as though there could be a link between environmental rhythms/conditions and moulting. I searched a veterinary scientific article data base I have access to and found nothing! The articles I did find were parasite control. Aargh. Google seems better.
NO surprise, there's very little biology info on Ts. Plenty of taxonomy and some amount of genetic/evolution/ecology oriented articles. But cell bio/physiology etc very, very little.
 

Scourge

Arachnoknight
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Interesting question! On the topic of weather affecting moults, there was some talk on here a few years ago speculating that a drop in barometric pressure could provide a cue for spiders to moult or drop eggsacs.
 

Toxoderidae

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The original information came from a comparative biology paper I took ages ago, it ended with a story about fishermen trying to get larger crayfish by removing the eyes of undersized crayfish and wondering why their catch was not improving... Blind crayfish cannot see predators.

I found this book. https://books.google.com.au/books?id=F7A8AAAAIAAJ&pg=PA150&lpg=PA150&dq=arthropod+eyes+release+hormone+controlling+ecdysis&source=bl&ots=M7cKG8o3mB&sig=WwIfWTNsYfMRjxgChUZECjGt6Ig&hl=en&sa=X&ved=0ahUKEwiqlcXc47vOAhWIoJQKHSE_AOUQ6AEIKDAD#v=onepage&q=arthropod eyes release hormone controlling ecdysis&f=false

And then googled corpora cardacia function. Apparently in spiders it sits in the ventral brainstem so pretty central.

I also found an article describing the hormone secreting cells as lying along the trachotheca (spelling?) I cannot find it just now and am worried about timing out so will look later. I wish there was more easily available information out there.

Thanks for the replies.
One thing you gotta remember with crustaceans, they are far more advanced than any other arthropod, especially Ts.
 

Janie

Arachnopeon
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Aug 7, 2016
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It is interesting, I have been searching the Internet the last few days and not found anything more of note.

But I was thinking posting tarantulas that have been under a heat lamp may be more the link than damage? Two days flying and travelling in winter (Australia) without heat may be enough? Just guessing.

It was a bit wishful of me to think minor damage could sometimes be ameliorated by initiating a moult.

Spiders are awesome by the way, I find myself watching them in the "wee smalls". My husband says that I have arachnoplillia.

I am off to join the American Tarantula Society as I hear there is a good discussion going on.

Thanks again
Janie
 

Janie

Arachnopeon
Joined
Aug 7, 2016
Messages
6
It is interesting, I have been searching the Internet the last few days and not found anything more of note.

But I was thinking posting tarantulas that have been under a heat lamp may be more the link than damage? Two days flying and travelling in winter (Australia) without heat may be enough? Just guessing.

It was a bit wishful of me to think minor damage could sometimes be ameliorated by initiating a moult.

Spiders are awesome by the way, I find myself watching them in the "wee smalls". My husband says that I have arachnoplillia.

I am off to join the American Tarantula Society as I hear there is a good discussion going on.

Thanks again
Janie
Oops I am about to join the arachninological society.. Not T.
 
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