How does leg regeneration work?

[kaolincash]

Hi folks,

Something I've been curious about for a while is just how the actual process of regenerating a leg.... happens?

What are the stages, where is the leg before the molt happens, etc.?
Does it begin small and increase in size over subsequent molts?

I'm finding it difficult to search for specific enough terms on google to find out anything more specific than "don't worry if your spider loses a leg, it will grow back".

Thanks!

 

[NYAN]

The leg develops under the old exoskeleton, and upon molting it shows itself.

 

[BrokenLegBaboon]

Does it begin small and increase in size over subsequent molts?

I don’t know what or how the process works but the regenerated leg will start out small and it will become normal after another molt or two.

 

[NYAN]

I don’t know what or how the process works but the regenerated leg will start out small and it will become normal after another molt or two.

Not always. Sometimes the entire thing will be fully developed.

 

[kaolincash]

The leg develops under the old exoskeleton, and upon molting it shows itself.

Where under the exoskeleton? How does it make room? That's what I can't wrap my head around.

 

[viper69]

Does it begin small and increase in size over subsequent molts?

yes

 

[Minty]

Where under the exoskeleton? How does it make room? That's what I can't wrap my head around.

The new exoskeleton that is growing, underneath the one that is currently on the outside, is incredibly soft and flexible, that's why when a spider moults, it needs a few days for the new exoskeleton to harden up.

 

[kaolincash]

The new exoskeleton that is growing, underneath the one that is currently on the outside, is incredibly soft and flexible, that's why when a spider moults, it needs a few days for the new exoskeleton to harden up.

I understand that, that's not what I'm asking.
What I'm asking is where specifically the leg grows; for the rest of the legs they grow inside the current sheath their exoskeleton is providing, of course, but there *isn't* a leg-sleeve for the new one to grow inside. Does anybody know the position of the leg within the old exoskeleton that the new leg takes?

Has this sort of thing been anyone's area of study, academically or as an amateur? If so, does anybody know of a diagram I could look at, or a time-lapse of how the leg develops inside the outer exoskeleton?
I'm absolutely fascinated by how it develops and interacts with the rest of the body as it prepares to molt.

 

[Minty]

I understand that, that's not what I'm asking.
What I'm asking is where specifically the leg grows; for the rest of the legs they grow inside the current sheath their exoskeleton is providing, of course, but there *isn't* a leg-sleeve for the new one to grow inside. Does anybody know the position of the leg within the old exoskeleton that the new leg takes?

Has this sort of thing been anyone's area of study, academically or as an amateur? If so, does anybody know of a diagram I could look at, or a time-lapse of how the leg develops inside the outer exoskeleton?
I'm absolutely fascinated by how it develops and interacts with the rest of the body as it prepares to molt.

Squash a sock up against a wall and you'll get an idea.

 

[Chris LXXIX]

It's like the 'Red' skeleton/s* of 'Castlevania' games: those regrow, always, thanks to some ancient magic

*Since you love skeletons, like my brother woman, had to say that

 

[kaolincash]

Squash a sock up against a wall and you'll get an idea.

Ah!! So they just don't fill the leg with haemolymph until they're molting?

It's like the 'Red' skeleton/s* of 'Castlevania' games: those regrow, always, thanks to some ancient magic

*Since you love skeletons, like my brother woman, had to say that

I haven't actually played any metroidvania style games (except duck tales on the original gameboy, if that counts) but I get the point, very good

 

[Moakmeister]

The new leg has no blood in it and is completely folded up beneath the exoskeleton. During molting, the new leg gets blood pumped into it and it inflates to its normal shape.

 

[kaolincash]

The new leg has no blood in it and is completely folded up beneath the exoskeleton. During molting, the new leg gets blood pumped into it and it inflates to its normal shape.

So they just don't fill the leg with haemolymph until they're molting

 

[AphonopelmaTX]

Hi folks,

Something I've been curious about for a while is just how the actual process of regenerating a leg.... happens?

What are the stages, where is the leg before the molt happens, etc.?
Does it begin small and increase in size over subsequent molts?

I'm finding it difficult to search for specific enough terms on google to find out anything more specific than "don't worry if your spider loses a leg, it will grow back".

Thanks!

For an overview of how leg regeneration works in spiders, see this article by Dr. Robert G. Breene at the American Tarantula Society website. Click "Cancel" on the prompts for a username and password. It is a free PDF download. The American Tarantula Society web site has been neglected for years. If you have problems with the site, let me know in a PM and I will send it to you.

For more articles, see the Downloads page at the American Tarantula Society web site. Again, click "Cancel" on any prompts for a username and password.

The short article answers all of your questions in this post. I also recommend buying the book "Biology of Spiders" by Rainer Foelix. It is an academic text that covers just about everything you would want to know about spider biology and physiology. The more specific one's questions get, the harder the answers are to find on the internet. Spiders are just not popular enough for extensive online treatments of the subject. Sometimes the answers are not on the internet but are in those old fashioned paper products called books.

 

[The Grym Reaper]

So they just don't fill the leg with haemolymph until they're molting

Pretty much, from what I gather, the new leg forms like some sort of empty skin sock under the old exoskeleton and is then "inflated" with haemolymph during/after moulting.

 

[Nightstalker47]

Not always. Sometimes the entire thing will be fully developed.

Really? In which species, they have always come out smaller from what I have seen...usually takes two or three molts to be back to normal size.

 

[NYAN]

Really? In which species, they have always come out smaller from what I have seen...usually takes two or three molts to be back to normal size.

I’ve seen it happen in true spiders before, so I imagine it could happen for tarantulas.