Colour mutations in Theraphosidae

[KezyGLA]

Hi all,

A while back I posted up a picture of one of my adult female Grammostola pulchra and it caused a little confusion. A lot of people were very fast to suggest 'hybrid'.

I think it is important for me to share these photos to show that colour mutations do happen. They are very rare but do happen.

I have seen this happen in a couple species of Aphonopelma (chalcodes & anax) where specimens turned a dark black all over after a moult and then returned to regular colours upon the next.

Recently another member posted up a picture of their Nhandu chromatus which had turned brown upon its most recent moult. Even though before it had typical Nhandu chromatus colours and patterns. And again people suggested 'hybrid'.

The purpose of me starting this thread was to share my specimen which had a mutation. I would also like to ask other members who have had mutations happen to please share them here along with some details about that specimen.


Grammostola pulchra

When this specimen first arrived in my care it looked exactly as it does in photograph 1. I was very curious when the previous owner (local to me) said it was a pulchra. He said it had always been black all over until its most recent moult in his care and then the legs had turned beige/brown. I believed him and happily took it as it looked like what it should be apart from the colours.

Now the specimen has finally moulted in my care. It has returned to jet black and upon inspection of the spermathecae, it is definitely pulchra.

I have attatched the photos below. Please share your photos and experiences with colour mutations if possible.

 

[miss moxie]

Huh, that's fascinating. Besides that N. chromatus post recently I've never seen anything about color shifts in tarantulas. I mean it's not "out of this world" when you consider it. Genetic mutations occur naturally even in organisms as simple as bacteria.

 

[Venom1080]

Same thing with P metallica black form, some people swear it's old females, but others say its been black from 2".

Was that Nhandu not a hybrid then?

@AphonopelmaTX any insight into why this sometimes happens?

 

[KezyGLA]

Huh, that's fascinating. Besides that N. chromatus post recently I've never seen anything about color shifts in tarantulas. I mean it's not "out of this world" when you consider it. Genetic mutations occur naturally even in organisms as simple as bacteria.

Yup. Thats why it can be frustrating when people say "that's a mongrel" or "you shouldn't breed that". When you know it is what you are saying it is

 

[KezyGLA]

Same thing with P metallica black form, some people swear it's old females, but others say its been black from 2".

Was that Nhandu not a hybrid then?

I have had my share of black metallicas. I am sure that is an age thing though.

Most species of Harpactira will go black with age in captivity. I have no idea why this is.

I dont think that members chromatus was a hybrid to be honest. But thats just my opinion for now. Hopefully they will post here or elsewhere with an update when it molts.

 

[miss moxie]

Yup. Thats why it can be frustrating when people say "that's a mongrel" or "you shouldn't breed that". When you know it is what you are saying it is

Right, when you're sure of your sling's/T's source and breeding then to heck with what other people say. To be honest there are probably a bit of hybridization in the genetics of some of the hobby Ts without our knowing. It's be almost impossible to tell unless everyone kept -perfect- records and could trace everything. Like...the AKC (American Kennel Club) but for tarantulas.

If 20 years ago an A. metallica was bred with an A. avicularia and then the offspring was sold and bred as an A. avicularia and their offspring was sold and bred as A. avicularia.... You get what I mean? One of your Ts could have a hybrid great great great grandpa so to speak. That's part of why hybridization is detrimental. BUT I bet it's slightly more common than people would think.

On the topic of your pulchra however, I'd be very interested to see if sometime in the future those brown legs showed up once more after a molt.

 

[KezyGLA]

Example of Harpactira hamiltoni

Adult female in the wild
https://www.tarantupedia.com/images...aHamiltoni/HarpactirahamilotniAdultFemale.jpg

My adult female in captivity

 

[KezyGLA]

Harpactira guttata

Young adult female


Older adult female



Wild specimens are much lighter in colour.

They seem to darker with age in captivity like metallica do. I would be interested if anyones metallica have returned to blue after going dark. Or if specimens in the wild get darker and lose the blue. My specimens seemed to just go silver then black and never went blue again.

 

[Vanessa]

Since you have said that this mutation manifests itself upon moulting, I am wondering if the enzymes released within the moulting fluid can somehow react with the new exoskeleton resulting in more of a degradation, or 'bleaching', of the new exoskeleton as opposed to a mutation?. When I think of the term mutation, I think of something that is a permanent DNA anomaly and not a temporary situation, which this seems to be. In the cases that you have come across, is it always that the tarantula gets lighter than normal, or have you seen individuals become darker and then return to their lighter colour?
Could loss of hormones not cause a colour change in older individuals? Especially really old ones? I don't see why that couldn't be a possibility. Hormone loss is associated with bone degradation in mammals, maybe the lessening of hormones affects their exoskeleton and setae negatively?

 

[Chris LXXIX]

Theraphosidae mutations and whatnot are due to the "break trough the other side". I mean, a strong liquor, a peyote and that 'OBT' all of a sudden looks like a unicorn I tell you.

 

[BobBarley]

Very interesting. I wonder if these mutations/variations are related to environmental stimulus or genetics. @KezyGLA I hope you have plans to breed this specimen to see if any of the offspring exhibit this strange transformation. Obviously that's a very long-term project, but it's one I think, would be very valuable to the trade.

 

[AphonopelmaTX]

Same thing with P metallica black form, some people swear it's old females, but others say its been black from 2".

Was that Nhandu not a hybrid then?

@AphonopelmaTX any insight into why this sometimes happens?

Short answer is that I have no idea. Color in tarantulas is made by two means- pigment cells and iridescence. Iridescence has been studied in tarantulas, but to my knowledge the presence and type of pigment cells hasn't been studied at all in this group. In araneomorph spiders it has, but what makes tarantulas unique is that the color is in the hairs not in the cuticle. Shave a tarantula and you will see the hardened exocuticle is black. So I have no clue as to why a tarantula's color that is made by pigment cells would change color.

Iridescence in tarantulas is caused by the hairs being formed in layers of small (in the nanometer range) cuticle plates with air between them. These layers of cuticle and air reflect some wavelengths of light and absorb others depending how narrow these layers are. The blue and yellow in Poecilotheria metallica is made in this fashion so for the blue in an individual of this species to turn black as it ages would mean the structure of those hairs change over time to absorb all light. I would think that a black P. metallica isn't completely jet black, like a Grammostola pulchra for instance, just because I wouldn't think every single blue hair would change it structure the exact same way to absorb all wavelengths of light. The same thing applies to how the bright iridescent blue chelicerae of Ephebopus cyanognathus turns purple as an adult. The blue hairs are changing their structure over time to reflect different wavelengths of light which changes the color. This is something I hope someone out there is studying in more depth. The research published thus far has explained iridescence, but is hasn't confirmed structural changes in the hairs as a tarantula goes through its life.

On another note, here is my thread from two years ago on how my Aphonopelma anax changed color. I'm not good at documenting anything with photos so I never followed up on it. This spider did turn back to the typical color of the species- dark brown with tan carapace. Click click

 

[KezyGLA]

In the cases that you have come across, is it always that the tarantula gets lighter than normal, or have you seen individuals become darker and then return to their lighter colour?

Yeah, the Aphonopelma are the only ones I have seen that go dark and then go lighter again though.


@AphonopelmaTX thankyou! I was looking the boards to find some thread were example of the Aphonopelma turning black then back to normal. There was a thread about a chalcodes going black too but I couldnt find it. I think there are images somewhere in the gallery.




Here is a screenshot (which I have permission from the owner to post here) of a young chalcodes that turned dark upon a moult and then returned to normal on the next. -

 

[spotropaicsav]

Hi all,

A while back I posted up a picture of one of my adult female Grammostola pulchra and it caused a little confusion. A lot of people were very fast to suggest 'hybrid'.

I think it is important for me to share these photos to show that colour mutations do happen. They are very rare but do happen.

I have seen this happen in a couple species of Aphonopelma (chalcodes & anax) where specimens turned a dark black all over after a moult and then returned to regular colours upon the next.

Recently another member posted up a picture of their Nhandu chromatus which had turned brown upon its most recent moult. Even though before it had typical Nhandu chromatus colours and patterns. And again people suggested 'hybrid'.

The purpose of me starting this thread was to share my specimen which had a mutation. I would also like to ask other members who have had mutations happen to please share them here along with some details about that specimen.


Grammostola pulchra

When this specimen first arrived in my care it looked exactly as it does in photograph 1. I was very curious when the previous owner (local to me) said it was a pulchra. He said it had always been black all over until its most recent moult in his care and then the legs had turned beige/brown. I believed him and happily took it as it looked like what it should be apart from the colours.

Now the specimen has finally moulted in my care. It has returned to jet black and upon inspection of the spermathecae, it is definitely pulchra.

I have attatched the photos below. Please share your photos and experiences with colour mutations if possible.

View attachment 248996 View attachment 248997 View attachment 248998 View attachment 248999 View attachment 249000

I can see why it can contribute to confusion in the hobby. Glad you posted, informative!

 

[boina]

B. albiceps seems to be another species that can change color.

I bought a sling, it turned out female (yay!), looking like an albiceps is supposed to look and then it molted and turned completely brown with a slightly lighter carapace . I decided there was no way that was an albiceps and I was so upset, because I really, really wanted one. I even went and bought a new female albiceps that looked right. Yesterday that brown albiceps molted again and now has its black legs and light carapace again...

Unfortunately I didn't take a pic of the brown albiceps and it's too late now, so you will have take my word for it.

 

[mconnachan]

Example of Harpactira hamiltoni

Adult female in the wild
https://www.tarantupedia.com/images...aHamiltoni/HarpactirahamilotniAdultFemale.jpg

My adult female in captivity
View attachment 249005

Yeah huge difference, that's really interesting, I've never had this occur before, although I'm sure at some point it will happen.

 

[Exoskeleton Invertebrates]

Hi all,

A while back I posted up a picture of one of my adult female Grammostola pulchra and it caused a little confusion. A lot of people were very fast to suggest 'hybrid'.

I think it is important for me to share these photos to show that colour mutations do happen. They are very rare but do happen.

I have seen this happen in a couple species of Aphonopelma (chalcodes & anax) where specimens turned a dark black all over after a moult and then returned to regular colours upon the next.

Recently another member posted up a picture of their Nhandu chromatus which had turned brown upon its most recent moult. Even though before it had typical Nhandu chromatus colours and patterns. And again people suggested 'hybrid'.

The purpose of me starting this thread was to share my specimen which had a mutation. I would also like to ask other members who have had mutations happen to please share them here along with some details about that specimen.


Grammostola pulchra

When this specimen first arrived in my care it looked exactly as it does in photograph 1. I was very curious when the previous owner (local to me) said it was a pulchra. He said it had always been black all over until its most recent moult in his care and then the legs had turned beige/brown. I believed him and happily took it as it looked like what it should be apart from the colours.

Now the specimen has finally moulted in my care. It has returned to jet black and upon inspection of the spermathecae, it is definitely pulchra.

I have attatched the photos below. Please share your photos and experiences with colour mutations if possible.

View attachment 248996 View attachment 248997 View attachment 248998 View attachment 248999 View attachment 249000

Color mutation maybe true and all. One thing for sure a lot of Grammostola species spermathecae look the same, so it's hard to say what spermathecae belongs to what species.

As for the color mutation I have another theory and by the way not saying yours is a hybrid at all. With my experience with numerous of hybrids I've seen hybrids have different appearances, there are times that may look the same of each molt than all the sudden the next molt has a totally different appearance. It's almost like if it's having an identity crisis. I've seen this with Brachypelma baumgarteni and Pterinochilus murinus.
There is an old thread here on AB the owner of her hybrid specimen Brachypelma baumgarteni/boehmei, she mentions that her specimen hybrid has gone through changes that was strange to her of what was happening to her spider when she molts. I have mentioned this as well with my hybrids that I have owned in the past.

So my point is tough to say wether it's just a natural occurrence or something/someone has messed with their genes.

 

[mconnachan]

So my point is tough to say wether it's just a natural occurrence or something or someone has messed with their genes.

I would say it's a natural occurrence, due to the number of times it is happening, it seems to much of a coincidence for it to be hybridisation, I'm no expert on this subject, but from what I can gather from the posts I've read and the little research I've done myself, it can only be a natural occurrence. IMHO

 

[Exoskeleton Invertebrates]

I would say it's a natural occurrence, due to the number of times it is happening, it seems to much of a coincidence for it to be hybridisation, I'm no expert on this subject, but from what I can gather from the posts I've read and the little research I've done myself, it can only be a natural occurrence. IMHO

About 11 years ago I knew a guy that was trying to mate with his Grammostola pulchra female with his mature male Grammostola pulchra. The female was aggressive towards the male and was not able to mate them. Eventually he gave up and tried a different approach. This person decided to mate the Grammostola pulchra female with the Grammostola rosea mature male, they both mated with no problem at all, female was receptive with no aggression at all. It was strange to see how the female was so eager to kill her own species but yet would allowed a different species mate with no hesitation to kill the male of a different species. A lot of things I find strange of what happens in the tarantula kingdom.

I had a similar case happened to me, however it had to do with the same species. I have over 20 female Nicaraguan albopilosum, and at that time I had a couple of males that were making their rounds. What was interesting is that there were a couple of females that were tapping for the males, but when tried to pair some of those males with the females, the females would attack the males instead. So I had to switch the males and see if I could get them to mate. Once the males were switched females calmly mated with them no aggression towards the males. Strange behavior very strange..............

 

[KezyGLA]

Color mutation maybe true and all. One thing for sure a lot of Grammostola species spermathecae look the same, so it's hard to say what spermathecae belongs to what species.

As for the color mutation I have another theory and by the way not saying yours is a hybrid at all. With my experience with numerous of hybrids I've seen hybrids have different appearances, there are times that may look the same of each molt than all the sudden the next molt has a totally different appearance. It's almost like if it's having an identity crisis. I've seen this with Brachypelma baumgarteni and Pterinochilus murinus.
There is an old thread here on AB the owner of her hybrid specimen Brachypelma baumgarteni/boehmei, she mentions that her specimen hybrid has gone through changes that was strange to her of what was happening to her spider when she molts. I have mentioned this as well with my hybrids that I have owned in the past.

So my point is tough to say wether it's just a natural occurrence or something or someone has messed with their genes.

Interesting you mention those two species. Is baumgarteni still thought to be a natural hybrid?

With murinus I know that different forms are bred within the wild and captivity so thats no surprise.