Old World urtication?

[blackacidevil]

The petstore I frequent is more of an "exotic" pet store but I guess they can't know everything. They have a tarantula labeled as a Thailand Black and when I asked what the scientific name was they said Haplopelma_minax. The weird thing about it is that it was more brownish and seemed to have a bald abdomen(w/chevron markings). It is already kind of big (and very leggy). The guy told me it was real fiesty and that's why it was bald but i know old worlders don't do that......anybody know what happened? The only thing that didn't look right is that there might not have been enough humidity, other than that the conditions seemed fine.

 

[Henry Kane]

As far as I know, o/w T's don't go bald. sounds like a (major) mis-id to me. I'm curious as to what sp. it could be though. Chevron markings but a hair kicker...hmmm...
how big is it? Any idea of the sex? Arboreal or terrestrial?

Atrax

 

[Doug H]

hmmm.more brownish ,seemed to have a bald abdomen with chevrons and very leggy ,almost sounds like a P.pulcher.they are blondish/brownish,have a very smoth abdomen with darker markings and are leggy
just my wild guess

Doug

 

[Mojo Jojo]

Psalamopoes do not kick urticating hairs, even thouth they are New World.
--

 

[Doug H]

BD
I know they dont ,It's just that the original post said that it seemed to have a bald abdomen. If you look up some pics of P.pulcher they kind of "seem" to have a bald abdomen. In a wierd sort of a way.its just there color is so light

check out Rick west's site,or even better if you have "T's and other Arachnids" by Marshall ,the second ed.on page 16 is a perfect pic.of a P.pulcher that demonstrates this.
Doug

 

[Mojo Jojo]

Originally posted by Doug H
BD
I know they dont ,It's just that the original post said that it seemed to have a bald abdomen. If you look up some pics of P.pulcher they kind of "seem" to have a bald abdomen. In a wierd sort of a way.its just there color is so light

check out Rick west's site,or even better if you have "T's and other Arachnids" by Marshall ,the second ed.on page 16 is a perfect pic.of a P.pulcher that demonstrates this.
Doug

Yeah, I did that right after I posted. I wasn't sure if the dark area on that pic from Rick West was an anomoly of the photo or if that was natural for the species. I do agree with your statement.

Jon

 

[Steve Nunn]

Originally posted by blackacidevil
The weird thing about it is that it was more brownish and seemed to have a bald abdomen(w/chevron markings). It is already kind of big (and very leggy). The guy told me it was real fiesty and that's why it was bald but i know old worlders don't do that......anybody know what happened?

Hi blackacidevil,
Two things come to mind, there's a 1% chance it's a true H.minax, they're mis ID'd in the pet trade. And old world T's can go bald, through stress. It's actually quite common to find WC old world T's with bald abdomens (particularly Asians). While they don't urticate, they will scratch off the dorsal abdominal setae if kept incorrectly. Incorrect temps, humidity, lack of a hide, wrong substrate, too much lighting, or all of the above can cause an old worlder to go bald. I only keep old worlders and I've seen it before, on more then one occassion.

Hope this helps,
Steve

 

[blackacidevil]

Re: Re: Old World urtication?

Originally posted by Steve Nunn
While they don't urticate, they will scratch off the dorsal abdominal setae if kept incorrectly. Incorrect temps, humidity, lack of a hide, wrong substrate, too much lighting, or all of the above can cause an old worlder to go bald. I only keep old worlders and I've seen it before, on more then one occassion.

Hope this helps,
Steve

That's probably what is going on AND maybe the lighter color is just 'cause it is approaching a molt. I have seen it there for quite a while and it used to be much darker....also compared to pictures that I've seen on the net it does look much like a Haplopelma.

 

[Steve Nunn]

Re: Re: Re: Old World urtication?

I find it quite interesting how urticatious setae are an apomorphic character (derived from the original/primitive state), yet old world spiders (from Asian regions) who have never had urticatious setae also rub off the setae on thier abdomens when stressed.

Here's a theory for y'all: maybe the Asian old worlders are going through a stage of adaption and development (evolution in progress). This "abdominal scratching", such as you noticed on the Haplopelma sp., may well be the first sign of develoment of urticatious setae. Lets face it, what are the chances of this being coincidence? Is it just a coincidence that new world T's urticate from their abdomens AND Asian old world T's will also rub the setae off their abdomens (the exact same area!)when stressed?

If one were to look at the entire range of T's, various adaptions can be noted, Avicularia are definately the most advanced, they have adapted to life in the trees (their ancestors lived in burrows) AND, they have also developed urticatious setae (the only arboreal T with urticatious setae), cool stuff from a scientific point of view. Of course these adaptions have come about as theraphosids spread around the world and evolved to suit their new environments, Avicularia becoming arboreal probably due to constant flooding.

If you have a further look at the picture, you'll see that the genus Avicularia has a massive range, one of the largest for any genus of theraphosid. This is probably because of their ability to adapt to their environment so well, they have been able to migrate quicker, and with greater success then any other genus. Dontcha just lurrrv evolution?????

Cool stuff indeed.

Cheers,
Steve

 

[conipto]

Steve,

Since we're plaiyng hypothetical evolutionists right now, and given the things you just mentioned.. why is it Avicularia don't have airborne urticating setae? Would you consider having to press them into irritating things more or less advanced?

Bill

 

[Steve Nunn]

Originally posted by conipto
Steve,

Since we're plaiyng hypothetical evolutionists right now, and given the things you just mentioned.. why is it Avicularia don't have airborne urticating setae? Would you consider having to press them into irritating things more or less advanced?

Bill

Hi Bill,
Good question! Well, I would consider Avicularia have developed an urticatious setae to suit their needs. Because they aren't terrestrial, they don't face the same predators those with airborne setae do (carniverous mammals, etc). For me to say that this type of setae is more advanced is a little more conjecture then I might throw out there (I haven't seen their natural environment and don't know what exactly predates upon them), but I will say that this type of setae is an adaption to it's environment.

I will say that Avicularia, along with some of the other arboreal genera (eg:Tapinauchenius) has further developed apomorphic characters (extreme setation of limbs) to evade predation (thus possibly eliminating the need for airborne urticatious setae, in Avicularia's case) providing the ability to "jump and swim".

From a cladistical point of view, the fact that Avicularia have urticatious setae would say that these setae were developed prior to the spider becoming arboreal, meaning it probably at one stage had the exact same type of urticatious setae as it's relatives on the ground (the subfamily Therahosinae). This being the case, Avicularia further developed those setae to suit it's environment, meaning these setae are also an apomorphic character themselves, they changed from the original urticatious setae type to suit it's needs.

Cheers,
Steve

 

[invertepet]

As many have noticed, Avicularia tend to 'wipe' urticating setae on their silk retreats (and intruders). One could theorize that kicking them would be a waste, since they would simply drift down to the ground.

Rainforest floors are also pretty still in terms of wind, unlike being up in the trees. Another reason why 'the direct approach' to urtication might have come about.

bill

 

[Steve Nunn]

Hi Bill S,
I would say your theories are pretty good and would definately suit their circumstances.

Still, everything we've mentioned here is pure conjecture, none of it proven/ supported by scientific authorities. It is interesting to go out on a limb though and throw some theories into the wind....it's part of the beauty of the tarantula hobby, so much is yet to be studied, it's an exciting arena that remains just as new to the experienced keepers as it does to the beginners.

Cheers,
Steve

 

[belewfripp]

Re: Re: Re: Re: Old World urtication?

Originally posted by Steve Nunn
I find it quite interesting how urticatious setae are an apomorphic character (derived from the original/primitive state), yet old world spiders (from Asian regions) who have never had urticatious setae also rub off the setae on thier abdomens when stressed.

Here's a theory for y'all: maybe the Asian old worlders are going through a stage of adaption and development (evolution in progress). This "abdominal scratching", such as you noticed on the Haplopelma sp., may well be the first sign of develoment of urticatious setae. Lets face it, what are the chances of this being coincidence? Is it just a coincidence that new world T's urticate from their abdomens AND Asian old world T's will also rub the setae off their abdomens (the exact same area!)when stressed?

I don't want to sound like I'm being critical or something along those lines, I understand everything said is conjecture, and everything I'm about to say is just conjecture, too.

I do, however, have some questions about what you've stated here. First, for the asians who have scratched setae off of their abdomens, do they do it when under direct stress, i.e. your head is looming over them or you poke them in the butt with a pair of forceps, like with a new world spider that is trying to get the item/being bothering it to go away? Or are they doing it under indirect stress due to factors you noted (improper care, etc)? I keep parakeets and I know that if left alone with nothing to play with, whether toys or other birds, and kept in a plain tank with little room to do anything, they will sometimes turn to pecking out their own feathers to amuse themselves. Let's now imagine some hypothetical demon-budgie that has irritating feathers that it can somehow cause to become airborne (let's say through feather ruffling or wing flapping) when you bug it. I'm not trying to suggest these bald asians are rubbing themselves bald for the purpose of amusement, but these potentially are two different situations, one a sort of 'nervous tic' caused by improper environment, the other caused by some big looming shape they think might try to eat them.


I also have to wonder about the evolutionary deductions. If the asians, or some of them, are scratching off hairs as a response to the same kind of intrusions that prompt that reaction from new worlders, how do we know that urticating bristles are a more recent development? Perhaps this is actually the sort of leftover behavior from a time when they used to have them, and we've caught them in transition out of having had urticating bristles, or maybe the two are completely unrelated. I admit that I am not versed in the evolutionary or taxonomic information that I probably ought to be when asking these questions, so if I'm stating anything utterly ridiculous (beyond the satanic budgie) my apologies.


Adrian

 

[Steve Nunn]

Re: Re: Re: Re: Re: Old World urtication?

Hi Adrian,
I kinda got a kick out of your satanic budgie theory

Look at it this way: Both old world and new world disperse abdominal hair when stressed. Stress can be measured from many angles too. Did you know that "stress" from a medical standpoint is only an applicable term in Australia and the US(I just learned that one)? So maybe this term is not so good to use.

Comparing any behaviour between vertebrate and invertebrate is not a good option, but I do get your point. Consider this though, feathers "grow", setae/bristles don't. Vertebrates possess nothing like arachnid setae, the two are in absolutely no way related in any form. Your thoughts on differences in abdominal baldness between old world and new world is quite valid nonetheless and you have a good point, you could be right, they may be in no way related.

And lastly, urticatious setae are proven to be an apomorphic character of the theraphosines, and not the other way round. This much IS fact and scientifically proven, giving the basis to my "theories".

Thanks for the input, that's what conjecture is all about.

Steve

 

[belewfripp]

Removing the troublesome vertebrate example, let's see if it is better stated as follows: we observe a Stress type 1 and a Stress type 2 (this is an arbitrary designation on my part), type 1 corresponding to a Stress reaction A and type 2 to a Stress reaction B. We observe that A and B are similar and so, without noting the difference between 1 and 2, postulate that B is related in some way to A.

Regarding evolution of urticating hair, point taken. I did not know that was a fact, but now I do. It is amazing to think about how much I've learned after getting into Ts. Three years ago I knew next to nothing about Ts or spiders in general, and probably would have thought urticatious setae was another one of the 75 shades of 'white' paint.

Adrian

 

[Steve Nunn]

Originally posted by belewfripp
we observe a Stress type 1 and a Stress type 2 (this is an arbitrary designation on my part), type 1 corresponding to a Stress reaction A and type 2 to a Stress reaction B. We observe that A and B are similar and so, without noting the difference between 1 and 2, postulate that B is related in some way to A.

Yup, pretty much so. Taking it a little further, how did the urticatious setae come about in new world theraphosids? Did they begin scraching their abdominal setae off for some reason, I mean, if the setae aren't urticatious, what's the point of scratching them off? Something got them started, stress??? Maybe, maybe not.

These old world T's scratch their abdominal setae off when stressed, but what purpose does it serve for them to do so? Is this reaction instinctive, or does it in some way comfort the spider physically? My thoughts are that simply maybe it's the beginning of a new evolutionary trait.

Steve

 

[belewfripp]

That would certainly be interesting if it were. What were some of the specific circumstances you've had with Asians doing this? I've never had a bald abdomened Asian (though one of my H. lividum rubbed off a bunch of hair on the front of the prosoma when she had a mite infestation) so I'm curious to hear about it.

Also another question to add to your list; apparently the environment in the New World was such that those Ts had a sufficient 'reason' for developing urticating hair. Has something changed in the environments of parts of Old World habitats that is mimicking the environments New World Ts encountered, thus provoking a similar evolutionary response?

Adrian

 

[Steve Nunn]

Originally posted by belewfripp
Also another question to add to your list; apparently the environment in the New World was such that those Ts had a sufficient 'reason' for developing urticating hair. Has something changed in the environments of parts of Old World habitats that is mimicking the environments New World Ts encountered, thus provoking a similar evolutionary response?

Ahhh, another good question!

Firstly, old world T's will scratch off their abdominal setae in what seems to be several circumstances. Lack of a hide is the most prevalent, it seems insecurity is a major stress point for them. Too much light is another, although to a lesser extent. Basically, anything that may force an old worlder into a situation it doesn't want to be in. Too many feeder items thrown in with them is another. Regular enclosure changes will also cause an old worlder to go bald.

Regarding the question above, much has changed in theraphosid habitat all over the world, human intrusion at many levels probably causing the snowball effect. It may not be humans directly, but ever since cavemen decided to hunt and proliferate, many animals have been forced into habitats they otherwise wouldn't be in. This of course affects every living creature right on down the food chain. There are other, older eliments too. As the worlds rainforest dry up, many animals have been forced to migrate to new areas, with new predators thrown into the mix. As you are aware, the world is everchanging, forcing evolutionary traits to roll with it. Animals have adapted to take new prey items and those prey items in turn must come up with new defenses to survive. As to mimicking new world tarantula environments, I couldn't postulate. I think to answer that one much in depth research would be needed to even come remotely close. But I think you are on the money with that question. Given the geographic barriers between old and new world environments, the chances of a tarantula developing a mirrored trait between the two areas MUST be remote, unless, the trait had it's origins before the various species went their own way. A vast cladistical analysis would be required to determine if this is even possible and even then, may be impossible to determine until after the fact.

Thankyou for this conversation Adrian, it's opening my eyes a little further.

Steve

 

[belewfripp]

No, thank you for the conversation, I've learned a great deal.

Adrian