P. metallica parasite help

[Bruce Maclean]

Hi Dianne,

Having read the ATS discussion, I think going with the jelly initially is probably the best bet, but I'd still strongly recommend getting a vet to do the procedure if it comes to that. Having (possibly - nobody knows in tarantulas!)) some analgesia from the gaseous anaesthetic, and the availability of fluids to inject to compensate for any fluid loss in the procedure would I think make a difference to the chances of survival. It would still be quite risky surgery though.

You mentioned you had an exotic vet I think, he/she should know someone interested in tarantula work if he/she doesn't want to do it themselves.

Good luck,

Bruce.

[DianeDFisher]

Hi Dianne,

Having read the ATS discussion, I think going with the jelly initially is probably the best bet, but I'd still strongly recommend getting a vet to do the procedure if it comes to that. Having (possibly - nobody knows in tarantulas!)) some analgesia from the gaseous anaesthetic, and the availability of fluids to inject to compensate for any fluid loss in the procedure would I think make a difference to the chances of survival. It would still be quite risky surgery though.

You mentioned you had an exotic vet I think, he/she should know someone interested in tarantula work if he/she doesn't want to do it themselves.

Good luck,

Bruce.

I sent a total synopsis fax of the situation to the vet who helps me with my chameleons and water dragons and throughly outlined the hazards of handling this tarantula without it being knocked out. I will see what he has to say in response. I told him I was planning to do something, with or without his assistance. He's a great guy so we'll see what he has to say.
I am pretty terrified of handling this particular species alone. Di

[Nick L]

Firstly, as Phil Rea says (particularly given that you’ve had it 8 months) it is highly unlikely to be a parasite. While quite a few types of spider parasite are known there are none that I’m aware of that produce any signs such as this. The worm you observed in the exuviae (I’m deducing that it was small given you observed it under 40X magnification [so, say a few to 10mm max.] and was transparent [=’clear’] rather than opaque) was just one of the many ubiquitous soil species that are everywhere. While there are many species of such, all rather similar looking, nematodes there are some potentially significant ones here – the ‘entomophathogen’ (=insect killing) nematodes (Steinernematidae and Heterorhabditidae, Order Rhabditida). With these the nematodes enter the body of its host via any opening available (in a T, via the anus, book-lungs, etc.) or rarely burrow directly through the cuticle. Within the host they feed and multiply. Eventually the host is killed, not directly by the nematodes but indirectly by symbiotic bacteria that live in the nematodes guts, these are released into the body of the host and when their population reaches ‘critical’ the host dies. The nematodes continue to feed on the corpse, multiply and then disperse and seek new hosts once the body is consumed. I had thought that it would be one of these that would be identified as the ‘problem’ being seen in Ts but they appear to have been identified as of the Panagrolaimidae (Order Rhabditida) – to date these are generally considered to be ‘bacterivores’ (=bacteria eating) but I guess (assuming the ID is correct) that these particular ones have adopted a different ‘life style’ akin the known entomopathogens. Anyway, such small, transparent nematodes would need to be present in their 100s+ before I’d suspect their involvement. The common nematode parasites of spiders are related to the familiar ‘roundworms’ and belong to the Mermithidae (Order Nematoda). They are large (many cms long), opaque (white-, pink-, cream-coloured, etc.) and are usually solitary. To my mind a parasite is highly unlikely.

However, I’m pretty confident that what you see is the result of a ‘puncture’ injury sustained shortly before molting. I’ve reproduced similar looking ‘marks’ on some of my spiders and while not claiming that I know definitively what’s going on I think I have a fair idea – some more thought and experimentation is needed though before I’d be at all confident in stating it as a fact…

If I haven’t bored the pants off you already I’m about to do so as to explain my thinking/reasoning you need to know about the structure of the exoskeleton and the molting process… This is a simplified, but hopefully accurate, account within the bounds of simplification but without doing so this will become an even more bloated post!

Being arthropods Ts have a hard external ‘shell’ – the exoskeleton. In Ts the exoskeleton is composed of cuticle, which consists of a protein and chitin microfibres. Depending upon how these are laid-down produces distinct layers. The cuticle consists of 3 layers (there is actually a fourth, the outermost ‘epicuticle’ but this is more of a ‘waxy’ coat that can be re-secreted by special glands); the ‘exocuticle’ [= the outer layer], the ‘mesocuticle’ [= the middle layer] and the ‘endocuticle [=the innermost layer]. Each layer has different physical/mechanical properties depending upon the way that chitin fibres are interlaced and augmented with the protein component. The exocuticle is hard, tough and rigid; the mesocuticle is flexible (but still quite tough too!) and elastic; the endocuticle is very flexible and elastic but not very ‘tough’. The proportional thickness of these cuticular layers varies over different parts of the Ts’ body depending upon what is required. So, the carapace has a very thick layer of hard/rigid exocuticle (for the attachment of strong motor muscles) whereas the abdomen has virtually no exocuticle and is composed mainly of ‘quite tough’ and elastic mesocuticle.

Molting… Given that the composition of the cuticle varies over the body of a T the process of ‘molting’ is not ‘homogenous’ by which I mean, it does not occur all-over, at the same time. The initial stages start where the cuticle is thickest. The process of molting begins long before the actual shedding of the skin that we observe and has a number of stages to it. The first signs are increased cell division within the hypodermal layer of cells (=the layer of cell below the endocuticle). Glands then start secreting ‘exuvial fluid’ between the hypodermal layer and the endocuticle. As this fluid increases in volume it ‘pushes through’ the plane between the two forming pools that eventually coalesce. The ‘exuvial fluid’ consists mainly of a bunch of enzymes that become active at various stages under hormonal control but basically dissolve the old cuticle from the inside, out. The enzymes DO NOT dissolve the exocuticle (or epicuticle) and this is all that the shed skin of a T consists of (the meso- and endo-cuticles have been dissolved and re-absorbed). This process of separation of the ‘old’ cuticle is called apolysis. On the innerside of these ‘pools’ of exuvial fluid a layer of exocuticle is at first laid-down (remember that exocuticle is not ‘dissolved’ by the exuvial fluid). The new cuticle is gradually formed under this in the same layer-proportions as before but ‘crinkled’ to allow for expansion/growth once the ‘old’ skin is shed. [Apolysis is actually VERY complex in that sensory and fine motor function is maintained with the ‘old’ skin right up until the very end – I will however COMPLETELY ignore this!!!]. Once apolysis is complete and the old exoskeleton has been dissolved down to the exocuticle the ‘observable’ process of molting as we know it occurs. Once the skin is shed excess haemolymph/fluid that has been purposefully accumulated is drawn out of the abdomen and into the prosoma; the prosoma/appendages are ‘pumped up’ to expand the new exoskeleton. Over the next few days/week the exoskeleton hardens.

The timescale of the molting process is something that I have a problem with, particularly with Ts given the rather limited published investigations (solely with araneomorphs). If you divide the time between molts into 4 the published studies suggest that the ‘initiation’ starts around the beginning of the second quarter. I would suggest that it doesn’t begin until the beginning or middle of the third quarter. But, this is just intuition/anecdotal and I have no proof for it. Since you can’t KNOW exactly when a molt will occur I think it is rather a subjective rather than objective area and therefore up to much speculation.

Ah, my 'missing' student has finally turned up for her tutorial! [=An hour and a half late!!!] I will try and continue this post later this evening…

[Phil Rea]

Ah, my 'missing' student has finally turned up for her tutorial! [=An hour and a half late!!!] I will try and continue this post later this evening…

Keeping us in suspense Nick

[Nick L]

Keeping us in suspense Nick

Nubile, young, female, students, especially when they have a brain, certainly get my juices flowing…!!! but I’ll relieve your suspense…

So, “How/why do I think it’s an injury?”… Apart from having seen numerous photos of bulges/marks on the forums I hadn’t encountered anything until a year ago when I received a specimen in the post with a bulging ‘hernia’ on the side of its abdomen; it died a few weeks later, up-side-down, preparing to molt [The specimen was apparently fine when sent.]. It was summarily plonked in a jar of alcohol and forgotten about for a while. Subsequently I observed a few marks/blemishes in other spiders. From preliminary experimentation I now think I know what is going on… An injury within the first-quarter of the molt cycle is, at best repaired over the next molt COMPLETELY, at worst it appears as a slight blemish. An injury (even very slight such as pin pr*ck) during the last quarter of the molt cycle produces a very pronounced and expansive mark post-molt. Having looked at histological sections the ‘dark’ area IS homologous with ‘exocuticle’, the pale ‘bulging’ area ‘mesocuticle’. What I think happens is that once apolysis starts the effects of even minor injury can be produce devastating effects dependant upon where and when it occurs. An ‘injury’ during this period can be varied – puncture (spine of cricket/locust/cockroach), tear/split/cut, from a fall, or from excess exposure to heat (heat-mat burn). ANYTHING that causes disruption to apolysis could have a serious effect. I think that the immediate response to injury in a T is to lay-down exocuticle and once secure lay-down mesocuticle. Any disruption to apolysis results in a new ‘separation layer’ being formed behind the damaged area in preparation for the forthcoming molt.

All I have done so far is stick a pin in the abdomen of Ts during various times of the molt cycle. Observations fit with the above. The dark/black areas visible after molting correspond with areas of injury if done during the last quarter of the molt cycle. I have also observed this area immediately after molting and it is clear/transparent but gradually becomes opaque and darkens over the coming days/weeks [=becomes like a scab]. This area bulges-out too; next molt and it is gone completely.

If the ‘mark’ you see was on the dorsal surface of the abdomen it would be barely noticeable after the next molt. Being on the ventral surface it can be more problematic as the effected area of the exoskeleton extends beyond what you can see from the outside and if that extends into areas with ‘architecture’ such as spinnerets, anus, genitals, book-lungs, etc. then ‘definition’ of a separation zone for the next ecdysis becomes much more difficult. The ecdysis zone can become so convoluted that the old skin becomes stuck and causes a tear in the new exoskeleton so resulting in death.

I’ve glanced through the ATS thread posted and am not convinced that ‘surgery’ or indeed ANY intervention will do any good. For a start these ‘bulges’ are NOT ‘hernias’ in the mammalian sense – indeed the abdomen is NOT under any great hydraulic-pressure – such a bulge is not about to burst or needs ‘lancing’. You could argue ‘surgery’ as appropriate either way, right or wrong. But, ONLY during the first or second quarter of the molt-cycle; beyond that I’d GUARANTEE that it would be more detrimental rather than helpful!!! Prior to that, I don’t know…

The ‘little sticky out bit’ in what you see could be lots of things… It could be the spine from a cricket/locust/cockroach that has broken-off and become imbedded in the cuticle, it could be a sliver of cuticle, a hair follicle that didn’t disengage properly, etc, etc. There are lots of things that it could be but I doubt that it is a parasite.

So to sum up – it’s an injury. In my opinion ‘leave it be and hope for the best’!!! It looks to be in about the best ventral position anyway so you may well be OK!

Yrs,

Nick

[alex smith]

Just a quick observation from a hobbyist -that i dont think anyone has mentioned here, but that looks like a juv.P.Met.As far as im aware no one, is, has or would have collected juv.specimens of this species-making it more than likely captive bred and very unlikely to be harbouring parasites.

[Phil Rea]

Just a quick observation from a hobbyist -that i dont think anyone has mentioned here, but that looks like a juv.P.Met.As far as im aware no one, is, has or would have collected juv.specimens of this species-making it more than likely captive bred and very unlikely to be harbouring parasites.

I thought I'd mentioned earlier in the thread that unless it was wild caught it was unlikely to be a parasite

Just out of interest, why wouldn't juveniles of a species be collected?

[alex smith]

Ive not been collecting Phill.I must have missed your sentance.
Juvs tend to hide away more so than adults making them I WOULD THINK more difficult to locate in the wild.I would hope that from a conservation point of veiw only adults would be collected-and collecting adults would provide a breeder with a more rapid return to his/her collecting trip costs and breeding potensial.I have never seen Juv.WC of this species being offered for sale in the UK or Europe.Have you?I was just trying to add a consructive reply.

[Phil Rea]

No, I haven't seen any either

[DianeDFisher]

First, I must thank you ALL for your help. You brought up so many possibilities that I would never have thought of myself. It is such an ugly blight on this beautiful tarantula and the first thing that came to mind was: parasite. I thought that 8 months to molt in a 2 in. (less than 5 cm) tarantula was way too long, but evidently that is not the case. I am copying a post I just put on the ATS site, as I don't want to re-type it. Nick, whoever you are, many thanks for your detailed explanation of what may have happened to my T.
"My T is not very happy in the 40 dram vial. Rather than cooling her I shot these in the sunlight streaming from my west-facing window this afternoon-right before my battery crapped out. Today the "wound" is sticking out again. Yesterday evening when I moved her it was in. It's almost like a belly button that's an "innie" one day and an "outie" the next. Someone named Nick on BTS took a lot of time and effort to relay development information and pre-molt/post-molt conditions of the skin cuticle and he feels that I should leave this alone and that it may be trauma due to an unknown injury. If I understood him correctly, it basically boils down to WHEN an injury occurs in the molt cycle determines the severity/progression of the injury. This may correct itself. Obviously, it may not as well and none of us can say for sure. I have povidine iodine in my herp care kit and based on some info Christian provided, I believe I will cleanse the area with that and let nature take it's course, unless something drastic changes my mind. If the T dies, I'll keep 70% ethanol here and the spider's remains will go to Christian for necropsy and analysis. It may help one of you in the future. " Di

[Peter Lacey]

I would hope that from a conservation point of veiw only adults would be collected-and collecting adults would provide a breeder with a more rapid return to his/her collecting trip costs and breeding potensial.I have never seen Juv.WC of this species being offered for sale in the UK or Europe.Have you?I was just trying to add a consructive reply.

You might want to take a read of this, but obviously this is another topic entirely: http://www.iucnredlist.org/details/63563


Fingers crossed for you Diane and thanks once again Nick for a very informative reply.

[DianeDFisher]

Thanks, Peter. We have a recent link to that post on the ATS. Another very important reason to try to save this youngster. While I enjoy observing tarantulas, I am attempting to breed them as well. I find males for my females and send my males off to fullfill their destiny as soon as they mature to give back to a hobby that brings me much joy. My son works for an India-based company and has spent time in South Eastern India. They are a growing country and habitat destruction abounds. We all have to do what we can to help keep many of the Poecilotheria species alive. Di

[alex smith]

Good luck with this one Dianne.I think from what has been said you should remain optomistic-lets hope this little one can survive the next moult.Interesting reading Pete.Thanks for that.These new pics show the juv.holding its palps back under its self.Could this be neamatodes as well as the 'injury'??

[DianeDFisher]

Good luck with this one Dianne.I think from what has been said you should remain optomistic-lets hope this little one can survive the next moult.Interesting reading Pete.Thanks for that.These new pics show the juv.holding its palps back under its self.Could this be neamatodes as well as the 'injury'??

It's interesting that you bring up the palps since the T has apparently autotomyzed them. At first I thought I caused the damage when I tried to cool the T and apply iodine to the "wound". She bolted and I had to use a rather small vial to corral her. I wondered how I damaged a palp since they are shorter than her legs, but...it came off. Then this morning the other was found in the water bowl. I swear I am a good tarantula keeper and this situation is tearing me up inside. I don't see any signs of nematodes around the mouth. I have moved the T to a dark, quiet area where humidity remains 55-65% and temps stay a constant 78-80F. She is in a container with only a water bowl and cork. I put a small discoid roach in earlier, which has yet to be consumed. I guess it's best to now leave her alone. I'll offer her food periodically and hope for the best. I really appreciate the guidance and if any of you know why she removed her own palps, I'm all ears. Di

[Andrew Ferguson]

I've just come across this thread (been busy helping another (non-tarantula) forum get established) and have read it with great interest. Has there been any update on the P.metalica's situation?
I'm sure all those that have contributed to the thread would be interested to know too.

Andrew