Breeding T's from same eggsac

[AlbaArachnids92]

But let's be real, we really don't know. Everything we have on "inbreeding bad" is just based on what we know about different organisms and not tarantulas in particular. And like mentioned before, established captive population of certain species of tarantulas can possibly be traced down to only a handful of wild caught specimens.

Could it be that they evolved to get rid of the negative effects of inbreeding in order to survive millions and millions of years? I mean they had all the time they needed to do so. Maybe? No? Yes? We don't know.

If they did, is it really the strangest and most unbelievable thing in nature? I don't think so considering we have animals that can even regenerate a whole body from a single limb.

That's exactly what I'm trying to be about this, a realist! So, thank you for replying just trying to understand a little more

From my reading here and another thread it appears to be another "we don't actually know" fully.
I understand there are several limitations on how effectively you could 'prevent' it. I use prevent very loosely especially due to initial captive specimen numbers and lack of similar practices to "stud books".
My question though is still, if we do not know and it is possible to select a wider genetic gap between mating partners, would it not be wise to err on the side of caution? Especially when it comes to sac mates where they will share initial biological load from identical parent to each other.

I want to make it clear that I'm not insinuating that people are gung ho advocating inbreeding......more so that we do not seem to have evidence of ill effect or otherwise and should act as such where feasible.

 

[Dry Desert]

I've pondered with this in the past and asked the best source I have here.

Martin Gamache from Tarantula Canada, he's definitely the best dealer here Canada. To give him credit for those who don't know him, he went on expeditions to French Guyana and the island of Trinidad in the past and observed tarantulas in the wild; both known and unknown species in the hobby. He's friends with people in the hobby such as Rick West, Jean-Michel Verdez and Martin Hüsser - just to name a few. He was also invited by the Commision for Environmental Cooperation(CEC) as a guest speaker in the Tarantula Trinational Trade and Enforcement Workshop Supporting Sustainable Trade of CITES Species held in Guadalajara, Mexico.

had this to say when I asked him about this topic:

"Until specimens started coming out of Guyana, I am told that P. irminia was bred for years in the hobby from only 4 original specimens

For 35 years, Stromatopelma calceatum was bred in the hobby from 8 original specimens collected by a lady in Sierra Leone until more stock was imported. The specimens that live on the same tree are all related, like one big family.

Most species in the hobby are established by a few specimens collected by private collectors. There is almost never such a thing as "different bloodlines" even if some sellers might want you to believe that."

Adding to this,

The most popular pet lizard in Europe, and possibly the State's, is the Bearded Dragon - all in captivity bred from several initial pairs, due to the very, very strict Australian wild life export regulations.

There now must be millions bred from the initial imports.

 

[campj]

In that thread I'd linked earlier, they talk about a guy who inbred OBTs to the seventh generation with no apparent ill effects. And as mentioned earlier here, we've got species in the hobby who have genetic pools that are an inch deep and a mile wide. It's fine to breed sacmates, and the more I think about it the more I'm convinced that's a fact. Where's the proof that it's detrimental? All I see is people's feelings about it and generalizations.

 

[A guy]

In that thread I'd linked earlier, they talk about a guy who inbred OBTs to the seventh generation with no apparent ill effects. And as mentioned earlier here, we've got species in the hobby who have genetic pools that are an inch deep and a mile wide. It's fine to breed sacmates, and the more I think about it the more I'm convinced that's a fact. Where's the proof that it's detrimental? All I see is people's feelings about it and generalizations.

If there are dire ill effects to it, considering how captive bred specimens were established in the hobby, we should've seen mutants by now.

And it's true, whenever we ask for proof that there are detrimental ill effects; people always bring up other animals and not tarantulas in particular because there are no evident ill effects to it

 

[darkness975]

Why does this topic keep coming up?

I recently talked with an entomologist who mentioned that the dispersal by ballooning of some spiders, like jumping spiders, might very well explain the fact that reducing inbreeding in these spiders is desirable if one wants to end up with strong individuals. Theraphosids, which do not disperse much, if at all, and certainly do not use ballooning, are almost immune to many negative effects that inbreeding could bring.

Is there published evidence for this claim?

Also what's your take @The Snark ?

 

[Dorifto]

There isn't any ill effect until it happens.

If a big numbers of specimens share similar genetic expresions, it's much more probable that someday all of them they could get affected by any kind of illness, than the group that has more diverse genetic expresions.

I can't find the article right now, but there was a lizard species that basically clone itself, now it's facing a huge decrease in population due to most of them are affected by a illness.

Same could happen in our hobby. Keep in mind that in our hobby there is not natural selection to choose the stronger and better specimens. It's more about money...

How long will it take? Who knows.

In addition to this, there was a study about inbreeding, I believe it's the second one I posted, where they show that they were negative effects after long inbreedings, but that those effects were miticated after breeding them with not closely related individuals.

 

[campj]

Kind of unavoidable in some cases, unless you're able to convince Brazil, Chile, Sri Lanka, India, and others to allow exportation. Either that or just stick to spiders that have been heavily imported WC over the years and have a high chance of being unrelated.

How many egg sacs of these rare species would you wager are hatched each year in the US, especially in the beginning? So I buy a sling from xxxx dealer, Jimmy buys a sling from yyyy dealer, both dealers bought 40 slings each from zzzz breeder who had a successful sac this year. Mine ends up female and I've been feeding her twice a week, Jimmy's ends up male and he's been feeding it once a month, and I decide I want to breed... buy the MM from Jimmy with no idea that they're sac mates.

How about importation of CB slings from Europe? Who's to say that the dealer is Germany isn't sending five spiders from the same sac? Should we not breed and distribute them unless we can verify that they're not related?

Not trying to be combative, just think that this stuff goes on all the time and has for decades, and unless it gets brought up in a thread as a hypothetical question nobody seems all that concerned with it.

 

[The Snark]

Also what's your take @The Snark ?

I'd need to read clinical findings to form any kind of opinion. And I'd prefer DNA analysis to some guy who inbred seven generations and noted no adverse effects.

I have read that evolutionary evolved mass dispersal is paradoxical the the 'desert island' isolation effect that produces parthenogenesis. Ballooning isn't the only method for mass dispersal. By observation the spiderlings of a H Venatoria spread out to roughly an acre within 24 hours. Given that they don't develop full mobility for a few instars it seems likely that a single hatching could spread over a square mile or so. From observing L Hesperus, they do disperse over a wide area. While it's extremely difficult or even impossible to track dispersal, pre-mature adults have often been discovered; taken home in recreation vehicles from camp sights where there's one or two adults behind every public toilet.

 

[A guy]

There isn't any ill effect until it happens.

If a big numbers of specimens share similar genetic expresions, it's much more probable that someday all of them they could get affected by any kind of illness, than the group that has more diverse genetic expresions.

I can't find the article right now, but there was a lizard species that basically clone itself, now it's facing a huge decrease in population due to most of them are affected by a illness.

Same could happen in our hobby. Keep in mind that in our hobby there is not natural selection to choose the stronger and better specimens. It's more about money...

How long will it take? Who knows.

In addition to this, there was a study about inbreeding, I believe it's the second one I posted, where they show that they were negative effects after long inbreedings, but that those effects were miticated after breeding them with not closely related individuals.

Again, why comeback to lizards and studies on other animals? Why not focus on the actual tarantulas?

Why is establishing and sustaining a population for the entire hobby that stems from only a hand full of specimens not proof and overlooked?

I would think that "how long would it take" is not the proper question anymore. I think it should be "is there even?"

 

[campj]

I'd need to read clinical findings to form any kind of opinion.

Who is doing these studies then?

 

[AphonopelmaTX]

If there are dire ill effects to it, considering how captive bred specimens were established in the hobby, we should've seen mutants by now.

And it's true, whenever we ask for proof that there are detrimental ill effects; people always bring up other animals and not tarantulas in particular because there are no evident ill effects to it

Who is to say we haven't seen mutants and haven't realized it? Do you think mutations are only expressed in a form we can all easily observe? Maybe there are spiderlings out there in collections that die off because of a mutation in a gene that doesn't create a protein needed for proper development. Tarantula deaths in captive populations could very well be happening all the time due to inbreeding, but we would never know it.

 

[Dorifto]

Again, why comeback to lizards and studies on other animals? Why not focus on the actual tarantulas?

Why is establishing and sustaining a population for the entire hobby that stems from only a hand full of specimens not proof and overlooked?

I would think that "how long would it take" is not the proper question anymore. I think it should be "is there even?"

I have posted two studies that are openly available with spiders, not lizards, where they found significant changes in size, fertility etc. I don't need another specific research with Ts to have an aproximate idea about what will happen.

Genes are genes.

There was smuggling, there is smuggling and it will be smuggling. So even if in the begginings there were few individuals that were inbreed, it doesn't mean that over time those offsprings could not have mixed with "new blood". In one of those studies you can find that you only need to breed once an inbreed spider with an outbreed one to mitigate/revert the negative effects of the inbreeding, so why such system could not exist also in Ts?

There are thousands of species that evolved to avoid inbreeding, using same methods like Ts do, like different maturing times, which naturally helps prevent inbreeding with the closest relatives. Imho that's the clearest sign that they actively avoid inbreeding.

Also it could be reasonable to think, that inbreeding won't affect Ts as fast as other animals that evolve faster. But it doesn't mean that they are not affected at all.

 

[The Snark]

" Darwin saw two distinct kinds of variation: (1) rare abrupt changes he called "sports" or "monstrosities" (example: Ancon sheep with short legs), and (2) ubiquitous small differences (example: slightly shorter or longer bill of pigeons).[119] Both types of hereditary changes can be used by breeders. However, for Darwin the small changes were most important in evolution. " - Winther, Rasmus G. (2000), "Darwin on Variation and heredity", Journal of the History of Biology" 33, pp. 425–455

 

[FredSlaine]

For my own understanding, is this that the effects do not seem to have an adverse outcome to the overall function of the T? Or that they lack the genes that would otherwise be affected through inbreeding?

DaveM summed up a pretty good explanation. Although, all this being said, we must still keep in mind that this (afaik) hasn't been properly researched and basically all this comes down to observations from hobbyists over time. So very anecdotal and not very scientific in the strict sense.

Why does this topic keep coming up?



Is there published evidence for this claim?

Also what's your take @The Snark ?

None I'm aware of, this was a personal communication and an educated guess based on anecdotal observations. Mainly that he was running into massive sling die-offs and very skewed sex ratios around the 4th or 5th generation of inbreeding jumping spiders.

 

[curtisgiganteus]

So, because I was asked, here is my 2¢. Please keep in mind, I am no geneticist.

1: Inbreeding is unavoidable in captive populations of organisms like the tarantula hobby due the the reliance on imports and WC specimens to introduce new genetic material.

2: Genes may be genes however there is a distinct difference in vertibrate genetics and invertebrate genetics. Apples to oranges etc…

3: For species regularly available such as C versicolor, C cyanopubesence, P. Murinus, etc, every attempt should be made when pairing to avoid inbreeding.

4: Inbreeding in the few pairs or sling groups brought to the states when a new species is introduced here is not as detrimental as some would make it out to be. This has been done time and time again, albeit in a responsible manner (hopefully) by reputable and experienced keepers/breeders. Hence why some species, upon introduction, demand such a high price. It guarantees, for the most part, that the spiders go where they can best be raised and bred as your average keeper in this hobby is not going to spend 400$+ on a single sling. And increasing the genetic pool once the base population has been established is something we have done in the hobby for years. If you look at the science behind Island biogeography and how it relates to the genetic diversity of island populations, it supports this practice. At least in theory.

5: We all know the amount of data and published research by accredited institutions on the inbreeding of theraphosids is almost non existent. None here are engaging in argumentum ab auctoritate, so it’s useless and antagonistic to question what authority someone is speaking from. If you can’t contribute meaningfully to the discourse, even if we are kicking a dead horse, then don’t bother responding.

 

[A guy]

Unfortunately, like any other thread with this subject; everything we have is anecdotal.

I, myself only have what I was told by a person who has been in the hobby for years with his own contributions and his connections with some very good names in the hobby. But again, there is no scientific evidence. We only have what others have experienced.

So to answer the OP's original question: We don't really know.

 

[curtisgiganteus]

Unfortunately, like any other thread with this subject; everything we have is anecdotal.

I, myself only have what I was told by a person who has been in the hobby for years with his own contributions and his connections with some very good names in the hobby. But again, there is no scientific evidence. We only have what others have experienced.

So to answer the OP's original question: We don't really know.

I feel like the only thing keeping said persons experience from being autorative is an accreditation from a scientific institution. An arachnologist would like do the same thing with more professional control groups and a nicer table lol

 

[darkness975]

I would avoid it.

 

[A guy]

I feel like the only thing keeping said persons experience from being autorative is an accreditation from a scientific institution. An arachnologist would like do the same thing with more professional control groups and a nicer table lol

That would take years and years! When he and his wife discovered new undescribed species in French Guiana, they sent photographs, exuviae they found from abandoned burrows and they sent all those materials to various arachnologists friends they had all over the world.

It took 15 years for one of the arachnologists to get back to them and say "Yes, what you saw was a new and undescribed species".

 

[curtisgiganteus]

I would avoid it.

My I ask how you would approach establishing a new species with limited genetic material to start with?

That would take years and years! When he and his wife discovered new undescribed species in French Guyana, they sent photographs, exuviae they found from abandoned burrows and they sent all those materials to various arachnologists friends they had all over the world.

It took 15 years for one of the arachnologists to get back to them and say "Yes, what you saw was a new and undescribed species".

Exactly why I am going to school for Arachnology with a focus on taxonomy.