Interbreeding....

[invertepet]

I've posted this a few times already, but here goes again:

In 1991 (or 92, can't recall precisely) I imported a couple of Poecilotheria fasciata. Back then there weren't many of these around, so there wasn't much of a breeding pool available (at least not easily). I got them when they were approx. 1.5" in legspan. They were both from the same brood.

After about 3-4 months, I was able to sex one of the two as male. I proceeded to feed him a bit less and the female a bit more, upping her temp a tad as well.

What resulted was a fairly small but sexually 'mature' (or at least 'capable') female at the time that the male had his ultimate molt. I bred the two and got a 75-spiderling sac which the female carried to full term. The babies were hardy and equally patterned/colored as the adults. I sold all but one which matured into a, adult male, and one I gave a close friend did likewise.

bill

 

[skadiwolf]

can't beat the Egyptians, they were so paranoid they often married their siblings. ew.

man, i would kill my brother if i lived with him my whole life, much less married him....gross.

 

[Code Monkey]

Re: Re: Interbreeding....

Originally posted by Professor T
If you breed close genetic relatives generation after generation, this leads to a phenomenon known as inbreeding depression. There is strength in diversity, a phenomenon known as hybrid vigor.

The counter argument to this is that depending on the species in question and the circumstances of their existence, the lessening/lack of diversity from inbreeding may be of no consequence in captive conditions. Plenty of inverts such as feeder roaches, crickets, mealworms, dermestid beetles, etc. are into thousands, if not hundreds of thousands, of sequential generations of inbred/extremely limited gene pools with no obvious deletrious effects.

I'm against it on general principle and think that breeding from the same sack to be extremely poor practice without a very good reason, but as Wade says, it's probably not the huge taboo many people make it out to be.

Your average person automatically thinks "inbreeding = bad" but that's really only true for captive lines if it means you're increasing the frequency of deletrious alleles. Take an ideal pair of siblings with no "bad" genes, and inbreeding for the purpose of captive specimens is almost guaranteed to be a better deal than any outcrossing. The catch is that it's impossible to know if any given tarantula is really that ideal of a breeding specimen so odds are you are better off hedging your bets by avoiding inbreeding.

 

[Tangled WWWeb]

Originally posted by Martin H.
Hi,

Do they really do? Are there any research results published about this or where does this/your opinion come from?
In the last years I have made several times the experience, that females have matured earlier than the males which have been raised under the same conditions =>


This has been my experience as well. I have had females get a full 2 instars ahead of their male siblings, when kept under identical circumstances. I have had it happen the other way as well.

 

[Wade]

I think that the impression that males mature faster may be based on the fact that females mature at a smaller size then we expect. We assume that a female is not mature due to her small size, but she may in fact be (which brings us back to the idea I expressed in my previous post). I suspect it is probably still wise to hold off breeding small (albiet mature) females anyway, as I have heard rumors that females bred at a young age do not grow as large as those who are unbred (this was discussed on arachnid world not too long ago). I'm NOT suggesting that we not breed them at all to grow super spiders, but rather to allow them to put on enough size to become really good breeders.

Of course, all this only relates to the hobby. What they do in the wild is anybody's guess.

Wade

 

[Code Monkey]

As a followup to my earlier post and a bit of interesting real world example: At my new job, one of the strains of German cockroaches that I'm working with has been in continuous culture in labs since 1952. That's millions and millions of roaches derived from a very small initial sample and crossed and recrossed, and recrossed some more, thousands of times and still perfectly healthy.

 

[versus]

hi there......
anyway, how do u guys know that ...erm..for example, those tarantulas that being bred from a same eggsack, then being trade to different petshops across an area... then ppl started to purchased them, then when all those matured, ppl might not knowingly breeded them..and this is also called as inbreeding too ....am i right?? how do u make sure that the tarantulas that ppl purchased, i meant same species...doesn't come from a same eggsack?? we don't know it right?? and...in the wild, a gravid female will came out with hundreds of youngs, and then the spiderlings lives by their own once they molted into second instars... and when they grew matured in the future... we will not know wether they will meet their borthers or sisters from the same eggsack.... true?? can anyone define this??? pls correct me if i'm wrong...coz these thoughts keeps running on my mind :? .... thankssssssss

 

[Scorpiove]

Versus you are correct. All those things can and probably have happend. Inbreeding happens a lot in the wild.

 

[versus]

so does it affect the developing of the spiderlings from an interbred eggsack??? :?

 

[FryLock]

I think i said this on a diff thread you have to remember a LOT of T's in the hobby come from at best a few adults and/or a sac or two because they have been smuggled from there native countries, for example L.para come AFAIK from two egg sac that Ronald Baxter received (or received young from) in the late 80's are the 9"-10" span girls (and adult male that lived 3.5 years) ppl are still getting now undersized :?

 

[versus]

I think i said this on a diff thread you have to remember a LOT of T's in the hobby come from at best a few adults and/or a sac or two because they have been smuggled from there native countries, for example L.para come AFAIK from two egg sac that Ronald Baxter received (or received young from) in the late 80's are the 9"-10" span girls (and adult male that lived 3.5 years) ppl are still getting now undersized :?

thanks alot...mate~...really appreciate that..

 

[Windchaser]

Digging up an old topic, I am curious what are the current views on the subject. Recently there was an article indicating the with humans the problems associated with inbreeding are not as bad as they were first thought. Also, in the wild, how widely do tarantulas dispurse?

 

[danread]

Digging up an old topic, I am curious what are the current views on the subject. Recently there was an article indicating the with humans the problems associated with inbreeding are not as bad as they were first thought. Also, in the wild, how widely do tarantulas dispurse?

Do you have a link to this article?

 

[Windchaser]

Do you have a link to this article?

I read the story about a month ago and had to go back and look for it. Anyway, here it is: Kissing Cousins. Not exactly the premier scientific journal, but the article does make one wonder.

 

[DR zuum]

I read the story about a month ago and had to go back and look for it. Anyway, here it is: Kissing Cousins. Not exactly the premier scientific journal, but the article does make one wonder.

But the risk is greater by 1.7 to 2.8 percent,as it says this is the additional risk,so instead of the normal unrelated 3 to 4 percent,with cousins you would have 4.7 to 6. 8 if the study is accurate.I wonder what it would be for brother and sister double that?Maybe 9.4 to 13.6? Hey hey hey break out the banjos,walla,walla walla.

 

[kyle_de_aussie]

WOW!! i know a hell of a lot of people that are breeding spiders from the same sac as each other and breeding the mother with one of the sons and all sorts of crap they all told me it was perfectly safe and there would be no problems at all doing it
Sounds like they might be wrong!!

 

[danread]

WOW!! i know a hell of a lot of people that are breeding spiders from the same sac as each other and breeding the mother with one of the sons and all sorts of crap they all told me it was perfectly safe and there would be no problems at all doing it
Sounds like they might be wrong!!

I think as always, the truth lies somewhere inbetween. It's quite clear that breeding siblings doesn't have an immediately bad effect on the offspring, as this occurs reguarly in the hobby. What we can't be sure about is the long term effects of having individuals continually inbreeding. What ever anyone says, we really don't know the truth. Personally i think it would be a good idea to avoid inbreeding wherever possible, but in some cases it can't be avoided (i.e with very few individuas to start with).

 

[Windchaser]

But the risk is greater by 1.7 to 2.8 percent,as it says this is the adidtional risk,so instead of the normal unrelated 3 to 4 percent,with cousins you would have 4.7 to 6. 8 if the study is accurate.I wonder what it would be for brother and sister double that?Maybe 9.4 to 13.6? Hey hey hey break out the banjos,walla,walla walla.

True, but this is not the significant increase in risk that you commonly hear people talk about. Most people believe the risk is significanlty higher for the offspring of closely related couples. All I am saying is that the risk may not be as bad as some believe. Also, if the initial couple were fairly genetically "clean" (not many bad genes in there) wouldn't the offspring actually have less of a chance of birth defects?

 

[DR zuum]

No dont get me wrong, i was surprised it was that low in humans as well.I assumed it would be higher.I was being facetious. :8o As to being better genetically id like to see what they were like atfer a few generations.