Tarantula Genetics and Inbreeding

[MindUtopia]

Just wondering...what are the rules about breeding tarantulas when it comes to inbreeding? I would imagine that tarantulas are probably like just about any other creature in that inbreeding (i.e. mating two siblings) would be a genetically bad idea, is this true? What happens when siblings are bred? And if it's not a good idea to breed siblings, where do you draw the line? For instance, is it okay to breed half-siblings (for example, spiders who have the same mother, but different fathers, or vice versa)? How genetically distant must tarantulas be to be safely bred? I'd be interested to hear what breeders out there have to say about this.

Thanks,
Karen

 

[syndicate]

im not to sure how much is really known about tarantula genetics to even be able to anwser that question.i wonder if inbreeding occurs in the wild at all

 

[David Burns]

Not this topic again. There is never a decisive answer. Usually alot of arguing and then it gets padlocked. For a history on this topic, type inbreeding into the search function at the top of the page.:wall:

 

[AfterTheAsylum]

Males and females in the same clutch do not mature at the same time.

 

[GoTerps]

Males and females in the same clutch do not mature at the same time.

I'd be careful making blanket statements like that. Female tarantulas can be sexually mature far before reaching full-grown size (at least a lot of them can, need to be careful about making blanket statements myself!).

How many clutches (of any species) have been tracked from eggsac to maturity in the wild?

In captivity it can be quite easy to slow down the growth of males and speed up females. I also have groups of siblings here in which the females have outgrown the males under identical conditions.

 

[David Burns]

Males and females in the same clutch do not mature at the same time.

I would like to throw a blanket over this statement. It is basically untrue. I have proved this with my own spiders.

 

[AfterTheAsylum]

I knew someone was going to do that. I was waiting for it. Just because some females grow faster, it doesn't necessarily mean that they mature faster. Unless you are intentionally trying to control their growth rate, I don't see the issue. In the wild, a male and a female have the same probabilities of catching food, so they won't be drastically different in maturity rates. I cannot give a 100% answer, but I am inclined to this. I too asked this question when I starting getting into it. So I asked my breeders. They gave the same short answer I did. Above all, why would you want to bother with mating brother and sister? Just mix it up.

By the way, I have many spiders from the same clutch, and none of the males have been mature at the same time as the females. These include Pamphos, Theraphosas, etc. So hey, maybe it is just my luck. They all eat the same and cages are all identical in set-up, humidity, temperature, substrate, etc. So I think I will stick to my guns with this one. Not to disagree, for I am sure it is possible, but in likelihood? I dunno.

Cheers

The Sickness

 

[David Burns]

Not this topic again. There is never a decisive answer. Usually alot of arguing and then it gets padlocked. For a history on this topic, type inbreeding into the search function at the top of the page.:wall:

Around and around we go.

 

[Tony]

Am I still coming here?

 

[Darwinsdad]

It has been rumored that if siblings were mated with oneanother in all likelyhood the resulting offspring would be sterile hence wasting the opportunity to enlarge the captive breed numbers of the species. Wether or not this is true is like all the other maybes and probiblies related to this topic. Who knows but you now have one more rumor to keep you awake at night.

 

[MindUtopia]

Thanks for your replies. Sorry to incite too much debate, it's certainly easy to do around here! Just curious, but what Darwinsdad said makes sense...why take the chance with sterility of offspring if you don't have to. I was more just curious because while I try to know where the spiders I have come from, you just never know when you aren't buying directly from a breeder where they may have come from, unless people are meticulous with their records. I just wanted to know how concerned I should be given the small possibility that inbreeding could occur unintentionally, meaning that I try to breed two spiders that I don't know are related. I'm sure it's a tiny chance of that happening overall, but probably much greater with some of the spiders that newer to captive breeding. I'll check out the other thread though too.

Thanks!
Karen

 

[GoTerps]

Hey Soulsick, don't get pissed at me, I'm not intending to be rude, but I am gonna pick on you for a bit here!

In your first post you say,

Males and females in the same clutch do not mature at the same time

But then in your next post you say,

In the wild, a male and a female have the same probabilities of catching food, so they won't be drastically different in maturity rates.

Aren't you contridicting youself?

You also say,

By the way, I have many spiders from the same clutch, and none of the males have been mature at the same time as the females. These include Pamphos, Theraphosas, etc.

I noticed you just posted today, in another thread, that you keep the following Pamphobeteus:

I have 5 platyomma, 1 Ecuador sp. 1, 1 Ecuador sp. 2, 2 antinous, and 1 nigricolor.

Is it really fair for you to say that none of your male and female Pamphobeteus from the same clutch have been mature at the same time? How can you possibly come to that conclusion from the above collection? Maybe your speaking only of sp. "platyomma" in which you have 5 (still a small group). How big are they now? How would you be sure the females aren't mature when the males are?

 

[MindUtopia]

Thanks, the reference someone gave to the other thread was very helpful. I'd definitely recommend it for anyone who is interested in reading more on this topic.

 

[Brandon]

I’m sure scientifically, if we looked at it on a grander scale we would most likely see that inbreeding is ok to certain extent. Think about all of your favorite boa color morphs, most of these would not be possible without some form of inbreeding. If you know your genetics this would make allot of sense. But after a certain amount of inbreeding you eventually get snakes with bug eyes or bad bone structure, however inbreeding has not shown to produce many sterile animals.

Sincerely,

Brandon

 

[danread]

It has been rumored that if siblings were mated with oneanother in all likelyhood the resulting offspring would be sterile hence wasting the opportunity to enlarge the captive breed numbers of the species. Wether or not this is true is like all the other maybes and probiblies related to this topic. Who knows but you now have one more rumor to keep you awake at night.

This isn't true. There are many examples of tarantulas in the hobby that have been started off with a relatively small gene pool, i think A. geniculata is meant to have started off with a single imported gravid female! I also know of examples of P. regalis siblings that have been bred together producing viable offspring.

Cheers,

 

[M.F.Bagaturov]

Yep, DAn, You're right indeed.
It is clearly shows here in Russia.
Some species here was firstly presented by several siblings from the sole eggsac but now is widespread in hobby.
They're perents were brother/sisters.
And that's all over the world.
This is not a sphear of knowledge of tarantulas somebody can tell something for sure (in fact, I dunno any seriouse examination of these except one-two cases) but some evidences are known.

 

[Crotalus]

This isn't true. There are many examples of tarantulas in the hobby that have been started off with a relatively small gene pool, i think A. geniculata is meant to have started off with a single imported gravid female! I also know of examples of P. regalis siblings that have been bred together producing viable offspring.

Cheers,

There was more then a single specimen of adult geniculata offered when they first came into the hobby. And a few of these were gravid and layed eggsack which hatched out.
The "importer" that brought these into the hobby wasnt the guy who settles with ship one or two specimens...
Go figure.

But siblings do produce fertile offspring but its not as common as breeding female/son since the males mature faster then females.

I know Rick tried to inbreed a Chilobrachys sp. and the slings produced was clearly weaker.

/Lelle

 

[Darwinsdad]

This isn't true. There are many examples of tarantulas in the hobby that have been started off with a relatively small gene pool, i think A. geniculata is meant to have started off with a single imported gravid female! I also know of examples of P. regalis siblings that have been bred together producing viable offspring.

Cheers,

Well I did place in my post that it was a rumor and I personly could not verify or discont it.

 

[Galadriel]

Being fairly new to the invert hobby this is something I've looked into a little, just for the sake of knowledge. Unfortunately, it's all speculation at this point. I can tell you, however, when it comes to "line breeding" snakes, genetic defects don't start to occur until F7 or F8. And the only time sterility becomes an issue is during cross breeding with most species (but not all). As tarantulas are not as genetically complex as reptiles, I'd imagine it would take more generations than that to start seeing deformities. Even with human beings, it takes 3 or 4 generations of inbreeding for defects to start cropping up.

Latha math an drasda

Galadriel

 

[Nerri1029]

OK..

I was recently the target of a local cancer researcher, he wanted me to come work for him..
he has a strain of mice that produce tumors (Breast Cancer).. VERY regularly.

He breeds ONLY brothers and sisters.. why: to keep the tumor gene present..
The mice are normal EVERY other way except that they produce tumors.

even in humans sibling ( and other close relative) offspring are normal... UNLESS there are recessive genes present.. THEN the likely hood of those genes surfacing is increased..
SOOO unless this is the case.. there is no biological reason why offspring of siblings would be anything else but normal.

as unsavory as this topic is to people, I've seen the results personally..
there was a family near my home town who's patriarch impregnated his daughter twice. those kids are normal today ( they were taken out of that house by their mother and grew up in a fairly normal setting )