Breeding Q

[GoTerps]

*Chris covered all the replies I had to Stan's post, so I'll leave that alone*

Hi Wicked,

Yes, males mature faster than the females, but if breeding is your aim, buying a group is a good idea.

I do have to say that I don't agree with this blanket statement.

It's been the overwhelming case for me, that when males mature, their female siblings are ready to breed... likely not full grown, but sexually mature none the less. I'm not suggesting this is the case with all species (I'm not making a blanket statement of my own!), but it has been the case for me with most of the species I've worked with in captivity.

Eric

 

[wicked]

Hi Wicked,


I do have to say that I don't agree with this blanket statement.

It's been the overwhelming case for me, that when males mature, their female siblings are ready to breed... likely not full grown, but sexually mature none the less. I'm not suggesting this is the case with all species (I'm not making a blanket statement of my own!), but it has been the case for me with most of the species I've worked with in captivity.

Eric

Hi Eric

Ah yes, I know I have read multiple threads dealing with females that were bred at a suprisingly small size, I just didn't know what the general consensus was on that in relation to their male siblings. Have you noticed a difference between the faster growing species and the slower growers at all? I wonder if species with shorter life spans would be more prone to it, or if it is across the board.
As mortified as I am that I didn't get back to edit my original post before it was qouted, I am kind of glad I didn't. This thread brought out a lot of the experienced members as well as some great links to more in-depth discussions, and well balanced for both sides. Very informative posts, so long as they skip mine.

 

[Stan Schultz]

While I certainly respect your knowledge of this hobby, I question this post. My study of invertebrate physiology, ...

Wrong science. You don't need physiology (the study of organs and organ systems and how they operate) to understand inbreeding and its effects. You need genetics (the study of how characteristics are inherited, mis-inherited or not inherited at all).

... Do you have references or proof as to damage that may be caused by inbreeding? ...

Yup! 15,000 years of accumulated experience breeding hundreds of kinds of domestic plants and animals. Look in any animal or plant husbandry textbook.

And, the following articles dealing specifically with tarantulas:

West, R.C. 1998. The Dreaded "I" Word. Forum Magazine. 7(1):27. Am. Tar. Soc. Carlsbad, NM.

Reinhart, K. 1998. Inbreeding. Forum Magazine. 7(6):206. Am. Tar. Soc. Carlsbad, NM.

I have not read the following article but am listing it anyway because of the title:

Clapp, J.P. 1996. Inbreeding of Tarantulas. Journal of the British Tarantula Society. 11(4):132-134. Brit. Tar. Soc.

Hope this helps.

 

[GoTerps]

I hope no one will conclude that inbreeding has deleterious effects in theraphosids from those sources alone!

Yup! 15,000 years of accumulated experience breeding hundreds of kinds of domestic plants and animals. Look in any animal or plant husbandry textbook.

Books mostly dealing with plants and vertebrates!

Eric

 

[ShadowBlade]

Yup! 15,000 years of accumulated experience breeding hundreds of kinds of domestic plants and animals. Look in any animal or plant husbandry textbook.

I'm sorry, but this is also wrong science. Because you're talking about different forms of life.

-Sean

 

[ironmonkey78]

lol yeah me too
No offence Stan,
but it seems to me that some of the small pops of Aphonopelmas in Texas would be seriously hampered by inbreeding if it was a big problem. I know of one site that is only about a half acre wiht maybe 100 Ts population and they are isolated, no known Ts for miles around. and they are fine. Actually i think they may be a species that was not known to be in that part of the state at all. MAybe even undescribed. but ...there isnt enough of them to even get them described if they arent.


they are very docile, healthy and beautiful. and i am sure they are very inbred.
of course that depends on how you define inbreeding

I agree you cant in any logical sense think that with a population of even 1000 in such a secluded area there is no inbreeding. even in the hobby you cant be sure, granted its more likely that its cousin cousin rather than brother sister, I mean we all buy from the same people,at some point it all comes down to genes. I dont believe that inbreeding wouldnt happen in the wild, even if there are other Ts relatively close I dont think Ive read anything anywhere about tarantulas finding a mate and not mating based on relation.

 

[Stan Schultz]

... What is this advise based on? I only ask this because in the threads I linked to the evidence seems to suggest that the inbreeding of tarantulas is not a big problem, if indeed it is a problem at all. ...

I hope no one will conclude that inbreeding has deleterious effects in theraphosids from those sources alone!

Books mostly dealing with plants and vertebrates!

Eric

I'm sorry, but this is also wrong science. Because you're talking about different forms of life.

-Sean

No. Sorry. You have no clue as to the depth and profundity of what you're arguing.

We're talking about the laws of eukaryote genetics (EG), a phenomenon that may have been around for well over 2 billion years, far older and far more firmly entrenched in our biology than perhaps 75% of any of the other biological phenomena you're familiar with.

EG, for instance, may predate predation. Or, multicellularism. Or, an oxygen/nitrogen atmosphere! Right off the top of my head, there are only a few hundred biochemical reactions and possibly the principles of evolution that may be as old or older.

These are the laws of heredity that all nucleated forms of life on Earth follow, from Paramecium and other single celled organisms across the evolutionary spectrum through fungi, green plants, and yes, even tarantulas and man. Any organism on our planet that reproduces sexually at one time or another in its life cycle MUST follow these basic laws. Any that failed to do so went extinct long before "modern" life (just about everything post-Precambrian) was anything but a flicker in the Creator's eye. If you ever wanted to look one of Tolkien's Balrogs in the eye, this is as close as you can get in the real world.

From the standpoint of EG, the differences between tarantulas and humans are merely interesting ripples in a vast sea. We're almost indistinguishable! If we ever share a common denominator with tarantulas, and indeed with most other life on Earth, this would be it!

To think that tarantulas can violate such a far reaching and absolutely binding biological principle as EG on the basis of less than a generation of extremely limited personal experience is folly.

In a more specific sense:

1. Are natural populations of tarantulas inbred?

Yes, without question. There is probably limited "outbreeding" by exceptional wandering males, however. After all, how do you think the isolated colonies got where you find them in the first place except by exceptional wandering tarantulas. But the norm among wild tarantulas is "Love thy siblings, love thy cousins, love thy parents and with a frenzy that would embarrass most rabbits!"

2. Then why don't wild populations display all the bad inheritable things that we think should be there?

For one simple fact: The attrition rate among wild, breeding tarantulas is ghastly! On average, out of any given eggsac fewer than one or two babies may ever reach reproductive age. We're talking nearly a 99.99% death rate!

If any of the babies from any eggsac has any defect, however small, that might interfere with its ability to survive, it becomes something else's lunch. If it's even the tiniest bit unlucky, "burnt toast" doesn't do it justice! The survivors, the ones you so blithely pick from their burrows or buy from the neighborhood pet shop are the cream of the cream of the cream. That's why you should treasure them like the magnificent art pieces that they truly are.

The danger is that we DON'T cull the breeding population anywhere near as brutally as Mother Nature does. And like humans, we tend to conserve every little defect that arises. As we breed them generation after generation, the natural background mutation rate inexorably takes its toll, like a moving glacier, and those genetic mistakes gradually accumulate.

We've done this many times before: For example, as far as I can tell, all golden hamsters in captivity can trace their lineage back to a litter of eight babies that were dug out of a long burrow in Syria in the 1930s and were first bred as laboratory animals by the pharmaceutical industry. During the intervening 70 years of inbreeding dozens of mutations have been produced. One must only go to a neighborhood pet shop to see the result. But, along with all those cute mutations comes a bunch that you can't see as readily that we've learned to compensate for in captivity, and that would surely get the hamster killed within hours back in Syria!

Another example: Man has been breeding the common scalare for many decades. (You know these as freshwater angelfish.) When the Germans first started breeding them, in fine German tradition, they culled them ruthlessly. But it wasn't long before the fish farms in Florida got hold of them and within a few years had perfected the practice of mass producing them in outdoor ponds. The problem is that they also inbred them excessively, and in such a semi-wild but highly protected environment there was almost no culling whatsoever.

Shortly after that the southeast Asians learned how to breed them in their homes by the millions. They were easy to breed and brought in much needed cash. But the people who were doing this often bred their own stock, generation after generation after generation without any new genetic blood or serious effort to weed out the deformed ones. After all, the bad ones made as much money as the good ones when sold to the ever ravenous tropical fish hobby.

Today, the common angelfish, in all its fin configurations and color forms, carries a gene that accounts for a serious deformity of the fish's gill cover. Go to any pet shop and look over their stock of baby angelfish. Up to 25% of them may have deformed gill covers. It took us decades to get to this juncture, and now we can't get out of it! There is no way to turn back the clock and breed that gene out of the population. There are just too many affected angelfish.

There are other examples that I won't bore you with. You get the picture.

We are just starting out on a very new venture: We're beginning to breed tarantulas! At this point, at the very beginning of the hobby and the industry, we have two choices:

1. We can understand the problem and work diligently to reduce it.

2. We can ignore it and let our children suffer the consequences.

If we ignore the problem we're much worse than those first Florida fish farmers or the pharmaceutical industry. They merely did what they did out of ignorance. We've been warned about it. And, we're committing the same sin anyway. But this time it's out of blatant stupidity!

 

[Aragorn]

As always, Stan, you've made a very good point. But is there certain amount of inbreeding that is safe, I mean just enough to get a desirable trait, but not enough to bring out any bad recessive genes? I hear a very popular breeder of leopard gecko bred the female giant form of this particular reptile back to its giant father to get super giant leopard geckos. I'm sure even in nature there is a little inbreeding. Isn't that how organism evolve? But I'm sure in nature it takes thousands of years to get new species and by that time this isn't even noticable. So how do you suggest we go about breeding tarantulas? I'm sure some inbreeding is necessary to get desirable trait, but how much is too much?

 

[Tescos]

Hi Mr Schultz

No. Sorry. You have no clue as to the depth and profundity of what you're arguing.

First I am not argueing anything I am questioning and second I find this rather patronzing of you to start of a reply by stateing how clueless I am. I would put a little sarcasim in here now but have for once in my life decieded not to stoop this low.
I think I have already stated that my knowedge in such things like genes is quite low but I will persist even if the end result for you is :wall: or me saying sorry I can see you are right after all (although at this point I am not saying your wrong either).

We're talking about the laws of eukaryote genetics (EG), a phenomenon that may have been around for well over 2 billion years, far older and far more firmly entrenched in our biology than perhaps 75% of any of the other biological phenomena you're familiar with.

EG, for instance, may predate predation. Or, multicellularism. Or, an oxygen/nitrogen atmosphere! Right off the top of my head, there are only a few hundred biochemical reactions and possibly the principles of evolution that may be as old or older.

OK I will take your word for this.

These are the laws of heredity that all nucleated forms of life on Earth follow, from Paramecium and other single celled organisms across the evolutionary spectrum through fungi, green plants, and yes, even tarantulas and man. Any organism on our planet that reproduces sexually at one time or another in its life cycle MUST follow these basic laws. Any that failed to do so went extinct long before "modern" life (just about everything post-Precambrian) was anything but a flicker in the Creator's eye. If you ever wanted to look one of Tolkien's Balrogs in the eye, this is as close as you can get in the real world.

How do and where to the plants that self pollinate, those large groups of social spiders that are (so I read) all related to each other, those fly's that Mr Gabriel mentioned in the other thread I linked to, and the countless other examples fit into this then?
Tolkien's Balrogs just confuse me in this subject even more!

From the standpoint of EG, the differences between tarantulas and humans are merely interesting ripples in a vast sea. We're almost indistinguishable! If we ever share a common denominator with tarantulas, and indeed with most other life on Earth, this would be it!

To think that tarantulas can violate such a far reaching and absolutely binding biological principle as EG on the basis of less than a generation of extremely limited personal experience is folly.

Is this just another way to say that we are all carbon based life forms and made up of the same blocks just rearanged in different ways?

1. Are natural populations of tarantulas inbred?

Yes, without question. There is probably limited "outbreeding" by exceptional wandering males, however. After all, how do you think the isolated colonies got where you find them in the first place except by exceptional wandering tarantulas. But the norm among wild tarantulas is "Love thy siblings, love thy cousins, love thy parents and with a frenzy that would embarrass most rabbits!"

ok I get that .

2. Then why don't wild populations display all the bad inheritable things that we think should be there?

For one simple fact: The attrition rate among wild, breeding tarantulas is ghastly! On average, out of any given eggsac fewer than one or two babies may ever reach reproductive age. We're talking nearly a 99.99% death rate!

But is that proven or an educated guess? Can you say this for all species also? I mean when you look at the living habits of for example that Pampobeteus species that is so dubbed "the chicken spider" then the survivel rate I think could be quite higher.

If any of the babies from any eggsac has any defect, however small, that might interfere with its ability to survive, it becomes something else's lunch. If it's even the tiniest bit unlucky, "burnt toast" doesn't do it justice! The survivors, the ones you so blithely pick from their burrows or buy from the neighborhood pet shop are the cream of the cream of the cream. That's why you should treasure them like the magnificent art pieces that they truly are.
The danger is that we DON'T cull the breeding population anywhere near as brutally as Mother Nature does. And like humans, we tend to conserve every little defect that arises. As we breed them generation after generation, the natural background mutation rate inexorably takes its toll, like a moving glacier, and those genetic mistakes gradually accumulate.

When you say defect, how are you meaning it here? I ask this because I have seen photos of wild tarantulas (sub adult) with a double abdomen and the only other defects I can think of where they survive, is on those species with chevlons that have the extra or lack of chevlons on the abdomen, but as a phiysical handycap I really can't see how this would effect their growth in the wild. I have off course heard about and seen photos of a couple of gynandromorph spiders (one of which went on to produce a fertile eggsac with a normal male) but these also could I think survive in the wild also, given the fact that butter flys with this same type abnormity have also been found in the wild.
Wether or not the offspring from that gynandromorph spider were affected I can't say but will endever to find out the next time I see the author of the article when I read it.
Another interesting article along these lines is...
Gabriel. R....Variation in the Abdominal Pattern and Colour of Poecilotheria regalis. Journal of the British Tarantula Society August 2006 Vol.21 No.4 (pp. 116 - 120)

We've done this many times before: For example, as far as I can tell, all golden hamsters in captivity can trace their lineage back to a litter of eight babies that were dug out of a long burrow in Syria in the 1930s and were first bred as laboratory animals by the pharmaceutical industry. During the intervening 70 years of inbreeding dozens of mutations have been produced. One must only go to a neighborhood pet shop to see the result. But, along with all those cute mutations comes a bunch that you can't see as readily that we've learned to compensate for in captivity, and that would surely get the hamster killed within hours back in Syria!

Another example: Man has been breeding the common scalare for many decades. (You know these as freshwater angelfish.) When the Germans first started breeding them, in fine German tradition, they culled them ruthlessly. But it wasn't long before the fish farms in Florida got hold of them and within a few years had perfected the practice of mass producing them in outdoor ponds. The problem is that they also inbred them excessively, and in such a semi-wild but highly protected environment there was almost no culling whatsoever.

Shortly after that the southeast Asians learned how to breed them in their homes by the millions. They were easy to breed and brought in much needed cash. But the people who were doing this often bred their own stock, generation after generation after generation without any new genetic blood or serious effort to weed out the deformed ones. After all, the bad ones made as much money as the good ones when sold to the ever ravenous tropical fish hobby.

Today, the common angelfish, in all its fin configurations and color forms, carries a gene that accounts for a serious deformity of the fish's gill cover. Go to any pet shop and look over their stock of baby angelfish. Up to 25% of them may have deformed gill covers. It took us decades to get to this juncture, and now we can't get out of it! There is no way to turn back the clock and breed that gene out of the population. There are just too many affected angelfish.

There are other examples that I won't bore you with. You get the picture.

This still doesn't explain the examples of natural inbreeding I said about. Also something else that nags me here about the wandering male syndrome and how one of these isolated colonys got started.Imean....
Lets just say for arguements sake that one female spider did walk, say, just 20 miles away from the rest of the colony to set up home.
Now it is alone and it grows to become mature and stays put. Now one day just by shear chance a male comes wandering by from that same colony and yes it is unrelated to the female and they mate, the female has an eggsac , and the spiderlings all dispurse around the mother in a kind of satalite way.
From there on in if any breeding is now going to happen then it is going to stay in the family, unless of course that 1 in a million shot of a male comes a wandering by from the nearist conlony again one year, and what are the chances of that happening twice?
Ok I know it is maybe a far fetched story but how else are these very remote small colonys surviving if not just a bunch of inbreeds? And how long have they been there Weeks?, months? years ?more? are they looking ok?

When the Germans first started breeding them, in fine German tradition, they culled them ruthlessly

Ok could you point out this tradition to me because I have now lived in Germany with my German wife for a little while now and have so far failed to see or find any fine German tradition that involves the culling of anything?

We are just starting out on a very new venture: We're beginning to breed tarantulas! At this point, at the very beginning of the hobby and the industry, we have two choices:

1. We can understand the problem and work diligently to reduce it.

2. We can ignore it and let our children suffer the consequences.

If we ignore the problem we're much worse than those first Florida fish farmers or the pharmaceutical industry. They merely did what they did out of ignorance. We've been warned about it. And, we're committing the same sin anyway. But this time it's out of blatant stupidity!

And so I ask how long is it going to be before these deformitys start to show then?
I ask this because with the higher animals like humans etc certain deformitys start to show quite early so I am lead to belive, and with certian tarantulas there have been no apparent side effects due to inbreeding up to 4th generation inbreeds, yet the gene count (I think this is the right word or?) for tarantulas is a whole lot lower than it is for humans so would you not expect the abnormitys to show themselfs alot earlier? I mean with 4th generation inbred humans surly there would be signs or?

Like I say I still can not see anything at this point that proves it for me especially after reading that other thread on this subject also.

Saying I am blatantly stupid is not going to change my mind on this either.
All the best
Chris

sorry for the big quotes only it is easyier to see where I am repling to...I hope?

 

[Stan Schultz]

... is there [a] certain amount of inbreeding that is safe, ...

"Safe," like beauty, is a relative thing dependant largely on the beholder. I'm trying very hard not to trample on anyone's opinions and beliefs unless I can marshal a good scientific (or at least rational) argument for it. Hence, I can't answer this one.

... I mean just enough to get a desirable trait, but not enough to bring out any bad recessive genes? ...

The laws of genetics do not recognize any difference between "good" genes and "bad" genes. Like death and Judge Judy, they show no prejudice. When you inbreed a population to gain individuals that are homozygous for a character (the formal word for "purebred") that you deem "good" or desirable, genetics automagically throws in a few that are also homozygous for the "bad" or undesirable character.

The job is not to inbreed up to, but not beyond, some magic brink when "bad" characters will start to appear. In any given population at least some "bad" characters are already there and any sort of inbreeding is going to replicate them along with the "good" characters. The real job is to try to recognize who in your population is homozygous for all the "good" traits and doesn't have any of the bad traits; and not allow any of the others to breed because they'll be passing at least a few of the bad traits down to their offspring.

... I'm sure even in nature there is a little inbreeding. ...

There is a LOT of inbreeding in nature, but natural selection is such an unremitting, powerful pressure that some level of incest is permissible, even necessary, if for no other reason than to maintain a sufficient population density. (With most organisms, there is a minimum population density below which the organisms can no longer breed frequently enough to maintain the population. This, of course, is a massive oversimplification. The interested reader should look in books on population dynamics and ecology for more information.)

... Isn't that how organism evolve? ...

How different species evolve is far too complex a topic to even barely touch on here, so I can't answer your question beyond saying that inbreeding and natural selection do play a large part (but not the whole part) in speciation.

... But I'm sure in nature it takes thousands of years to get new species and by that time this isn't even noticable. ...

Not "years." "Generations" might be a better word. And I have no actual data to present, but it would seem reasonable to expect at least a few hundred, minimum. There is some disagreement among biologists about whether species form slowly over large numbers of generations or sporadically and abruptly over relatively few generations whenever the opportunity presents itself. I wouldn't be a bit surprised to find that the truth lies somewhere in between and is actually quite variable. (But note that this is a "fuzzy" question because biologists still haven't developed a "hard" definition of a species.)

... So how do you suggest we go about breeding tarantulas? I'm sure some inbreeding is necessary to get desirable trait, but how much is too much?

Inbreeding with a coincidental lack of proper selection is a double whammy and the core of the problem. Inbreeding is essential if you wish to develop a strain or population of organisms that possess a given characteristic. The trick is to ruthlessly cull out the individuals that do not fit your criteria. These culls must somehow be removed from the breeding population. With dogs, for instance, we neuter or spay the puppies. With other animals we merely euthanise the unwanted ones. With plants we compost or burn them.

Tarantulas pose a problem in that they are not easily neutered or spayed. So what do we do with all the culls? Sell them to the pet industry? Pass them out to friends? (How may friends DO you have, anyway?) Keep them forever in your basement? Or destroy them? I'm sure this topic alone would start another dozen or so threads!

 

[Stan Schultz]

First, I need to apologize for my late response. We were on the road for two days, returning to Calgary, and of course, I can't drive and play with the computer at the same time.

Now that we're back in Calgary I am in a position where I do not have ready Internet access. This slows my responses down a bit because I have to drag my laptop off to someplace where I can connect through someone else's wireless network.

Lastly, you are almost as long-winded as I am ( ), and it's taken me no small length of time to respond to each of your concerns. Sorry again for the delay.

... First I am not argueing anything I am questioning ...

Sorry if this caused you any consternation. The verb "to argue" has many meanings in the English language. In the commonest vernacular it means roughly the same as a "verbal fight." However, it has other meanings as well, i.e., "give reasons or cite evidence in support of something." Please consult dictionary or use "dictionary argue" (without the quotes) in Google for more information.

... second I find this rather patronzing of you to start of a reply by stateing how clueless I am. I would put a little sarcasim in here now but have for once in my life decieded not to stoop this low.

And I appreciate your self control!

However, I believe that I began that essay with a quote from your pervious posting and followed it with quotes from two other people. That was intended to immediately announce the fact that I'm not responding to you alone.

And, I do this on a message board/Internet forum that is open to the public and that has hundreds or thousands of members. Whenever I post anything on these forums I presume beforehand that 5, 50 or even 500 people may read it, not just the recipient.

Lastly, it is not too uncommon for some of my essays to be reprinted in the American Tarantula Society's Forum Magazine. Thus, another several hundred people will potentially see what I type.

I did not intend to appear patronizing to you. In fact, I have almost no idea who you are and haven't formed much of any opinion about you whatsoever. Rather I was speaking to a somewhat larger audience about a subject that is of importance to anybody who might want to breed tarantulas. I was merely using your questions and those of the other respondents as a means of focussing the discussion.

I also fully understand that members of the audience I referred to may live in a number of different countries and come from a number of different ethnic backgrounds, are a wide spectrum of ages, have had a wide spectrum of educations from almost no education whatsoever up to a PhD. In a situation such as that some of those people are going to have to be "given a jump start" to bring them up to the level where they can understand the gist of my message. And, of necessity that's going to sound a little like I'm "talking down" to some. I'm sorry about that, but it's the best I can do. If you know a better way, please teach me!

... How do and where to the plants that self pollinate, those large groups of social spiders that are (so I read) all related to each other, those fly's that Mr Gabriel mentioned in the other thread I linked to, and the countless other examples fit into this then? ...

Self-pollination, social spiders and a lot of other such natural inbreeding all falls under that same category: "Inbreeding." The most prevalent defence against it is brutally intensive natural selection as I stated in an earlier post.

One might question how natural selection could work in a colonial spider's colony? Someplace, sometime in the life of that colony every spider must run the gauntlet. It must somehow not be cannibalized by its colony mates. It must avoid being eaten by birds, parasitized by flies, carried off by wasps, etc. For each such case there is a similar story. One must merely look for it.

In nature this is a gauntlet that the tarantulas must run with virtually no possibility of survival. For example, in west Texas we may consider some species of Aphonopelma. The females may live 25 years, and during that time they may produce 10 eggsacs. And each eggsac may hold an average of 150 eggs. (DON'T QUOTE ME ON THIS! These are not scientifically verified data! I'm pulling more or less believable numbers out of the air here.)

That means that over the course of her life span a female will have produced a total of about 1500 eggs. Since the production of those 10 eggsacs required 10 different males, in order to maintain a constant population in her area only 11 of those 1500 eggs had to live long enough to reproduce. (Ten males plus the female.) Divide 11 by 1500, express it as a percentage and you have a survival rate of about 0.7%. Less than 1%!

To survive in a world like that, not only must you carry a near perfect set of genes, you must also be incredibly, unbelievably lucky!

... Tolkien's Balrogs just confuse me in this subject even more!

Is this just another way to say that we are all carbon based life forms and made up of the same blocks just rearanged in different ways? ...

Sorry to confuse you. A Balrog is "A creature of the ancient world," a monster described in J. R. R. Tolkien's book The Lord of the Ring but carried to a dramatic height in the movie The Lord of the Ring: Fellowship of the Ring . Supposedly the Balrog was left over from the fires of creation. I might recommend that you gain a copy of the book and read it. It's considered by many to be one of the best fictional books of the 20th Century. The movie (from which the quote above was taken) isn't bad either. I used it as an example of an ancient, primeval creature symbolic of the age and profoundness of eukaryotic genetics.

Just as an aside, to give equal billing as it were, there is another branch of genetics that deals with heredity in prokaryotes. For those of you who aren't familiar with this sort of thing, eukaryotes are organisms whose cells contain nuclei. And, those nuclei are little packets that contain the chromosomes. The chromosomes are composed of a central thread of DNA surrounded by a protective layer of proteins and other substances. And lastly, the genes are merely stretches of DNA that encode instructions for the production of proteins and some other chemical compounds necessary for life. A lot of single celled creatures and all multicellular ones are eukaryotes: Paramecium, Amoeba, sponges, flatworms, fishing worms, green algae, kelp, mushrooms, fish, Tyranosaurus rex, tarantulas, humans... Even your cousin Darrel!

Prokaryotes have DNA and chromosomes, but they aren't held in a nucleus. They're suspended in and more or less mixed with the other cell contents. Examples of prokaryotes are the dark, blue-green algae that makes your fish tanks stink, bacteria and some things called Archeans (most of which live up to several thousand metres underground) that you may not even know exist. (I think I got that name correct. I'm not much of an expert in this branch of biology, I'm afraid.) I do not know much about prokaryotic genetics, but I'm given to understand that there are some weird twists...

... But is that proven or an educated guess? ...

I think that the science of genetics is firmly enough "synchronized," coordinated with, and accepted by, the rest of biology that there is no serious question of it.

And, we've been breeding plants and animals long enough that no one seriously questions the principles of animal and plant husbandry including such things as inbreeding, selection and culling.

... Can you say this for all species also? I mean when you look at the living habits of for example that Pampobeteus species that is so dubbed "the chicken spider" then the survivel rate I think could be quite higher. ...

As far as I have ever heard, eukaryote genetics applies to every creature on planet Earth whose cells have a nucleus and that reproduce sexually.

Here, "sexually" does not refer to some Saturday night in the back seat of your Dad's Chevy when you were 17! The formal definition for sexual reproduction requires that genetic material be transferred from both parents to the offspring. (Sorry. But at the moment I can't quote the formal definition. Maybe someone could look it up in Wikipedia or something?) Asexual reproduction includes dividing (as in protozoa), budding (as in Hydra), cloning (as in Dolly the sheep), cuttings (in nurseries and horticulture), etc. In asexual reproduction the offspring receive only the genetic material from the one and only parent.

I can't imagine too many scenarios where anything that I've discussed wouldn't apply, even with "chicken spiders." Distilled down to the essentials, if the organism is too successful at reproducing we end up to our armpits in them. The human population is a good example of this.

If the organism can't breed fast enough to maintain its numbers it goes extinct and carries its genetic legacy with it.

... When you say defect, how are you meaning it here? ...

Perhaps my choice of words was no very wise. Perhaps a better word might have been "mutations."

In a collateral posting to "Aragorn" I stated:

" 'Safe,' like beauty, is a relative thing dependant largely on the beholder. I'm trying very hard not to trample on anyone's opinions and beliefs unless I can marshal a good scientific (or at least rational) argument for it."

The same goes for defects. For instance, one might consider albinism in tarantulas a defect. Someone else wishing to make a lot of money selling them might consider them a Godsend! There are a lot of potential mutations that no one will argue are not defects, e.g., a lethal gene that kills the tarantula before it can mature and reproduce. But there are lot of other genes that may be "defects" in wild tarantulas but inconsequential or even definitely advantageous to captive raised ones. For instance, while albino hamsters would be considered not good for much but a quick lunch by predators in nature, in the hands of man they have resulted in more hamsters currently being alive and apparently well in captivity than ever existed in nature! Is albinism in hamsters a "defect?"

... I ask this because I have seen photos of wild tarantulas (sub adult) with a double abdomen and the only other defects I can think of where they survive, is on those species with chevlons that have the extra or lack of chevlons on the abdomen, but as a phiysical handycap I really can't see how this would effect their growth in the wild. ...

In a general sort of way, mutations will occur in nature and persist. The length of time that they persist depends on a number of variables such as how badly they put the owner at risk, if they are in fact a beneficial mutation (rare but known to occur) or perhaps merely on how lucky the owners are. For instance, two headed snakes occur from time to time. While they are occasionally found in nature, they seldom live in the wild long enough to reproduce.

... I have off course heard about and seen photos of a couple of gynandromorph spiders (one of which went on to produce a fertile eggsac with a normal male) but these also could I think survive in the wild also, given the fact that butter flys with this same type abnormity have also been found in the wild. ...

One thing that will tend to foil our best efforts is that not all abnormalities are necessarily the result of an inheritable mutation. "Stuff" happens, and a lot of "freaks" are merely developmental accidents. The only way to tell if such is really inheritable is if it shows up in several closely related individuals or over several generations.

... Also something else that nags me here about the wandering male syndrome and how one of these isolated colonys got started. I mean....

Lets just say for arguements sake that one female spider did walk, say, just 20 miles away
from the rest of the colony to set up home. Now it is alone and it grows to become mature and stays put. Now one day just by shear chance a male comes wandering by from that same colony and yes it is unrelated to the female and they mate, the female has an eggsac , and the spiderlings all dispurse around the mother in a kind of satalite way.

From there on in if any breeding is now going to happen then it is going to stay in the family, unless of course that 1 in a million shot of a male comes a wandering by from the nearist conlony again one year, and what are the chances of that happening twice? ...

Actually probably pretty good. Remember that we're talking about animals that live for many years to decades. And, the colonies may persist for millenniums. And those wandering males are positively DRIVEN to march until they are eaten by something. If one of them doesn't make it to your isolated colony this year or next, another one will surely stumble across it within the next decade.

In the meantime, inbreeding will maintain the size of the colony (and it may actually increase in size) while the various selective pressures will tend to weed out any that display any substantive defects. And, life will go on as always, year after year until that one exceptional male wanders through and breeds 3 or 4 females before he's eaten by a bird, jackal or coyote. His infusion of fresh genetic material will carry them on for another few decades, a century or millennium.

... Ok could you point out this tradition to me because I have now lived in Germany with my German wife for a little while now and have so far failed to see or find any fine German tradition that involves the culling of anything? ...

That's too bad. Decades ago the Germans were famous for being able to breed tropical fish and if an American dealer could honestly say that some of his stock came from German sources, it was almost immediately snapped up by American fanciers because it was presumed to be of very high quality, i.e., ruthlessly culled so that it would breed true with few or no defects. My guess is that they are still around, quietly enjoying their hobby in their basements or back rooms, trading stock with each other and once in a while allowing a little to enter the commercial market.

I know of such a fellow who now breeds killifish (small, extremely pretty top minnows) who lives in Traverse City, Michigan. You wouldn't recognize his name (and I wouldn't be so bold as to advertise it without first gaining his permission), but he is a member of the American Killifish Association and trades with other members. He and other members of that organization take the breeding and maintenance of their fish very seriously.

... And so I ask how long is it going to be before these deformitys start to show then? ...

They're already here! If you search these forums you'll see reports of people whose stock of babies experience higher than expected incidences of problems molting, reports of defective eye fields, reports of missing spinnerets, etc.

... Saying I am blatantly stupid is not going to change my mind on this either. ...

Many years ago, while I was still in university, I thought I might like to be a biology teacher. So I entered a program that would gain me a teacher's certificate. I was then presented with a list of courses that I had to take.

First, I must comment that these were the silliest courses that I'd ever sat through. As a budding scientist who wanted ardently to teach biology in high school or college, these were patently useless. I was a natural scientist and this was my first exposure to the social sciences and humanities. I now honestly know why most of the kids graduating from public school can't balance a check book!

One and only one thing of a full year's worth of enduring those classes came through as having any value, and as I've progressed through life it seems more and more true. One of the teachers (Could any of these people actually have risen to the stature of "Professor" with this drivel?) in one lecture stated that there were almost no really stupid people in this world, especially in America. Why? Because virtually every one of them had managed to master one of the world's most difficult languages to at least get by in one of the world's most difficult and challenging societies. If we couldn't get through the fog to teach them, it wasn't their fault. It was ours because we just weren't approaching the problem from the correct direction.

As a result, with the single exception of the buffoon who almost ran me off on the highway this afternoon, I call almost no one "stupid." I may call you a bunch of other things, some of them complimentary, others not, but you can apparently speak several languages fluently, you can use a computer adequately and you keep tarantulas a pets. You, my friend, are most definitely NOT stupid!

Now, sadly, I must withdraw from this thread. I have taken on another responsibility that will consume most of my waking time and I will not in the future be able to afford much time to monitor this forum more than very casually and very occasionally. (Any of you may still contact me by normal E-mail.)

One and all, take care. Best of luck. Enjoy your tarantulas!

 

[pinkfoot]

Thanks, Stan.

 

[Tescos]

Hi Mr Schultz

Sorry firstly as I think I may have taken some of your previous replies the wrong way. I wont dwell on this however, as to quote all that last reply for this aid would I think you agree be pointless.

Thankyou for the small insight into the bacics of genetics that even I could understand to a point. There are however a number of things that for me don't still add up. Again I wont go into everything.

In the meantime, inbreeding will maintain the size of the colony (and it may actually increase in size) while the various selective pressures will tend to weed out any that display any substantive defects. And, life will go on as always, year after year until that one exceptional male wanders through and breeds 3 or 4 females before he's eaten by a bird, jackal or coyote. His infusion of fresh genetic material will carry them on for another few decades, a century or millennium.

This can not explain colonies of spiders that have been cut off from others for thousands of years. I truly do not believe that species like Mascaraneus remotus could exists if it was as clear cut as you say.

They're already here! If you search these forums you'll see reports of people whose stock of babies experience higher than expected incidences of problems molting, reports of defective eye fields, reports of missing spinnerets, etc.

Sorry but this is total speculation I think. There is no way you can pin any of these things down to having anything to do with inbreeding depression. There could be any number of reasons rangeing from bad husbandy to some infected food that was offered? With the defective eye fields in how many spiders was this noticed from a batch of how many?
Also nothing so far of what has been said has explained any of the things that Mr Gabriel mentioned in those other threads.

All the best
Chris

 

[FryLock]

Bloody hell sweaty man is back from south east asia or i'v been away to long..

Interesting reading from all but I have to say as far as culling goes I don't think it's in anyway possible for human husbandry to apply anything but the very crudeist selective culling to any organisms in a artificial setting.

i.e. in a spiders case leg's falling off every other moult ect so we deem it unfit to live, but by turn do we know how well it's seemingly fitter siblings would do at escaping a flooded burrow or hiding from a cotamundi, maybe something about our missing legs spider may have made it better at doing these things then them even with a missing leg or three and by removing it from our captive gene pool of it's species they as a whole have lost something?, granted that takes time but be it plant or animal we simply can't expose our charges to the full range of challenges they would face in-situ and any culling pressure given is still human and therefore not a natural ecological pressure something that we have to keep in mind if what were trying to achieve is an animal that still suits it's nature and not what our idea of what it should be, not easy trying to keep times from a changing as i think some chap named Bob once said.

 

[Stan Schultz]

Just popped in for a quick peek and had to respond to your comments.

Bloody hell sweaty man is back from south east asia or i'v been away to long..

Interesting reading from all but I have to say as far as culling goes I don't think it's in anyway possible for human husbandry to apply anything but the very crudeist selective culling to any organisms in a artificial setting. ...

Not quite true. With the possibility of establishing a "tarantula genome" we, at least in theory, could test each of our pets and establish breeding populations of species of tarantulas that had none of the less desirable characteristics we know about. And in that sense our culling would be absolute and 100% perfect. All it would take is a multi-billion dollar investment for each of the known species of tarantulas. Fat chance.

In the meantime we can only do the second best we know how: Cull out those individuals with missing legs, difficulty molting, etc. It's called "playing God," but at a vastly imperfect level.

... i.e. in a spiders case leg's falling off every other moult ect so we deem it unfit to live, but by turn do we know how well it's seemingly fitter siblings would do at escaping a flooded burrow or hiding from a cotamundi, maybe something about our missing legs spider may have made it better at doing these things then them even with a missing leg or three and by removing it from our captive gene pool of it's species they as a whole have lost something?, granted that takes time but be it plant or animal we simply can't expose our charges to the full range of challenges they would face in-situ and any culling pressure given is still human and therefore not a natural ecological pressure something that we have to keep in mind if what were trying to achieve is an animal that still suits it's nature and not what our idea of what it should be, not easy trying to keep times from a changing as i think some chap named Bob once said.

While your points may be valid, do not confuse culling in captive bred populations with natural selection in the wild. They operate in vastly different ways with endpoints (I hesitate to use the term "purpose" because I'm not sure that there really is a purpose in natural selection) that in many cases are diametrically opposite.

I compare the two only in a general sense to help those who aren't accustomed to thinking along those lines to understand the basics.

However, natural selection and captive bred culling have similar effects in a very general sense: They both manage to produce breeding populations that are best fitted for surviving in their respective environment/milieu/ecology... either the wild, natural world "out there," or a much different, highly constrained, artificial world in our homes.

Good points, though. Cheers.