Inbreeding newts?

[Red Eft14]

Okay,I'll get a pair of Kaiseri that are sibling(I talked to other people and they say that since amphibians are mass breeders just like fish they can inbreed)

 

[Azhael]

Wow, i´m hearing weird stuff here...
Just because a species produces large quantities of offspring (what is called r-strategy) it doesn´t mean it can be inbred without problems. In addition to that, not all fish are mass breeders and i put the example of guppies who have suffered a serious decay due to reckless breeding.
Also, Michael, limited gene pools don´t cause mutations, they "fix" them. I know that many mutations are favored by the breeders but many others are certainly not. There is a variety of lethal genes that can be very problematic in certain bloodlines (guess why? inbreeding), plus cases of highly reduced fertility, high larval mortality, and some seemingly recessive traits like eyelessness, dwarfism, kinks, etc.
I find the affirmation that there is nothing wrong with inbreeding caudates to be completely unjustified and very dangerous. Sure, a few generations won´t necessarily cause any problems, they have a higher tolerance than others, but in the long run they can be affected just as any other animal group.

Reduced genetic pools are a hugely undesirable thing. To lose genetic variability on purpose is absurd but sadly, widespread, because of people´s desires to preserve particular mutations. Making an effort in preserving a rich, varied gene pool is a worthwhile idea that would guarantee the well being of our captive populations for much longer.


"We don't need color morphs of an endangered species!!"
Jackson, i like how you put it xD Unfortunately there are pleeeeeenty of people who would like nothing more. Oh, and i meant no accusation with my question, i just wanted to clarify because i had understood it incorrectly and it had struck me as odd. As i say, i find it objectionable regardless of the species, but i agree, when it´s an endangered species it´s even worse.

 

[Mark]

I’m going to agree with Michael on this one. There have been a number of studies into amphibian inbreeding and the affects on fitness and genetic variation - both in the wild and captivity. They generally conclude that there is no effort made to avoid inbreeding in wild populations and the resulting inbred offspring are no less fit than those that are not inbred. Inbreeding does not influence growth, development or survival. Lethal recessive traits are thought to be removed at the early embryonic stage. Studies on highly inbred populations of wood frogs demonstrated that lethal recessive alleles are purged from the gene pool. The same study compared inbred wild vs inbred captive and found that captive inbred frogs were actually fitter than their wild inbred counter parts – who knows why (good for us though). Further studies on isolated, inbred populations of tiger salamanders have shown that deformities and abnormalities are not due to genetic background. Malformed salamanders were no more inbred than rest of the population.

I think the other important thing to note is that animals in hobbyists collections will never make it back into the wild or be used in ex-situ conservation efforts. I would rather see a species be removed from the hobby due to poor genetics than see fresh animals collected from the wild. One of my bug bears in the amphibian hobby is people using the phrase “I’m working with x species”. They’re pets, nothing more. There is no “working with” and people who use this phrase are not making a contribution to the species’ survival. It’s just a phrase that helps justify keeping some animals in a tank… *rant over*…

I’m not saying we shouldn’t make the effort to avoid inbreeding where possible (and often in this small hobby it isn’t possible) but in comparison to, say, mammals, amphibians appear to be quite well adapted to cope with inbreeding.

 

[Azhael]

Interesting stuff. In the case of lethal alleles, i´m aware that homozygous individuals die soon and certainly don´t reproduce, and i´m aware that the allele is not caused by inbreeding. I mentioned it because what is related to inbreeding is the prevalence of those alleles in specific breeding pairings. In other words, it´s endogamy what´s causing some of the offspring to be homozygous. In nature the alleles will be purged, but in captivity, if you have an heterozygous pair that you keep breeding, you are going to get the same results over and over, and you´ll keep producing heterozygous offspring too (which if paired endogamously, will cause the same results). In the same way, i mentioned certain types of deformities as the result of homozygocity through endogamy, not as a result of inbreeding itself (it´s the alleles that cause those).
I´d be very interested to see how many generations of inbreeding and to what degree those studies were working with. It´s one thing to have a population with a small genetic pool and another to breed brother/sister for generations with no selective pressures weeding out the very unfit.

It´s clear that caudates are tough and that they can take several generations of direct inbreeding without apparent problems, nobody is disputing that, but to extrapolate from that to total "inmunity" is far fetched in my opinion. An inbred wild animal does not represent what happens in captivity.
There are plenty of examples of populations with very reduced gene pools and even asexual reproduction producing only clones (you don´t get a smaller gene pool than that). It can work in nature because there are selective pressures operating over those populations, refining and determining which alleles work. I don´t think that´s how things work in captivity at all, at least broadly speaking.

As for captive animals never going to go back to the wild, i agree, but there are exceptions to the rule, both accidental and intentional. Some species scape or are dumped. Sure, the probability that those species will be released even close to their original range is remote, but not imposible. Also there have been a handful of cases of captive animals from hobbyists being used in reintroduction efforts as is the case of Aphanius iberus. As i say...exceptions, but nevertheless they happen.
While i agree that the phrase "i´m working with x species" is quite nonsensical, if the goal is to work towards stablishing a CB market instead of depending on wild populations, i consider that good work. To some extent that has some conservational value.

One last thing and i promise i´ll sut up. We have examples of mammals that are highly inbred with no ill effects, laboratory mice! They are actually required to be highly inbred in order to have a consistent and uniform strain with which to work. This was possible due to selective breeding oriented to eliminating all negative alleles that could cause problems through homozygosis. By "cleaning" the genes of the mice, the effects of endogamy were hugely reduced.
It would be possible to do the same with caudates, but that´s not what´s going on, not even remotely....people select for color or don´t select at all, but they don´t select for health or genetic fitness.

 

[JacksonR]

Regardless if inbreeding is bad for caudates or not is irrelevant. Just to be be sure...you shouldn't do it. Maybe it doesn't hurt them..but still don't do it.

What if it goes extinct in the wild? Are you saying the captive stock would then be ignored anyway. I think I am "working with" the species...

 

[Nowicki418]

Here's an idea. What if we bred caudates in captivity and simply "replace" them with WC eggs. Take 500 WC eggs from a pond and release 500 CB eggs back into it. In the case of an endangered species you could even alter this ratio. Release 1000 CB eggs into a pond for every 500 WC eggs you take out. If it was done right and you picked the right CB animals to release it might even help some populations bounce back. This doesn't seem too complex and I'm sure there are people both able and willing to do something like this.

With a more reliable source of wild unaltered amphibians breeders could inbreed salamanders without feeling insecure. I don't want a domestic breed to replace wild salamanders but if we could manage to have both? It would be so cool to have a domestic salamander AND a wild salamander at the same time.

 

[Molch]

One of my bug bears in the amphibian hobby is people using the phrase “I’m working with x species”. They’re pets, nothing more. There is no “working with” and people who use this phrase are not making a contribution to the species’ survival. It’s just a phrase that helps justify keeping some animals in a tank… *rant over*… .

I admit the "working with" phrase is a bit of a pet peeve of mine too. It sounds a bit...well, pompous - unless of course these folks have a secret I am not aware of.

I have repeatedly tried to encourage my newts to "work with me" - I have shown them how to siphon a hose and how to turkey baster up their waste and how to vacuum the tank bottom - but the truth is, I can't even get them to all poop in one corner so it'll be easier for me to clean up. At every attempt to put them to work they have blown me off. I threatened earthworm withdrawal, but they just laugh in my face. The truth is, I work for them, not with them. All they do is eat and poop. Oh, and breed, in which case I have to work to raise their little brats, too, because, you know, they haven't bothered to evolve any parental care. It's a good thing I have a soft heart and strong mother instincts, or I would've kicked their little butts out in the snow by now..... ok, rant over! :dizzy:

 

[bichogrilo]

Just wanted to say thankyou for such a brilliant and well argued debate from both sides, best read i have had in a while. As a lowly art teacher i would not even dare to have an opinion but thanks for yours.

 

[Mark]

What if it goes extinct in the wild? Are you saying the captive stock would then be ignored anyway. I think I am "working with" the species...

I’m saying that ex-situ conservation is really a last resort in most cases. It’s preferable to protect and conserve the habitat and the animals within rather than try to re-populate a species through captive breeding and release programs. Given the proper conditions most amphibian populations are very capable of bouncing back without the addition of extra animals. In all likelihood nobody will ever ask you to donate your pets to help save the species from extinction.

As Molch points out “work” can be defined in a number of ways! For me the “working with” phrase as used by amphibian hobbyists implies some mysterious goal being worked towards in an effort to discover something new and exciting about a species which will perhaps prevent it’s decline into the abyss. In reality they discover nothing new, have no affiliation with a conservation body and will invariably get bored despite the grandeur of “working with”. Why people can’t just admit they keep some pet amphibians is beyond me. I guess it really boils down to personal interpretation. Anyway, this digresses from the original topic somewhat.

With regards to natural selection I think the pressures on wild amphibians are varied and do not always select for fitness. Drought or disease will not spare the fit, nor will an ambush predator. Amphibians use the numbers game to increase the chances of offspring survival. That doesn’t mean the ones who get sacrificed along the way were necessarily less fit than the survivors. Their aim is to create as many fit offspring as possible in the hope some get lucky. To mimic the selection pressures in captivity is practically impossible. To do it properly you’d even need to apply selection to your adult animals – natural selection isn’t something that just applies to larvae and metamorphs.

 

[Azhael]

I think the problem relies in the concept of fitness if it´s understood as the strongest, fastest, biggest, fiercest. What i´m talking about is fit in the sense of best adapted to whatever pressure may be acting on them.
While there are pressures that seem to kill indiscriminately, like drought, there´s still some possitive selection since some individuals will be physiologically more apt to survive a drought than others. Droughts tend to not completely wipe out populations, and while some will survive out of sheer luck, others will survive because they are physiologically more tolerant to withstand the ordeal.
As i said earlier there is an element of chance, of course there is, but nevertheless, yes, those that survive are largely fitter than those that died, even if on occasion the fittest get eaten too. At an individual level it may seem that it´s all luck, but when you look at a population (which is what matters), the work of selective pressures is obvious and very clearly driving their population genetics.
I personally disagree partially with your phrase "Their aim is to create as many fit offspring as possible in the hope some get lucky", Mark, i think it works more like "Their aim is to produce as much variability as possible in the hope that some will be fitter for whatever pressures act on them at that given time", but there´s an element of truth in both.

Don´t get me wrong, i fully agree that we have no hope of recreating natural pressures in captivity. What i propose is at least some degree of possitive selection on the basis that some, even if little, is better than none. I have no delusions of mimicking nature, but i still think things can be done better in captivity than they have generally been done to date.

 

[Mark]

II personally disagree partially with your phrase "Their aim is to create as many fit offspring as possible in the hope some get lucky", Mark, i think it works more like "Their aim is to produce as much variability as possible in the hope that some will be fitter for whatever pressures act on them at that given time", but there´s an element of truth in both.

You're right of course . As a non-scientist I simplify it down to numbers because it's the most obvious survival strategy. There are clearly more subtle evolutionary processes and adaptations taking place.

 

[Azhael]

I just realized that those two sentences actually represent sexual/asexual reproduction quite well!
Your statement would be descriptive of what you find in species that reproduce asexually. If the environment is stable, it´s better to produce offspring that will already be fit for it and asexual reproduction guarantees that. If these genes work and the environment constantly selects for them, then why mess with it? Just produce lots of them and let it play out.
My statement represents sexual reproduction in "unstable" environments where what matters is variability so that you have a chance of producing fit offspring for a number of possible future pressures which you can´t possibly predict.
It´s a compromise either way. In the first scenario, if the environment changes, you are in serious trouble, and in the second one, if the environment remains stable, you waisted a lot of offspring.
Both strategies occur in nature, although sexual reproduction is much more common simply because environments that remain stable for a long time are very rare.

Anyway, that has nothing to do with the topic, sorry!
Ah...biology is so bloody interesting...xDD

 

[Nowicki418]

If preventing the evolution of a species is impossible ( and it is acording to Hardy Weinberg Equilibrium ) AND if controling the evolution of a species is extremly difficult. How can we expect people to do it? Many people that have salamanders keep them as pets, period. They may not know all the biology information some of us do and aren't going to be as willing to do anything to meet this predicament.

Not to say this is what I belive but here's a different point of view. If the domestization of salamanders is inevitable than why should we discourage inbreeding? Instead why not increase the domestization process to quickly seperate the pets from the wild animals and avoid the problem completly?

 

[michael]

Here's an idea. What if we bred caudates in captivity and simply "replace" them with WC eggs. Take 500 WC eggs from a pond and release 500 CB eggs back into it. In the case of an endangered species you could even alter this ratio. Release 1000 CB eggs into a pond for every 500 WC eggs you take out. the same time.

Releasing amphibians into the wild is illegal everywhere in the U.S. and I would hazard a guess it is not legal in most countries. You could quickly spread disease and animals that are not the same as the ones in the area where you are doing the release. Collecting eggs is a good idea where permitted. Of course some scientists and zoos are working on special programs to preserve species and populations and do get permits for release. Animals should only be released when raised under strict guidelines in a certified program.

 

[JacksonR]

Dismal...sad...Just keeping the species because it's pretty..not to help it. If you don't have a good captive population and they go extinct in the wild, you can't then start a "back up" that would become a captive population. What??

I guess I won't feel as guilty when they die someday.

Topic? Debating natural selection isn't the point. Everyone agrees on it...no fun. I left youtube evolution debating a long time ago...

 

[JacksonR]

I guess that's why no one commented on "beautiful kaiseri." No one cares about their behavior or their beauty or their personality. You just care about debating inbreeding. What's the point of keeping caudates...maybe I should stick to turtles.

 

[Nowicki418]

I guess that's why no one commented on "beautiful kaiseri." No one cares about their behavior or their beauty or their personality. You just care about debating inbreeding. What's the point of keeping caudates...maybe I should stick to turtles.

Actually, I happen to enjoy debates. Bringing a diversity of ideas together gives us a better and more rounded understanding of the topic. The more we understand Caudates the more we can enjoy their beauty. Debating isn't the same as agruing or complaining at all! I didn't mean to upset people when I tried to bring a new perspective into things and wildlife rehabilitaion has been done successfully before, I don't think we should cast it aside so rashly. In fact there are a number of amphibians that are now extinct in the wild ( and CB specimens are being reintroduced ). I think the reason my idea was met with dissent is because you guys thaught I meant a hobbyist releasing pets into a local pond when I was really refering to zooligical societies and herpetologists. I know I'm only in high school but I still know enough to have an honest opinion. But I am getting off topic.

Red Eft14 started this thread by asking if inbreeding will cause genetic deformalities. Many many posts later we still have not reached an true agreement on if inbreeding is right or wrong but it was mentioned that inbreeding occurs all the time in the wild. All the points made in this thread seem to discuss the long term effects of inbreeding while the original question was refering to short term effects. I agree that inbreeding over and over again can have destructive results but I don't think a single generation will do any harm. It was also mentioned that we should attempt to copy some aspects of natural selection in captivity. If inbreeding occurs naturally than wouldn't inbreeding need to occur on the rare occasion? Therefore I do not think it is our place to judge anyone on their decision to inbreed or not as I'm sure any of us could theoretically write an essay both for and against it. If anyone does inbreed in the future I can't say I wouldn't be curious to hear about the results and for those of you strongly against it I'm sure you have a bit of curiosity in the back of your mind too.

 

[Molch]

No one cares about their behavior or their beauty or their personality.

aah, friend, don't be discouraged. The one and single reason we all have in common for keeping newts is that we love them. We love their beauty, their personality, their behavior. All of us. We're addicted to them. We can't get enough of them. We can't wait to go home at night so we can sit and watch them and feed them and admire them...

That's the big picture, the grand headline. If you read the fine print below that you'll find that each person has their own subtle motivations for keeping caudates. And there's not a single person on this board who doesn't want to see caudates thrive in wild populations. As for me, I wouldn't at all mind if the world regressed back to the carboniferous age, when big fat newts the size of small cars ruled the world

Don't be discouraged when not everyone agrees. Remember, the issue of captive breeding and conservation is complex. Human brains are also complex. When complexity meets complexity, you'll get infinite possibilities; it is unlikely that we will ever all agree on the matter....

....meanwhile...we LOVE our newts

 

[JacksonR]

Well, I guess we all agree that neurergus is a wonderful genus...Not the same captive management though.

I'm gonna avoid inbreeding regardless.

I do love coming home every day to see them.

 

[Azhael]

If all we did in this forum was say "oh, those newts are beautiful" what would be the point?
The way i see it, it´s of the utmost importance that we have discussions, that we share information, learn from one another´s experience, etc. Discussions like this have one goal in mind, improving the way we keep caudates in captivity.
You may find comentaries about natural selection boring or irrelevant, but i don´t. And i certainly was not debating evolution xD I think possitive selection is a key point in long term viability of captive populations and discussing how it compares to natural selection is very relevant the way i see it.
Just because i haven´t participated in a particular thread it doesn´t mean i don´t apreciate this species. I happen to think that the whole genus is fascinating in every way, hell, the entire order is! As Molch says, we are caudate freaks, we love them, dream about them, worry about them, it´s a fricking obsession xD
We do all agree that Neurergus are brilliant, and we do have disagreements on their captive care, that´s why discussions are so important!!

The issue of helping the species through captive breeding is complicated. Like Mark commented, reintroductions are literally the very last resort. If reintroductions are necessary it´s because everything else has failed misserably. The best strategy is habitat conservation. If there´s no good habitat, then releasing animals is worthless. I used to have this idea of "working with the species" too, thinking that i could actually do something from home by breeding them, but i soon found out just how naive that was. However as i commented earlier, the good thing about what we do is that stablishing captive populations reduces wild collections which means less pressure on them, plus promoting education and awareness. That to me has a conservational value, but that´s about it.... If anyone really, really wants to help a particular species, help conserve their habitats, that´s real help!


Nowicki, we all know that a single generation of inbreeding in caudates is nothing....even 6-7 generations of direct endogamy have produced healthy offspring. The issue with caudates is long term effects. We are very much aware that short term effects are minimal if they exist at all.
In the wild, caudates also get eaten, does that mean we should let a predator have a little party in our tanks every once in a while too? The goal is not mimicking nature, i think that´s been made clear. The goal is learning how to manage captive populations better, because frankly we can do better.
I´d also like to say that justifying activities that affect the quality of life of our animals just because of curiosity is simply wrong. I´m an extremely curious person (it´ll probably kill me some day) but my priority is the well being of my animals, period.