High metamorphosis rate of A. andersoni

[Daniel]

Since some months there are c.b. A. andersoni available in Germany.
Unfortunately, reports on A. andersoni going through metamorphosis pile up lately. I do not have any reliable statistics at hand but as far as I can see from people telling, the metamorphosis rate seems to be up to 30 to 50% of the c.b. juveniles (especially F2 as far as I know - I do not breed them myself).
This species is usually neotenic so it is rather surprising that so many of them morph.

There are a lot of speculations going on, none of which has proven right so far (too much calories in their diet, wrong food, too much stress).

I know that there are several keepers of A. andersoni in the USA and I know that Michael Shrom has bred them successfully. Can any of you give me information if there is a heightened metamorphosis rate with your animals? Does anyone has a clue what the reasons might be?

 

[SludgeMunkey]

I have read a good many reports of them morphing here in the states too. In fact, quite a few breeders sell them "pick up only" or will only ship eggs for this reason.

 

[slowfoot]

The person to ask about this might be Dr. Randal Voss at the University of Kentucky (here's his lab web page: Home Page of Dr Randal Voss). I know he's worked with this species in captivity for quite some time. When I worked with him we did have some metamorphs, but I don't remember it ever being as high as 50%.

He's a very nice guy and easy to talk to :happy:

 

[taherman]

The original description mentions spontaneous transformation of animals in the laboratory:

A New Species of Salamander (Family Ambystomatidae) from Michoacan, Mexico
Salome Litwin Krebs and Ronald A. Brandon
Herpetologica, Vol. 40, No. 3 (Sep., 1984), pp. 238-245

I would guess that andersoni is just a species with some retained plasticity in this regard, and it's quite possible that metamorphosis occurs in natural populations but just hasn't been witnessed (or morphing animals are selected against in the wild).
-Tim

 

[Kaysie]

I agree with Tim. What is their common rate of metamorphosis in the wild? Is it close to 50%, or more like 1%? If they metamorph at a higher rate in the wild, that would explain why they metamorph at a higher rate in captivity.

 

[Daniel]

Thanks for your input. I re-read the article by Krebs and Brandon (I did so quite some time ago but have to admit that I forgot about it). As Tim said, there are several metamorphing specimen mentioned - they morphed at different ages, but most of them did not survive for long (no explanation given there).

 

[Newtility]

Hi folks,

the problem with metamorphosing andersoni bears some tragedy but obviously has probable reason. As most of the andersoni F2 spread around in Europe and the USA origine from my stock I can say that NEVER EVER any andersoni out of well 200 has morphed in my setup, and I handed them out at well half grown size. All my personal andersoni are in the water and there is not the slightest sign of any of them going to morph. The same for well 1000 Axolotl I raised in the past two years. To me there is little doubt that the morphing in andersoni (rumors speak of up to 80 %!) as well as in Axolotl have two reasons: first of all the water in which they are kept. In many regions there is natural iodine in the tap water, in some regions it is added to avoid cancers. Strikingly enough many breeders I know of having morphing animals are living in areas with salt mines or where water is naturally extremely soft thus being hardened up and iodined. Second reason is the *four letter word* cheap pellet food (= dirt) containing high amounts of fishmeal. This may be good for certain species in aquaculture but is more than doubtful in the use for neotonic Ambystoma. It doesn´t matter whether promoted as "high protein pellets" (BS! They all contain high protein as they are used to fatten up fish quickly) or "Axolotl pellets" (no producer has pellets designed especially for Axolotl). Fishmeal consists of mostly shells, decapods, seapocks and other "fishing litter" and not that much of fish. The pellets I use are for special aquaculture and only contain very little fishmeal (as producer informed me it doesn´t work without) but bloodmeal. The concentration of iodine in these is given with <25 mg/kg. That´s literally nothing. And the fact I never had any morphing Ambystoma is all I need to believe that.

BTW Randall Voss and the AGSC received andersoni from my stock and from another german breeder in 2008.

From my experience these are the only obvious sources of metamorphosis generating hormons or iodine. I feed nightcrawlers, earthworms, dendrobaena even with egg rings (containing sexual hormons), I even feed shelled seawater shrimp, mussel meat, krill and nothing happens. The body of seafood generally contains not more, often even less salt and iodine than the human body or that of our Ambystoma. But the shells of clamps, crayfish, mollusks etc. is loaded with these substances.

Finally, the critical substances first have to accumulate in the body of an Axolotl to cause metamorphosis (which in fact never is "spontanuous" but the result of a slow process, if not intentiously forced). This can easily (in my mind) be avoided by not feeding cheap pellets (or let´s say not those with high amounts of fishmeal), and checking your tap water for iodine. At least in Germany water suppliers must hand out an actual analysis of the water quality. In the USA the water often is chlorinated like crazy. And for the sake of "public health" (cf. swineflue rip-off) I expect to have fluorin and iodine added in many parts of the USA as well. And elsewhere in the world, too.

Perhaps it would make sense to collect data from all keepers with metamorphosed andersoni, and Axolotl to see if tap water is a major factor or not.

And to all: keep your fingers off pellets if not having an analysis of their ingredients!

Best regards,
Steffen

 

[NewtZoo]

Could this be due to inbreeding? I'm not much of a population geneticist but this could be an example of hybrid breakdown. Maybe there is a relationship between morphing individuals and lack of genetic variance.

 

[michael]

I have read a good many reports of them morphing here in the states too. In fact, quite a few breeders sell them "pick up only" or will only ship eggs for this reason.

Where have you seen A. andersoni eggs or metamorphosed A. andersoni available in the U.S. I follow this pretty close and have only seen 1 metamorphosed individual in the U.S.

 

[michael]

Since some months there are c.b. A. andersoni available in Germany.

I know that there are several keepers of A. andersoni in the USA and I know that Michael Shrom has bred them successfully. Can any of you give me information if there is a heightened metamorphosis rate with your animals? Does anyone has a clue what the reasons might be?

I have never had any of my Ambystoma andersoni metamorphose. The reason my adults are for sale for pick up only is because adults are difficult to ship due to the required water. If they were to metamorphose they would be easy to ship. I'm aware of 1 imported A. andersoni that metamorphosed in the U.S. It is in Japan now. It was easy to ship because it only had to be in damp moss.

 

[Greewok]

Where have you seen A. andersoni eggs or metamorphosed A. andersoni available in the U.S. I follow this pretty close and have only seen 1 metamorphosed individual in the U.S.

I like to know this too...?

 

[Coastal Groovin]

I have had four A. andersoni now for over 4 months while they are growing quickly they show no signs of morphing. I feed mine worms, rosey reds, and snail meat. I have looked for these morphed A andersoni online and cannot find them. Can someone show me the link. thanks.

 

[michael]

Since some months there are c.b. A. andersoni available in Germany.
Unfortunately, reports on A. andersoni going through metamorphosis pile up lately. I do not have any reliable statistics at hand but as far as I can see from people telling,

Hi Daniel,
Please find specifics. I've heard reports of many Ambystoma andersoni in the U.S. metamorphosing. When I dug in and tried to find specific information I found only 3 confirmed cases of imported c.b. Ambystoma andersoni that metamorphosed in the U.S. and no cases of c.b. produced in the U.S. Ambystoma andersoni metamorphosing. At least 2 of them were described to me as switching because they were not properly cared for by students. I can double check but I think the 3rd one was in a tank where the filter failed.

Out of the reports that many have transformed under proper care I find confirmation that 3 in the U.S. transformed and 2 of them and probably all 3 were not being cared for properly. This reminds me of a childrens game we used to play. It was called whisper down the line. We would all sit in a circle or line. One person would quickly whisper something in the next persons ear. This information would be passed down the line by whispers from person to person. The last person in the line would say what he heard. It was rarely what the first person said. I hope to get accurate information from this forum and not 2nd or 3rd hand information, anecdotal data, and supposition.

From my observations and information I've gathered from other keepers of Ambystoma andersoni I would hypothesize that they rarely metamorphose when cared for properly. I would also hypothesize that Ambystoma andersoni and Ambystoma mexicanum may be triggered to metamorphose by improper nutrition, temperature, and water quality parameters.

 

[Coastal Groovin]

Ok who here on caudata has a picture of their morphed andersoni?

 

[Jake]

I have read a good many reports of them morphing here in the states too. In fact, quite a few breeders sell them "pick up only" or will only ship eggs for this reason.

Where have you seen A. andersoni eggs or metamorphosed A. andersoni available in the U.S. I follow this pretty close and have only seen 1 metamorphosed individual in the U.S.

I like to know this too...?

I would love to know where you've seen eggs offered in the US too! Maybe I won't have to sell my liver on the black market to get a group of them after all!

 

[Newtility]

As for the "inbreeding" - this is a topic again and again raising up but there is no evidence for it at all. First of all, the actual andersoni in captivity are F2, from this season F3. And all stock decents from 2 females. My stock is mixed from both wc females. Anyway, ALL Axolotl in the world basically are decendents of the one pair which was used in the laboratory of Mr. Humphrey in the 1960s. If there was any inbreeding in caudate amphibians, they would be eradicated for long. Same for other species being in the hobb y for long. A way bigger problem is that people still - for the sake of avoiding inbreeding - happily mix different morphs and locations of species which in a long run can have a fatal effect on the stock e.g. the situation of Triturus marmoratus in Germany and Europe. For decades all different types have been mixed, strains from France, Spain, and Portugal. Plus the smaller sibbling species pygmaeus. The result today are "breeding groups" which do not properly breed anymore. I had one myself which I received as pure strain from Bilbao. Over 500 eggs, just 2 larvae, nill reaching metamorphosis. Congratulations to all who took and take part in this madness. Inbreeding can be a serious threat to mammals, even reptiles but not at all in amphibians to my knowledge. Degenration from bad maintenance often is blamed as to be inbreeding. There are many species of caudates occurring in micro-populations which following the idea of inbreeding should all have become extinct already. Most new species are the result of drifting apart of populations. Many populations have been founded on just a few specimen, e.g. the Ambystoma gracile (or was it Taricha granulosa?) population on one canadian island which was transplanted by floating wood and now is highly abundant there. And a healthy population, too.

Best regards,
Steffen

 

[Azhael]

Sorry to interrupt and change subjects, but Newtility...that commentary about receiving animals from Bilbao just felt wrong. By receiving a pure strain you mean you received locally collected T.marmoratus??? If so, you should know that what you did was ilegal and very much immoral.

 

[michael]

. Anyway, ALL Axolotl in the world basically are decendents of the one pair which was used in the laboratory of Mr. Humphrey in the 1960s.

This statement simply is not accurate. W.C. axolotls have been exported to other countries quite a few times in the past. I don't think their has been a lot of exporting from Mexico recently but would not rule it out among researchers.

You are correct in your statement about many times results of poor husbandry techniques are wrongly blamed on inbreeding.

 

[Jan]

......Most new species are the result of drifting apart of populations. Many populations have been founded on just a few specimen, e.g. the Ambystoma gracile (or was it Taricha granulosa?) population on one canadian island which was transplanted by floating wood and now is highly abundant there. And a healthy population, too.

Best regards,
Steffen

Perhaps you were thinking of Aneides vagrans?

 

[Coastal Groovin]

I read once that it was believed that humans numbering about a dozen spread from Africa to all around the world. Which is proof of the effect on inbreeding when I look around at the mall this holiday season. A good gene pool can't hurt us or our caudatas.