Kaiseri x.x ?!

[Linus]

I have 6 juvi Kaiseri, (unable to sex due to their age). How do you guys think they will pan out as far as # of females to male ratio? Ultimately I'm hoping to breed them, just wondering your thoughts on how a group of 6 may turn out.

Thanks as always,
Eric.

 

[Mark]

I take it you've seen this handy table? Caudata Culture Articles - Pair Odds

You have a 97% chance of a pair.

 

[Linus]

Excellent! Thank you Mark I'd never seen that before, greatly appreciated. Looks like i'll be all set =)

 

[Allistor]

This made me to remember a case of a person that bought 6 axolotls and all become females.

 

[Linus]

LOL that's rough. The article states that happens when they're all under horrible temp conditions or they're all the largest or smallest of a clutch. We'll see what happens.. if I get 6 of one sex.. ugh. (knocking on wood).

 

[cg]

That's a good article, but it fails to mention that sex is often determined by the temp at which the eggs are kept at as they develope. If the breeder had the eggs too warm or too cool they may still be all one sex.

 

[Azhael]

Such a thing is an exception in caudates. Sex is determined by chromosomes, so sex ratios are theoretically 50/50 in the majority of species. The exceptions are such as in the case of P.waltl, where genetic gender can be modified during development by extreme conditions or hormonal action.

 

[eljorgo]

Yup, actually the have sexes since they formed in metamorphosis but those are still too unprepared and can be shown until they reach sexual maturity. Both male and female sex organs are inside the body unlike us humans. If both woman and man sexes were invisible we would all be a sort of a third gender until we be like 15 or 18 lmao. So awkward but so true... I guess the probability is way too high for them to be all from same sex. Simply impossible... you will get some sort of 3.3, 2.4, 4.2, 1.5, 5.1 but pointing to 3.3 no doubt. I have myself a group of other newts of only 4 individuals and I am completely sure it will come out a pair at least, in your case, 3% is way VERY VERY unlikely to happen....

Cheers,

 

[cg]

I still have to disagree Azhael. Going back to my herpetology courses I remember having to do a paper on A. maculatum and finding out that sex is largely decided on temp. Even though it is widely known with reptiles I found out that it is also fairly common in amphibsl. I just did a quick search online with no luck, but when I get home I`ll see if I still have that book.

 

[Azhael]

Please, do post the information! This is a fascinating subject which i´m always happy to learn more about.
It´s always been my understanding that while temperature controlled sex ratios definitely exist in amphibians, it´s not the norm, but the exception.
It´s also interesting that at least in the case of P.waltl, the temperatures required to affect chromosomal gender are very high indeed (over 30ºC). In addition, it only works one way, with females undergoing masculinization and becoming neomales (completely functional). Unlike in certain reptiles, you can´t get a whole clutch of females.
It´s likely the extreme temperatures affect hormonal production or activity and result in masculinization, which would perhaps mean it´s not an strategy, but more likely a malfunction.

The fact that caudates have sex chrosomomes in undisputable, so to me that indicates that chromosmal sex determination is the normal and generalized method, with temperature sex determination being either a fluke caused by extreme temperatures or hormonal situations, or a minoritary strategy.

 

[caleb]

Triturus cristatus and carnifex can apparently produce neomales when reared at high temperatures, and neofemales at low temperatures:

www.ijdb.ehu.es/web/pdfdownload.php?doi=11128575

Assuming that this isn't happening with Linus' animals, the probabilities for all possible permutations are:
0.6 1.563%
1.5 9.375%
2.4 23.438%
3.3 31.250%
4.2 23.438%
5.1 9.375%
6.0 1.563%

 

[Linus]

Thank you

 

[Azhael]

Cheers Caleb. First time i ever hear of neofemales, fascinating!
That article is a very interesting read. It does reinforce my opinion that sex reversal in caudates is likely to be a malfunction at extreme conditions rather than any adaptation. Well, at least sex reversal influenced by high temps. Perhaps sex reversal at low temps could be adaptive, after all producing extra females definitely sounds more adaptive.