Axolotl sex change

Does anybody know for sure if axies can change sex? much in the same way that guppies do.
I know this probably seems crazy but I was searching on ABEbooks for axolotl books and came across the following:
http://www.abebooks.co.uk/servlet/B...hurl=bt.x=0&bt.y=0&kn=sex&sortby=3&tn=axolotl
http://www.abebooks.co.uk/servlet/B...churl=bt.x=0&bt.y=0&sortby=3&sts=t&tn=axolotl
and then I googled it and came accross these:
http://www.bio.net/bionet/mm/urodeles/1997-March/000295.html
http://www.bio.net/bionet/mm/urodeles/1997-January/000283.html

Does anybody know the answer? I was thinking of maybe buying what's in the first two links but it is probably scientific mumbo jumbo that i wouldn't understand.

No they can't.

Ok, I just thought since i found papers for sale on the subject that maybe it was true.
Thanks anyway.

I think Rayson has been a bit dogmatic. Sex in axolotls is determined by chromosomes, unlike humans it is the male which has similar sex chromosomes and the female which has different ones.

There are gender bending chemicals which make males grow ovaries and like nearly all species some animals are going to be chimeras and intersexes. Hormone producing tumours may also produce apparent sex changes.

The general rule is they do not change sex, the usual cause of female to male apparent change is that they are sometimes hard to sex correctly and can mature very late.

In terms of definition, at least in veterinary and genetics and pathology. The sex of an animal is determined by the chromosomes. Even haemaphrodites and intersex animals can be definitively 'sexed' genetically. There are rare cases of chromosomal variation such as klinefelters and turner syndrome in people that can perhaps make this strict categorisation into male and female difficult but then even still XO/XXX are 'female' while XXY are still 'male'.

Despite differences in external genitalia phenotype, sterility/fertility issues and even behavioural/sexual characteristics, ultimately an intersex animal is still biologically (chromosomal) of one sex. Pathology as a result of sex hormone secreting tumours, gonadal/ovary transplant or medical intervention or experimentation are an external manipulation exerting an effect on the usual normal sexual characteristics.

For example, in some men, they develop a condition called gynaecomastia. In terms of hormonal or external features, you can say they are 'changing sex', however, they are still male biologically. They have not 'changed sex' but rather have their usual hormonal balance disrupted which resulted in a physical change.

While chromosomes are the usual gold standard for defining sex they do not always correspond with common sense. For instance atrazine discussed in:
http://www.caudata.org/forum/showthread.php?t=60582
causes genetically male Xenopus to develop into fully functional females. I understand the eggs are capable of fertilisation and all develop as males (unless atrizine is again used) because the offspring do not carry the female chromosome.

I guess what applies to Xenopus will apply to axolotls.

Atrazine is toxic to amphibians. Much like teratogenic, carcinogenic and other substances capable of causing cellular and hence intercellular reactions, atrazine is an external manipulation that causes the profound disruption to physiology. This is not a naturally occuring spontaneous sex change event.

Effects of atrazine are NOT specific to causing 'sex change'. Atrazine causes a myriad of disorders such as deformities (aplasia, hypoplasia,dysplasia of organs), widespread immunosuppression and failure of normal differentiation and maturation of immune cells, sterility, increased propensity of neoplasia and such.

Atrazine causes disruption to the steriodocorticoid type hormones - sex hormones and hence is affecting the circulating levels of hormones. Females with increased male hormones develop masculine characteristics whereas male animals with decreased male hormones/ and increased female hormones will become feminised. However, it doesnt affect the animal at a chromosomal level on a permanent basis. Thus traits/behaviour/physiology of one sex again belies the true chromosomal sex.

Again i can list some examples in other species that has a similar pattern of pathobiology. Male animals such as ruminants exposed to very high levels of phytooestrogen in plants/soy can disrupt their usual hormonal regulation and physiology. Other than fertility issues, they can behave in a more feminine manner and even attract other male animals (pheromone changes / behaviour etc). Some 'male' species of mammals are also capable of lactation, a trait associated with females. However, we can't say they have a sex change in terms of scientific definition. Rather, they have a pathobiology affecting their sexual hormonal/physiological response that is reversed when the pathology/external manipulation is removed. They are still inherently of one sex.

If there are sex differences in axies like in humans eg. testosterone affects male brain development etc.. do you think there are quantifiable differences in male/female axies behaviour or does it make little difference?, just an interesting side point

It depends on magnitude and duration - how high/abberant the hormonal levels are and for how long a period of exposure.

The stage at which the animal is affected is also important. Developing embryos are greatly affected compared to a fully matured adult. In growing animals, abnormal hormone levels usually become very evident in terms of physical/behavioural characteristics. The impact is less profound on fully matured adults. Hormones almost work like a key with a lock. The hormones being the key and the lock being responsive receptors. Having just hormonal level increases without the corresponding receptors increase will result in less apparent changes.

In theory and logic, its possible to cause long term developmental changes (all organs not just brain) over a period of time if exposed to untreated abberant levels of circulating hormones. Hyperthyroidism, hyperadrenocorticism, pituitary gland abberations (darfwism, agromegaly) etc. are some examples in other species. Behavioural changes normally also accompany.

This has not been studied in axies but i speculate an axie with sex hormonal imbalance will be likely either infertile or unreceptive to breeding.