Artificial neoteny in alpine newts

[cg]

I have always wanted to acquire some neotenous alpine newts. I was just reading in Richard Griffiths book that neoteny is common in alpine newt populations where it is really cold, and that it is possibly caused because the effect of thyroxine is reduced in cold water. The main question here is, has anyone tried to rear alpine newt larvae in cold water to cause neoteny. And if so, what where the results? I was planning on taking some of this springs larvae and rearing them in cold water to see if they become neotenous. Is there any other way of supressing the effects of thyroxine? Any comments or suggestions are welcome.

 

[keegan]

Interesting to find this question here (and unanswered). A number of the pictures (mostly on sites in languages I don't know!) that I've found on the net have neotenous, and I wondered if folks ever "encourraged" or"forced" this in captivity.

 

[caleb]

I've seen neotenous smooth newts (T. vulgaris) quite a few times in Cambridgeshire, and have kept them on occasion. They always metamorphosed within a few weeks of capture.

The ponds involved were not particularly cold, or difficult for the newts to escape from, so obviously some other factor was involved.

It's possible there's a genetic factor. This would be encouraged by harsh terrestrial conditions (e.g. cold, or sparse habitat), giving a breeding advantage to newts that stay in the water all year round.

I gave some eggs, from a neotenous newt that I caught, to a hobbyist interested in trying to keep them neotenous- he managed to get them to remain larvae over the winter, but they metamorphosed in the spring.

Overwintering larvae are not uncommon, so it seems unlikely that a cold spell alone would be able to induce neoteny. I don't know about rearing in prolonged cold, though.

By the way, neoteny is usually now referred to as 'paedomorphosis' in the scientific literature.

 

[kai]

Hi Caleb,

What size/sex were those vulgaris?

For alpestris the way to go for "overwintering larvae until sexually mature" seems to be cold water with ample food supply. However, mature Triturus seem be difficult to prevent from metamorphosing in captivity from all accounts I know of.

OTOH, Tylototritoin verrucosus seem to need warm temperatures for enhanced likelihood of extended larval phase (with a few individuals even reproducing as larvae).

BTW, neoteny is a special case of paedomorphosis. Thus, it seems perfectly reasonable to use the term neoteny if appropiate - paedomorphic Bolitoglossa are widely different from axolotls...

Best wishes,
kai

 

[caleb]

Hi Kai.

The neotenous newts I saw were of various sizes, up to full adult size. I only ever saw 2 neotenous males, out of perhaps 50 sightings in 4 ponds. All but one of the ponds had T. cristatus present as well.

I published a small note about one of the ponds in the BHS Bulletin 31:28(1990). That pond dried out completely in 1990, and I've not seen a neotenous newt there again (I've not been there in spring since 1996).

You're right about neoteny/paedomorphosis- I was just mentioning the term, as it might be more useful to look for 'paedomorphosis' in web/abstract searches.

 

[TJ]

You might want to acquire this article relating to paedomorphosis:

Observations on paedomorphic newts (Triturus vulgaris) from the former Soviet Union

By S. N. Litvinchuk, A. M. Rudyk, and L. J. Borkin

"The reliable data on paedomorphosis in two subspecies of the common newt Triturus vulgaris lantzi (Abkhazia, western Caucasus) and T. v. vulgaris (the vicinity of St. Petersburg) are given for the first time for the former Soviet Union. Data on the appearance, occurrence, development and distribution of paedomorphic larvae are given based on field and laboratory observations beginning in 1986. The life cycles of paedomorphic and metamorphosed newts are discussed."

Source: Russian Journal of Herpetology, 1996, Vol. 3, No. 1

http://www.folium.ru/en/journals/rjh/contents/1996/1996-01.htm

If you do, don't neglect to forward me a copy

 

[caleb]

That paper is available at Spartak Litvinchuk's home page:

http://www.callisto.ru/amphibia/spartak/spartak.htm