Cristatus group egg problem - a legend?

[stavroske]

From the 80 eggs I collected, 35 hatched. More than 50% died in the egg while develloping.

 

[JM29]

OK. Concerning these 50% :
Unless one deals with hundreds of fresly laid eggs and provides optimal development conditions to the embryos, there is almost no chance to obtain exactly 50%.

That's the statistical law of geat numbers.

With small numbers, one can obtain very different percentages, only by chance.
If the conditions are bad during incubation, that may lessen the percentage.
If moulding eggs are not collected, it may incease the percentage.

 

[uwe]

so my first small group all hatched or deceased. The rate was 5 larvaeout of 11eggs, which is in the range predicted!

So i have set up new 11 eggs from the continous egg-laying, but I am pretty convinced about this 50/50 rate.

What convinced me even more than the pure number, was that all 11 eggs were fertile, that means they developed and 6/11 just stopped on a certain point of development (as described in lit) and degredaded.

Thanks for all the input.

Uwe

 

[shnabo]

So I was digging back to old threads and I came across this one, and something I had read previously came back to me. After spending a while looking for it, I finally found it:

http://www.caudata.org/triturus/temp/dan.gif

This article is about inducing a second breeding via artificial hibernation, which is nothing new to us at this point/probably isn't the best for your animals anyways in terms of stress/needing that time to recover, but there was one line I did find very interesting.

On the right hand side, he states "If the females are kept without males, they will deposit less than a dozen unfertilized eggs." So I am wondering if the earlier post about the two different crested newts producing more than 50% hatch rate, may have been because the female was kept separate prior?

Has anyone attempted this, or noticed such a thing? I had kept females separate from a male just because I didn't have some before breeding season, but haven't been able to observe that yet, however I will be keeping my eye open in the future and may attempt to keep males and females separate (of the same species) until breeding time and see if it yields any interesting results.

 

[uwe]

Hallo,

the reason for the 50% rate is not the separation of male/female. It is a genetic abaration in this family. In addition all eggs are fertile, but 50% decease.

About the article of Dan: On the right hand side, he states "If the females are kept without males, they will deposit less than a dozen unfertilized eggs." So I am wondering if the earlier post about the two different crested newts producing more than 50% hatch rate, may have been because the female was kept separate prior?

He described that it is possible to have more than one breeding/year in this group. The separation increases the appetition of the genders.

Best

Uwe

 

[caleb]

Hallo,
all eggs are fertile, but 50% decease.

Yes, they start to develop, then stop at the tail-bud stage. This was first described in 1979, and was illustrated with this image (arrested larvae on the left, successful hatches on the right).

The abstract of the paper is here:
https://link.springer.com/article/10.1007/BF00293412