Do newts lay unfertilised eggs?

[Alpestris350]

Hello

I recently got back into keeping amphibians and got 5 (2M 3F) Alpine Newts less than a week ago. I have kept Chinese Fire Belly Newts, Fire Salamanders, Alpine Newts etc in the past and have many newts living in my garden pond so I am familiar with their behaviour.

I know it is their breeding season but was still surprised to find several eggs in the java moss today. I have not seen any egg laying myself but 2 of the 3 females seem quite gravid. All 5 (Italian subspecies) went aquatic straight away after releasing them onto the java moss which provides a small area to peek their heads out of the water. They have been eating earthworms and waxworms from a few hours after arriving and I did see some tail waggling although not as much as I would've expected for this time of the year.

Anyways, I wanted to ask whether female newts may lay unfertilised eggs like anurans might. Is there any way from telling (apart from if they go undeveloped and mouldy after some time) if they are unfertilised?

From my understanding, I thought they reabsorbed any unfertilised eggs. It is possible they mated before I received them and also of course in my care when I was not watching, but I am just surprised how quickly they are laying! I am keen to raise larvae so will probably separate the eggs from the adults.

Thanks for any help

 

[Niels D]

Newts can definitely lay unfertilised eggs. It depends on the species how to recognise them if they are recently deposited. These eggs will develop a moldy coat and show no development, so no matter if you can't see it in the beginning, after a while you will.

In my experience unfertilised eggs from Triturus and Ichthyosaura have a slightly larger (and rounder) nucleus.
Cynops/Hypsolotriton and Paramesotriton eggs will have a nucleus which is 50/50 bicolour (brown/white), unlike fertilized eggs. These are more beige and have one colour.
I don’t see this in popei eggs though, which seem more identical to Triturus regarding to being unfertilised.