Difference between aquatic and terrestrial

[Niels D]

My gf wanted to raise our noto lavae in a terrestrial setup. I wanted to keep them aquatic. We each made our own setup and we put 2 in an terrestrial setup and 1 in an aquatic one. We had more larvae this year, but they were lost due to an accident that happened when we were on vacation, but that's another story.

All three of the larvae are eating. The terrestrial ones are on a diet of tiny crickets, fruit flies and collembola. The other one's offered daphnia, tubifex and bloodworms. When they got seperated they had the same size. The seperation took place only 2 weeks ago. Now look at the difference:

I knew it would make a difference and that the aquatic one would grow faster, but I never expected such a result in just 2 weeks.

Sorry for the fact I don't know if I had to call them larvae of efts.

 

[caleb]

The spots on the aquatic one are much redder too, presumably from the extra Daphnia.

I've just taken some photos of Lissotriton italicus juveniles that show the differences I've seen this year in colour and growth between aquatic & terrestrial rearing. Scale is the same for all photos. Apologies for the poor quality, this is my first attempt at using a squeezebox for newt belly photos.

First two photos are the parents- these are aquatic all year round, and get Daphnia, whiteworm, mosquito larvae, bloodworm etc.

Next is a terrestrial juvenile, fed on springtails, fruitflies and whiteworms.

Last two are two aquatic juveniles, fed almost exclusively on Daphnia, with the odd bloodworm or whiteworm.

Belly colour is clearly redder in the aquatic individuals, and they've grown much faster- they're nearly as big as the parents, at only a few months after metamorphosis. They're actually even redder than this in real life, the photos don't really do them justice. They even have a pinkish tinge on the upper surface.

 

[slowfoot]

I'm trying the same thing with my Noto efts - leaving 2 aquatic. They are doing well in the water so far, though I'm very careful to watch for any distress. I mostly want to avoid the terrestrial stage because they are so hard to feed and keep alive. Mine are much smaller, so I'll have to see how it goes.

It would be a lot easier to keep and breed Notos if we could skip the terrestrial stage entirely. I'm glad to see yours is doing so well.

 

[Niels D]

I've kept the aquatic noto in a tank with only a little bit of boulder sticking out of the water. I kept on offering all the food in the water. The noto stayed on the rock for about 2 days, then he became more and more aquatic until he completely avoided the boulder. It wasn't my idea. A experienced noto keeper told me about this method. Eft will not turn red unfortunenately, no matter what subspecie you've got, I believe.

The terrestrial ones are indeed missing a lot of carotenoids, though they were raised with artemia in the very beginning. It doesn't bother me though. Next time I will keep the little ones in the water. When my gf and I can have some kids, we will raise them in the bathtub as well.

 

[Niels D]

Though the terrestrial noto's are growing in a lower rate, they don't seem to have a smaller appetite.

 

[slowfoot]

A experienced noto keeper told me about this method. Eft will not turn red unfortunenately, no matter what subspecie you've got, I believe.

The terrestrial ones are indeed missing a lot of carotenoids, though they were raised with artemia in the very beginning. It doesn't bother me though. Next time I will keep the little ones in the water. When my gf and I can have some kids, we will raise them in the bathtub as well.

Even though it's true that the efts raised in captivity will never actually be 'red efts' (and mine won't anyway because they actually don't have a 'red' stage), I've noticed that their red spots do turn red as they mature no matter what I feed them. My captive bred adults (3 years old) look exactly like their wc parents.

I see that your aquatic juvenile already has his red spots, while the terrestrial one has orange spots. My little aquatic guys still have orange spots, but they are quite a bit younger than yours.

 

[Niels D]

No red stage? Does that mean you've got louisianensis?

 

[slowfoot]

I have dorsalis. They have an eft stage but they aren't red in the wild - just a nice orange.

 

[Azhael]

Efts raised in captivity can have a very stricking red colour, it´s all dependent on the diet. If you feed CB efts the right stuff, they´ll be as red as if they were in the wild. I have some CB viridescens that are veeeeeery red indeed, and a single remaining one from a different breeder which has no red whatsoever (my attempts to feed it carotene rich foods failed miserably and i no longer care so it´ll remain greenish xD).
I find it remarkable that you´ve succeeded in keeping viridescens juveniles aquatic! I can´t get mine to even tolerate the touch of water. Even a light spraying makes them panic and run for their lives...it´s ridiculous.

 

[slowfoot]

I guess my point was that trying to feed a diet to induce 'redness' really doesn't matter since the adults will apparently have red in the right places even if fed a regular diet and the eft stage is only temporary. Unless you really want red efts

 

[Molch]

so...what would be some terrestrial food items then that have a high carotenoid content? Something like isopods maybe? centipedes?

 

[Azhael]

Isopods would work, although they would have to be a significant part of the diet to make any difference and would have to be fed foods with a decent content of carotenes. Gammarids work really well but would obviously have to be fed with tweezers.

That´s the thing, Erin, apparently they won´t produce red spots unless the diet allows it. Granted, it seems that you don´t need high levels of carotenes for them to be able to accumulate enough in the red spots, but as far as i know they have absolutely no physiological hability to produce the colour by themselves.
Mind you, as you say, it´s only if you really want red efts or red spotted adults...otherwise the lack of such colouration sems to have no ill effects so it doesn´t really matter.

 

[slowfoot]

Well, I've noticed with mine that a normal diet (live blackworms mostly - I made no attempts to feed carotenoids) will still result in red spots as adults. They had orange-ish spots as efts, but the spots turned red when they matured.

So... I don't know. Do you have any pictures of captive-bred adults without red spots?

 

[Niels D]

I didn't know dorsals didn't have a red fase. Interesting.

The method of keeping them aquatic was really not my idea, but it seems to work. We had 20 larvae. Allas my dad made an error while we were in Italy on our holliday. He took great care for all of our other animals though, so I don't blame him. Eventually we only had 3 larvae left.

When they started to loose their gills we offered them a bit of land (pebbles). We kept on offering the food in the water (daphnia, bloodworms etc). My gf wanted to raise at least one noto on land, so we decided to wait for a while and see which noto's were still on land.

After a while one was completely aquatic and another one was completely terrestrial. The third noto resided on land for most of the time, but returned to the water to feed. I'm convinced that if we kept on keeping the noto's in this setup it would result in all the noto's becoming aquatic.

I know keepers who give their animals like FBN a product with carotenoids in it which is used for the colouration of birds. This seems to work well and you only need a really small dose. I don't know how this works though.

 

[Azhael]

Erin, there was a fantastic photo of a CB adult with yellow spots somewhere, but i seem utterly unable to find it :S I´ll keep trying.

Niels, those products, like Nekton Rep-Color and the like, work very well, but as with any other supplement, they can cause trouble if used in excess. Newer brands use canthaxantine and astaxanthine rather than vitamin A, so the risk of overdose or organ damage is smaller. I´ve used them in the past with excellent results.

 

[Niels D]

I've never used them, but maybe I will when I get my next batch of H.orientalis larvae. I don't think I will be using any supplement for N.viridescens though. I'm planning to raise all the noto larvae I get in the future in an aquatic setup, so they will never become red efts no matter what I feed them.

I've witnessed amplexus going on for more than a month now. I'm hoping that I will find some eggs soon. If this won't happen then I'm guessing I will have to wait for springtime.

 

[slowfoot]

Thought I'd share a picture of my little aquatic morph. He's not as impressive as Niels', I'm afraid. He eats well, but doesn't seem to grow very quickly. That might have something to do with the fact that he just grew a new leg after an unfortunate incident as a larva.

He is fast and hard to get a good shot of:

 

[Ed]

There are three different sources of coloration in amphibians. One is diet related and the other two are not. Blue coloration and metallic colorations are due to reflection of light from crystaline deposits in iridopores. Iridopores also impact green coloration as bluish light can be reflected through yellow pigments resulting in green. Yellows and reds in the skin can be due to pterins which are typically stored in the same chromatophores as the carotenoids. Pterins are not affected by diet (as can be seen in captive bred C. pyrrhogaster fed a diet that lacks red carotenoids). The last class of pigments that impact coloration are the carotenoids. Unlike birds, amphibians have not been shown to modify the carotenoids and simply store them in certain organs and the skin. The vast majority of supplements on the market supply beta carotene as the sole carotenoid which only helps yellows and to a lesser extent orange (lightens it), and greens. There are six carotenoids that are the most commonly found in amphibians on analysis. For diet to help with reds, astaxanthin and canthaxanthin are two of the best options for the hobby. At this time the vast majority of supplements only use beta carotene for the carotenoid source and this isn't going to help with reds, and deep oranges.

I haven't found anything that indicates that terrestrial isopods are a good source of red carotenoids (and some were even steamed to see if they turned pink (which indicates astaxanthin or canthaxanthin seperating from the binding protein) in general most terrestrial arthropods are considered to be poor sources of carotenoids.

For those who are members of TWI, there was an article on a large portion of this in the last issue.

Ed

 

[Molch]

that's interesting, Ed.

So...a red eft living in the wild then must get his carotenoids from some type of terrestrial diet - does anyone know which? Ants? Centipedes? Beetles?

 

[Ed]

that's interesting, Ed.

So...a red eft living in the wild then must get his carotenoids from some type of terrestrial diet - does anyone know which? Ants? Centipedes? Beetles?

If we assume that the red coloration in an eft (which on the anecdotal reports here may not be the case) is carotenoid based then the first source maybe from copepods and other crustaceans during the larval stage. Otherwise, there is variation in the invertebrates (not a whole lot of profiles to look at..) but caterpillars and beetles are reported as having higher carotenoids levels than some other inverebrates. We should also keep in mind that plant matter consumed incidentally with the prey species can also supply carotenoids.
Keep in mind that the red in the eft may also be pterin based (which makes a lot of sense as it would enable the warning color regardless of the dietary availability) or both (again would make sense).

See for example http://users.utu.fi/sayrhe/Eeva_JCE.pdf (and associated references)

Ed