Cynops cyanurus larvae (Part 1)

[TJ]

 

[TJ]

Anybody able to post photos showing what C. cyanurus larvae look like shortly before morphing?


(Message edited by TJ on November 19, 2005)

 

[terry]

Hello Tim,
My compliments on such lovely photos! I keep comparing them somehow to my triturus larvae as they share a similar colouration! How long is the incubation of the eggs and when did they hatch, Tim?

 

[TJ]

Thanks Terry. They sure do look similar. About the hatching period for the eggs, I don't have an personal experience, but maybe Nate, Ed or Erik can tell you. All I know is what I read in:

Studies on the Breeding Ecology of Cynops orientalis
By Yang Daode and Shen Youhui
Zoological Research 14 (3): 215-220
1993

...in which it said the period is approximately 16.5 days for C. cyanurus compared with 13-24 for C. orientalis. I suppose it would also depend on water temperature.

I'd like to propose that people breeding this species collect and exchange such data. I'm removing new eggs daily so I can easily tell when a new egg is laid. And the room temperature is stable. So assessing the average hatching period at a given temperature should be an easy enough task for starters. I would prefer though doing it as part of a group effort.

 

[TJ]

Ah, and as to when they hatched, it's hard to say as I have larvae hatching all the time since a week or so ago, and eggs are being laid daily. I've just been posting pics at random, and not following the development of any one larva. The one in the first pic above is obviously more than a few days out of the egg, the one in the second pic is a day or two since hatching, and the other two pictures show larvae that are somewhere in between.

 

[terry]

Hello Tim!

There is an odd sense of order in the apparent randomness of your pictures, chronologically speaking. I made mostly a lot of speculation and guesswork, measuring the temperatures where you are at and the times of the pics posted, the changes in the larvae and so on ( I did something similar, observing your marbled newt thread).
The incubation period of my pygmaeus eggs are 19-21 days from the first batch till the first natural hatching. dobrogicus took 24 days from the first egg laid till the first hatching of a larva. As I write, 5 more have hatched today.
Water temperature does indeed play a part for hatching. As does the season. As an experiment, I placed different batches of eggs in varying temperatures. some warmer than usual and some close to their natural temperatures if they were to hatch in the wild. My pygmaeus eggs for example failed to hatch when placed in room temperatures (21ºC) and the larvae were beginning to outgrow their egg-sac. Something I did must have triggered off the hatchings proper. The eggs which are kept in cooler temperatures have not hatched yet though the larvae are developing normally.

However, it was when the dobrogicus hatched normally that I discovered what that factor was/ might have been. They were stimulated to hatch because of the sunlight. The apparent warmth of the sun must have triggered them to hatch when they sensed that conditions were right. I have helped none of my danube newts in hatching. I however will not take the risk of placing the batches outside to see what happens as the weather is cooling down and such variance in temperatures my harm the embryos. Something to look into when it is spring.

p.s. I forgot to mention the fertility rate of T.dobrogicus seems higher than T.pygmaeus.

(Message edited by terryschild on November 19, 2005)

(Message edited by terryschild on November 19, 2005)

 

[TJ]

Well, as long these eggs hatch, I really don't care how long they take

I had C. cyanurus eggs and a few larvae late last year but didn't give them enough attention, so I ended up having nothing to show for the minimal effort I put in. This time I'm more dedicated and have many more eggs to work with than before.

 

[TJ]

 

[josh]

Wow thats a beautiful picture of your larva!

 

[terry]

Hello Tim,

While updating my page I decided to look at your thread to make comparisons. Cynops cyanurus larvae seem to posses longer gills than those of Triturus larvae, despite the pigmentation upon hatching. Nevertheless it does not cease to amaze me everytime I make comparisons.
How are your larvae faring?

 

[TJ]

Thanks Josh.

Terry, I don't know what to think about the gill thing as I've seen larvae of the very same species with larger and smaller gills, and maybe like axoltls it depends on water temperature, oxygen content, or whatever...

As for the larvae...don't ask

It seems I lost several, though I only found one dead one. Thankfully, most of the eggs -- and there are a lot -- have not hatched and I'm still getting new ones daily.

I don't know if the deaths had to do with too much aeration, too little aeration, too much food, too little food, water quality. etc.. But I've done an overhaul of tank conditions, and I'm now using a specialized gravel sold for use with those sensitive red-and-white miniature shrimp that are so popular here. It's somehow supposed to have a beneficial effect on water quality, but it looks nice in any case. Also, I replaced the elongated airstone with a small sponge filter set on low, and added a lot of Egeria densa to oxygenate the water and absorb that carbon dioxide (though the opposite occurs once it's lights off!). And I freshened the water using cycled water from another tank.

They're being fed brine shrimp hatchlings. If anything, I must have been feeding them too little rather than too much as I read in an Axoltl Colony document that axoltl larvae that died were found with a large number of brine shrimp clogging up their gills!

Any advice from people who have successfully reared C. cyanurus to metamorphosis would be appreciated! Are larvae of this species by any chance less hardy than those of other Cynops?

(Message edited by tj on November 23, 2005)

 

[terry]

Tim,
I nearly forgot thew factors of high and low oxygen content and gill development.

It grieves me to hear that some larvae are lost. I hope your new setup will eliminate the problem. These shrimp sound familiar. do you have a picture or a website which describe them? The Japanese have always been famous for making pets and pet kits cute! You know all to well what they do for kabuto-mushi and kuwagata-mushi in Japan. Specialised feeding jellies and even refined sawdust for larvae, "bedding mats, clean dried oakwood (Kunugi or Konara) for egg deposition (mostly stag beetles)

Tim, I myself prefer natural systems and avoid brine shrimp larvae altogether. Maybe it is the purist/naturalist in me but I do not believe in feeding brine shrimp to my newts. Rather, I would feed them prey organisms they would find if they lived in the wild. The small crustaceans of the freshwater ponds are more than enough for me. For me, that worked fine.

 

[mark]

Can you get hold of daphnia? It would be interesting to try a separate set-up with a different food source. Maybe some larvae are more vulnerable to salt than others.

That substrate looks interesting. I don’t think I’ve seen it in the shops over here.

 

[TJ]

Terry, I think they're called "bee shrimp" or "bumble bee shrimp" or "crystal red shrimp" or something like that. They're big here in Japan, though nothing compared with the stag beetle craze that has spawned a whole industry of toys, games and assorted products (as did axoltls years and years ago...though not to the same extent).

Terry and Mark, I haven't a clue how to go about, in the city and in the winter, regularly getting as much daphnia as I'd need. There's some tiny ponds near my house with only shallow muddy water. When I've dipped my net in there before, I got only got crud. Can one use a light to attract daphnia to the surface at night? Aren't you afraid of vectors?

I wouldn't mind going the natural route if it isn't too much of a hassle, but at the same I have no objections to feeding my animals brine shrimp hatchlings, which are rinsed of salt in a separate container before being fed. Once larvae get big enough, I sort out the smallest tubifex worms I can find to feed them.

It just so happens that as we speak, I have some of those salmon pellets that Jen spoke of in her recent "confession"

on the way to me by post. Wouldn't it be nice if Cynops larvae fed on them just as Uwe found that his Salamandra larvae did?!

As for the specialized gravel, I like it but don't have any unrealistic expectations of it. I haven't even read up on its merits yet, but will let you know when I do

 

[mark]

I am fortunate enough to have a pond in my garden which I sift for bugs (when it’s not covered with ice!). I get most of my daphnia however, through the post from fish supply companies and then culture them (although demand is usually greater than the growth of the culture and I end up buying more). I don’t think the torch method will work, you are better off buying a starter culture. The animals will most probably have been cultured in fairly restricted environments (no amphibians) thus reducing the risk of vectors, although this isn’t guaranteed. I’m having good success with chopped frozen bloodworms, about 1mm chunks, which is time consuming due to the constant cleaning demands. About 50% of my larvae have adapted to this diet, the reluctant ones are still on daphnia.

 

[terry]

Oh now I know what you mean Tim. CHERRY SHRIMP! LOL they sold them a lot as they are good algae eater's but they are somewhat fragile. Minami Numa Ebi is what we called them while I was back in Malaysia. Yeah, they are a fab. I often get giddy and puppy-like when I encounter something the japanese introduce. Obviously because of their habit of refining or "marketing"their pets into something cute!

I collect my daphnia in the daytime, never at night. They live in small ponds here and are rather concentrated. a good scoop provides me with a little jar full of daphnia...and copepods, fairy shrimp and sometimes Asellus, dragonfly larvae, midge larvae, the works. If it were not for my newts, a single pond dipping is worth observing in a tank on its own!

I feed my Cynops bought bloodworms as well as Possum shrimp dipped from a pond. I usually transfer the shrimp into a vessel of water that that rinses them before netting up the amount i need to feed the newts.

 

[edward]

Hi Tim,
For me I have about 1/3 of the eggs are infertile and then I always lose some while they are really small. This seems to be animals that just don't start feeding or have problems figuring out how to feed. You can use live brine shrimp naupli, grindle worms or even microworms to get more of them past that stage. If you are feeding them brine shrimp naupli then you need to be careful about the shrimp dying on the bottom as the resulting organic debris seems to tangle or suffocate some larva. To get around this you can try keeping some small snails like some of the ramshorn snails in the tank to clean up the organic debris.

Ed

 

[TJ]

Thanks for all those remarks, guys. I'l get to them later, but for now, here are some before-after pics of a C. cyanurus larva that's being fed brine shrimp, taken a few minutes after it started eating and then again about 10 minutes later. You can see that the color of its belly, immediately to the right of its gills, has turned become darker in shade as it fills with shrimp.

 

[TJ]

This is the tank and here is a bag of the soil, which is low to neutral Ph and consists of 48.2% SiO<font size="-1">2</font> (silica), 23.9% Al<font size="-1">2</font>O<font size="-1">3</font> (fused aluminum oxide) and 11.3% Fe<font size="-1">2</font>O<font size="-1">3</font> (red iron oxide).

(Message edited by TJ on November 30, 2005)

 

[terry]

That shrimp is clearly a cherry shrimp, Tim. Lovely! let us know if the soil was truly beneficial as they claim to be! I might be interested in odd marketed specialised gravel after all!

Lovely photos of a newt feasting of BBS!