Ilian Velikov wrote:Michal, that's very interesting! Do you have a source? I thought salamandra larvae are enclosed in egg capsules while inside the female.
Jose Luis Perez wrote:Ilian, Salamandra salamandra ssp. bernardezi is viviparous...
Alexander Pieh wrote:I would speculate that cold (oxygen rich) water allows the larvae to feed for a longer time on water organism and to grow larger until they metamorphose. This might be an advantage if they change into the land habitats. So, it might be an advantage to release the larvae in winter.
Alexander Pieh wrote:Is a larger size better than a faster metamorphosis? – depends on predators in the water / terrestrial habitat etc…
Michal Szkudlarek wrote:Ilian Velikov wrote:Michal, that's very interesting! Do you have a source? I thought salamandra larvae are enclosed in egg capsules while inside the female.
They can leave egg capsules. Piotr Sura wrote in his book published in 2005 that adelophagy is known in Salamandra atra, Salamandra lanzai, 2 subspecies of S. salamandra, Lyciasalamandra spp. and Typhlonectes compressicaudus. Włodzimierz Juszczyk wrote in the eighties that this phenomenon can be present in axolotls and in oviducts of S.salamandra and it happens when female is far from water and does not give birth to larvas.
Ilian Velikov wrote:Thanks Jeroen, and Alexander again. You both certainly have a point. The conditions Alexander describes are very close to these at our spot except that the breeding pool/puddle (I won't even call it a pond) is tiny and is basically at the base of a spout from which the spring water flows creating a constant (but not strong) current. For some reason I always thought this is the preferred breeding habitat (clean oxygen rich flowing water) for Salamandra at least here because I've never seen lavae in still water and even some of the other (maybe dirtier) streams are never used. Maybe it's to do with wider habitat and bigger choice of spots. Anyway, there's very little variety of food at our local spot, actually besides a good number of Gammarus and maybe the occasional drowned worm I don't think there's much else for the larvae to eat. There are also pretty much no predators. I'm sure there are no aquatic ones and for over 20 years I've never seen a snake there. There's also no chance of the larvae drifting downstream. Nevertheless, a (very) small number of the larvae survive to metamorphosis which makes me think that there's a good amount of cannibalism going on (although I've never seen it). This leads me to metabolism which should be directly connected to grow rate. So, my question is - are some (the bigger) larvae adopting better to the winter conditions hence metabolising faster (and growing faster) or are they simply better hunters catching more food? In other words is it possible that there's different metabolic rates between individual larvae (like in humans)? The other thing in this race to grow which I notice is that some larvae are just born larger than others. Do they ever manage to make up for this or are they destined to be food for the larger ones?
Users browsing this forum: No registered users and 0 guests