Re: It's always worth it to go out (for Salamandra) ;-)
Posted: Tue Dec 11, 2018 4:45 pm
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?