Peter Engelen wrote:I hope you're right and only the big larvae are from waltl. Otherwise there's a big problem. In my own garden pond the M.alpestrislarvae are very black so I will go to another pond today to see how they look overthere.
I. alpestris larvae can vary in color, they can be dark grey and they can have very light colors even within a population, so you should be careful by trying to distinguish between larvae based on color.
I think Liam mentioned something interesting, that the crest of the Pleurodeles larvae starts right behind the head. That seems to be better for distinguishing between the two species. Most alpine newt larvae that I know have a crest starting on their backs behind the front legs.