That's for blue-cristal to define really, in conjunction with exactly what order of complexity the organisms are which are being proposed as founders.
I understand that it happens, and my post was not intended to suggest this is not the case. I did specify "higher organisms", and I do not consider drosophila to be particularly well suited to that category.
Others may disagree I suppose, so this is clarification for those who do: the order of complexity which I am considering in the likelihood of a founder event is equal to or greater than the order of complexity for the groups we have been discussing throughout the thread (birds etc).
Meh, it was late, brain functions, leave me alone, etc.
Let me dig out my typewriter. By golly, Nature won't know what hit them!