An Enigma

I thought I had just taken a record shot of some nettle rust fungus, Puccinia urticata, but I got a surprise when I viewed it on the computer.  There were five pink grubs/larvae on the surface! (may be a bit clearer in the 'extra')

Are they burrowing in or burrowing out? Or just there by chance?

Are they (fungus) gnat larvae?

Are they feeding on the fungus or on the nettle?

Or is this a symbiotic relationship?  I have come up with a hypothesis, based on nothing at all, that there is a complex relationship going on.  What if the gnats act as a vector to spread the spores of the fungus?  What if the fungus caused the nettle to create a safe cavity for the gnat larvae to develop in?  What if the fungus gnats inocculate the next nettle with fungus spores when ovipositing?

All that is a possibility - but I don't have the means to prove it.