Shorty, I don't know of any studies that directly answer your question. I do know that it is quite clear that pumpkinseeds can and do overpopulate. They are easily controlled by LMB, just as are BLG. They are not the "redear of the north" as I discovered quite a few years ago. They are similar in their habits of feeding on snails, but not in reproductive potential.
Maybe Eric will know of any studies on the BLG/Pump seed question that you asked.
