Shock news delivered by the BBC, as a study shows that earthworms don't just pass soil through their bodies extracting nutrients – they actively eat seeds and young seedlings. Clearly this doesn't change a thing from the point of view of Joe Public and his lawn, since it's been full of worms all along and there hasn't been an evident problem. However in places where worms were not previously present, such as northern North America, invading worms can wipe out whole plant species. I get the impression this correlation was previously known but not understood, so this new research on their eating habits helps to explain it.