I think the allegedly discrepancy between their weight and their ability to fly has something to do with the fact that their wings rotate, so that calcualtions for a fixed wing are not correct. I have noticed, but not read, several articles in science and physics journals on the topic of bumblebee fligth in the last year or so. Perhaps a keyword search would pull them out. Liz Day University of Illinois at Chicago [log in to unmask]