Does anyone know of any work relating pollen size to the efficiency of transfer by bees? - or any other insects. I am not particularly interested in the known correlations between pollinator size and pollen size, style length, stigma depth, flower size etc. (although these may be of interest if I have not seen them before), what I am after is results of experimental studies. Is there any evidence that plants are better off with large grains than small grains when pollinated by bees - or vice versa? (leaving aside complications of buzz pollination) William Kirk Keele University, UK.