On Sept. 30, William Kirk requested information on efficiency of pollen transfer by bees. Oct 03 LDHARDER gave some information on the subject, and he suspects that a correlation with some unmeasured variable might be involved. Our observations on pollen-collecting behaviour of honeybees in a bee flight room with controlled environment suggest, that not the size of the pollen grains, but the efficiency with which the gathering bee can collect the pollen, governs the attractivity of the pollensource. The more recalcitrant to removal (sticky) the pollen is, the less attractive the source will be. The last remark of LDHARDER points in the same direction. If this holds plants with anthers with pollen grains that are quicker collected by bees would be better off, independant of the size of the single pollen grain. Bernd Brinkschmidt/Job v. Praagh Bee Research Institute D-3100 Celle