And, don't forget The Foraging Behaviour of Honeybees (Apis mellifera L.) on Brussels Sprout (Brassica oleracea L.) which includes the text: Bees soon learned to rob flowers and the ease with which they did so, increased as a flower became older and its perianth segments spread apart. Most foragers visiting some cultivars were robbers, particularly at the later stages of flowering. However, some cultivars with small flowers were not robbed even when their flowers were old. Flowers were less likely to be pollinated by robber bees than by bees that entered them. Robbing can be discouraged by selecting Brussels sprout cultivars with inner nectaries easily reached by bees and also by increasing the proportion of pollen to nectargatherers visiting the crop.