Centaurea cyanus
The pollen of "Centaurea cyanus" is used by several different insect species. Insects of the orders Hymenoptera and Diptera are particularly attracted by the flower. As "Centaurea cyanus" is a self-incompatible species, it needs external pollination. The nectar of "Centaurea cyanus" is very sweet with a sugar content of 34 %. Due to its high sugar production of up to 0.2 mg sugar per day and flower, the species is highly appreciated by beekeepers.