Leafcutter bee (Megachile sp.) pollinating a senna flower (Colutea sp.). As the bee sucks nectar from the flower, its abdomen rubs against the stamen - picking up grains of pollen. Each pollen grain contains a male gamete which, when deposited on another plant of the same species, can fertilise an ovule and produce seeds. This bee gains its name from its method of building a nest. It cuts off sections of leaves with its sharp mandibles and uses them to line a hole it has found.