For fertilisation to occur, the pollen (male gamete) of a flower must come in contact with the ovule (female gamete), which is contained within the pistil, of another flower. A pollinator (insect such as a bee) travels from flower to flower in order to feed on the plant's nectar. While doing so, the pollen located on the flower's anthers rubs off and sticks onto the pollinator. The pollinator transports the pollen to the next flower it will feed on. There, the pollen is deposited on the pistil's stigma. From there, a pollen tube travels down the stigma to the ovule and fertilises the plant.