Pollination is the preferred method of reproduction used by plants. It is the process of transporting a grain of pollen from the stamen (the male reproductive organ) to the stigma (the female reproductive organ).
As they explore flowers looking for nectar, insects (including bees) rub the stamen and accidentally pick up grains of pollen (up to 100,000 of them), which they then leave on another flower. Each insect often specialises in collecting pollen from a few species in particular, so the pollen is often transported from one flower to another of the same species.
Around 225,000 species of flowering plants are pollinated by 200,000 species of animals, including insects at the top of the list (data published by INRA).
Pollination by insects, known as entomophily, is essential for the fertilisation of most flowering plant species that we grow for their seeds (rape, sunflower, buckwheat), their fruit (apples, pears, kiwi fruit, melons), their roots or their bulbs (carrots, radishes, onions) and their leaves (cabbage, salads etc.).
More than 70% of crops (including almost all fruit trees, vegetables, oil and protein crops, spices, coffee and cocoa, so 1/3 of our diet) depend heavily or totally on animal pollination (figures published by the FAO).