Why do butterflies and other insects fly from flower to flower?

Butterflies and other insects fly from one plant to the next to feed on the sweet nectar—and sometimes the pollen—located in the interior of flowers. The sugar in nectar supplies insects with the energy they need, and pollen contains protein, fat, vitamins, and minerals. In the process of feeding, many insects transfer pollen—which sticks to their bodies—from one plant’s flower to another. Pollen, which is a fine powdery grain from a flower’s male reproductive organ, must be transferred to the female reproductive organ of a flower for fertilization to take place and seeds to form.