Plants and pollinating animals need each other.
Pollen is the yellow, white or brown powder produced at the center of most flowers. You can see it by gently rubbing a finger over the upright structures inside an open flower.
Pollen serves two purposes for plants: it stimulates the creation of fruit and seeds, and it contains the plants' genetic code. When pollen from one plant cross-pollinates the flowers of another plant, the resulting seeds contain a combination of the characteristics of both plants. When pollen moves freely between plants, genetic characteristics are distributed, making the whole plant population healthier.
Pollen is also important for many animals, including insects. It is high in protein (between 7-35%), starch, and vitamins, and it is a vital food especially for insect pollinators and their larvae.
Plants and their pollinating animals have co-evolved in a symbiotic relationship. This means that two organisms of differing species (in this case, different kingdoms -- animals and plants!) interact for a win-win situation. Plants depend on animals to carry their pollen from flower to flower, and the animals depend on pollen and flower nectar for food.