E.g., bees, moths, butterflies
It is the most sure and least wasteful method. Insects, visit the flowers not to effect pollination but to collect nectar, edible pollen or for shelter. As the insect visits a flower, its body gets dusted with pollen grains. When the loaded insect visits another flower, its body brushes against the stigma and inadvertently transfers the pollen to it bringing about pollination.
Some of the characteristic features of insect pollinated flowers are
The flowers are large, conspicuous and brightly coloured.
When flowers are small, they aggregate in the form of inflorescence.
The flowers have a pleasant fragrance and sweet nectar.
Pollen grains are usually rough and sticky and often show spinous outgrowths.
The common bird pollinators are humming birds, sun – birds and honey – eaters. Birds can obtain only one staple food from flowers and that is nectar. The bird pollinated flowers have funnel – shaped or tubular corollas which are brightly coloured. The floral parts are commonly leathery and they produce copious amount of nectar and large quantities of pollen which are sticky.
Common bird – pollinated plants are Bombax (red silk cotton), Erythrina (coral tree) Bigonia, Lobelia, Agave.
Bats bring about pollination only in the tropics. Bats are nocturnal animals and the flowers they visit are large and emit a strong odour. They move very fast and transport pollen to long distances. Bat pollinated flowers generally produce more nectar than ornithophilous flowers. They also have a large number of stamens.