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Pollination mechanisms 2

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Four different insect pollinaters and a ruby throated hummingbird.

Play the Pollination GamePlay the pollination game

(Try to guess which is the correct pollination vector)

Wind: Many flowers are wind pollinated. It is not an efficient method of pollination because much pollen must be produced with the hope that some of it may land on a receptive stigma of the right species.

Characteristic features of wind pollinated flowering plants include:

bullet5.gif (1078 bytes) They produce huge amounts of non sticky pollen
bullet5.gif (1078 bytes) They often lack a large and showy calyx or corolla
bullet5.gif (1078 bytes) They have many flowers packed into a inflorescence
bullet5.gif (1078 bytes) They have large stigmas
bullet5.gif (1078 bytes) They have large, well exposed anthers

Water: Pollination by water is not common but a few seed grasses and water weeds release their pollen into the water which is passively carried to other flowers by water currents.

Insects: A great many flowers are pollinated by insects. These flowers do not tend to have any common characteristics because many different types of insects have very different ways of  pollinating flowers e.g. bees (the most common insect pollinators), butterflies, moths, beetles and wasps.

Many insect pollinated flowers not only have bright colours, but their petals have nectar guides which contain UV absorbing pigments. The nectar guides lead the insect towards the nectar - the reward the insect receives for visiting the flower. Pollen is deposited on the insect from the stamens when it visits the flower to collect or drink the nectar, and is deposited on the stigma of the next flower it visits.

Flowers which are visited by nocturnal insects have less showy corollas but are often strongly scented. Other flowers are brown in colour and smell like carrion and attract flies, which  pollinate them. Some flowers may get robbed of their nectar by insects which do not pollinate them. Some plants have therefore developed complex structures which prevent all but specific insects species from reaching the nectar and getting pollen deposited on them, which will  transferred to the stigma of the next flower they visit.

Mammals: Some flowers are pollinated by small mammals such as bats and rodents.

Mammal pollinated flowers have the following characteristics:

bullet5.gif (1078 bytes) They often have a strong scent e.g. those which attach mice have a yeasty odour.
bullet5.gif (1078 bytes) They are often brown or white in colour.
bullet5.gif (1078 bytes) They are quite sturdy in structure in order to bear the vigorous activity of the small mammals while they are feeding on the nectar they provide.
bullet5.gif (1078 bytes) They offer their mammal pollinators a reward of  large amounts of nectar

 

Birds: Bird pollinated flowers are much more common than mammal pollinated flowers. Two large groups of birds which pollinate flowers are the sunbirds of  Africa and Asia and the Hummingbirds of the Americas. Both groups of birds have long beaks which allow them to reach inside the corolla tubes of flowers. Hummingbirds are well known for their ability to hover in front of the flowers while drinking the nectar. Sunbirds however sit on the flower stalk and collect the nectar.

Bird pollinated flowers have the following characteristics:

bullet5.gif (1078 bytes) They often have a red, orange or yellow corolla, calyx, bracts or stamens which are attractive to birds
bullet5.gif (1078 bytes) The are not usually scented because most birds do not have a well developed sense of smell
bullet5.gif (1078 bytes) They provide a large amount of nectar as a reward for the bird pollinators

 

 

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