ADAPTATIONS RELATED TO INSECT AND WIND

POLLINATION

• Pollination: the transfer of pollen grains from anthers to the stigmas;

• external agents are needed –

• (1) by insect

• (2) by wind

• Comparison of anemophilous (wind-pollinated)

and entomorphilous (insect-pollinated) flowers

wind-pollinated insect-pollinated

Example: grass Example: Bauhinia

Plants often occur in dense groups covering large areas

…in small groups

Flowers occur in groups

(inflorescences) on the plant

…may be solitary or in groups

Flowers often unisexual with an excess of male flowers

Mostly bisexual

wind-pollinated insect-pollinated

Petals are dull and

much reduced in size

…large & brightly coloured, conspicuous to insects

No scent or nectary Scent and/or nectary to attract insect

Stigmas protrude outside flower on long styles

…lie deep inside corolla

Stigmas are feathery, giving them a large surface area to filter pollen from the air

…relatively small because they are easily touched by insects

wind-pollinated insect-pollinated

Anthers hang outside flower on long filaments so the pollens are easily released into the air

…lie inside flower to touch insects when they come to collect nectar

Large number of pollens are produced to offset the high degree of wastage during dispersal

Less pollens because high chance of successful pollination and to reduce wastage

Pollen is smooth, light & small and sometimes have wing-like extensions to aid wind transport

…larger and often have projections to adhere to insects