- Students will be able to:
- describe how pollen can be moved from flower to flower
- explain what both animal pollinators and plants gain from their relationship.
Why do flowers need pollinating?
Flowers need pollinating so they can produce seeds. To produce a seed, pollen is moved from the anther of one flower to the stigma of a another flower of the same type. This process is called pollination, which leads to fertilisation and seed formation within the lower part of the flower.
How is pollen moved from flower to flower?
There are two main ways pollen is moved from flower to flower:
- Pollen is blown by wind: These flowers are said to be wind pollinated. Wind blows pollen in all directions, so a wind pollinated plant needs to make lots of pollen for some of it to reach the right flowers. Grass and cereal crops like wheat and oats use wind pollination.
- Pollen is carried by animals (mostly insects and birds in New Zealand): These flowers are said to be insect pollinated or bird pollinated. Less pollen is needed because insects and birds fly from flower to flower placing it, by accident, where it needs to be.
How do plants get animals to do the pollinating?
Plants have evolved cunning ways of getting animals to move pollen from flower to flower. Because pollen is a rich protein and vitamin source and nectar is high in energy, animals want to feed on them. So they move from flower to flower trying to get as much as possible. As they do this, pollen sticks to the animal's head, feet, hairs, feathers or body. Then, as they continue to forage it ends up sticking to the stigmas of other flowers, thereby achieving pollination.
How do flowers 'advertise' to pollinators?
To get pollinating animals to visit in the first place a flower might:
- have large, colourful petals
- make nice smelling scents
- have patterns on the petals such as 'landing strips' that direct an insect to the nectaries where nectar is found.
Once an insect or bird learns that there is food to be had, they will visit this type of flower over and over.
Photo credits: Thumbnail photo Cypripedium pollination (Beatriz Moisset CC BY-SA 4.0). Flower diagram (created brgfx - www.freepik.com, https://www.freepik.com/free-v...) .Bumble bee, honey bee and tūī photos (© Peter E Smith, NSIL.).