What is pollination?

You’ve probably heard people talking about the importance of insect pollinators, and how we should protect them. But what exactly is pollination?

In the simplest terms, pollination is the process by which flowering plants reproduce. To produce offspring, a plant must first be fertilised with pollen, which allows it to develop seeds that will grow into new plants.

How does pollination work?

Flowers have both male and female parts. The male part is called a stamen and is a long slender stalk with pollen at the end. Several stamen are normally found in the middle of the flower. The female part is called the stigma and sits at the very centre of the flower. It is the end of a tube, which runs down into the ovule, hidden inside the flower. The ovule contains the ‘eggs’ that will grow into seeds, once they have been fertilised with pollen.

Some plants can ‘self-pollinate’. This means the plant is fertilised when its own pollen finds its way from the stamens into the ovule. However, most plants are ‘cross-pollinated’. This means they need pollen from another plant of the same type to be fertilised. Pollen can be moved from plant to plant either by the wind or by pollinating animals such as bees and butterflies.

Why do pollinators visit flowers?

To attract pollinators, flowers produce nectar, a sugary liquid that is high in energy. Bees and butterflies will land on the flower to feed and while doing so pollen becomes attached to their body. When they move on to another flower, the pollen is transported with them. Some will find its way into the stigma, allowing the plant to reproduce.

Flowers evolved to have such bright colours and pleasant scent as a way of attracting pollinators. The interaction between plants and pollinators is an example of ‘mutualism’, with both parties benefiting from the relationship.

What is pollen?

Pollen is a small, powdery substance that normally has a yellowish colour. Look closely at the middle of a flower and you may be able to see pollen at the end of the stamen stalks. Bees will eat pollen as it is high in sugar and protein.

How do trees pollinate?

Many tree species rely on pollinators to reproduce. Hawthorn, crab apple and rowan are all examples of flowering trees that are pollinated by bees and other insects. Conifer species produce cones rather than flowers and rely on wind pollination. Male cones generate pollen, which is carried by the wind to female cones, which then use it to develop seeds.