Adaptations of insect-pollinated flowers

Maria is out walking with Sofia. Maria! Apple blossom! Mmm it smells nice! We’re not the only ones who like them.

Bees and other insects seem to love them too! Insects are really important for the apple tree. They transfer pollen between different flowers: a process called insect pollination. To attract insects to them, apple trees, and other insect-pollinated plants, have developed flowers with special features, or adaptations. These adaptations increase the chances that pollen from their own flowers will be carried to other flowers.

One of the most obvious adaptations is large, colourful petals. Bright colours make the flower stand out from the green leaves and stems around them: the flower is easily spotted by insects. But some insects, like moths, don’t see very well, so they are more attracted to smell. Other insects are attracted to both petals and smell. So, most insect-pollinated plants have both: colourful petals and distinctive smell.

But insects landing on the flower is not enough. They must also pick up pollen and carry it to another flower. So the flowers have adapted to that too. The male organs where pollen is produced, the stamens, are usually short, firm and surrounded by petals. The stamens produce grains of pollen that are rough or sticky and can easily stick to an insect.

Pollen is received by female organs, the carpels. Carpels have also adapted to make pollination easier. Carpels are small and sticky, and are found inside the flower. When the insect rubs against them, pollen is transferred from the insect to the carpel. Plants also need to make sure that the insects will carry the pollen to other flowers over and over.

So to motivate insects, insect-pollinated plants have developed rewards! One of these rewards is a sugary liquid: nectar. Nectar is sweet, and gives insects masses of energy. Ideal insect food! Nectar is usually at the base of the flower, surrounded by stamens.

So to reach it, insects will have to brush against the pollen. And when they want more nectar, insects move to another flower. The pollen they collected from the first flower, will get stuck on the carpel of the next flower and pollinate it. Insect-pollinated flowers often provide another food reward for the insects. The pollen itself.

Flowers produce extra pollen for insects to feed on. And because insects are messy eaters, pollen will get stuck to their bodies, and will be carried to the next flower. So insect-pollinated plants use various ways of attracting insects: from having bright coloured petals, to offering sweet nectar. There’s loads of insects around this apple tree, so it must be very well adapted. Maria, I want an apple now!