Insect pollination

Have fun and learn how insects pollinate flowers in this hands-on Bugwise activity.

How do insects pollinate flowers?

Fast fact: Charles Darwin found a very long tubular flower in the South American jungle and predicted someday someone would find an insect with a tongue of matching length to reach the nectar at its base. After much searching and over one hundred years later, a moth was found. More recently an even longer tube flower has been found in Madagascar and the search in on for the insect pollinator.

Pose the focus question
How do insects pollinate flowers? List and display all answers and questions as they arise.
What does pollinate mean? To pollinate means to mix the male (pollen) and female (stigma and ovule) parts of the flower so the flower can reproduce. If you get stuck, read through What is pollination? as a class.

Engage
Ask you students the following engage questions.

• Why does an insect pollinate a flower? Flowers hold rewards of nectar (just like lollies!).
• Are there different flower shapes? Tubes (daffodil) and dishes (daisy/gerbera).
• How do you think an insect would collect nectar from the bottom of a tube? Some insects like butterflies and bees have long ‘straw-like’ tongues they can suck up the nectar with.

Explore

1. Partner up with another student and decide if you want to represent a butterfly or a bee. There should be approximately the same number of bee and butterfly pairs in the class.
2. In your pairs, create the type of flower with the craft materials that matches your insect.
   1. Butterflies make tube flowers: Cut a length of straw 1 cm taller than the paper cup. Blue-Tack the straw to the bottom of the cup. Place a cotton wool bud on top of the straw. Make two tube flowers.
   2. Bees make dish flowers: Stick a cotton wool bud in the centre of the paper plate. Make two dish flowers.
3. Within the pairs, fill the tube flower or dish flower with a layer of popcorn. Cover the cotton bud in the centre with sherbet, cinnamon sugar or icing sugar. These will be the male flowers.
4. Your remaining tube or dish flower will be female flowers. Keep these with a plain cotton wool bud in the centre and no popcorn. Place this female flower several meters away from the male flower.
5. In your pairs, one person is the ‘insect’ the other is the popcorn counter.
   1. Butterflies: use a small length of straw (just shorter than the height of the cup) in your mouth to suck up a piece of popcorn, deliver it to the empty tube flower.
   2. Bees: use a very small length of straw (approx 2.5 cm) in your mouth to pick up the popcorn, one piece at a time and deliver it to the empty dish flower.
6. Once all the popcorn is transferred from one flower to the other, sit down near your flower and look at the ‘insects’ face. Is it covered in the cinnamon or sherbet you used as pollen?

Explain
Flowers are shaped so when a particular insect collects nectar, it gets covered in pollen. When it visits the next flower the pollen gets transferred. This is pollination – a seed or fruit will now appear!

Elaborate
Discuss different shaped flowers and different ways insects eat e.g. butterflies use long straw like tongues and so can reach the nectar in the bottom of long tube-like flowers. Bees only have short mouth parts and can only collect nectar from flat dish-like flowers.

Evaluate
Assess your students' understanding by posing questions.

• If insects were removed from the environment, could flowers still transfer pollen? Mostly, no.
• So what would happen to the plants? No fruit, no more flowers etc.

Insects obtain food from the flowers they visit, usually in the form of pollen or nectar. In return for this food the insects carry the pollen from one flower to the other, allowing the plant to reproduce. Flowers have characteristics that attract insects and insects have specialised mouth parts to gain access to nectar.

Reference
Proctor, M., Yeo, P and Lack, A. 1996.The Natural History of Pollination. Timber Press Inc. USA.