Insects in our gardens
What insects are visiting our garden and why?
Fast fact: Beetles were probably the world's first animal pollinators; they pollinated cycads long before flowering plants came on to the scene.
- Life in the Undergrowth, episode 4 [DVD]
- General flower anatomy diagram
- Pollinator preference key
- Plants and insects in our garden matrix
- Plant life cycle and processes
- Butterfly net
- Magnifying glass
- Flower and insect calendar
- Invertebrate Collection Manual
- Quick Invertebrate Guide
- P2P presentation
Pose focus question
- What insects are visiting our garden and why? 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.
Watch Episode 4 of Life in the Undergrowth or show P2P presentation. Create a concept map around plants and insects (use Plant life cycle and processes if you get stuck).
Move out to the playground or garden to address the focus question, using Structuring field observations to guide you. Get students into pairs, and use print outs of the Plants and insects in our garden matrix to help them collect data.
Using a camera or sketches, record which insects are visiting which flowers, and which flower types there are – include colour scent, shape, include weather data, and time. If you have time, collect invertebrates with nets or by leaf beating or similar techniques outlined in the Invertebrate Collection Manual to examine them closely and identify them (see the Bugwise Quick Invertebrate Guide).
Using the General flower anatomy diagram, describe basic flower anatomy using specimens of sunflowers, melon flower, lily and bottlebrush. If you can't find these flowers, use the plants you have in the playground or garden. Discuss flower shapes and classify them using the Flower and insect calendar.
Build on your field observations by answering the following questions.
- What are the cues that flowers exhibit to attract insect pollinators?
- What other evidence of insect visits are there (herbivory, eggs, larvae)?
In groups, create flowers (from craft equipment) which would entice specialist insect pollinators. Display the flowers and hypothesise about the pollinators adaptations. Discuss the diversity of garden flowers and the consequences for invertebrate diversity.
- Over millions of years flowers have evolved a remarkable range of strategies to guarantee that male pollen is transferred to female parts of the flower. Insects — especially bees and wasps, butterflies, moths, beetles and flies are the predominant animal pollinators.
- They have physical characteristics that make them extremely efficient in locating flowers and transferring pollen from one flower to another.
- The typical flower contains the necessary parts for enticing pollinators and producing seeds. The centre of a flower usually contains the female, pollen-receiving pistil or carpel. The stigma at its tip is often sticky designed to trap pollen. At the base of the pistil, the generally hidden ovary protects ovules (eggs), which become seeds when fertilized. The male parts, or stamens, typically surround the pistil. They may be quite long, to maximize exposure to wind and pollinators; hidden inside the flowers, to force pollinators to touch the stigmas on their way in or out; or able to lengthen and shorten over time, as needed.
- The stamen is made up of the filament that supports the anther which produces and releases huge quantities of pollen.
- The pollen descends down the style of the sigma and fertilizes an ovule, leading to seed production. Once fertilized, the ovary wall takes in moisture and swells, becoming the fruit, which surrounds and protects the developing seeds.