Pollination: the big view

Pollination is a process that has evolved over millions of years to benefit both flowering plants and pollinators. Although some plant species rely on wind or water to transfer pollen from one flower to the next, almost 90% of all plant species need the help of animals for this task vital to reproduction. There are approximately 200,000 different species of animals around the world that act as pollinators. Of these, only about 0.5% are vertebrates, such as birds, bats, and small mammals, and the rest are native insects, including flies, beetles, butterflies, moths, and bees. Native pollinators are adapted to local climate conditions, soils, and plant life and, thus, require limited management or maintenance.  Most are flexible and are able to interact successfuly with non-native plants of parks and gardens.

Pollinators visit flowers for many reasons, including feeding, pollen collection, and warmth. When pollinators visit flowers, pollen rubs or drops onto their bodies. The pollen is then transferred to another flower or a different part of the same flower as the pollinator moves from one location to the next. This process is a vital stage in the life cycle of all flowering plants and is necessary to start seed and fruit production in flowers.

By transferring pollen, insects are part of the flower's reproductive system and by providing nectar the flowering plant supplies the insects with an energy-rich food which bees store as honey for the development of their larvae.  The mutual benefits of these associations of flowers and insects may be described as lifecycle services. 

There is evidence from cave art made about 8000 years ago that early peoples raided these insect food stores.  Honey collection was probably an early behavioural adaptation that gave a nutritional spur to human social evolution.  It has come down today as the 'bee industry' which is often used as an example of human ecosystem services.

Not only do pollinators provide essential services in nature, they are also necessary for healthy, productive agricultural ecosystems as they ensure full-bodied fruit and fertile seed sets in many crops. Animals pollinate approximately 75 percent of the crop plants grown worldwide for food, fibre, beverages, condiments, spices, and medicines. It has been calculated that one out of every three to four mouthfuls of food we eat and beverages we drink is delivered to us by pollinators. As such, agricultural products that are produced with the help of pollinators make a significant contribution to the human economy. For example, it was estimated at the turn of the century that insect-pollinated crops directly contributed $20 billion to the United States economy. If this calculation were to include indirect products, such as milk and beef from cattle fed on legumes, the value of pollinators to agricultural production would be raised to $40 billion in the United States alone.

To this bigger picture may be added the delight that humans gain from the activities of pollinators in their gardens, parks and open spaces, which makes caring for pollinators an excellent entry point for learning about living sustainably.

A prehistoric honey collector

(transcribed from an 8000 year old cave painting, Valencia, Spain)

The above is a summary of an e-book that is being created as an educational module all about pollination.

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