Pollination | How It Works

Almost all life on Earth depends on plants, but it turns out plants are just as dependent on animals as we are on them. The truth is that most plants need a lot of help with pollination in order to be able to reproduce. Without animals to pollinate them, nature would be left bare of seeds, fruits, and vegetables.

Plants that bear flowers reproduce through a process known as pollination. For a flower to turn into a fruit, the pollen grains from its anther must reach its stigma. Without this, the plant would simply be unable to produce new plants. It wouldn't be an exaggeration to say that without pollination, the earth’s terrestrial ecosystem would not exist!

What Are Pollinators?

So, how exactly does this important process take place? With help from pollinators, of course! A pollinator is an animal that helps move pollen grains from a flower’s anther to its stigma. Bees, wasps, flies, beetles, and butterflies are popular pollinators around the world, but in some ecosystems, other animals like bats, birds and rodents lend a helping hand as well.¹ Many flowering plants have even evolved to attract specific pollinators and provide rewards such as nectar, pollen, lipid secretions, scents, resins, and material for nest building. Most insect-pollinated flowers also produce a number of signals, such as odours, colours, shapes, textures, and tastes, that help insects differentiate them from other flowers.²

Most Adansonia species (African Baobad) are pollinated by bats. Plants pollinated by bats often have pale nocturnal flowers. These flowers are often large and bell-shaped, and some bats have evolved specifically to reach the nectar at the bottom of them.

Grey-headed Flying Fox (Pteropus poliocephalus) eating flower nectar. The face and fur of this bat being covered with yellow pollen provides a good visual example of the role that bats have in pollinating Australian trees and bushlands.

Fun fact: Wind also helps certain plants with pollination. Strong winds can help to spread pollen long distances between flowering plants - though not great for those with pollen allergies!

Plants And Their Pollinators: A Complex Relationship

This relationship between plants and their pollinators can be of different types. Many relationships are facultatively mutualistic, meaning that the plant and animal derive benefit from each other but are not dependent on each other for survival. For example, most bees can meet their food and nest-building needs from a number of different flowers.³ Similarly, most flowers can be pollinated by different bees. However, some plant-pollinator relationships can be obligate mutualistic in nature. This means that either the plant, pollinator, or both cannot survive without each other. Fig trees and fig wasps, and yucca plants and yucca moths are famous examples of such relationships.

The fig tree and fig wasp have an obligate mutualistic relationship in nature. This means that either the plant, pollinator, or both cannot survive without each other.

Read about figs and their pollinating wasps

Foods That Need Pollinating

The most valuable benefit of pollinators to humanity is their role in helping many food and fibre crops reproduce. This is described as an ecological service whose economic value is estimated to be worth several billion dollars.⁴ Most foods that we consume today exist because pollinators help them reproduce. A diverse spectrum of fruits and veggies like potato, pumpkin, coconut, and soybean all share one common characteristic - they depend on pollinators for their continued existence!⁵

Wild & Native Pollinators

Traditionally, animals that are native to specific ecosystems carry out pollination for the plants that share their environment. Such animals are known as wild or native pollinators. In such a relationship, both the plants and the animal have evolved to share a mutually beneficial relationship. As a result, these pollinators are extremely effective at getting the job done.⁶ However, they need an undisturbed habitat for nesting, roosting and foraging.⁷

Farming Practices Impact Pollinators

Loss of habitat, intensive agriculture, use of pesticides, and climate change have seen wild pollinators deplete rapidly.⁷ To mitigate the effects of declining wild pollinator numbers, farmers introduce non-native pollinators (usually bees) into their orchards and farms. These are often called managed pollinators because beekeepers manage them in artificially created hives.⁸

Find out why ecologists don't always love honeybees

After the introduction of bees, farmers must take several precautions to make them stay. Manually removing weeds instead of using herbicides, practising mixed cropping, maintaining flower-rich field margins, and cultivating shade trees are some ways in which farmers try to retain managed pollinators. Managed pollinators, however, are known to adversely affect wild pollinators by competing with them, bringing about changes in their ecosystems, and transmitting diseases.⁹

Pollination management aims to enhance the pollination of a crop by understanding the particular crop's pollination needs, and by knowledgeable management of pollenizers, pollinators, and pollination conditions.

Fun Fact: The most widely managed pollinator in Europe is the honeybee (Apis mellifera).¹⁰ Bumble bees and mason bees are two other important managed pollinators.

Robot Pollinators: Science or Fiction?

Both managed and wild pollinators face threats due to the changing climate and increasingly intensive agricultural activities. With their numbers falling rapidly, the world faces a pollination crisis. While preventing this crisis from intensifying is a priority, scientists are also looking for ways to reduce our dependence on biological pollinators. This would mean employing new, innovative technologies to pollinate our crops.

Materially engineered artificial pollinators are an upcoming and successfully tested technology that use bio-inspired robotic drones for artificial pollination.¹¹ The drone mimics the movements of bees to pick up grains of pollen from the stamen and deposit them in the stigma. They use a sticky liquid known as an ‘ionic liquid gel’ for picking up pollen effectively without damaging the grains. Other techniques that have been tried previously include manual pollination by workers using a paintbrush and mechanical spraying of pollen.

How To Save Our Pollinators

Despite successful technologies that do not depend on animals, completely replacing biological pollinators would be immensely challenging. If we want to save biological pollinators from further depletion, we must invest in research and incorporate results from such research into agricultural and environmental policy. Pollinator conservation techniques include techniques commonly used in organic farming, such as increasing biodiversity on farms, using pesticides responsibly, and preserving wild habitats. Actively applying these techniques would help in not only improving the health of pollinators but also mitigating the impacts of climate change and maintaining sustainable food systems.