With over 75% of our flowering plants relying on pollinators, they have an important role to play in maintaining our ecosystems. Given that this week is National Pollinator Week, it seems like the perfect time to celebrate all the hardworking pollinators.
What are pollinators?
Pollinators enable plant fertilisation by moving pollen from the male parts of one plant to the female parts of another – a process known as cross-pollination. They are mostly insects like bees, wasps, butterflies, moths and flower beetles, but other animals, including bats and hummingbirds, also help to pollinate flowering plants. Once fertilised, plants produce seeds and fruit, which enables new plants to grow and provides a source of food for wildlife and for us; without pollinators, our diets would be a lot less varied.
Pollination is a mutually beneficial arrangement; pollinators receive food – nectar and sometimes pollen – and plants get fertilised.
The importance of pollinators
It is well known that many pollinator populations are declining but why are they important and why should we worry about a decline? Pollinators are extremely significant and without them, biodiversity would decline substantially, as many plants rely solely on pollinators for fertilisation, there would be no new flowering plants if they all disappeared. Pollinators facilitate fertilisation of 75–90% of flowering plants worldwide, which includes over 180,000 plant species and 1,200 crop species; without pollinators, there would be no chocolate or coffee.
Why are pollinators in decline?
One of the main problems impacting our pollinator populations are pesticides, which get taken up by plants and then ingested by pollinators. In high doses, pesticides can be deadly, but at lower concentrations, they are known to impact feeding behaviour, foraging activity, and navigation amongst other problems. Spread of parasites and disease have a substantial impact on bee populations, and loss of habitat is an issue for many pollinators. Urbanisation and population growth mean large areas of land now offer little food for pollinators, and even agricultural farms with fields filled with single crops can be an issue. Bees require a range of plants to get the nutrition they need, so single crop fields provide only a proportion of dietary requirements.
Other possible reasons for declines include increasing levels of air pollution, which could interfere with the ability of pollinators to locate flowers using smell. Changing temperatures and global warming are also an issue, as they could cause insects to emerge at unfavourable times when fewer flowering plants are available for them to eat.
What makes bees such effective pollinators?
Bees are probably most commonly associated with honey, but there are actually around 20,000 species of bee; not all stick to the yellow and black colouring that is so well-known, and very few actually produce honey.
In fact, bees are some of the greatest pollinators and are responsible for the pollination of around a 3rd of our world food supply. They feed only on nectar and pollen so rely solely on flowers for food, and their electrostatic charge and hairy body make them very good at collecting pollen. Many species also have specialised pollen carriers on their hind legs, known as scopas. Honeybees and bumblebees are slightly different; rather than having a scopa, they have a hind leg which is modified into a corbicula or pollen basket. Nectar and pollen are gathered to feed young as they are high in energy (nectar) and protein (pollen), but some gets passed between the flowers as they move around.
What can you do to help pollinators?
Pollinators need our help, but fortunately, there is something we can do to help. Planting a variety of pollen-rich flowers in your garden will provide an excellent food source and encourage them into your garden; lavender and foxgloves are great options for bees. Once in your garden, give them somewhere to nest; insect hotels are widely available in the shops, but making your own is fun and simple to do. Many solitary bee species nest in hollow tubes, tunnels or holes so drilling holes in old logs is a good option, as is providing hollow bamboo tubes. Finally, try to stick to natural pest control methods and avoid the use of harmful pesticides.