…an informative blog written by Emily Shaw, Buglife Conservation Officer delivering Neath Port Talbot B-Lines project, which concluded in September 2023.
Most people think of honeybees, when we talk about pollinators, but lots of insects help pollinate flowers including bees, flies, wasps, beetles, butterflies and moths. Even species such as houseflies, that have a bad reputation, are valuable pollinators!
To be an effective pollinator, insects need to actively visit flowers of the same species and be capable of carrying pollen on its body (think of hairy insects!) so that it transfers from one flower to another.
What is pollination?
In its simplest terms, pollination is how flowering plants reproduce to enable fertilisation and seed production. For a plant to be fertilised, they need pollen from another plant of the same species to develop seeds. Pollen needs to transfer from the flower’s male part called the anther, to the flower’s female part called the stigma.
So, how does this pollen get transferred? Some plants are pollinated through wind or water and others go it alone by self-pollinating. However, for the vast majority, plants have evolved to rely on animals, and mostly insects, for pollination. Putting this into numbers, globally, approximately 85% of all wildflower and flowering crop species are dependent on insects and other animals for pollination.
This is staggering – insects offer pollination services essential to being able to grow food, and without them our diets would be severely limited.
Plants and pollinators have a mutualistic relationship, kind of like an unwritten “agreement” that has developed over millions of years. Flowers provide pollinators with sweet sugary nectar and nutritious pollen for fuel and protein, and in return, pollinators move pollen from one flower to another facilitating plant reproduction.
Meet six unsung heroes of the pollination world
Bumblebees are excellent pollinators, their dense hairy bodies enable them to gather and transport pollen. Long-tongued species such as the Garden Bumblebee (Bombus hortorum) have specialised to forage on flowers with deep corollas (the collective unit of petals) such as Foxgloves and Monkshood that hide their nectar deep inside the flower.
Bumblebees can buzz pollinate, which means they can vibrate their bodies to dislodge pollen from a flower. The bee then combs the nutritious pollen grains from her hairy body into little baskets on her hind legs, called pollen baskets or ‘corbiculae’ to take back to the nest to feed young larvae, but some grains are missed and transfer to the next flowers she visits.
Tomatoes, blueberries and aubergines are just some examples of the many plant species that rely on buzz pollination!
Beetles have been pollinating plants for millions of years, even since before the time of the dinosaurs! Not all beetles are pollinators though, only those that feed on pollen and nectar and are able to pick up sticky pollen grains on their bodies. Approximately 250 species in the UK act as pollinators. These include the flower beetles, pollen beetles and longhorn beetles.
Beetles prefer flat, open structured flowers, which allow them to graze, and flowers in clusters such as cow parsley, ox-eye daisy and bramble. They are attracted to white and cream plants which are heavily scented. Although beetles do have colour vision, they also rely on their sense of smell to find flowers from distance.
Often when people think of bees, usually the honeybee comes to mind but in the UK, we have only one species of honeybee and a whopping 247 species of solitary bee! As the name suggests they create individual burrows or nests, although they can be found grouped together in aggregations.
These bees are highly effective pollinators and the vast majority of pollination is carried out by generalist solitary bees. Most bees collect pollen using specialised hairs on their legs and unlike bumblebees they cannot form pollen baskets so to make the grains stick better they may moisten the pollen with nectar. Other species such as leafcutter and mason bees collect pollen underneath their abdomen, whereas others cannot carry pollen at all so they swallow the pollen and regurgitate on their return to the nest.
Their nesting habitats are fantastically diverse, some species nest above ground and use a variety of substrates such as mud, resin or chewed leaves to seal their nests. These are the ones you are most likely to find using your bee hotel with the most common species being the Red Mason Bee (Osmia bicornis) and the Patchwork Leaf-cutter Bee (Megachile centuncularis)
The majority of British species nest in the ground and the females are highly specialised at excavating their own nests. There is even a group of solitary bees that nest in empty snail shells!
Solitary bees are not aggressive, the males lack a stinger and the females are highly unlikely to sting you if they are left alone.
While butterflies pollinate during the day, moths take over the nightshift, visiting pale flowers that stand out in the dark. A lot of these plants are also heavily scented, such as Honeysuckle, Evening primrose and Jasmine.
There are over 2500 species of moth (compared to just 59 species of butterfly) and 1500 of these act as pollinators.
Moths have very long tongues, or proboscis which they use to reach into the flower for nectar, and whilst doing so pollen can get stuck onto its furry body.
Moths are often dismissed as brown and dull, but many species are bright and colourful including the Elephant hawkmoth (Deilephila elpenor) and day-flying species such as the Cinnabar (Tyria jacobaeae) and burnet moths (Zygaena Sp.), not to mention the Hummingbird Hawkmoth (Macroglossum stellatarum) a fascinating migrant from southern Europe.
What’s the point of wasps, one might ask? Wasps might not be as loveable as our bees but they are valuable pollinators. Of the 9000 species of wasp, more than 2500 are considered pollinators.
These include hunting wasps, social wasps, ruby-tailed wasps and ichneumon wasps. Numerous species feed on pollen and nectar as adults and so can be considered as pollinators. Wasps have high energy needs, and when they aren’t finding it in the sweet drinks and jam scones of your picnics they access nectar from flowers.
Many wasp species are specialist pollinators meaning they are highly selective in their floral choices and only frequent one or very few plant species. A classic and undisputed example of co-evolution is the relationship between fig trees and fig wasps. Tiny fig wasps, at just a few millimetres long are responsible for pollinating over 750 species of fig trees. Each species is typically associated with a single species of fig tree.
Flies get a bad rap but they are invaluable as pollinators! Research has shown that flies are the most important pollinators after bees visiting 72% of food crops. In the UK we have over 7000 species in approximately 100 families and at least 1500 of these are pollinators! You can find them in nearly all habitats and biomes, making them prolific pollinators!
Hoverflies and blowflies are the unsung heroes of the pollination world, giving bees a run for their money. The adults eat pollen to aid their development and drink nectar to fuel energetic activities like flying. Pollen gets trapped on the hairs on their bodies as they feed and larger flies can carry hundreds and sometimes thousands of pollen grains as they fly from flower to flower tolerating a wider range of temperatures.
Highly migratory, they can travel hundreds of kilometres a day transporting huge amounts of pollen in the process.
Fantastic examples include Marmalade Hoverflies (Episyrphus balteatus) and bumblebee mimics: Dark-edged Bee-fly (Bombylius major) and Volucella bombylans.
Pollinators under pressure
Research has shown severe population declines in many insect groups including solitary bees, bumblebees, butterflies, moths and hoverflies across the globe including the UK. The main threats to pollinators are considered to be:
- Habitat damage, loss and fragmentation;
- Agricultural intensification and use of pesticides;
- Spread of diseases;
- Spread of invasive non-native species;
- Climate change.
How you can help
Buglife’s B-Lines initiative aims to restore at least 150,000 hectares of flower rich-habitat across the UK.
Making this happen will take time and will need farmers, land owners, wildlife organisations, businesses, local authorities and the public to work together to create flower-rich grassland in the best locations.
. Along with conservation partners, land managers, businesses and local authorities, we are helping to fill the mapped areas with restored and new wildflower-rich areas.
There are a number of different ways you can contribute to conservation of our pollinators in the UK:
- Find out more about our latest B-Line projects in Wales, Scotland, Northern Ireland and England and how you can help to create B-Lines in your local area.
- Join in with national recording schemes for pollinators: BeeWalk, POMS – UK Pollinator Monitoring Scheme
- Submit records of specific pollinator groups to their relevant recording schemes: Hoverfly Recording Scheme, National Moth Recording Scheme, UK Butterfly Monitoring Scheme and, BWARS
- Deliver pollinator-friendly actions and obtain Bee Friendly status for your school, community, business, or town!