Amazing pollinators

Pollinator diversity 

• There are approximately 350 000 pollinator species globally.
• 1 in 10 species of terrestrial animals on the planet is a pollinator.
• The great majority of pollinators are insects, including moths, butterflies, bees, wasps and flies.
• Vertebrates comprise a much smaller proportion of pollinators, including birds, bats, lizards and rodents.
• There is even evidence of aquatic pollination of marine seagrass by invertebrate animals.

The importance of pollination

It is currently estimated that animal (and particularly insect) pollination is important to the sexual reproduction of 86% of flowering plants, and that 75% of all fruits and vegetables increase production when visited by animals. About one third of food production requires pollination by animals.

In addition, a majority of wild plant species are directly dependent on animal pollination in order to reproduce. Therefore, pollination ensures survival of plants – and the animals that depend on them – and indirectly supports water purification, flood prevention and soil stabilization. In economic terms, pollination is an ecosystem service valued at 235–577 billion US dollars worldwide each year¹. In Switzerland, the estimated value of pollination by wild bees alone is 271 million Swiss Francs per year².

A quick quiz

Pollinators help us get a varied nutrient-rich diet and not just the calorific value. This sumptuous breakfast is the work of pollinators (apart from cereals). How many different pollination products can you count?

Not just honeybees

Domesticated honeybees are not the only pollinators. Wild insects provide more efficient and higher quality  pollination (leading to higher yield) in a range of global crops. In fact, research in Switzerland shows that pollination and fruit set are highest when crops are visited by both honeybees and wild pollinators. Check out our portraits of pollinators here. 

Pollinator decline

The number of pollinators is declining at local, regional and global scales. Declines have been reported for bees, hoverflies, butterflies and moths, wasps and vertebrate pollinators. Species with specialized traits or narrow habitat requirements are especially affected.

Why are pollinator numbers declining?

Insect numbers are declining throughout the world. In Germany, flying insect total biomass has dropped by 76% in 27 years³. In Switzerland, there are no data available on the total amount of insects but from 1 153 insect species included in the Red List 60% are threatened or near threatened⁴. Two main reasons for this decline are climate change and agricultural intensification.

Climate change

Pollinators need flowers to feed themselves and their offspring, plants need pollinators to reproduce. For this exchange to take place, the two parties need to be synchronized i.e. to be around at the same time. Climate change threatens the long-established synchronization of seasonal pollinator activity and flowering time. Temperature, which can be affected by climate change, strongly affects the emergence of pollinating insects after hibernation. When it gets warmer earlier in the year, insects also emerge from hibernation earlier. By contrast, flowering relies heavily on the time of exposure to light, which is not subject to climate change. Thus, pollinators might find themselves critically short of nutrition early in the season due to this mismatch.

Agricultural intensification

Agricultural intensification includes larger, more homogenous fields, fewer crop rotations and cover crops, the removal of hedgerows, field margins and other non-crop areas, fewer flowering weeds and greater inputs of pesticide and fertilizer. These are all associated with a decline in floral resources. A comprehensive historical nectar assessment of the UK revealed that total nectar availability in England and Wales fell by 32% between the 1930s and the 1970s, coinciding with the main period of agricultural intensification and the most rapid phase of pollinator extinction recorded in Britain. 

Importance of floral resources

Floral resources can be described through their four main characteristics which are all important and need to be understood together in order to ensure their suitability for pollinators. These are: 

1. resource quantity - the total amount of resource available in a landscape
2. resource quality or suitability, for example their diversity, nutritional value and accessibility to pollinators
3. the spatial arrangement of floral resources, for example their density, how they are distributed between floral patches and habitats and how far pollinators must travel to access them
4. the phenology or timing of these resources - whether they are available at the right time of year to match demand from pollinators