Of bees and men
According to a sentence rightly or wrongly attributed to Albert Einstein, « if the bee disappeared from the face of the earth, man would only have four more years to live ». Although no reliable source has ever confirmed that the quotation was from the major German physicist, it can still make you tremble.
And rightly so, the latest Intergovernmental Panel on Biodiversity and Ecosystem Services (IPBES) report has just issued a warning following in the steps of so many researchers: the world population of bees keeps declining. Which role do bees play in the ecosystem? How would the disappearance of these insects affect our society?
A fundamental actor in ecosystems
An ecosystem is an ecological unit in a natural environment made up of the whole set of its living and non-living constituents which are engaged in a multiplicity of interactions. Forests, peatland, soils, agrosystems are examples of ecosystems. Pollination is one of the processes which make these interactions possible. It is the transfer of pollen between the male and female gamets of flower plants of the same species, which enables fertilization and reproduction.
There is a number of pollination vectors among which the main ones are auto pollination, wind, water and, of course, insects. The most important groups of pollinators are syrphid flies, wild bees and managed bees. The beneficial relationships between bees and plants are of cooperative nature, since these insects ensure plant reproduction by carrying pollen from flower to flower. In turn, plants feed them with nectar and pollen.
Around 90 % of wild flower plants and 70 % of the 124 crops grown worldwide to provide food for humans directly depend on pollinators. Bees account for 80 % of insect pollination, among which 80% are managed bees. The latter is indeed the most common species used worldwide for crop pollination. Its organisation in colonies, made up of thousands of insects, provides a « labour force » which is a major asset for pollinating densely-flowered areas (canola, fruit crops…).
However, recent studies have shown that wild bees are far more efficient in terms of pollination than honey bees. This observation is valid for to both wild plants and crops. Besides, their activity is likely to complement and improve honey bees’ pollinating activity. Numerous studies clearly highlight wild pollinators’ added value on yields and on fruit and vegetable quality, even though where a great number of honey bees are also in operation.
A necessary contribution to human well-being
Whether managed or wild, bees are definitely part of ecosystems. All the productions resulting from the interactions between bees and their environment are called « ecosystemic services », i.e., services provided by nature to the benefit of human well-being.
The best-known service is the one that enables the production of honey, pollen, wax, royal jelly or propolis. Benefits are nutrients provided by honey consumption, but also permanent contribution to beekeeper livelihoods. In France, honey sales yield a yearly 200 million euros (this figure only concerns sales in small, medium-sized and large retailers). These products are the result of a transformation process performed in the beehive, i.e. it concerns only managed bees. But it would be oversimplified to limit bees’ contribution to this service alone. The pollination of crops performed by all types of pollinators actually produces food and other raw material. For the sake of comparison, the pollinators’ contribution to agricultural production amounts to 1,5 billion euros in France and to 153 billion at the international level, that is about 10 % of the world agricultural GIP.
The distribution of pollinator-dependent crops is not the same across the world. All countries are pollinator-dependent but some more than others. Some regions are heavily dependent (North America, Europe, North Africa), as opposed to some which are less so (Central America, South Africa, Oceania), thanks to more diversified farming or based on crops that are non-dependent.
Not all crops are pollinator-dependent. Most cereals, sugar and tuber crops do not need bees. Entomophilous crops are mostly fruit (for instance, strawberries), vegetables (zucchini), nuts (almonds), spices (nutmeg) and stimulant crops (coffee, cocoa). Hence, humans would not die of hunger if bees were to disappear, but consequences would still be significant: 40% of our nutrients come from pollinator-dependent crops, among which 90 % vitamin C.
Consequently, bees heavily contribute to our diet, but also to the economic balance of agriculture. Added to that, they play an active role in the production and reproduction of the wild fauna and flora of our urban and rural landscapes. Bees actually provide a nonmarket service – the preservation of ecosystems – which, in turn, offer other services (for instance, the amenity of a flowered field).
The consequences of bee decline
And yet, these extremely precious insects are declining. Experts agree that agricultural intensification, destruction of natural habitats, chemicals (insecticides, herbicides…), diseases, invasive alien species such as the Asian hornet and climate change account for the decline. All these factors are partly due to farming policies which have boosted productivity against quality.
The example of a strawberry farmer suffering from some pollination deficit will help understand the actual consequences of the disappearance of bees. It will impact his yields, hence increase the marginal costs of his farm. His profit will decrease. And what if the pollination deficit affects not only one farmer, but a whole area (even France)? The French strawberry offer will decrease, which will result in an increase of the French strawberry market price. Consequently, consumers will have to pay more for their local product, but also for imported strawberries.
Finally, if the deficit spreads worldwide, the strawberry world offer will decrease and prices will skyrocket. Economic consequences are quantified in consumer surplus losses, which estimates the difference between the maximum price consumers will agree to pay and the price they actually pay. Some analysts have calculated that these losses could reach over 260 billion euros if one takes into account the impact of a total decline of all pollinators on the overall production of all crops (Gallai et al. 2009). In addition, the human diet balance will be disturbed due to the loss of some nutrients provided by pollinator-dependent crops.
Last of all, the impact would not be limited to markets. There would be a huge loss in biodiversity. Some consequences might even not be noticeable as pollination closely interacts with other processes within ecosystems. Some others would be more obvious on landscaping and more particularly related to the importance of the aesthetics of landscapes. Among the few current studies, some British researchers have calculated that willingness to pay for protecting these landscapes amounted to 420 million euros.
Safeguard bees…, but how?
Because bees are so vital, we must safeguard them for our own sake. Very concrete proposals based on the IPBES report have been put forward by experts (see box). In concrete terms, a number of efforts have been made in France with, among others, the launching of the national action “France, a land for pollinators”, or in Europe where three toxic neonicotinoids have been banned since April 2018. These actions entail changes in practices which very much depend on how actors consider the role of bees. Their approach depends on the information they have which is often incomplete. The real part played by bees in the production of various crops remains poorly recognized just as the contribution of wild bees (more efficient but more vulnerable) is very little known.
Research in economy, agronomy, ecology, biology… must make up for this lack of information and provide answers by supplying new value measures (monetary or not) that will enable the public to be properly informed and thus change their approach.
Crédits images en CC : Pixabay OpenClipart-Vectors, juliemac814, Clker-Free-Vector-Images