The Importance of Bee Pollination

April 01, 2014

Bee pollination is more crucial to fruit quality than originally thought.

Bee pollination is more crucial to fruit quality than originally thought, according to a recent study from Göttingen University in Germany and published in Proceedings of the Royal Society. The study found that bee-pollinated fruits were heavier with better shape and more durable than fruits pollinated by wind or self-pollination.

“We were inspired by the idea that the benefits of pollination could be much larger than known so far. There were some results available about pollination increasing not just yield, but also crop quality. However, a comprehensive study that focused on several different yield and quality traits was missing. Also, a commercial value has seldom been calculated for pollination benefits on crop quality. We thought that showing that the benefits of crop pollination were higher than calculated before would impact future policy decisions and thus contribute to the conservation of pollination as an ecosystem service. This is also quite important in the light of a rising world population and simultaneously threatened food security,” says study author Dr. Björn K. Klatt.

Researchers looked at strawberries as a model system, setting up a field experiment with nine commercially important strawberry varieties and then accessing the influence of self, wind and bee pollination on crop quantity, quality, shelf life and market value. Bees made up 98.5% of the flower visitors, with wild bees being the most abundant (64.6%), followed by honeybees (33.9%) and non-bee pollinators like flies (1.6%).

They found that bee pollination resulted in fruits with the highest commercial value. In other words, the fruits were well formed and heavier (11% heavier than wind pollinated fruits and 30.3% heavier than self-pollinated fruits), and more often rated commercial grade for market. They also had improved firmness, which potentially relates to shelf life: calculations showed that after four days in storage, 40.4% of the bee-pollinated fruits remained in marketable condition, while only 29.4% of the wind-pollinated and none of the self-pollinated fruit were still marketable. Since more than 90% of fruits can become non-marketable after four days (a very short shelf life), this is a significant finding.

While bee pollination contributed to the sugar-acid ratio differently depending on the strawberry variety, in general the process lowered the ratio. Most varieties were made a more intense red color through the process of bee pollination as compared to fruits resulting from wind and self-pollination. In addition, bee pollination was much more efficient than the other methods, resulting in a higher number of fertilized achenes (seeds) per fruit across all varieties – bee pollination increased the average number of fertilized achenes about 26.8 % compared with wind pollination and about 61.7 % compared with self-pollination. A higher number of fertilized achenes due to bee pollination mediate processes that result in heavier, better-formed, firmer strawberries that have a better shelf life than strawberries with lower numbers of fertilized achenes from the other pollination treatments. Shelf life is a major factor for the commercial value of pollination, as between one-third and a half of all fruits and vegetables are lost due to handling, storage and transport post harvest.

With 30 to 50% of all crops tossed at retail and consumer levels and growing global food demand, improving crop quality should be a top priority for producers. Pollination appears to have a much greater economic impact on agriculture than we once thought, says Klatt. As the benefits of bee pollination also apply to other crops, like coffee and blueberry, Klatt believes that their findings may be transferable to a high variety of crops. Bee pollination appears to greatly contribute to crop quality and should be further researched to improve the products being brought to market.

“Pollination usually influences seed set and fruit set, which is often correlated to quality traits. Together with the few former findings about pollination benefits on crop quality, this makes an overall contribution to the quality of other crops most likely,” says Klatt.

Klatt also says that knowing that pollination increases crop quality gives farmers and policy makers the chance to react and hopefully contribute to the conservation of bees by lowering intensity and providing bee habitats adjacent to their fields. A higher output per hectare can lower the amount of agricultural area needed and thus leads to lower energy outputs in agricultural landscapes, including the reduction of pesticides and fertilizer. Increasing the shelf life of crops contributes to the income of several players within the food chain such as retailers and consumers – and it contributes to food security by lowering food loss and waste. Overall this could mean that less agricultural area is needed to support food security. Bees are no brainer too – several wild bees and honeybees are easy to establish.

“Next steps for the conservation of pollination services must be done in collaboration with farmers, policy makers, retailers and consumers. An important point would be to create more sustainable, but still highly productive agricultural management. However, several steps are needed and experts still find more and more topics that have to be considered. Agricultural intensification is still a main threat, but additional impacts that affect pollinators such as climate change and other anthropogenic threats are also of increasing importance,” says Klatt.

Currently, unmanaged pollinators, mostly wild bees and syrphid flies, still seem to be on the decline, says Klatt, while the amount of crops that depend on pollination is increasing. Honeybee hives are also still on decline due to an interaction of several factors such as varroa mites, pesticides, and several viruses and the aging of bee keepers. Recently, it has been found that parasitoids and viruses can be spread from honeybees to bumble bees, which is increasing the threat on future pollination services. 

“Consumers and thus also retailers show an increasing awareness about the quality of agricultural products – and this effects producers as well. Quality attributes, such as color and shape, lead to a better appearance and together with shelf life, this influences the purchasing behavior of consumers. Bees are still the main pollinators of crops in temperate areas,” says Klatt. “They are crucial.”