Improved pollination and climate adaptation in fruit production

For fruit growers, it is increasingly important to stimulate a wide diversity of pollinators. Climate change is causing fruit-bearing vegetation to flower earlier and earlier, which also increases the risk of this vegetarion being affected by cold spells during flowering periods. In various projects, the Louis Bolk institute, together with its partners, is studying the effects of introducing various bee species on the quantity and quality of fruit, as well as what would be the best bee management practises and how native wild bees could be stimulated. 

Bee species respond differently to certain weather conditions 

Research shows that honey bees fly and, therefore, also pollinate well if the weather is fine. However, they may be absent in cold or inclement weather. Certain wild bees, however, like bumblebees and mason bees, will continue to fly under such conditions. This is why some fruit growers specifically focus on managing mason bees, while others choose to increase the numbers of wild mining bees, who also fly at the time the fruit-bearing vegetation is flowering.  

1. Introducing mason bees into orchards 

In recent years, growers have gained experience in managing mason bees — predominantly for soft fruit, but also for hard fruits. Mason bees are particularly interesting with regard to fruits that flower early or are rather difficult to pollinate. However, there are many gaps in the knowledge on, for example, the different levels of efficiency of the various bee species, such as between the red mason bee and the European orchard bee. It is important to determine if the resulting increase in yield outweighs the investment, particularly, in the way of labour.  

2. Bed & breakfast

The timing of releasing the bees and preventing them from flying away in search of better feeding grounds are subjects that receive attention in the B&B project. To prevent them from leaving the orchard, the Louis Bolk Institute conducts experiments with offering the bees ‘a breakfast’ — an additional supply of early spring flowering plants on the orchard. This is essential for male bees that fly before the orchard is in bloom. Growers are also advised about offering the right type of ‘bed’ (i.e. overwintering facilities), as well as about what would be the best time for releasing the bees in the spring. 

3. Creating bee banks

For some fruit growers, adapting the environment so as to increase the wild bee population is a more attractive option. Some mining bee species, in particular, fly early enough in the season to be interesting for pollinating pear and cherry trees. By offering nesting sites, such as bee banks around the orchard, we are studying whether this indeed increases the pollinating mining bee population. 

For this project, we made a leaflet on how to build bee hotels (Handout Aanleg Bijenbanken) that can be downloaded here.