Pollination
Many species of bees are attracted to shaded polycultures that have a variety of flowering plants in addition to coffee. This increase in bee abundance results in a direct increase in the pollination of shade trees as well the coffee plants themselves. A study in Indonesia showed that bee species diversity increases fruit set in coffee; coffee plants visited by 3 species of bees had 60% fruit set while those with 20 species or more had 90% fruit set.
Read more about this topic: Shade-grown Coffee, Ecological Impacts, Biotic Processes