Are honey bees (Apis mellifera ssp. carnica) in South Tyrol (Italy) choosing their pollen resources in apple orchards (Malus domestica)?

Apple tree (Malus domestica) production in South Tyrol (Italy) is a very important economic sector with more than 3,500 beekeepers managing 38,000 honey bee colonies (Apis mellifera). Here, we elucidate to what extend apple orchards were used by honey bees in 2016–2020, especially outside the blooming period, performing palynological analyses of pollen pellets and combined with vegetation surveys. The results indicate that apple orchards were the major pollen source for honey bees during the apple blossom. However, before and after the apple blossom, apple orchards played a minor role for the pollen supply of honey bees, as a wide range of insect pollinated or anemophilous flowers, such as from broadleaved trees, were the main pollen sources, even when not offering nectar to honey bees. Strikingly, herbaceous plants were less attractive to honey bees, which actively selected for the availability of blooming plants throughout the blossom and foraging season.