Chilean sonicating bees can achieve high efficiency in pollinating highbush blueberry crops

Hives of the honeybee (Apis mellifera) and bumblebee colonies (Bombus terrestris) are widely managed for blueberry pollination in Chile and worldwide. While B. terrestris contributes to high blueberry yields due, partially, to their ability to sonicate flowers, its introduction generates serious problems for native pollinators. Honeybees, on the other hand, rarely use blueberry flowers as a source of pollen due to their inability to sonicate and tend to present a lower per-visit pollen deposition rate than some other species. Although many groups of Chilean native bees belong to taxa recognized as able to sonicate, no studies evidence the performance of native Chilean fauna to pollinate blueberries. Therefore, we aimed to compare the effect of visits with and without sonication and visitor identity to pollinate highbush blueberry cultivars in Chile. Per-visit pollination performance (stigmatic pollen deposition) and visit frequency were measured and the presence of sonication behavior of flower visitors was evaluated for five cultivars in two blueberry orchards located in southern Chile. Visits with sonication deposited on average 238.4 (+/- 175.4) pollen tetrads on the stigma surface, about three times more than visits without this behavior. Some native sonicating bees were better pollinators than A. mellifera and similar to the managed bee B. terrestris. One single visit of Cadeguala occidentalis, a native bee, deposited 4.8 times more pollen than a visit of A. mellifera. Instead of continuing to rent or pay for managed beehives, consideration should be given to the service provided by native pollinators.