The impact of pollination requirements, pollinators, landscape and management practices on pollination in sweet and sour cherry: A systematic review

Insect-mediated pollination is crucial for global production of multiple pollinator-dependent crops, including high-value crops like sweet and sour cherry. In the face of increasing agricultural demand and continued pollinator decline, it is essential to identify targeted management strategies to safeguard pollination services. Hence, we performed a systematic review on how cherry pollination is influenced by intrinsic and environmental requirements, flower-visiting insect communities, surrounding landscape and on-farm management practices. We found that most research was conducted in sweet cherry compared to sour cherry, and originated from North America and Europe, disregarding key global production areas. Cherry cultivars can be either self-compatible or self-incompatible, but insect pollination consistently benefits fruit set. Temperature has a strong effect on pollination success by mediating pollen germination, pollen tube growth and ovule longevity. Insect-mediated pollination is essential for adequate fruit set of both crops, whereas pollen limitation was detected for sweet, but not for sour cherry. A great diversity of insects visits cherry blossoms, with 185 species recorded, of which 142 were bees and 36 flies. With a mean relative abundance of 57 % across studies, honeybees were the dominant flower visitor. Little is known about the pollination performance of different taxa, with only one study comparing bees' single-visit efficiency, suggesting that mason bees and mining bees are more efficient pollinators compared to honeybees and bumblebees. This could explain why observational studies detect a positive relationship between wild pollinator visitation and cherry fruit set, which was not detected for honeybee visitation. Studies on managed pollinators focused on honeybees and mason bees, while bumblebee management was neglected. In sum, we conclude that pollination shortages can be improved by the promotion of wild pollinators, managed pollinators, or both, depending on the landscape context and pollination requirements of the cultivars. Wild bee visitation can be enhanced through conserving semi-natural habitats around orchards. Enhancing floral resources as an on-farm measurement has mixed results on pollinators, whereas other management practices such as polytunnels or pesticide effects on pollinators are understudied. Development of targeted guidelines for pollination management practices for farmers to enhance pollination services in cherry orchards should take into account multiple aspects, spanning from horticulture and agronomy (e.g., how to best manage flower strips) to applied entomology and landscape ecology (e.g., adding a landscape perspective to optimize honeybee management).