Apple Pollination: Demand Depends on Variety and Supply Depends on Pollinator Identity

Insect pollination underpins apple production but the extent to which different pollinator
guilds supply this service, particularly across different apple varieties, is unknown. Such
information is essential if appropriate orchard management practices are to be targeted and
proportional to the potential benefits pollinator species may provide. Here we use a novel
combination of pollinator effectiveness assays (floral visit effectiveness), orchard field surveys
(flower visitation rate) and pollinator dependence manipulations (pollinator exclusion
experiments) to quantify the supply of pollination services provided by four different pollinator
guilds to the production of four commercial varieties of apple. We show that not all pollinators
are equally effective at pollinating apples, with hoverflies being less effective than
solitary bees and bumblebees, and the relative abundance of different pollinator guilds visiting
apple flowers of different varieties varies significantly. Based on this, the taxa specific
economic benefits to UK apple production have been established. The contribution of insect
pollinators to the economic output in all varieties was estimated to be £92.1M across the
UK, with contributions varying widely across taxa: solitary bees (£51.4M), honeybees
(£21.4M), bumblebees (£18.6M) and hoverflies (£0.7M). This research highlights the differences
in the economic benefits of four insect pollinator guilds to four major apple varieties in
the UK. This information is essential to underpin appropriate investment in pollination services
management and provides a model that can be used in other entomolophilous crops
to improve our understanding of crop pollination ecology.