Widespread pollination deficits in pear (Pyrus communis L.) orchards: The role of pollinators, landscape context and pesticide risk

European pear ( Pyrus communis L.) is an important entomophilous crop, and most varieties are self-incompatible, therefore strongly dependent on insect pollinators for fruit set. However, harsh conditions during bloom and low sugar content of nectar compared to other co-flowering fruit trees often lead to low pollinator visitation rates, causing shortfalls in production. Pollination deficits and the contribution of pollinator communities to pollination services have been well studied in apples, but we know much less about pollination services in pears. The aim of this study was to assess pollination services and detect pollination deficits in pear orchards, and to analyze the effects of local factors (pesticide load and other orchard management) and landscape factors (“pollinator-friendly” cover) on pollinators and pollination services. Despite the effect of orchard management on fruit retention, our results confirm the dependence of fruit set on pollination (mean: 37 %; range: 0 %-80 %). Our results also report significant pollination deficits across pear orchards (mean: 31 %, range: 0 %-74 %), and low pollination service (mean: 17 %, range: 0 %-60 %). The most abundant flower visitors were honeybees and Diptera Muscidae, while wild bees were the least abundant group. However, “pollinator-friendly” cover at 1.5 km had significant positive effect on wild bees’ visitation rate. Managed (honeybees and bumblebees) and wild pollinators (all other pollinators) had no effect on pollination deficit, but higher bumblebee visits negatively affected seed set. Chemical analysis of pear flowers revealed high levels of pesticides residue, as all flowers were contaminated with at least four different pesticides, and pesticide risk had a negative effect on fruit set. Our results indicate insufficient pollination services in pear orchards and raise concerns about the management of pollination provision, highlighting the importance of semi-natural areas to boost wild bee visits and reduce pesticide pressure on pollinators. • Pyrus communis is dependent on insect pollinators for fruit set. • Low pollination service and high pollination deficits across orchards. • Pollinator-friendly landscape enhanced wild bees visits to pear flowers. • High pesticide contamination in all orchards.