Windborne migration amplifies insect-mediated pollination services

Worldwide, hoverflies (Syrphidae: Diptera) provide crucial ecosystem services (ES) such as pollination and biological pest control. Although many hoverfly species exhibit migratory behavior, the spatiotemporal facets of these movement dynamics and their ES implications are poorly understood. In this study, we use long-term (16 yr) trapping records, trajectory analysis and intrinsic (i.e., isotope, genetic, pollen) markers to describe migration patterns of the hoverflyEpisyrphus balteatusin China. Our work reveals long-range, windborne migration with spring migrants originating in northern China and exhibiting return migration during autumn. Given the substantial night-time dispersal ofE. balteatus, this species possibly adopts a ‘dual’ migration strategy. The extensive genetic mixing and high genetic diversity ofE. balteatuspopulations underscore its adaptive capacity to environmental disturbances e.g., climate change. Pollen markers and molecular gut-analysis further illuminate howE. balteatusvisits min. 1,012 flowering plant species (39 orders) over space and time. By thus delineatingE. balteatustrans-regional movements and pollination networks, we advance our understanding of its migration ecology and facilitate the design of targeted strategies to conserve and enhance its ecosystem services.