The Role of Diptera as Primary Pollinators in Tropical Shallot Agroecosystems

Dipteran pollinators remain undervalued in tropical agroecosystems despite managed bee declines and climate change. This review establishes Diptera as primary pollinators in tropical shallot ( Allium cepa var. aggregatum Group) True Shallot Seed production. Global surveys document 405 crop‐pollinating Diptera species across 254 genera, dominated by Calliphoridae, Syrphidae, and Muscidae. While temperate regions report dipteran visitors in supplementary roles (40%–65%), tropical systems show functional transformation: Indonesian highland observations reveal that Diptera dominate both community composition (58.5%) and visitation‐based service contribution (77.3%; Endarto et al., 2026). Critically, relative humidity, not temperature, drives dipteran activity in tropical highlands, with higher abundance during elevated moisture despite substantial temperature variation. This humidity‐dominant pattern contrasts with temperature‐driven temperate systems, positioning precipitation changes as greater threats than warming. Shallot organosulfur volatiles (dipropyl disulfide/trisulfide) selectively recruit saprophagous flies through carrion‐mimicry. Three complementarity mechanisms explain effectiveness: (1) temporal partitioning with morning activity synchronization, (2) foraging behavior maximizing outcrossing, and (3) functional redundancy through diverse resource dependencies. Climate projections (2°C–4°C warming, increased precipitation variability by 2100) will intensify bee stress while reducing flowering‐period humidity, thereby increasing dipteran importance. Management strategies include field margins, pesticide timing, irrigation, and augmentative releases. These establish Diptera‐focused approaches as climate‐adaptive alternatives to bee‐centric systems.