Yuvasri T
Global declines in pollinator populations have shifted research focus toward non-bee pollinators, especially hover flies (Diptera: Syrphidae), which provide dual ecosystem services as adult pollinators and larval biocontrol agents. Despite their ecological significance, hover fly diversity and associated plant interactions had remained undocumented in the coastal agricultural and horticultural landscapes of Karaikal, Union Territory of Puducherry, India. This study aimed to assess the species richness and the temporal dynamics of hover flies at the Pandit Jawaharlal Nehru College of Agriculture and Research Institute between October 2024 - June 2025. The investigation recorded a total of 10 hover fly species in the agricultural ecosystem and 9 in the horticultural ecosystem, with interactions involving 15 different flowering plant species. The results revealed higher species diversity (1.07), evenness (0.61) and dominance (0.77) within the horticultural ecosystem. Furthermore, plant-pollinator network analysis showed higher nestedness (29.36), connectance (0.29) and linkage diversity (3.73) in the horticultural ecosystem when compared to the agricultural ecosystem. The Principal Coordinates Analysis demonstrated that the hover fly assemblage in the agricultural ecosystem was influenced by crop phenology, whereas assemblages in the horticultural ecosystem were driven by floral resource pulses. Most of the hover flies showed a strong negative correlation with maximum and minimum temperatures, while showing a positive correlation with relative humidity and sunshine hours. These findings highlight the ecological importance of weed flowers in supporting the hover fly community. The study concludes that maintaining high floral diversity is essential for the conservation of hover fly populations and ensures the delivery of sustainable pollination services.