ATTRACTIVITY OF FLORAL VOLATILE–BAITED TRAPS TO HOVERFLIES (DIPTERA: SYRPHIDAE) IN AGROECOSYSTEMS

Abstract

Hoverflies (Diptera: Syrphidae) provide essential ecosystem services in agroecosystems through adult pollination and larval biological control of aphids, yet their capture as bycatch in pest-monitoring traps using floral volatile lures remains poorly understood. This study evaluated the attractivity of semiochemical-baited VARL+ funnel traps to hoverflies across three field experiments in Romanian and Hungarian agroecosystems (maize, poppy, 2022–2024), testing floral blends (e.g., phenylacetaldehyde-based AGBIS, FLO, SSS), pheromones, fermenting odors, and unbaited controls.

A total of 10,281 hoverflies were captured, with floral volatiles significantly outperforming controls in two experiments (p<0.05). In Experiment 1 (maize-forest edge, 2023), AGBIS and combined treatments yielded highest catches; Experiment 2 (poppy, 2024) showed strong responses to FLO/SSS blends. However, results varied by year, site, and lure composition—pheromones consistently underperformed, and Experiment 3 (drought-stressed maize, 2022) showed no lure superiority.

Floral lures increased hoverfly abundance and likely species richness, with assemblage shifts indicating active behavioral attraction rather than passive interception. These findings demonstrate that pest-monitoring infrastructure can be repurposed as a cost-effective tool for agrobiodiversity assessment, converting "waste bycatch data" into actionable ecological insights. Recommendations include routine hoverfly identification in monitoring networks and lure optimization to minimize non-target impacts while enhancing IPM and pollinator surveillance