Syrphid communities (Diptera: Syrphidae) and their trophic relationships in horticultural crops of Central Argentina

Syrphids play diverse roles in agroecosystems, acting as pollinators and biological control agents. Despite their importance, syrphids and their trophic interactions have been rarely studied in horticultural systems in Argentina. In this work we examined syrphid communities, spatiotemporal distribution of its species and trophic interactions among syrphids–aphids–horticultural crops and syrphids–floral resources in wild plants along field margins. Thirteen horticultural fields near the City of Córdoba were sampled during the 2015–2016, 2018–2019, and 2019–2020 spring and summer seasons. Six syrphid species were collected in crops, three of them were associated with four aphid species on several cultivated plants. Eleven syrphid species were found in field margins that visited 12 flowering wild plants, with Asteraceae being the most visited family. Allograpta exotica (Wiedemann) was the most abundant and frequent species, dominating spatiotemporal distributions and interactions in crops and field margins. It became evident that the abundance of syrphid reared from polyphagous aphids in a given host crop was not proportional to its frequency of occurrence in the field. Understanding syrphid interactions with key resources (aphids and flowers) is crucial for developing pest management strategies that are compatible and sustainable with the environment.