Ground-cover vegetation composition shapes the abundance of Sphaerophoria scripta (Diptera: Syrphidae) in Mediterranean olive groves.

The ground-cover vegetation, commonly found in olive groves, provides shelter and vital floral resources for syrphids. Such resources can contribute to syrphids' growth, development, reproduction, and survival, allowing them to maximize their function as natural pest enemies, pollinators, and decomposers of organic matter. Therefore, identifying the flowering plant families driving the abundance of Sphaerophoria scripta Linnaeus, 1758, is essential to promote its presence and abundance. Here, we described the flowering plants present in the vegetation cover of olive groves and studied how these flowering plant families shape the abundance of S. scripta. A total of 90 plant species belonging to 20 families were identified. Asteraceae was the dominant flowering family, followed by Poaceae. The generalized linear model showed that the presence of flowering plants of the families Campanulaceae, Asteraceae, Orobanchaceae, and Plantaginaceae in the ground-cover vegetation promotes the abundance of S. scripta in olive groves. Conversely, flowering plants of the families Poaceae and Polygonaceae were associated with the decreased abundance of this syrphid species. Our results suggest that increasing particular plant families and decreasing others in the ground-cover vegetation may favor S. scripta abundance in the Mediterranean olive groves.