Dipteran abundance and family richness across different olive landscape contexts

Landscape complexity favours the abundance and richness of several groups of beneficial arthropods in olive groves while reducing the abundance of pest insects. In addition to beneficial or harmful dipterans, canopy-dwelling flies in olive groves play a role in the sustainability of the agroecosystem by providing alternative prey to important predators. The abundance and family richness of dipterans were studied in the olive-growing area of south-eastern Madrid, Spain, across 15 olive groves representing a gradient of landscape complexity. Dipterans were sampled during the early summer of two years using yellow sticky traps, and the landscape structure was characterised using composition and configuration indices, which were calculated with Fragstats in ArcGIS. Dipterans belonging to 32 families were recorded, with Chloropidae and Sciaridae being the most abundant. Some families with predatory or parasitoid behaviour were also recorded. No strong landscape effects were detected. The area of the olive groves had a slight negative effect on both the abundance and family richness of Diptera. However, a negative effect of Shannon’s evenness index was observed. Thus, Dipteran populations in olive canopies appear to be relatively stable across different landscape contexts. This presence of alternative prey contributes to biological control, thereby enhancing the resilience of the agroecosystem.