A simple and cost-effective molecular method to track predation on Drosophila suzukii in the field

Abstract

The vinegar fly Drosophila suzukii (Matsumura) is an invasive species that attacks ripening fruits and berries, leading to considerable losses in fruit production. So far, management mainly relies on chemical and cultural control, but additional measures such as biological control are needed. Hence, for the development of sustainable control measures of this pest it is important to identify potential natural enemies such as generalist predators that feed on D. suzukii. Here, we established a simple and cost-effective assay to specifically detect D. suzukii DNA in the guts of arthropod predators. Furthermore, we developed a general Drosophila spp. primer pair to identify predators of Drosophila species in general that might also feed on D. suzukii and to compare predation rates on D. suzukii to those of other Drosophila species. We applied the assays to field-collected predators and identified three predator taxa—earwigs, spiders and predatory bugs—that had fed on D. suzukii. The assays provide a first step towards unravelling the predator community attacking D. suzukii that should be considered as biological control agents but also as non-targets potentially affected by other measures to control this invasive pest.