Novel Aspects of Drosophila suzukii (Diptera: Drosophilidae) Biology and an Improved Method for Culturing this Invasive Species with a Modified D. melanogaster Diet

Abstract Drosophila suzukii (Matsumara) (Diptera: Drosophilidae), the spotted wing drosophila, is a global pest of soft fruits now rearable on a standard D. melanogaster (Meigen) diet containing the fly's own natural food: soft-skinned berries. The techniques tested here can save 40% of cultures from microbial contamination that develops after combining artificial food sources (e.g., standard drosophila media) with unsterilized host plant material (berries). A suitable ratio for mixing dietary ingredients for a vial or test-tube rearing system includes, by weight, 1 part berry tissue for oviposition, 1.5 parts dry diet media for carbohydrate, 7 parts clean water for moisture, and ∼5 grains (0.8 mg) of dry yeast for protein. One or two blackberry or blueberry fruits used by spotted wing drosophila as edible oviposition substrates doubled and tripled pupal and adult production in standard 68 mL culturing vials. To prevent mold from spoiling the diet, the exocarp of berries was sterilized in an 80 or 90% eth...