Location: Southern Horticultural ResearchTitle: NOVEL ASPECTS OF SPOTTED WING DROSOPHILA BIOLOGY AND IMPROVED METHODS OF REARING
|KARLA, ADDESSO - Tennessee State University|
|OSCAR, LIBURD - University Of Florida|
|LINDSY, IGLESIAS - University Of Florida|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/15/2016
Publication Date: N/A
Interpretive Summary: The vinegar fly, the spotted wing Drosophila (SWD) isberry pest that can now be more efficiently reared on a standard fruit fly diet containing the fly’s own natural food: soft-skinned berries. Our proposed diet greatly reduces incidents of bacterial and fungal disease in the fly cultures. Recommended ingredients include (by weight) 1 part berry tissue, 1.5 parts dry diet media, 7 parts clean water, and ~5 grains of dry yeast. One or two blackberry or blueberry fruits serve as substrates onto which female fly can lay their eggs. Fruits doubled and tripled pupal and adult production within standard (68 mL) vials at rearing temperatures from 21 to 25 deg. C. Preventing fruit-borne molds from contaminating media requires berries be steriled in 80% or 90% ethanol for ~5 min followed by a thorough rinsing in clean water. Water rinses importantly prevent flies from becoming acutely poisoned. In addition to promoting SWD oviposition, fruit also prevents the buildup of fly-killing bacterial. FlyNap, a common fly anesthetic, proved toxic to SWD adults also. Alternatively, a 5-s blast of carbon dioxide gas or exposure to cold temperatures (4 – 5oC) for =30 minutes can more safely immobilize adult SWD.
Technical Abstract: Drosophila suzukii (Mats.) or the spotted wing Drosophila (SWD), is a global pest of soft fruits that can now be reared on a standard Drosophila diet containing the fly's own natural food: soft-skinned berries. The techniques tested here can thwart bacterial and fungal disease that can destroy more than 40% of cultures when artificial food sources (e.g., standard Drosophila media) are combined with unsterilized host plant material (berries). The optimal 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 as edible oviposition substrates doubled or tripled SWD pupal and adult production within standard 68 mL vials. To prevent mold from spoiling the diet, the exocarp of berries was sterilized in an 80% or 90% ethanol bath at room temperature for ~5 min, followed by a thorough rinsing with deionized water to remove any residual alcohol that could poison D. suzukii, a highly ethanol-intolerant species. Sterilized fruit disrupts the growth of biofilm-producing bacteria capable of suffocating flies. Identical body size in reared SWD adults and wild-caught D. suzukii substantiates nutritional similarity between the fruit/media-based diet and the fly's own natural food (i.e., whole berries). Maintaining cultures for 2 to 4 wks at 5oC yielded the darker, winter morph of D. suzukii.