Grant: Engage Grants Program

Spotted wing drosophila (SWD), Drosophila suzukii, is a recently introduced alien invasive species, which has become a fruit crop pest to North America. Unlike most other vinegar (i.e. 'fruit') flies which largely choose overripe, dropped and rotting fruit for egg-laying and as hosts for their larvae, female SWD oviposit eggs directly into ripening fruit. Subsequent feeding by the larvae softens the fruit, can introduce disease, and makes infested fruit unmarketable. Damage in a wide array of fruit crops (apples, peaches, plums, cherries, grapes, and most berry crops) can reach up to 80%, and result in millions of dollars in crop losses. It is currently established in 5 provinces in Canada, including Nova Scotia. The primary method for detecting these insects is via relativel ineffective 'beer bait' traps using yeast and sugar water mixture to find infestations, but to date, their reliability has been questionable. This study will initiate a collaboration between Acadia University and Nova Agri to investigate the mechanisms of host choice by SWD. Our key question: Why does this species prefer ripening fruit versus rotting fruit, typically preferred by many other fruit flies of the same family? We believe that there is a fundamental difference in sensory system of this species which creates this preference. By answering this question, we can identify potential odors which will augment detection and monitoring of SWD to enable improved control and management by Nova Agri. Comparisons will be made between Drosophila melanogaster (a 'laboratory' species which has been extensively studied, and has good genetic tools for future study), and SWD to determine where potential shifts in have occurred. We will use 'single sensillum recording' to document differences in sensitivity to both 'typical' fruit fly attractants, versus odors produced by fresh fruits to discriminate these differences. Key odorants will further be tested as augmentative lures in standard 'beer bait' traps to determine if these will synergize catch rates, and improve catch thresholds.