The Microbiome of Fruit Flies as Novel Targets for Pest Management

Invasive fruit flies are global threats to food security and economy because they are destroying crops and inflicting multibillion-dollar losses annually. In the United States, regions with subtropical climates such as Florida, Georgia, and California with yearlong availability of cultivated crop and noncrop hosts, offer ongoing opportunities for fruit fly invasion. Incidences of tephritid invasion have resulted in unprecedented losses and eradication efforts. Drosophila suzukii (Matsumura) is another serious pest that has swept across 42 states since it first invaded California in 2008, causing millions of dollars in losses because of reduced crop yield and expenses associated with control measures and sorting processes for both fresh and processed fruits. Despite decades of research and pest management efforts on invasive fruit flies, several critical gaps of knowledge on their basic biology remain, including: How are they able to colonize and develop in vastly different host plants? To what extent are their life history traits (longevity, reproductive output, and dispersal) shaped by utilizing different food sources? And how do adults navigate the environment and make foraging or oviposition decisions? These important questions can be tied together by focusing on the extended phenotype of the flies' microbiome in shaping the plant environment and feedback on pest fitness (such as larval development, starvation resistance, longevity, reproduction, and behavior such as mating, foraging, and oviposition). In this chapter, we review the latest developments in basic and applied microbiome research on invasive fruit flies, leading to a discussion of innovative microbial-based approaches that can be implemented into fruit fly management programs. Three different avenues will be discussed: suppression of fly performance by modifying the fly microbiome, development of microbial-based attractants and repellents, and optimization of sterile insect techniques using probiotics. The chapter uses the invasive D. suzukii as an example and outlines opportunities and obstacles for exploiting the microbiomes in D. suzukii management. © 2019 American Chemical Society.