Microbiome composition and co-occurrence dynamics in wild <i>Drosophila suzukii</i> are influenced by host crop, fly sex, and sampling location

Microbial control of insect pests offers promising alternatives to traditional pesticides. However, the microbial communities and factors influencing these communities within insect hosts remain poorly understood. This study examined the whole-body bacterial communities in wild <i>Drosophila suzukii</i>, commonly known as spotted wing Drosophila (SWD). Fly samples were collected from two farms growing wild Himalayan blackberries near blueberry crops, one blackberry farm, and one elderberry farm across four locations in the United States. Our analyses showed significant differences in microbial communities in flies across various host crops and sampling locations. We identified co-occurring bacterial genera, dominated by <i>Gluconobacter</i> and <i>Morganella</i>, and the overall microbiome was distinct from those found in laboratory-grown flies. Our findings suggest that the host crop, sex of the fly, sampling location, and their interactions play a crucial role in shaping microbial communities in SWD, indicating the influence of various ecological interactions. While no significant differences in microbiome composition were observed between male and female flies, network analysis revealed distinct sex-specific microbial co-occurrence patterns. Female flies displayed a more stable and interconnected microbial network than male flies, suggesting that sex-specific factors might influence bacterial interactions. Interestingly, the most abundant microbial taxa were not necessarily the most connected in the networks, showing that less abundant taxa may also play a significant role in shaping the fly microbiome. This study underscores the complexity of microbial ecology in SWD and highlights the necessity of considering these dynamics when developing pest management strategies in agriculture.IMPORTANCEStudies on the microbiome of spotted wing Drosophila (SWD) have primarily focused on laboratory-reared flies in controlled environments and fed artificial diets. In contrast, we examined microbial communities in wild flies from various host crops across four locations in the United States. Our findings show that these communities are distinct from those of laboratory-grown flies and are influenced by the fly's sex, host crop, geographical location, and their interactions. Our study identifies several dominant bacterial genera across samples, suggesting that these may represent the core microbial communities in wild SWD. Given that microbial communities influence physiological activities in SWD, manipulating the microbiome may have either a positive or negative impact on insect fitness. This study enhances our understanding of microbial dynamics in understudied wild SWD populations, emphasizing the importance of these dynamics in effective integrated pest management strategies.