Bacterial-driven odorant receptor expression shifts alter olfactory behavior in the oriental fruit fly

This work reveals a previously unknown mechanism by which gut microbiota modulate insect sensory ecology, demonstrating that Enterobacter sp. MU-1, a gut symbiont of the invasive pest Bactrocera dorsalis, reprograms host olfactory behavior through specific suppression of odorant receptor OR67c. Our integrated approach combining behavioral assays, transcriptomics, and functional validation establishes a novel paradigm of tripartite interplay between gut microbiota, chemoreceptor tuning, and behavioral adaptation. Key findings include: MU-1 colonization converts avoidance behavior to attraction in axenic flies (P < 0.01, Figure 1), while RNAi-mediated knockdown of OR67c reverses this behavioral shift (55% gene downregulation, P < 0.05, Figure 4). Temporal qPCR analysis confirms that MU-1 specifically suppresses OR67c expression (FPKM > 2-fold change in antibiotic-treated vs. recolonized flies, Figure 3), with no equivalent effects on other olfactory receptors. This microbiota-chemosensory axis represents a significant advance in understanding how symbiotic bacteria fine-tune insect behavioral plasticity—a phenomenon with critical implications for developing novel management strategies against this globally invasive species.