橘小实蝇Bactrocera dorsalis (Hendel)是一种毁灭性果蔬害虫和世界性检疫性害虫，严重影响我国果蔬生产安全和国内外贸易市场。橘小实蝇肠道内栖息着对橘小实蝇具有重要生理功能、以肠杆菌为优势菌的稳定微生物群落，但肠道微生物群落稳态调控机制尚不清楚。本研究将利用转录组学测序、RNAi技术等分子生物学手段鉴定橘小实蝇免疫缺陷（IMD）信号通路主要负调控基因，并阐述IMD通路主要负调控基因在橘小实蝇肠道微生物群落稳态维持及调控中的作用，以及维持肠道微生物稳态平衡对于宿主正常生理生态的重要性。以期为阐明昆虫肠道微生物群落稳态调控机理提供科学基础，并为靶向害虫肠道菌群的橘小实蝇防治新思路、新途径提供科学依据和作用靶标。

Bactrocera dorsalis (Hendel) is a devastating pest of fruits and vegetables, also a quarantine pest worldwide, influences seriously production safety, the domestic and international trade market of fruit and vegetable. B. dorsalis harbors a stable microbial community with dominant composition of Enterobacteriaceae, which plays an important physiological function in the host. But the regulating mechanism of intestinal microbiota homeostasis is still unknown. In this study, we will employ transcriptome sequencing, RNAi etc. molecular methods to identify the negative regulative genes of immune deficiency (IMD) signalling pathway, and illustrate the role of the negative regulative genes in regulating intestinal microbiota homeostasis of B. dorsalis, and the importance of maintaining the intestinal microbiota homeostasis to the normal physiology and ecology of host. The study will provide a basis of clarifying the mechanism of regulation of the intestinal microbiota homeostasis in insects, and provide scientific basis and targets of new ideas and ways to prevent and control of insect pests targeting on intestinal microbiota.