BACKGROUND Mass-rearing, domestication and gamma irradiation of tephritid fruit flies used in sterile insect technique (SIT) programmes can negatively impact fly quality and performance. Symbiotic bacteria supplied as probiotics to mass-reared fruit flies may help to overcome some of these issues. However, the effects of tephritid ontogeny, sex, diet and irradiation on their microbiota are not well known. RESULTS We have used next-generation sequencing to characterise the bacterial community composition and structure within Queensland fruit fly, Bactrocera tryoni (Froggatt), by generating 16S rRNA gene amplicon libraries derived from the guts of 58 individual teneral and mature, female and male, sterile and fertile adult flies reared on artificial larval diets in a laboratory or mass-rearing environment, and fed either a full adult diet (i.e. sugar and yeast hydrolysate) or a sugar only adult diet. Overall, the amplicon sequence read volume in tenerals was low and smaller than in mature adult flies. Operational taxonomic units (OTUs), belonging to the families Enterobacteriaceae (8 OTUs) and Acetobacteraceae (1 OTU) were most prevalent. Enterobacteriaceae dominated laboratory-reared tenerals from a colony fed a carrot-based larval diet, while Acetobacteraceae dominated mass-reared tenerals from a production facility colony fed a lucerne chaff based larval diet. As adult flies matured, Enterobacteriaceae became dominant irrespective of larval origin. The inclusion of yeast in the adult diet strengthened this shift away from Acetobacteraceae towards Enterobacteriaceae. Interestingly, irradiation increased 16S rRNA gene sequence read volume. CONCLUSIONS Our findings suggest that bacterial populations in fruit flies experience significant bottlenecks during metamorphosis. Gut bacteria in teneral flies were less abundant and less diverse, and impacted by colony origin. In contrast, mature adult flies had selectively increased abundances for some gut bacteria, or acquired these bacteria from the adult diet and environment. Furthermore, irradiation augmented bacterial abundance in mature flies. This implies that either some gut bacteria were compensating for damage caused by irradiation or irradiated flies had lost their ability to regulate bacterial load. Our findings suggest that the adult stage prior to sexual maturity may be ideal to target for probiotic manipulation of fly microbiota to increase fly performance in SIT programmes.

中文翻译：

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饮食和辐照对驯化的普通和成熟昆士兰果蝇小实蝇（Bactrocera tryoni（Diptera：Tephritidae））肠道中细菌群落组成和结构的影响。

背景技术在无菌昆虫技术（SIT）程序中使用的替比利特果蝇的大量繁殖，驯化和伽马射线辐射会对果蝇的质量和性能产生负面影响。作为益生菌提供给大量繁殖的果蝇的共生细菌可能有助于克服其中的一些问题。然而，尚不清楚特霉的个体发育，性别，饮食和辐射对其微生物群的影响。结果我们已经使用了下一代测序技术，通过产生源自58个个体，男性和男性，不育男性的胆量的16S rRNA基因扩增子文库，来表征昆士兰果蝇Bactrocera tryoni（Froggatt）内的细菌群落组成和结构。以及在实验室或大量饲养环境中以人工幼虫饮食饲养的可育成年苍蝇，并以完全成年饮食喂养（即 糖和酵母水解物）或仅含糖的成人饮食。总体而言，与成熟的成年果蝇相比，在矿物中的扩增子序列读取量低且较小。属于肠杆菌科（8 OTU）和醋杆菌科（1 OTU）家族的操作分类单位（OTU）最普遍。肠杆菌科以饲喂基于胡萝卜幼虫饮食的菌落为主，实验室饲养的ten葬物，而醋杆菌科则以饲喂以卢塞恩谷壳为基础的幼虫饮食的生产设施菌落为主的大规模饲养的eral葬物。随着成年果蝇的成熟，肠杆菌科成为占主导地位的幼虫。在成人饮食中加入酵母菌加强了从醋杆菌科向肠杆菌科的转变。有趣的是，辐照增加了16S rRNA基因序列的读取量。结论我们的研究结果表明，果蝇中的细菌种群在变态过程中会遇到严重的瓶颈。ten蝇中的肠道细菌数量较少，种类也不多，受到菌落起源的影响。相比之下，成熟的成年蝇对某些肠道细菌有选择性地增加了丰度，或者从成年饮食和环境中获得了这些细菌。此外，辐照增加了成熟果蝇中的细菌丰度。这意味着有些肠道细菌正在补偿因辐照造成的损害，或者辐照过的果蝇失去了调节细菌负荷的能力。我们的发现表明，性成熟之前的成年阶段可能是理想的靶点，以便对蝇微生物群进行益生菌操作，以提高SIT计划中的蝇性能。