The Mediterranean fruit fly, Ceratitis capitata, is a cosmopolitan agricultural pest of worldwide economic importance and a model for the development of the Sterile Insect Technique (SIT) for fruit flies of the Tephritidae family (Diptera). SIT relies on the effective mating of laboratory-reared strains and natural populations, and therefore requires an efficient mass-rearing system that will allow for the production of high-quality males. Adaptation of wild flies to an artificial laboratory environment can be accompanied by negative effects on several life history traits through changes in their genetic diversity and symbiotic communities. Such changes may lead to reduced biological quality and mating competitiveness in respect to the wild populations. Profiling wild populations can help understand, and maybe reverse, deleterious effects accompanying laboratory domestication thus providing insects that can efficiently and effectively support SIT application. In the present study, we analyzed both the genetic structure and gut symbiotic communities of natural medfly populations of worldwide distribution, including Europe, Africa, Australia, and the Americas. The genetic structure of 408 individuals from 15 distinct populations was analyzed with a set of commonly used microsatellite markers. The symbiotic communities of a subset of 265 individuals from 11 populations were analyzed using the 16S rRNA gene-based amplicon sequencing of single individuals (adults). Genetic differentiation was detected among geographically distant populations while adults originated from neighboring areas were genetically closer. Alpha and beta diversity of bacterial communities pointed to an overall reduced symbiotic diversity and the influence of the geographic location on the bacterial profile. Our analysis revealed differences both in the genetic profile and the structure of gut symbiotic communities of medfly natural populations. The genetic analysis expanded our knowledge to populations not analyzed before and our results were in accordance with the existing scenarios regarding this species expansion and colonization pathways. At the same time, the bacterial communities from different natural medfly populations have been characterized, thus broadening our knowledge on the microbiota of the species across its range. Genetic and symbiotic differences between natural and laboratory populations must be considered when designing AW-IPM approaches with a SIT component, since they may impact mating compatibility and mating competitiveness of the laboratory-reared males. In parallel, enrichment from wild populations and/or symbiotic supplementation could increase rearing productivity, biological quality, and mating competitiveness of SIT-important laboratory strains.

中文翻译：

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遗传结构和地中海果蝇的全球自然种群的共生轮廓，地中海实蝇

地中海果蝇（Ceratitis capitata）是一种世界性的农业害虫，在世界范围内具有重要的经济意义，是开发用于蝇科（Diptera）果蝇的不育昆虫技术（SIT）的模型。SIT依赖于实验室饲养的菌株与自然种群的有效交配，因此需要一个有效的大规模饲养系统，以生产高质量的雄性。野生蝇适应人工实验室环境会伴随着其遗传多样性和共生群落的变化而对几种生活史特征产生负面影响。此类变化可能导致生物质量下降，以及与野生种群的交配竞争力。对野生种群进行概要分析可以帮助理解甚至逆转，伴随着实验室驯化的有害影响，因此提供了可以有效地支持SIT应用的昆虫。在本研究中，我们分析了分布在欧洲，非洲，澳大利亚和美洲等世界各地的天然梅蝇种群的遗传结构和肠道共生群落。用一组常用的微卫星标记分析了来自15个不同人群的408个个体的遗传结构。使用单人（成人）基于16S rRNA基因的扩增子测序，分析了来自11个种群的265个个体的共生群落。在地理上相距遥远的人群中检测到遗传分化，而来自邻近地区的成虫在遗传上更接近。细菌群落的α和β多样性指出共生物种总体减少，以及地理位置对细菌谱的影响。我们的分析揭示了地中海果蝇自然种群肠道共生群落的遗传特征和结构上的差异。遗传分析将我们的知识扩展到以前没有分析过的种群，我们的结果与有关该物种扩展和定殖途径的现有情景一致。同时，已经对来自不同自然梅蝇种群的细菌群落进行了表征，从而拓宽了我们对该物种微生物群的了解。设计带有SIT组件的AW-IPM方法时，必须考虑自然种群和实验室种群之间的遗传和共生差异，因为它们可能影响实验室饲养的雄性的交配相容性和交配竞争力。同时，从野生种群中富集和/或共生补充可以提高重要的SIT实验室菌株的饲养生产力，生物质量和交配竞争力。