Persistence of a Wolbachia infection frequency cline in Drosophila melanogaster and the possible role of reproductive dormancy

Field populations of arthropods are often polymorphic for Wolbachia but the factors maintaining intermediate Wolbachia frequencies are generally not understood. In Drosophila melanogaster, Wolbachia frequencies are highly variable across the globe. We document the persistence of a Wolbachia infection frequency cline in D. melanogaster populations from eastern Australia across at least 20 years, with frequencies generally high in the tropics but lower in cool temperate regions. The results are interpreted using a model of frequency dynamics incorporating cytoplasmic incompatibility, imperfect maternal transmission and Wolbachia effects on fitness. Clinal variation is less pronounced in eastern North America which may reflect annual recolonization at higher latitudes. Limited samples from Africa from latitudes matching our tropical and subtropical samples from Australia and North America show comparably high infection frequencies, but some equatorial samples show lower frequencies. Adult ...

节肢动物的野外种群通常存在沃尔巴克氏体（Wolbachia）多态性，但维持中间频率沃尔巴克氏体感染的驱动因子目前仍未明确。在黑腹果蝇（Drosophila melanogaster）中，全球范围内的沃尔巴克氏体感染频率存在显著差异。本研究记录了澳大利亚东部黑腹果蝇种群中持续至少20年的沃尔巴克氏体感染频率渐变群格局：热带地区感染频率普遍较高，而凉爽温带区域则相对较低。本研究通过整合胞质不相容性、不完全母系传播以及沃尔巴克氏体对宿主适合度影响的频率动态模型，对上述结果进行了解释。北美东部的渐变群变异则相对不显著，这或许反映了高纬度地区存在年度再定殖现象。非洲采集的、纬度与本次研究中澳大利亚和北美热带、亚热带样本匹配的有限样本，其感染频率同样处于较高水平，但部分赤道样本的感染频率相对更低。成虫……