Institute for Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom.
University of Coimbra, Marine and Environmental Sciences Centre, Department of Life Sciences, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal.
J Invertebr Pathol. 2023 Jul;199:107947. doi: 10.1016/j.jip.2023.107947. Epub 2023 Jun 5.
Heritable microbes that exhibit reproductive parasitism are common in insects. One class of these are the male-killing bacteria, which are found in a broad range of insect hosts. Commonly, our knowledge of the incidence of these microbes is based on one or a few sampling sites, and the degree and causes of spatial variation are unclear. In this paper, we examine the incidence of the son-killer microbe Arsenophonus nasoniae across European populations of its wasp host, Nasonia vitripennis. In preliminary work, we noticed two female N. vitripennis producing highly female biased sex ratios in a field study from the Netherlands and Germany. When tested, the brood from Germany was revealed to be infected with A. nasoniae. We then completed a broad survey in 2012, in which fly pupal hosts of N. vitripennis were collected from vacated birds' nests from four European populations, N. vitripennis wasps allowed to emerge and then tested for A. nasoniae presence through PCR assay. We then developed a new screening methodology based on direct PCR assays of fly pupae and applied this to ethanol-preserved material collected from great tit (Parus major) nests in Portugal. These data show A. nasoniae is found widely in European N. vitripennis, being present in Germany, the UK, Finland, Switzerland and Portugal. Samples varied in the frequency with which they carry A. nasoniae, from being rare to being present in 50% of the pupae parasitised by N. vitripennis. Direct screening of ethanol-preserved fly pupae was an effective method for revealing both wasp and A. nasoniae infection, and will facilitate sample transport across national boundaries. Future research should examine the causes of variation in frequency, in particular testing the hypothesis that N. vitripennis superparasitism rates drive the variation in A. nasoniae frequency through providing opportunities for infectious transmission.
具有生殖寄生特性的可遗传微生物在昆虫中很常见。这些微生物中有一类是雄性致死细菌，它们存在于广泛的昆虫宿主中。通常，我们对这些微生物的发生情况的了解是基于一个或几个采样点，而空间变异的程度和原因尚不清楚。在本文中，我们研究了其黄蜂宿主烟色丽蝇（Nasonia vitripennis）在欧洲种群中雄性致死微生物阿氏菌（Arsenophonus nasoniae）的发生情况。在初步工作中，我们注意到在荷兰和德国的一项野外研究中，有两只雌性烟色丽蝇产生了高度雌性偏置的性别比例。经过测试，德国的卵群被发现感染了阿氏菌。然后，我们在 2012 年完成了一项广泛的调查，从四个欧洲种群的废弃鸟巢中收集了烟色丽蝇的蝇蛹宿主，让烟色丽蝇黄蜂成虫出茧，并通过 PCR 检测来检测阿氏菌的存在。然后，我们开发了一种基于蝇蛹直接 PCR 检测的新筛选方法，并将其应用于从葡萄牙大山雀（Parus major）巢中收集的乙醇保存材料。这些数据表明，阿氏菌广泛存在于欧洲的烟色丽蝇中，在德国、英国、芬兰、瑞士和葡萄牙都有发现。样本中携带阿氏菌的频率各不相同，从罕见到烟色丽蝇寄生的蝇蛹中有 50%携带阿氏菌。直接筛选乙醇保存的蝇蛹是一种有效的方法，可以揭示黄蜂和阿氏菌的感染情况，并将有助于样本在国家间的运输。未来的研究应该检验频率变化的原因，特别是通过检验烟色丽蝇超寄生率通过提供传染性传播的机会来驱动阿氏菌频率变化的假设。
