Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.
Australian Infectious Disease Research Centre, School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia.
J Invertebr Pathol. 2019 May;163:1-7. doi: 10.1016/j.jip.2019.02.005. Epub 2019 Feb 23.
Wolbachia are common intracellular bacteria that are generally found in arthropods, including a high proportion of insects and also some nematodes. This intracellular symbiont can affect sex ratio with a variety of reproductive anomalies in the host, including cytoplasmic incompatibility (CI) in haplodiploids. In this study, we questioned if the parasitoid wasp, Habrobracon hebetor (Hym.: Braconidae), an important biological control agent of many lepidopteran larvae, is infected with Wolbachia. To test this, DNA was extracted from adult insects and subjected to PCR using specific primers to Wolbachia target genes. The results showed a high rate of Wolbachia infection in this parasitoid wasp. To determine the biological function of Wolbachia in H. hebetor, we removed this bacterium from the wasps using antibiotic treatment (cured wasps). Results of crossing experiments revealed that Wolbachia induced CI in H. hebetor in which cured females crossed with infected males produced only males, while both male and female progeny were observed for other crosses. Also, we showed that the presence of Wolbachia in females increased fecundity and female offspring of this parasitoid wasp. The presence of Wolbachia in the males had no significant effect on fecundity and female production, but might have incurred costs. We also investigated the effect of Wolbachia on mate choice and found that Wolbachia affects mating behavior of H. hebetor. Together, we showed that Wolbachia induces CI in H. hebetor and affects host mating behavior in favor of its transmission. Wolbachia utilize these strategies to increase the frequency of infected females in the host population.
沃尔巴克氏体是一种常见的细胞内细菌，通常存在于节肢动物中，包括很大一部分昆虫和一些线虫。这种细胞内共生菌可以通过宿主的各种生殖异常来影响性别比例，包括单倍二倍体中的细胞质不亲和性（CI）。在这项研究中，我们质疑寄生蜂，Habrobracon hebetor（膜翅目：Braconidae），一种对许多鳞翅目幼虫具有重要生物防治作用的寄生蜂，是否感染了沃尔巴克氏体。为了验证这一点，我们从成年昆虫中提取 DNA，并使用针对沃尔巴克氏体靶基因的特定引物进行 PCR。结果表明，这种寄生蜂感染沃尔巴克氏体的比例很高。为了确定沃尔巴克氏体在 H. hebetor 中的生物学功能，我们使用抗生素处理（处理过的寄生蜂）从寄生蜂中去除这种细菌。交叉实验的结果表明，沃尔巴克氏体在 H. hebetor 中诱导了 CI，其中经过处理的雌性与感染的雄性交配后只产生雄性，而其他交叉产生了雄性和雌性后代。此外，我们还表明，雌性中沃尔巴克氏体的存在增加了这种寄生蜂的繁殖力和雌性后代数量。雄性中沃尔巴克氏体的存在对繁殖力和雌性后代的产生没有显著影响，但可能会产生成本。我们还研究了沃尔巴克氏体对配偶选择的影响，发现沃尔巴克氏体影响 H. hebetor 的交配行为。总之，我们表明沃尔巴克氏体在 H. hebetor 中诱导 CI，并影响宿主的交配行为，有利于其传播。沃尔巴克氏体利用这些策略来增加宿主种群中感染雌性的频率。
