EF 03: Evolutionary Ecology of Male-Killing Wolbachia in Drosophila Innubila

沃尔巴克氏体是一种细胞内的、通过母体传播的细菌寄生虫，存在于大多数昆虫物种中;它们的传播是通过操纵宿主繁殖的各种手段来完成的。 尽管沃尔巴克氏体具有潜在的生态和进化重要性，但关于沃尔巴克氏体动态及其对田间宿主昆虫种群的影响的研究很少。 该项目的重点是果蝇innubila和它所感染的杀死雄性的沃尔巴克氏体之间相互作用的生态学。 果蝇栖息在亚利桑那州和新墨西哥州天空岛的中高海拔森林中。 沃尔巴克氏体导致几乎100%的死亡率感染的男性胚胎和感染的女性在这些自然种群的相当大的一部分。本项目将确定D.温育让杀死雄性的沃尔巴克氏体得以传播 将进行一系列实地实验，以评估感染的苍蝇是否比未感染的苍蝇遭受更少的竞争。 该项目还将探索三种机制，以防止宿主种群中的雄性杀死沃尔巴克氏体的固定：通过不完全的母体传播随机损失，通过含寄生虫的蘑菇治愈感染，以及环境温度。 因为D. innubila分布为孤立的天空岛屿种群，该物种是研究环境梯度对Wolbachia动态影响的理想物种。 最后，该项目将量化沃尔巴克氏体感染对种群水平的性比，交配频率和性选择的影响。暗示 它将专门测试预测，即在大量感染频率下存在男性杀死Wolbachia导致人口中女性偏向的性别比例，女性交配率较低，以及选择男性在选择配偶时具有歧视性。 该建议的生态重点将有助于了解男性杀死沃尔巴克氏体在自然种群中的动态，从而阐明利用这些内共生体故意操纵昆虫种群的可行性。

Evolutionary ecology of male-killing Wolbachia in Drosophila innubilaJaenike, John R.University of RochesterWolbachia are intracellular, maternally transmitted, bacterial parasites present in the majority of insect species; their spread is accomplished by various means of manipulating host reproduction. Despite the potential ecological and evolutionary importance of Wolbachia, there has been very little research on Wolbachia dynamics and their effects on host insect populations in the field. This project focuses on the ecology of interactions between Drosophila innubila and the male-killing Wolbachia with which it is infected. Drosophila innubila inhabit mid- to high elevation forests in the sky islands of Arizona and New Mexico. Wolbachia cause almost 100% mortality of infected male embryos and infect a substantial fraction of females in these natural populations. This project will determine how the ecology of D. innubila allows the spread of male-killing Wolbachia. A series of field experiments will be carried out to assess whether infected flies suffer less competition than do uninfected flies. The project will also explore three mechanisms proposed to prevent fixation of male-killing Wolbachia within host populations: stochastic loss via incomplete maternal transmission, curing of the infection by antibiotic-containing mushrooms, and environmental temperature. Because D. innubila is distributed as isolated sky island populations, this species is ideal for investigating the effect of environmental gradients on Wolbachia dynamics. Finally, the project will quantify the effects of Wolbachia infections on the population-level sex ratio, mating frequencies, and sexual selection in D. innubila. It will specifically test predictions that the presence of male-killing Wolbachia at substantial infection frequencies results in a female-biased sex ratio in the population, lower rates of female mating, and selection on males to be discriminating in their choice of mates. The ecological focus of this proposal will contribute to understanding the dynamics of male-killing Wolbachia in natural populations and thus shed light on the feasibility of using these endosymbionts for deliberate manipulation of insect populations.