Defensive symbiosis in the wild: seasonal dynamics of parasitism risk and symbiont-conferred resistance

Parasite-mediated selection can rapidly drive up resistance levels in host populations, but fixation of resistance traits may be prevented by costs of resistance. Black bean aphids (Aphis fabae) benefit from increased resistance to parasitoids when carrying the defensive bacterial endosymbiont Hamiltonella defensa. However, due to fitness costs that come with symbiont infection, symbiont-conferred resistance may result in either a net benefit or a net cost to the aphid host, depending on parasitoid presence as well as on the general ecological context. Balancing selection may therefore explain why in natural aphid populations, H. defensa is often found at intermediate frequencies. Here we present a two-year field study where we set out to look for signatures of balancing selection in natural aphid populations. We collected temporally well-resolved data on the prevalence of H. defensa in A.f. fabae and estimated the risk imposed by parasitoids using sentinel hosts. Despite a marked and c..., This data submission contains R scripts as well as raw & processed data to analyse the seasonal dynamics of aphid symbionts and parasitoids as described in the paper. See the README file for more information., Data files are provided as .csv tables; the scripts can be run with R. To run analyses including temperature variables, temperature data has to be requested from MeteoSwiss (Swiss Federal Office of Meteorology and Climatology) as described in the README file.寄生虫介导的选择（parasite-mediated selection）可快速提升宿主种群的抗性水平，但抗性性状的固定可能会受到抗性代价的制约。黑豆蚜（Aphis fabae）在携带保护性细菌内共生体汉密尔顿氏防御菌（Hamiltonella defensa）时，可获得对寄生蜂（parasitoids）的抗性提升优势。然而，由于共生体感染伴随的适合度代价，共生体介导的抗性对蚜虫宿主的净效应可能为收益或成本，这取决于寄生蜂的存在与否以及整体生态背景。因此，平衡选择（balancing selection）或许可以解释为何在自然蚜虫种群中，H. defensa通常以中间频率存在。 本研究开展了一项为期两年的野外调查，旨在探究自然蚜虫种群中平衡选择的特征。我们收集了时间分辨率较高的A.f. fabae种群中H. defensa的流行率数据，并利用哨兵宿主（sentinel hosts）估算了寄生蜂带来的风险。尽管存在显著且（原文截断）... 本数据集提交内容包含用于分析如论文所述的蚜虫共生体与寄生蜂季节动态的R脚本、原始数据与处理后数据。更多详情请参阅README文件。 数据文件以.csv表格形式提供，脚本可在R环境中运行。若需开展包含温度变量的分析，则需按照README文件中的说明，从瑞士联邦气象与气候局（MeteoSwiss）获取温度数据。