The likelihood of a successful host shift of a parasite to a novel host species can be influenced by environmental factors that can act on both the host and parasite. Changes in nutritional resource availability have been shown to alter pathogen susceptibility and the outcome of infection in a range of systems. Here, we examined how dietary protein to carbohydrate altered susceptibility in a large cross-infection experiment. We infected 27 species of Drosophilidae with an RNA virus on three food types of differing protein to carbohydrate ratios. We then measured how viral load and mortality across species was affected by changes in diet. We found that changes in the protein:carbohydrate in the diet did not alter the outcomes of infection, with strong positive inter-species correlations in both viral load and mortality across diets, suggesting no species-by-diet interaction. Mortality and viral load were strongly positively correlated, and this association was consistent across diets. This suggests changes in diet may give consistent outcomes across host species, and may not be universally important in determining host susceptibility to pathogens.

中文翻译：

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宿主物种间的病毒易感性在很大程度上与饮食中蛋白质与碳水化合物的比例无关。

寄生虫成功转移到新宿主物种的可能性可能受到可能同时作用于宿主和寄生虫的环境因素的影响。营养资源可利用性的变化已显示出可改变一系列系统中病原体的易感性和感染的结果。在这里，我们研究了饮食蛋白质对碳水化合物如何在大型交叉感染实验中改变易感性。我们在三种蛋白质和碳水化合物比例不同的食物上用RNA病毒感染了27种果蝇科。然后，我们测量了饮食变化如何影响物种间的病毒载量和死亡率。我们发现饮食中蛋白质：碳水化合物的变化并没有改变感染的结果，不同饮食中病毒载量和死亡率之间存在强烈的种间正相关性，表明没有饮食间的相互作用。死亡率和病毒载量呈极强的正相关，并且在各种饮食中这种关联是一致的。这表明饮食的变化可能会在宿主物种之间产生一致的结果，并且在确定宿主对病原体的敏感性方面可能并非普遍重要。