Data from: Food-environment mediates the outcome of specific interactions between a bumblebee and its trypanosome parasite

Specific host-parasite interactions, where the outcome of exposure to a parasite depends upon the genotypic identity of both parties, have implications for understanding host-parasite co-evolution and patterns of genetic diversity. Thus, grasping the extent to which these interactions are mediated by environmental changes in a spatially and temporally heterogeneous world is vital. In this study it is shown that the environment can influence specific host-parasite interactions in the well-studied system of the bumblebee Bombus terrestris and its trypanosome parasite Crithidia bombi. Naturally relevant variation in the quality of the food environment formed a three-way interaction with both host and parasite identity in determining the outcome of infection, with regard to the resistance of the host and the transmission of the parasite. The demonstration of such a host-genotype by parasite-genotype by environment interaction (GHxGPxE) shows the importance of considering environmental variation when investigating host-parasite interactions. Moreover, such interactions may to some extent explain levels of genetic diversity in natural host-parasite systems owing to the fact that they will create selection mosaics when environments are heterogeneous.特异性宿主-寄生虫相互作用（host-parasite interactions）指宿主暴露于寄生虫后的感染结局取决于双方的基因型特征，这类相互作用对于解析宿主-寄生虫协同进化机制与遗传多样性模式具有重要意义。因此，在时空异质性的自然界中，明确这类相互作用受环境变化调控的程度至关重要。本研究证实，在被广泛研究的大地熊蜂（Bombus terrestris）与其锥虫类寄生虫熊蜂短膜虫（Crithidia bombi）的模式系统中，环境能够影响特异性宿主-寄生虫相互作用。就宿主抗性与寄生虫传播能力而言，食物环境质量的自然变异与宿主、寄生虫的基因型特征共同构成三方互作，共同决定感染结局。这类宿主基因型×寄生虫基因型×环境互作（GHxGPxE）的发现表明，在开展宿主-寄生虫相互作用研究时，必须纳入环境变异的考量。此外，由于环境异质性会使得这类互作形成选择镶嵌格局，因此其可在一定程度上解释自然宿主-寄生虫系统中的遗传多样性水平。