Data from: Population of origin and environment interact to determine oomycete infections in spotted salamander populations

Spatial variation in disease risk in wild populations can depend both on environmental and genetic factors. Understanding the various contributions of each factor requires experimental manipulation of both the environment and genetic composition of populations under natural field conditions. We first examined natural patterns of oomycete composition and infection in the eggs of 13 populations of the spotted salamander Ambystoma maculatum. We then performed a fully factorial field transplant of the eggs of six populations to separate the contributions from population of origin and the environment on oomycete resistance in spotted salamanders. Among wild ponds, we found strong variation in oomycete infections in spotted salamander populations and differences in the composition of oomycete communities. In transplant experiments, salamander populations differed in their resistance to oomycete infections via a significant interaction between population of origin and environment. However, not all populations were locally adapted to local conditions. One population was significantly adapted to its home environment, and another one was significantly maladapted. These population effects could originate from differential adaptation of salamander populations to local oomycete communities or environmental conditions that mediate resistance, local adaptation and maladaptation of oomycetes to hosts, or from maternal transmission. Accounting for both environment and population of origin will often be necessary to understand disease dynamics in wild populations.

野生种群的病害风险空间异质性，同时受环境与遗传因素共同调控。若要厘清两类因素各自的贡献量，则需在自然野外条件下，对种群的环境与遗传组成开展实验操控。本研究首先调查了13个斑点钝口螈（Ambystoma maculatum）种群的卵中卵菌（oomycete）群落组成与感染情况的自然分布模式。随后，我们针对6个种群的卵开展了完全析因野外移植实验，以区分卵源种群与环境对斑点钝口螈卵菌抗性的影响。在野外池塘中，我们观测到斑点钝口螈种群的卵菌感染情况存在显著差异，且卵菌群落组成亦各不相同。在移植实验中，卵源种群与环境之间存在显著交互作用，导致不同钝口螈种群的卵菌抗性表现各异。但并非所有种群均能适应当地环境：其中一个种群对其原生环境具有显著的本地适应性，另一个种群则呈现出显著的适应不良表型。此类种群效应的成因可能包括：钝口螈种群对当地卵菌群落或介导抗性的环境条件存在差异化适应；卵菌对宿主的本地适应性与适应不良；亦或是母体传播效应。若要阐明野生种群的病害动态，通常需要同时考量环境与卵源种群两类因素。