Department of Biology, Aquatic Biology, Aarhus University, Ole Worms Allé 1, 8000 Aarhus C., Denmark.
Department of Biology, Arctic Research Centre, Aarhus University, Ole Worms Allé 1, 8000 Aarhus C., Denmark.
Int J Parasitol. 2020 Dec;50(14):1189-1194. doi: 10.1016/j.ijpara.2020.07.006. Epub 2020 Aug 29.
Blue mussels (Mytilus edulis) are important ecosystem engineers along Atlantic coastlines, where they are regularly subjected to rapid changes in temperature during the transition between tides. Global climate change and more frequent extreme weather events are expected to intensify this thermal stress even further. These increases in temperatures will not only affect intertidal mussels directly but also increase transmission dynamics of their parasites. Together, the effects of rises in temperature and parasitism will likely result in higher pressure on M. edulis and their ability to perform vital ecosystem services. In a set of experiments, we tested the effects of infections with the trematode Himasthla elongata and high temperatures during low tide air-exposure. Overall, we hypothesised that temperature and parasite infection intensity would each have significant negative effects on M. edulis survival, and that both stressors together would have a synergistic detrimental impact. Overall, high temperature levels had a strong negative effect on mussel survival. However, our results revealed a surprisingly more complex picture in infected individuals. While moderate parasite loads and increased temperature showed additive negative effects on mussel survival, high parasite infection intensities appeared to nullify the detrimental effects of temperature stress on mussels. Under climate warming, these benefits of parasites might actually outweigh the costs of infection and prove beneficial. Overall, these results suggest that the interactions between host-parasite systems and their changing environment are much more complex than a simple additive effect of multiple stressors.
贻贝（Mytilus edulis）是沿大西洋海岸线的重要生态系统工程师，它们在潮间带之间的温度变化过程中经常受到快速变化的影响。预计全球气候变化和更频繁的极端天气事件将进一步加剧这种热应激。这些温度的升高不仅会直接影响潮间带贻贝，还会增加其寄生虫的传播动态。总之，温度升高和寄生虫感染的综合影响可能会对贻贝及其执行重要生态系统服务的能力造成更大的压力。在一系列实验中，我们测试了感染吸虫 Himasthla elongata 和低潮时空气暴露高温对贻贝的影响。总的来说，我们假设温度和寄生虫感染强度都会对贻贝的存活率产生显著的负面影响，而且这两个胁迫因素共同作用会产生协同的不利影响。总的来说，高温水平对贻贝的存活率有很强的负面影响。然而，我们的结果在感染个体中揭示了一个令人惊讶的更为复杂的情况。虽然中度寄生虫负荷和温度升高对贻贝的存活率表现出相加的负面影响，但高寄生虫感染强度似乎抵消了温度胁迫对贻贝的不利影响。在气候变暖的情况下，寄生虫的这些益处实际上可能超过感染的成本，并被证明是有益的。总的来说，这些结果表明，宿主-寄生虫系统及其不断变化的环境之间的相互作用比多个胁迫因素的简单相加效应复杂得多。
