Data from: Host and parasite thermal acclimation responses depend on the stage of infection

1. Global climate change is expected to alter patterns of temperature variability, which could influence species interactions including parasitism. Species interactions can be difficult to predict in variable-temperature environments because of thermal acclimation responses, i.e. physiological changes that allow organisms to adjust to a new temperature following a temperature shift.
2. The goal of this study was to determine how thermal acclimation influences host resistance to infection and to test for parasite acclimation responses, which might differ from host responses in important ways.
3. We tested predictions of three, non-mutually exclusive hypotheses regarding thermal acclimation effects on infection of green frog tadpoles (Lithobates clamitans) by the trematode parasite Ribeiroia ondatrae with fully replicated controlled-temperature experiments. Trematodes or tadpoles were independently acclimated to a range of ‘acclimation temperatures’ prior to shifting them to new ‘performance temperatures’ for experimental infections.
4. Trematodes that were acclimated to intermediate temperatures (19–22 °C) had greater encystment success across temperatures than either cold- or warm-acclimated trematodes. However, host acclimation responses varied depending on the stage of infection (encystment vs. clearance): warm- (22–28 °C) and cold-acclimated (13–19 °C) tadpoles had fewer parasites encyst at warm and cold performance temperatures, respectively, whereas intermediate-acclimated tadpoles (19–25 °C) cleared the greatest proportion of parasites in the week following exposure.
5. These results suggest that tadpoles use different immune mechanisms to resist different stages of trematode infection, and that each set of mechanisms has unique responses to temperature variability. Our results highlight the importance of considering thermal responses of both parasites and hosts when predicting disease patterns in variable-temperature environments.

1. 全球气候变化预计将改变温度波动模式，这可能会影响包括寄生作用在内的物种间相互作用。在温度多变的环境中，由于温度驯化响应（thermal acclimation responses）——即生物体在温度变化后调整以适应新温度的生理变化——物种间的相互作用往往难以预测。
2. 本研究旨在明确温度驯化（thermal acclimation）如何影响宿主对感染的抵抗力，并检验寄生虫的驯化响应，这类响应可能在诸多关键方面与宿主的驯化响应存在差异。
3. 我们通过完全重复的控温实验，检验了3个非互斥假说的预测，这些假说围绕温度驯化对吸虫（trematode）寄生虫Ribeiroia ondatrae感染美洲绿蛙蝌蚪（Lithobates clamitans）的影响展开。实验前，我们先将吸虫或蝌蚪分别驯化至一系列“驯化温度”，随后将它们转移至新的“性能温度”下开展感染实验。
4. 驯化至中等温度（19–22℃）的吸虫，在各温度下的囊胞形成成功率均高于冷驯化或温驯化的吸虫。然而，宿主的驯化响应会因感染阶段（囊胞形成与寄生虫清除）而异：温驯化（22–28℃）与冷驯化（13–19℃）的蝌蚪，分别在高温与低温性能温度下的寄生虫囊胞形成量更少；而中等温度驯化（19–25℃）的蝌蚪在暴露后一周内清除寄生虫的比例最高。
5. 本研究结果表明，蝌蚪会借助不同的免疫机制抵御吸虫感染的不同阶段，且每套免疫机制对温度波动均有独特的响应模式。我们的研究结果凸显了在预测温度多变环境中的疾病流行模式时，同时考虑寄生虫与宿主的温度响应的重要性。