Department of Biology, Western University, London, ON, N6A 3K7, Canada.
Department of Earth and Environmental Sciences, University of Manchester, Manchester, M13 9BL, UK.
Oecologia. 2023 Apr;201(4):1005-1015. doi: 10.1007/s00442-023-05372-3. Epub 2023 Apr 11.
Climate change can alter predator-prey interactions when predators and prey have different thermal preferences as temperature change can exacerbate thermal mismatches (also called thermal asymmetry) with population-level consequences. We tested this using micro-arthropod predators (Stratiolaelaps scimitus) and prey (Folsomia candida) that differ in their temperature optima to examine predator-prey interactions across two temperature ranges, a cool (12 and 20 °C) and warm (20 and 26 °C) range. We predict that the lower thermal preference and optimum in F. candida will alter top-down control (i.e., interaction strength) by predators with interaction strength being strongest at intermediate temperatures, coinciding with F. candida thermal optimum. Predators and prey were placed in mesocosms, whereafter we measured population (predator and prey abundance), trait-based (average predator and prey body mass, and prey body length distribution), and predator-prey indices (predator-prey mass ratio (PPMR), Dynamic Index, and Log Response Ratio) to determine how temperature affected their interactions. Prey populations were the highest at intermediate temperatures (average temperature exposure: 16-23 °C) but declined at warmer temperatures (average temperature exposure: 24.5-26 °C). Predators consistently lowered prey abundances and average prey mass increased when predators were added. Top-down control was the greatest at intermediate temperatures (indicated by Log Response Ratio) when temperatures were near or below the thermal optimum for both species. Temperature-related prey declines negated top-down control under the warmest conditions suggesting that mismatches in thermal performance between predators and their prey will alter the strength and dominance of top-down or bottom-up forces of predator-prey interactions in a warmer world.
气候变化会改变捕食者-猎物相互作用，特别是当捕食者和猎物对温度有不同的偏好时，因为温度变化会加剧种群水平的热不匹配（也称为热不对称）。我们使用温度最优值不同的微节肢动物捕食者（Stratiolaelaps scimitus）和猎物（Folsomia candida）来检验这一假说，在两个温度范围（低温范围为 12 和 20°C，高温范围为 20 和 26°C）下检验捕食者-猎物相互作用。我们预测，F. candida 的较低热偏好和最优温度将改变捕食者的自上而下的控制（即相互作用强度），在中等温度下，相互作用强度最强，与 F. candida 的热最优温度一致。将捕食者和猎物放置在中观生态系统中，然后我们测量种群（捕食者和猎物的丰度）、基于特征的（平均捕食者和猎物的体重，以及猎物的体长分布）和捕食者-猎物指标（捕食者-猎物质量比（PPMR）、动态指数和对数响应比），以确定温度如何影响它们的相互作用。猎物种群在中等温度下最高（平均温度暴露：16-23°C），但在较暖温度下（平均温度暴露：24.5-26°C）下降。当添加捕食者时，捕食者始终降低猎物的丰度和平均猎物的体重增加。当温度接近或低于两个物种的热最优温度时，自上而下的控制最大（通过对数响应比表示）。与温度相关的猎物下降否定了在最温暖条件下的自上而下的控制，这表明捕食者与其猎物之间的热性能不匹配将改变捕食者-猎物相互作用中自上而下或自下而上力量的强度和优势，在一个更温暖的世界中。
