Department of Bioscience, Section for Soil Ecology and Ecotoxicology, Aarhus University, Silkeborg, Denmark.
Department of Bioscience, Section for Genetics, Ecology and Evolution, Aarhus University, Aarhus C, Denmark.
J Anim Ecol. 2019 Feb;88(2):258-268. doi: 10.1111/1365-2656.12916. Epub 2018 Nov 2.
Temperature influences biological processes of ectotherms including ecological interactions, but interaction strengths may depend on species-specific traits. Furthermore, ectotherms acclimate to prevailing thermal conditions by adjusting physiological parameters, which often implies costs to other fitness-related parameters. Both predators and prey may therefore pay thermal acclimation costs following exposure to suboptimal temperatures. However, these costs may be asymmetrical between predator and prey, and between the predator and different species of concurrent prey. We investigated whether thermal pre-exposure affected subsequent kill rate and predator fitness when foraging on prey that differ in ease of capture, and whether changes were primarily caused by predator or by prey pre-exposure effects. Specifically, we were interested in whether there were interactions between predator pre-exposed temperature and specific prey. Using the mesostigmatid mite Gaeolaelaps aculeifer as a generalist predator and the collembolans Folsomia candida and Protaphorura fimata as prey, we measured the impact of present temperature, predator pre-exposure temperature, prey pre-exposure temperature (all 10 or 20°C), prey species, and all interactions on prey numbers killed, predator eggs produced, and exploitation of killed prey in a full factorial design. Mites killed P. fimata in equal numbers independent of the presence of F. candida, but killed F. candida when P. fimata was absent. Mite kill rate and reproduction were significantly affected by mite pre-exposure temperature and test temperature, but not by prey pre-exposure temperature. Significantly more of the slower prey was killed than of the quicker prey. Importantly, we found significant synergistic negative interaction effects between predator cold pre-exposure and hunting prey of higher agility on predator kill rate and reproduction. Our findings show that the negative effects of cold and cold pre-exposure on kill rate and reproduction may be more severe when predators forage on quick prey. The study implies that predator cold exposure has consequences for specific prey survival following cold due to altered predation pressures, which in nature should influence the specific prey population dynamics and apparent competition outcomes. The findings exemplify how not only current but also preceding conditions affect ecological interactions, and that effect strength depends on the species involved.
温度会影响变温动物的生物过程，包括生态相互作用，但相互作用的强度可能取决于物种特有的特征。此外，变温动物通过调节生理参数来适应流行的热条件，这通常意味着对其他与适应相关的参数产生成本。因此，捕食者和猎物在暴露于不适宜的温度后可能会付出热适应的代价。然而，这些成本在捕食者和猎物之间，以及捕食者和不同种同时存在的猎物之间可能是不对称的。我们研究了热预暴露是否会影响捕食者在捕食猎物时的后续杀戮率和捕食者的适应性，以及这种变化是主要由捕食者还是猎物的预暴露引起的。具体来说，我们感兴趣的是捕食者预暴露温度与特定猎物之间是否存在相互作用。我们使用作为一种通用捕食者的Mesostigmatid 螨 Gaeolaelaps aculeifer 和作为猎物的球跳虫 Folsomia candida 和Protaphorura fimata，我们测量了当前温度、捕食者预暴露温度、猎物预暴露温度（均为 10 或 20°C）、猎物种类以及所有相互作用对猎物数量、捕食者产卵量和杀死猎物的利用的影响，这是在完全因子设计中进行的。当不存在 P. fimata 时，螨虫以相等的数量杀死 P. fimata，但当不存在 F. candida 时，螨虫杀死 F. candida。螨虫的杀戮率和繁殖受到螨虫预暴露温度和测试温度的显著影响，但不受猎物预暴露温度的影响。明显更多的缓慢猎物被杀死比快速猎物。重要的是，我们发现捕食者冷预暴露和捕食更高敏捷性的猎物对捕食者杀戮率和繁殖的协同负相互作用效应显著。我们的研究结果表明，当捕食者捕食快速猎物时，低温和低温预暴露对杀戮率和繁殖的负面影响可能更为严重。研究表明，由于捕食压力的改变，捕食者的寒冷暴露会对特定猎物的生存产生影响，这在自然界中应该会影响特定猎物的种群动态和明显的竞争结果。研究结果例证了不仅当前条件而且以前的条件如何影响生态相互作用，以及作用强度取决于所涉及的物种。
