Wehrli Micha, Slotsbo Stine, Ge Jian, Holmstrup Martin
Department of Ecoscience, Aarhus University, C.F. Møllers Allé 4, DK-8000 Aarhus C, Denmark.
Curr Res Insect Sci. 2024 Jul 4;6:100089. doi: 10.1016/j.cris.2024.100089. eCollection 2024.
The importance of thermal acclimation for the Thermal Death Time (TDT) landscape of the common soil living springtail, (Collembola, Isotomidae), was investigated. To this aim, we acclimated adult springtails at 10 °C (cold-acclimation) and 20 °C (warm-acclimation), respectively. In static thermal tolerance assays, we found the relationship between survival and exposure time at a number of stressful high and low temperatures. Using logistic modelling, we found, at each exposure temperature, the time until 50% mortality had been reached (Lt). The exponential functions of TDT curves were found by linear regression of log Lt values against exposure temperature. Results showed that cold acclimation significantly increased cold tolerance and increased the temperature dependence of cold injury accumulation rate (increased the slope by 4 orders of magnitude) in . Hence, cold acclimation changed the status of this species from chill-susceptible to moderately chill-tolerant. The cellular injury accumulation at sub-zero temperatures was not related to freezing of body water in this study. Congruently, we found a significant negative effect of cold acclimation on heat tolerance and that cold acclimation decreased the thermal sensitivity of the heat injury accumulation rate. Different slopes of the TDT curves between acclimation groups indicated that acclimation shifted the proportional importance of cellular injury mechanisms or the nature of injury mechanisms. Finally, we compare and combine the TDT curves at extreme high and low temperatures with previously published results on longevity at benign temperatures (from 0 to 30 °C) and describe the full thermal niche of .
研究了热驯化对常见土壤栖息弹尾虫（弹尾目，等节虫科）热死亡时间（TDT）格局的重要性。为此，我们分别在10°C（冷驯化）和20°C（热驯化）下对成年弹尾虫进行了驯化。在静态热耐受性试验中，我们在多个应激性高温和低温下发现了存活与暴露时间之间的关系。使用逻辑模型，我们在每个暴露温度下找到了达到50%死亡率所需的时间（Lt）。通过将log Lt值与暴露温度进行线性回归，得到了TDT曲线的指数函数。结果表明，冷驯化显著提高了耐寒性，并增加了冷损伤积累速率的温度依赖性（斜率增加了4个数量级）。因此，冷驯化将该物种的状态从冷敏感型转变为中度耐寒型。在本研究中，零下温度下的细胞损伤积累与身体水分冻结无关。同样，我们发现冷驯化对耐热性有显著负面影响，并且冷驯化降低了热损伤积累速率的热敏感性。驯化组之间TDT曲线的不同斜率表明，驯化改变了细胞损伤机制的比例重要性或损伤机制的性质。最后，我们将极端高温和低温下的TDT曲线与先前发表的关于良性温度（0至30°C）下寿命的结果进行比较和合并，并描述了该物种的完整热生态位。
