Zhao Fei, Zhang Wei, Hoffmann Ary A, Ma Chun-Sen
Climate Change Biology Research Group, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Yuan-Ming-Yuan West Road No.2, Beijing, 100193, China.
Laboratory for Integrated Pest Management of Insect, Institute of Plant Protection, Shanxi Academy of Agricultural Sciences, Wu-Cheng South Road No.59, Taiyuan, 030031, China.
J Anim Ecol. 2014 Jul;83(4):769-78. doi: 10.1111/1365-2656.12196. Epub 2014 Feb 25.
An asymmetric increase in night-time temperatures (NTs) on hot days is one of the main features of global climate change. But the biological effects of an increased night-time temperature combined with high daytime temperature are unclear. We used six thermal regimens to simulate NTs on hot days and investigated the effects of night warming on life-history traits of the English grain aphid Sitobion avenae. Experimental temperatures fluctuated in continuous diurnal cycles, increasing from 27 °C to a maximum 35 °C and then declining to 27 °C gradually before further dropping to different minima (13, 16, 19, 21, 23 or 25 °C) representing NTs. When compared to expectations based on constant temperatures, night warming raised the optimum temperature for development by 3 °C, in contrast to results from experiments where temperature variability was altered symmetrically or in a parallel manner. Night warming also reduced aphid survival under heat from 75% to 37% and depressed adult performance by up to 50%. Overall, night warming exacerbated the detrimental effects of hot days on the intrinsic rate of population increase, which was predicted to drop by 30% when night-time minimum temperatures exceeded 20 °C. Our novel findings on development challenge the 'Kaufmann effect', suggesting this is inapplicable to night warming likely to be encountered in nature. Although many average temperature models predict increasing pest outbreaks, our results suggest that outbreaks of some species might decrease due to the effects of night warming on population dynamics.
炎热天气下夜间温度（NTs）的不对称升高是全球气候变化的主要特征之一。但夜间温度升高与白天高温相结合的生物学效应尚不清楚。我们使用六种热方案来模拟炎热天气下的夜间温度，并研究夜间升温对麦长管蚜生活史特征的影响。实验温度在连续的昼夜周期中波动，从27°C升至最高35°C，然后逐渐降至27°C，再进一步降至代表夜间温度的不同最低温度（13、16、19、21、23或25°C）。与基于恒温的预期相比，夜间升温使发育的最适温度提高了3°C，这与温度变异性以对称或平行方式改变的实验结果相反。夜间升温还使蚜虫在高温下的存活率从75%降至37%，并使成虫性能降低多达50%。总体而言，夜间升温加剧了炎热天气对种群内在增长率的不利影响，预计当夜间最低温度超过20°C时，种群内在增长率将下降30%。我们关于发育的新发现挑战了“考夫曼效应”，表明这不适用于自然界可能遇到的夜间升温。尽管许多平均温度模型预测害虫爆发会增加，但我们的结果表明，由于夜间升温对种群动态的影响，一些物种的爆发可能会减少。
