Bozinovic Francisco, Bastías Daniel A, Boher Francisca, Clavijo-Baquet Sabrina, Estay Sergio A, Angilletta Michael J
Center for Advanced Studies in Ecology and Biodiversity, Departamento de Ecología, Pontificia Universidad Católica de Chile, Santiago 6513677, Chile.
Physiol Biochem Zool. 2011 Nov-Dec;84(6):543-52. doi: 10.1086/662551. Epub 2011 Oct 14.
Global climate change poses one of the greatest threats to biodiversity. Most analyses of the potential biological impacts have focused on changes in mean temperature, but changes in thermal variance will also impact organisms and populations. We assessed the combined effects of the mean and variance of temperature on thermal tolerances, organismal survival, and population growth in Drosophila melanogaster. Because the performance of ectotherms relates nonlinearly to temperature, we predicted that responses to thermal variation (±0° or ±5°C) would depend on the mean temperature (17° or 24°C). Consistent with our prediction, thermal variation enhanced the rate of population growth (r(max)) at a low mean temperature but depressed this rate at a high mean temperature. The interactive effect on fitness occurred despite the fact that flies improved their heat and cold tolerances through acclimation to thermal conditions. Flies exposed to a high mean and a high variance of temperature recovered from heat coma faster and survived heat exposure better than did flies that developed at other conditions. Relatively high survival following heat exposure was associated with low survival following cold exposure. Recovery from chill coma was affected primarily by the mean temperature; flies acclimated to a low mean temperature recovered much faster than did flies acclimated to a high mean temperature. To develop more realistic predictions about the biological impacts of climate change, one must consider the interactions between the mean environmental temperature and the variance of environmental temperature.
全球气候变化对生物多样性构成了最大威胁之一。大多数关于潜在生物影响的分析都集中在平均温度的变化上，但热变异性的变化也会影响生物体和种群。我们评估了温度均值和变异性对黑腹果蝇热耐受性、生物体存活和种群增长的综合影响。由于变温动物的表现与温度呈非线性关系，我们预测对热变化（±0°C或±5°C）的反应将取决于平均温度（17°C或24°C）。与我们的预测一致，热变化在低平均温度下提高了种群增长率（r(max)），但在高平均温度下降低了该增长率。尽管果蝇通过适应热条件提高了它们的耐热性和耐寒性，但对适合度仍有交互作用。暴露于高平均温度和高温度变异性环境下的果蝇比在其他条件下发育的果蝇从热昏迷中恢复得更快，并且在热暴露下存活得更好。热暴露后相对较高的存活率与冷暴露后较低的存活率相关。从冷昏迷中恢复主要受平均温度影响；适应低平均温度的果蝇比适应高平均温度的果蝇恢复得快得多。为了对气候变化的生物影响做出更现实的预测，必须考虑环境温度均值和环境温度变异性之间的相互作用。
