School of Biological Sciences, One Health & Veterinary Medicine, University of Glasgow, Scotland, United Kingdom.
Department of Computer Science, Mathematics, and Environmental Science, The American University of Paris, Paris, France.
J Evol Biol. 2024 Jan 29;37(1):1-13. doi: 10.1093/jeb/voad009.
Climate change is associated with the increase in both the mean and variability of thermal conditions. Therefore, the use of more realistic fluctuating thermal regimes is the most appropriate laboratory method for predicting population responses to thermal heterogeneity. However, the long- and short-term implications of evolving under such conditions are not well understood. Here, we examined differences in key life-history traits among populations of seed beetles (Callosobruchus maculatus) that evolved under either constant control conditions or in an environment with fluctuating daily temperatures. Specifically, individuals from two distinct genetic backgrounds were kept for 19 generations at one of two temperatures, a constant temperature (T = 29 °C) or a fluctuating daily cycle (Tmean = 33 °C, Tmax = 40 °C, and Tmin = 26 °C), and were assayed either in their evolved environment or in the other environment. We found that beetles that evolved in fluctuating environments but were then switched to constant 29 °C conditions had far greater lifetime reproductive success compared with beetles that were kept in their evolved environments. This increase in reproductive success suggests that beetles raised in fluctuating environments may have evolved greater thermal breadth than control condition beetles. In addition, the degree of sexual dimorphism in body size and development varied as a function of genetic background, evolved thermal environment, and current temperature conditions. These results not only highlight the value of incorporating diel fluctuations into climate research but also suggest that populations that experience variability in temperature may be better able to respond to both short- and long-term changes in environmental conditions.
气候变化与热条件的平均值和可变性的增加有关。因此，使用更现实的波动热环境是预测种群对热异质性反应的最合适的实验室方法。然而，在这种条件下进化的长期和短期影响还不是很清楚。在这里，我们研究了在恒定控制条件下或在波动日温度环境中进化的豆象（Callosobruchus maculatus）种群的关键生活史特征差异。具体来说，来自两个不同遗传背景的个体在两种温度下分别培养 19 代，一种是恒定温度（T=29°C）或波动的日周期温度（Tmean=33°C、Tmax=40°C 和 Tmin=26°C），然后在其进化环境或另一种环境中进行检测。我们发现，在波动环境中进化但随后切换到恒定 29°C 条件下的甲虫比在其进化环境中饲养的甲虫具有更高的终生繁殖成功率。这种繁殖成功率的增加表明，在波动环境中饲养的甲虫可能比对照条件下的甲虫进化出更大的热幅宽。此外，体型和发育的性二态性程度随遗传背景、进化的热环境和当前温度条件而变化。这些结果不仅突出了将日波动纳入气候研究的价值，还表明经历温度变化的种群可能更能够应对环境条件的短期和长期变化。
