Rooke Anna C, Burness Gary, Fox Michael G
Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada K9L 0G2.
Department of Biology, Trent University, Peterborough, Ontario, Canada K9L 0G2.
J Therm Biol. 2017 Feb;64:48-57. doi: 10.1016/j.jtherbio.2016.12.010. Epub 2016 Dec 27.
Contemporary evolution of thermal physiology has the potential to help limit the physiological stress associated with rapidly changing thermal environments; however it is unclear if wild populations can respond quickly enough for such changes to be effective. We used native Canadian Pumpkinseed (Lepomis gibbosus) sunfish, and non-native Pumpkinseed introduced into the milder climate of Spain ~100 years ago, to assess genetic differences in thermal physiology in response to the warmer non-native climate. We compared temperature performance reaction norms of two Canadian and two Spanish Pumpkinseed populations born and raised within a common environment. We found that Canadian Pumpkinseed had higher routine metabolic rates when measured at seasonally high temperatures (15°C in winter, 30°C in summer), and that Spanish Pumpkinseed had higher critical thermal maxima when acclimated to 30°C in the summer. Growth rates were not significantly different among populations, however Canadian Pumpkinseed tended to have faster growth at the warmest temperatures measured (32°C). The observed differences in physiology among Canadian and Spanish populations at the warmest acclimation temperatures are consistent with the introduced populations being better suited to the warmer non-native climate than native populations. The observed differences could be the result of either founder effects, genetic drift, and/or contemporary adaptive evolution in the warmer non-native climate.
热生理学的当代演变有可能帮助限制与快速变化的热环境相关的生理压力；然而，尚不清楚野生种群是否能够足够迅速地做出反应以使这种变化有效。我们使用了加拿大本土的蓝鳃太阳鱼（Lepomis gibbosus），以及约100年前引入西班牙较温和气候地区的非本土蓝鳃太阳鱼，来评估热生理学方面的遗传差异，以应对较温暖的非本土气候。我们比较了在共同环境中出生和饲养的两个加拿大蓝鳃太阳鱼种群和两个西班牙蓝鳃太阳鱼种群的温度性能反应规范。我们发现，加拿大蓝鳃太阳鱼在季节性高温（冬季15°C，夏季30°C）下测量时具有较高的常规代谢率，而西班牙蓝鳃太阳鱼在夏季适应30°C时具有较高的临界热最大值。不同种群之间的生长率没有显著差异，然而，加拿大蓝鳃太阳鱼在测量到的最温暖温度（32°C）下往往生长得更快。在最温暖的适应温度下，加拿大和西班牙种群之间观察到的生理差异与引入种群比本土种群更适合较温暖的非本土气候一致。观察到的差异可能是奠基者效应、遗传漂变和/或在较温暖的非本土气候中的当代适应性进化的结果。
