Thermodynamic effects drive countergradient responses in the thermal performance of Littorina saxatilis across latitude.
Thermodynamic effects drive countergradient responses in the thermal performance of Littorina saxatilis across latitude.
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DOI：
10.1016/j.scitotenv.2022.160877
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发表时间：
2022-12
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通讯作者：
Christopher Dwane;E. Rezende;O. Tills;J. Galindo;E. Rolán-Alvarez;S. Rundle;M. Truebano
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文献类型：
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作者：
Christopher Dwane;E. Rezende;O. Tills;J. Galindo;E. Rolán-Alvarez;S. Rundle;M. Truebano
热性能曲线(TPC)提供了一个强大的框架来评估暴露在不同纬度选择制度下的种群的热敏感度的演变。然而，对于补偿纬度温度变化的生理调节(代谢性冷适应；MCA)可能在多大程度上改变TPC的形状，包括对温度上限的潜在影响，还缺乏共识。为了解决这个问题，我们比较了潮间带褶皱Littorina saxatilis纬度分离种群的TPC的心脏活动。我们应用了一种非线性的TPC建模方法来探索控制TPC形状的不同指标如何随着局部适应和热适应而系统地变化。在最北端(冷适应)的人群中，临界上限和使心脏功能最大化的温度都较高，并显示出逆梯度的纬度趋势，在适应低温后最为明显。我们将这一反应解释为高纬度人群标准代谢率增加的连锁结果，表明与MCA相关的生理补偿可能间接影响纬度上温限的变化。我们的研究强调了在没有适当的机制和生态背景的情况下，假设TPC的任何一个方面的变化是适应性的危险。
Thermal performance curves (TPCs) provide a powerful framework to assess the evolution of thermal sensitivity in populations exposed to divergent selection regimes across latitude. However, there is a lack of consensus regarding the extent to which physiological adjustments that compensate for latitudinal temperature variation (metabolic cold adaptation; MCA) may alter the shape of TPCs, including potential repercussion on upper thermal limits. To address this, we compared TPCs for cardiac activity in latitudinally-separated populations of the intertidal periwinkleLittorina saxatilis. We applied a non-linear TPC modelling approach to explore how different metrics governing the shape of TPCs varied systematically in response to local adaptation and thermal acclimation. Both critical upper limits, and the temperatures at which cardiac performance was maximised, were higher in the northernmost (cold-adapted) population and displayed a countergradient latitudinal trend which was most pronounced following acclimation to low temperatures. We interpret this response as a knock-on consequence of increased standard metabolic rate in high latitude populations, indicating that physiological compensation associated with MCA may indirectly influence variation in upper thermal limits across latitude. Our study highlights the danger of assuming that variation in any one aspect of the TPC is adaptive without appropriate mechanistic and ecological context.