Oliveira Brunno F, Yogo Wendtwoin I G, Hahn Daniel A, Yongxing Jiang, Scheffers Brett R
Department of Wildlife Ecology and Conservation, University of Florida/IFAS, Gainesville, Florida, 32611, USA.
Department of Environmental Science and Policy, University of California-Davis, Davis, California, 95616, USA.
Ecology. 2021 Jul;102(7):e03368. doi: 10.1002/ecy.3368. Epub 2021 Jun 3.
The broadening in species' thermal tolerance limits and breadth from tropical to temperate latitudes is proposed to reflect spatial gradients in temperature seasonality, but the importance of seasonal shifts in thermal tolerances within and across locations is much less appreciated. We performed thermal assays to examine the maximum and minimum critical temperatures (CT and CT , respectively) of a mosquito community across their active seasons. Mosquito CT tracked seasonal shifts in temperature, whereas CT tracked a countergradient pattern with lowest heat tolerances in summer. Mosquito thermal breadth decreased from spring to summer and then increased from summer to autumn. We show a temporal dichotomy in thermal tolerances with thermal breadths of temperate organisms in summer reflecting those of the tropics ("tropicalization") that is sandwiched between a spring and autumn "temperatization." Therefore, our tolerance patterns at a single temperate latitude recapitulate classical patterns across latitude. These findings highlight the need to understand the temporal and spatial components of thermotolerance variation better, including plasticity and rapid seasonal selection, and the potential for this variation to affect species responses to climate change. With summers becoming longer and increasing winter nighttime temperatures, we expect increasing tropicalization of species thermal tolerances in both space and time.
从热带到温带地区，物种热耐受性极限和范围的拓宽被认为反映了温度季节性的空间梯度，但不同地点内部和之间热耐受性的季节性变化的重要性却很少受到重视。我们进行了热测定，以研究一个蚊子群落整个活跃季节的最高和最低临界温度（分别为CTmax和CTmin）。蚊子的CTmax跟踪温度的季节性变化，而CTmin则呈现出一种反梯度模式，在夏季具有最低的耐热性。蚊子的热范围从春季到夏季减小，然后从夏季到秋季增加。我们展示了热耐受性的时间二分法，温带生物夏季的热范围反映了热带生物的热范围（“热带化”），夹在春季和秋季的“温带化”之间。因此，我们在单个温带纬度的耐受性模式概括了跨纬度的经典模式。这些发现强调了更好地理解耐热性变化的时间和空间成分的必要性，包括可塑性和快速的季节性选择，以及这种变化影响物种对气候变化反应的可能性。随着夏季变长和冬季夜间温度升高，我们预计物种热耐受性在空间和时间上的热带化都会增加。
