Adaptation to temperate climates
Adaptation to temperate climates
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DOI：
10.1111/j.0014-3820.2004.tb00458.x
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发表时间：
2004-08-01
期刊：
影响因子：
3.3
通讯作者：
Holzapfel, CM
中科院分区：
文献类型：
--
作者：
Bradshaw, WE;Zani, PA;Holzapfel, CM
只有模式生物才生活在一个夏季无尽的世界里。在温带地区的适应性反映了自然界中生物体利用有利季节、减轻不利季节的影响以及及时从一种生活方式转换到另一种生活方式的能力。在此，我们将适应性定义为Ry，即在处理器控制的环境室中在其自然微生境中饲养的蚊子Wyeomyia smithii在所有四季中的全年队列替换率。首先，我们暴露了W。smithii，从南部，中纬度，和北方种群（30- 50 degreesN）到南部和北方的热年，在此期间，我们考虑了光周期反应的进化差异。我们发现了种群之间耐热性和耐寒性进化差异的明确证据。相对耐寒性的北方人口变得明显时，人口强调灭绝的边缘;相对耐热性的南方人口变得明显时，热的不利影响可以积累几代。第二，我们暴露在一个热良性的中纬度热年的南，中纬度，和北方人口的自然，中纬度日长。我们发现，光周期反应的进化差异（1）阻止了南方种群进入滞育，导致74%的健康下降，（2）迫使北方种群忍受暖季滞育，导致88%的健康下降。我们认为，在自然界中，跨纬度的相互移植总是混淆了热和光环境对健身的影响。然而，据我们所知，以前没有人在改变光年的同时保持热年不变。这一区别对于评估气候变化的潜在影响至关重要。由于全球变暖在北方进行更快的北方比在南半球的纬度，因为这种变化代表了改善的热环境和随之而来的增加的生长季节的持续时间，我们得出结论，应该有更快的光周期反应比耐热性的演变，全球变暖的后果之间的北方，温带外温动物。
Only model organisms live in a world of endless summer. Fitness at temperate latitudes reflects the ability of organisms in nature to exploit the favorable season, to mitigate the effects of the unfavorable season, and to make the timely switch from one life style to the other. Herein, we define fitness as Ry, the year-long cohort replacement rate across all four seasons, of the mosquito, Wyeomyia smithii, reared in its natural microhabitat in processor-controlled environment rooms. First, we exposed cohorts of W. smithii, from southern, midlatitude, and northern populations (30-50degreesN) to southern and northern thermal years during which we factored out evolved differences in photoperiodic response. We found clear evidence of evolved differences in heat and cold tolerance among populations. Relative cold tolerance of northern populations became apparent when populations were stressed to the brink of extinction; relative heat tolerance of southern populations became apparent when the adverse effects of heat could accumulate over several generations. Second, we exposed southern, midlatitude, and northern populations to natural, midlatitude day lengths in a thermally benign midlatitude thermal year. We found that evolved differences in photoperiodic response (1) prevented the timely entry of southern populations into diapause resulting in a 74% decline in fitness, and (2) forced northern populations to endure a warm-season diapause resulting in an 88% decline in fitness. We argue that reciprocal transplants across latitudes in nature always confound the effects of the thermal and photic environment on fitness. Yet, to our knowledge, no one has previously held the thermal year constant while varying the photic year. This distinction is crucial in evaluating the potential impact of climate change. Because global warming in the Northern Hemisphere is proceeding faster at northern than at southern latitudes and because this change represents an amelioration of the thermal environment and a concomitant increase in the duration of the growing season, we conclude that there should be more rapid evolution of photoperiodic response than of thermal tolerance as a consequence of global warming among northern, temperate ectotherms.