Beneficial acclimation hypothesis (BAH) is the phenotypic plasticity in response to changing environments which enables organisms to enhance their fitness. In recent years, however, BAH has received vigorous criticism and is still debatable. In this study, we tested thermal hardiness phenotypes (melanization, chill coma recovery, heat knockdown and percentage survival) on adult and pre-adult stages of Drosophila nepalensis, reared in different thermal environments (14, 17, 21 and 25 °C) to check whether increasing natural surrounding temperature and acclimation limit towards environmental change is detrimental or beneficial. Results showed that rearing D. nepalensis at higher temperatures (21 and 25 °C) reduces its melanization and cold hardiness but improves heat knockdown times. When temperature was raised to 26.2 °C (0.6 °C above the upper thermal maxima), to determine the short-term acclimation effects, survival and fitness of adults diminished approximately 1.5 to 2 folds. These results suggest that D. nepalensis has long-term developmental acclimation to both heat and cold which would be extremely beneficial as temperatures and climates alter in the region due to global warming. However, a lack of short-term heat acclimation suggests that rapid shifts in thermal extreme could be detrimental to D. nepalensis.

中文翻译：

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拒绝果蝇短期热驯化的有益驯化假说（BAH）

有益驯化假说 (BAH) 是响应不断变化的环境的表型可塑性，使生物体能够增强其适应性。然而，近年来，BAH受到了强烈的批评，仍然存在争议。在这项研究中，我们测试了在不同热环境（14、17、21 和 25 °C）中饲养的尼泊尔果蝇成虫和成虫前阶段的耐热性表型（黑化、冷昏迷恢复、热击倒和存活百分比）检查增加自然周围温度和适应环境变化的极限是有害还是有益。结果表明，在较高温度（21 和 25 °C）下饲养 D. nepalensis 会降低其黑色化和耐寒性，但会提高热击倒时间。当温度升至 26.2 °C (0. 6 °C 以上热最大值），以确定短期驯化效果，成虫的存活率和适应度降低了大约 1.5 到 2 倍。这些结果表明，D. nepalensis 具有对热和冷的长期发育适应性，这对于由于全球变暖导致该地区的温度和气候发生变化非常有益。然而，缺乏短期热适应表明极端热的快速变化可能对 D. nepalensis 有害。