Experimental evolution on heat tolerance and thermal performance curves under contrasting thermal selection in Drosophila subobscura

Ectotherms can respond to global warming via evolutionary change of their upper thermal limits (CTmax). Thus, the estimation of CTmax and its evolutionary potential is crucial to determine their vulnerability to global warming. However, CTmax estimations depend on the thermal stress intensity, and it is not completely clear whether its evolutionary capacity can be affected. Here, we performed an artificial selection experiment to increase heat tolerance using fast- and slow-ramping selection protocols in Drosophila subobscura. We found that heat tolerance evolved in both selection protocols, exhibiting similar evolutionary change rates and realized heritabilities. Additionally, we estimated the thermal performance curves (TPC) to evaluate correlated responses in TPC. We detected that thermal optimum increased in fast-ramping selection lines, but with a cost at the thermal performance breadth. Whereas, TPC changes were not detected in the slow-ramping selection lines, indicating that the...变温动物可通过进化调整其临界高温（CTmax）以响应全球变暖。因此，对临界高温及其进化潜力的估算，是确定其应对全球变暖脆弱性的关键依据。然而，临界高温的估算结果取决于热胁迫强度，目前仍不完全明确其进化能力是否会受到该因素的影响。本研究以暗果蝇（Drosophila subobscura）为实验对象，采用快速升温和慢速升温两种选择方案开展人工选择实验以提升其耐热性。结果显示，两种选择方案下耐热性均发生了进化，且展现出相近的进化变化速率与现实遗传力。此外，我们通过估算热性能曲线（TPC）来评估热性能曲线的相关响应：在快速升温选择系中，检测到其热最适温度有所升高，但在热性能广度方面存在代价；而在慢速升温选择系中未发现热性能曲线发生变化，这表明……