Climate plays a key role in shaping population trends and determining the geographic distribution of species because of limits in species’ thermal tolerance. An evaluation of species tolerance to temperature change can therefore help predict their potential spatial shifts and population trends triggered by ongoing global warming. We assessed inter- and intraspecific variations in heat resistance in relation to body mass, local mean temperatures, and evolutionary relationships in 39 bumblebee species, a major group of pollinators in temperate and cold ecosystems, across 3 continents, 6 biomes, and 20 regions (2386 male specimens). Based on experimental bioassays, we measured the time before heat stupor of bumblebee males at a heatwave temperature of 40 °C. Interspecific variability was significant, in contrast to interpopulational variability, which was consistent with heat resistance being a species-specific trait. Moreover, cold-adapted species are much more sensitive to heat stress than temperate and Mediterranean species. Relative to their sensitivity to extreme temperatures, our results help explain recent population declines and range shifts in bumblebees following climate change.

中文翻译：

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极端温度对野生大黄蜂的全球影响

由于物种的耐热性有限，气候在塑造种群趋势和确定物种的地理分布方面起着关键作用。因此，评估物种对温度变化的耐受性可以帮助预测由持续的全球变暖引发的潜在空间变化和人口趋势。我们评估了 39 个大黄蜂物种（温带和寒冷生态系统中的主要传粉媒介）与体重、局部平均温度和进化关系相关的种间和种内耐热性变化，跨越 3 个大陆、6 个生物群落和 20 个地区。 2386 个男性标本）。基于实验生物测定，我们测量了大黄蜂在 40 °C 热浪温度下热昏迷前的时间。种间变异是显着的，与种群间变异相反，这与耐热性是物种特异性特征一致。此外，与温带和地中海物种相比，适应寒冷的物种对热应激更敏感。相对于它们对极端温度的敏感性，我们的结果有助于解释气候变化后大黄蜂最近的种群数量下降和范围变化。