Recent research has shown drastic reductions in the global diversity and abundance of insects. This is a major concern given the expected cascade effects on ecosystem services, such as pollination. Understanding the patterns and drivers of changes in the distribution and abundance of species in our rapidly changing environment is therefore urgent. Cases of species showing trends that run counter to general population declines, especially when they deliver key ecosystem services, are especially interesting. The tree bumblebee (Bombus hypnorum), which belongs to a globally important group of pollinators, has substantially expanded its range in recent years in direct contrast to many other species within this group. Here we reconstructed the likely pattern of colonization of the UK based on RAD-seq population genomic data combined with Bayesian population modelling. This RAD-seq approach also enabled an analysis of genomic regions potentially under selection. We report a complex and dynamic colonization pattern that is most likely ongoing. Current evidence suggests that either a shift in its migration potential, and/or adaptive genomic changes have contributed to the recent range expansion of B. hypnorum. Genomic areas of potential adaptive significance included genes involved in regulation of transcription and gene expression, circadian rhythms and innate immunity. Our results are framed within the general context of understanding the factors driving successful population expansions.

最近的研究表明，昆虫的全球多样性和丰富性急剧下降。考虑到对授粉等生态系统服务的预期级联影响，这是一个主要问题。因此，了解在我们迅速变化的环境中物种分布和丰富度变化的模式和动因非常重要。物种趋势与一般人口下降背道而驰的案例尤其引人关注，特别是当它们提供关键的生态系统服务时。大黄蜂（熊蜂hypnorum）是全球重要的授粉媒介类之一，近年来与该授粉媒介中的许多其他物种形成鲜明对比的是，其范围已大大扩大。在这里，我们根据RAD-seq人口基因组数据与贝叶斯人口模型相结合，重建了英国殖民的可能模式。这种RAD-seq方法还可以分析可能处于选择状态的基因组区域。我们报告了一个很可能正在进行的复杂而动态的殖民化模式。目前的证据表明，其迁移潜能的改变和/或适应性基因组的改变都导致了催眠芽孢杆菌最近的范围扩大。。具有潜在适应性意义的基因组领域包括与转录和基因表达调控有关的基因，昼夜节律和先天免疫。我们的结果是在了解导致人口成功扩张的因素的一般背景下制定的。