Comparative Zoology, Institute of Evolution and Ecology, Tübingen University, Tübingen, Germany.
Department of Ecology and Environmental Sciences, Umeå University, Umeå, Sweden.
BMC Ecol Evol. 2022 Feb 1;22(1):8. doi: 10.1186/s12862-022-01963-5.
The environment is a strong driver of genetic structure in many natural populations, yet often neglected in population genetic studies. This may be a particular problem in vagile species, where subtle structure cannot be explained by limitations to dispersal. Consequently, these species might falsely be considered quasi-panmictic and hence potentially mismanaged. A species this might apply to, is the buff-tailed bumble bee (Bombus terrestris), an economically important and widespread pollinator, which is considered to be quasi-panmictic at mainland continental scales. Here we aimed to (i) quantify genetic structure in 21+ populations of the buff-tailed bumble bee, sampled throughout two Eastern European countries, and (ii) analyse the degree to which structure is explained by environmental differences, habitat permeability and geographic distance. Using 12 microsatellite loci, we characterised populations of this species with Fst analyses, complemented by discriminant analysis of principal components and Bayesian clustering approaches. We then applied generalized dissimilarity modelling to simultaneously assess the informativeness of geographic distance, habitat permeability and environmental differences among populations in explaining divergence.
Genetic structure of the buff-tailed bumble bee quantified by means of Fst was subtle and not detected by Bayesian clustering. Discriminant analysis of principal components suggested insignificant but still noticeable structure that slightly exceeded estimates obtained through Fst analyses. As expected, geographic distance and habitat permeability were not informative in explaining the spatial pattern of genetic divergence. Yet, environmental variables related to temperature, vegetation and topography were highly informative, explaining between 33 and 39% of the genetic variation observed.
In contrast to previous studies reporting quasi-panmixia in continental populations of this species, we demonstrated the presence of subtle population structure related to environmental heterogeneity. Environmental data proved to be highly useful in unravelling the drivers of genetic structure in this vagile and opportunistic species. We highlight the potential of including these data to obtain a better understanding of population structure and the processes driving it in species considered to be quasi-panmictic.
在许多自然种群中，环境是遗传结构的强大驱动因素，但在种群遗传学研究中往往被忽视。对于迁徙物种来说，这可能是一个特别的问题，因为细微的结构无法用扩散的限制来解释。因此，这些物种可能会被错误地认为是近乎完全混合的，因此可能会被错误地管理。有一种可能适用的物种是黄腹熊蜂（Bombus terrestris），它是一种经济上重要且广泛的传粉媒介，在大陆范围内被认为是近乎完全混合的。在这里，我们的目的是（i）量化在两个东欧国家采样的 21 个以上黄腹熊蜂种群的遗传结构，以及（ii）分析结构在多大程度上可以用环境差异、栖息地渗透性和地理距离来解释。我们使用 12 个微卫星基因座，通过 Fst 分析来描述该物种的种群特征，并用主成分判别分析和贝叶斯聚类方法来补充。然后，我们应用广义差异模型来同时评估地理距离、栖息地渗透性和种群间环境差异在解释种群分歧方面的信息量。
通过 Fst 量化的黄腹熊蜂遗传结构很细微，通过贝叶斯聚类无法检测到。主成分判别分析表明，存在着虽不显著但仍能察觉到的结构，略高于通过 Fst 分析得到的估计值。正如预期的那样，地理距离和栖息地渗透性对解释遗传分歧的空间模式没有信息。然而，与温度、植被和地形有关的环境变量则非常有用，解释了观察到的遗传变异的 33%至 39%。
与先前报道该物种大陆种群近乎完全混合的研究相反，我们证明了与环境异质性相关的细微种群结构的存在。环境数据在揭示这种迁徙和机会主义物种遗传结构的驱动因素方面非常有用。我们强调了在被认为是近乎完全混合的物种中纳入这些数据的潜力，以更好地理解种群结构及其驱动因素。
