Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK; School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK.
Mol Ecol. 2014 Jul;23(14):3384-95. doi: 10.1111/mec.12823. Epub 2014 Jun 30.
Land-use changes have threatened populations of many insect pollinators, including bumble bees. Patterns of dispersal and gene flow are key determinants of species' ability to respond to land-use change, but have been little investigated at a fine scale (<10 km) in bumble bees. Using microsatellite markers, we determined the fine-scale spatial genetic structure of populations of four common Bombus species (B. terrestris, B. lapidarius, B. pascuorum and B. hortorum) and one declining species (B. ruderatus) in an agricultural landscape in Southern England, UK. The study landscape contained sown flower patches representing agri-environment options for pollinators. We found that, as expected, the B. ruderatus population was characterized by relatively low heterozygosity, number of alleles and colony density. Across all species, inbreeding was absent or present but weak (FIS = 0.01-0.02). Using queen genotypes reconstructed from worker sibships and colony locations estimated from the positions of workers within these sibships, we found that significant isolation by distance was absent in B. lapidarius, B. hortorum and B. ruderatus. In B. terrestris and B. pascuorum, it was present but weak; for example, in these two species, expected relatedness of queens founding colonies 1 m apart was 0.02. These results show that bumble bee populations exhibit low levels of spatial genetic structure at fine spatial scales, most likely because of ongoing gene flow via widespread queen dispersal. In addition, the results demonstrate the potential for agri-environment scheme conservation measures to facilitate fine-scale gene flow by creating a more even distribution of suitable habitats across landscapes.
土地利用变化威胁到许多传粉昆虫的种群，包括大黄蜂。扩散和基因流动模式是物种对土地利用变化做出反应的能力的关键决定因素，但在大黄蜂中，这些模式在精细尺度（<10 公里）上的研究很少。本研究使用微卫星标记，确定了英国南部一个农业景观中四种常见的熊蜂物种（B. terrestris、B. lapidarius、B. pascuorum 和 B. hortorum）和一种衰退物种（B. ruderatus）的种群的精细空间遗传结构。研究景观中包含了播种的花卉斑块，代表了传粉昆虫的农业环境选择。我们发现，正如预期的那样，B. ruderatus 种群的杂合度、等位基因数和殖民地密度相对较低。在所有物种中，近亲繁殖不存在或存在但较弱（FIS = 0.01-0.02）。利用从工蜂亲缘关系和从这些亲缘关系中的工蜂位置估计的殖民地位置重建的蜂王基因型，我们发现 B. lapidarius、B. hortorum 和 B. ruderatus 中不存在显著的距离隔离。在 B. terrestris 和 B. pascuorum 中，虽然存在，但较弱；例如，在这两个物种中，相隔 1 米的殖民地中预期的蜂王亲缘关系为 0.02。这些结果表明，大黄蜂种群在精细的空间尺度上表现出较低的空间遗传结构，这很可能是由于广泛的蜂王扩散导致持续的基因流动。此外，这些结果表明，农业环境计划保护措施通过在景观中更均匀地分布适宜的栖息地，有可能促进精细尺度的基因流动。
