Galpern Paul, Johnson Sarah A, Retzlaff Jennifer L, Chang Danielle, Swann John
Faculty of Environmental Design University of Calgary Calgary AB Canada; Department of Biological Sciences University of Calgary Calgary AB Canada.
Department of Biological Sciences University of Calgary Calgary AB Canada.
Ecol Evol. 2017 Mar 12;7(7):2414-2422. doi: 10.1002/ece3.2856. eCollection 2017 Apr.
One of the most commonly seeded crops in Canada is canola, a cultivar of oilseed rape (). As a mass-flowering crop grown intensively throughout the Canadian Prairies, canola has the potential to influence pollinator success across tens of thousands of square kilometers of cropland. Bumble bees ( sp.) are efficient pollinators of many types of native and crop plants. We measured the influence of this mass-flowering crop on the abundance and phenology of bumble bees, and on another species of social bee (a sweat bee; ), by continuously deploying traps at different levels of canola cultivation intensity, spanning the start and end of canola bloom. Queen bumble bees were more abundant in areas with more canola cover, indicating that this crop is attractive to queens. However, bumble bee workers were significantly fewer in these locations later in the season, suggesting reduced colony success. The median collection dates of workers of three bumble bee species were earlier near canola fields, suggesting a dynamic response of colonies to the increased floral resources. Different species experienced this shift to different extents. The sweat bee was not affected by canola cultivation intensity. Our findings suggest that mass-flowering crops such as canola are attractive to bumble bee queens and therefore may lead to higher rates of colony establishment, but also that colonies established near this crop may be less successful. We propose that the effect on bumble bees can be mitigated by spacing the crop more evenly with respect to alternate floral resources.
加拿大种植最普遍的作物之一是油菜籽，它是油菜（）的一个栽培品种。作为一种在加拿大大草原广泛种植的大规模开花作物，油菜籽有可能影响数万平方公里农田上传粉者的成功率。熊蜂（ 属）是许多本土植物和农作物的高效传粉者。我们通过在油菜不同种植强度水平下持续设置诱捕器，涵盖油菜开花的开始和结束阶段，测量了这种大规模开花作物对熊蜂数量和物候的影响，以及对另一种群居蜜蜂（一种汗蜂； ）的影响。在油菜覆盖面积更大的地区，熊蜂蜂后数量更多，这表明这种作物对蜂后有吸引力。然而，在季节后期，这些地方的熊蜂工蜂数量显著减少，这表明蜂群的成功率降低。三种熊蜂工蜂的中位采集日期在油菜田附近更早，这表明蜂群对增加的花卉资源有动态反应。不同物种受这种变化的影响程度不同。汗蜂不受油菜种植强度的影响。我们的研究结果表明，像油菜籽这样的大规模开花作物对熊蜂蜂后有吸引力，因此可能导致更高的蜂群建立率，但在这种作物附近建立的蜂群可能不太成功。我们建议，通过使这种作物与其他花卉资源更均匀地间隔分布，可以减轻对熊蜂的影响。
