Bumble bees are essential, efficient pollinators of numerous crops, and scientists are increasingly concerned about their global decline. Although several potential causes have been put forward, the concurrent modification of landscape structure and pesticide use by agriculture are often pointed out as the main drivers of the decline. Yet, the mechanisms through which these factors cause species to decline remain elusive. Most field studies have been conducted at the individual level, and the few studies that addressed higher levels of organization only covered narrow ecological conditions. We undertook a field experiment in spring 2016 to overcome these limitations by placing four commercial Bombus impatiens colonies in each of 20 sites located along a gradient of agricultural intensity in southern Québec, Canada. We hypothesized that landscape habitat composition and configuration, as well as local floral resources, would affect colony development. We expected colonies surrounded by low‐intensity and/or flowering crops in heterogeneous landscapes to develop better and live longer, partly linked to more abundant and diversified food resources, than colonies embedded in landscapes dominated by high‐intensity crops. Colonies were weighed once a week, and workers were captured to assess pollen load diversity. Final colony weight, queen production, and presence of depredators (Aphomia sociella, Lepidoptera: Pyralidae) were also recorded. Landscape habitat composition and configuration were characterized within 1 km of colonies. Local availability of floral resources was assessed within 100 m of colonies every two weeks. As predicted, colony weight and longevity decreased with the proportion of intensive crops and increased with the amount of flowering crops, but queen production and the occurrence of A. sociella were not affected by landscape composition. Contrary to our prediction, local availability of floral resources also did not affect colonies. The pollen richness brought back to colonies decreased with the proportion of flowering crops and varied according to the proportion of intensive crops interacting with local floral resources. Our work contributes to generalize the more restrictive conclusion of local‐scale, crop‐specific studies that intensive crop farming undermines bumble bee colony development and that it may thus play a role in the large‐scale population decline of these insects.

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农业景观成分影响熊熊凤梨殖民地的发展和寿命

大黄蜂是多种农作物必不可少的高效传粉媒介，科学家越来越担心它们的全球衰退。尽管已经提出了几种潜在的原因，但人们经常指出，同时改变景观结构和农业使用农药是造成这种下降的主要动力。然而，这些因素导致物种减少的机制仍然难以捉摸。大多数现场研究都是在个人层面上进行的，而针对组织较高层次的研究很少，只涉及狭窄的生态条件。我们于2016年春季进行了田间试验，通过放置4枚商用Bombus凤仙花来克服这些限制加拿大魁北克南部沿农业强度梯度分布的20个地点中的每个殖民地。我们假设景观栖息地的组成和配置以及当地花卉资源会影响殖民地的发展。我们预计，与高强度作物为主的景观中的殖民地相比，异质地貌中的低强度和/或开花作物所包围的殖民地将发展得更好，寿命更长，部分与更丰富和多样化的食物资源有关。每周对殖民地称重一次，并抓捕工人以评估花粉负载的多样性。最终菌落的重量，蚁后产量和掠食者的存在（Aphomia sociella，鳞翅目：Pyralidae）也被记录下来。殖民地1公里以内的景观栖息地组成和配置具有特征。每两周在100 m的菌落中评估当地花卉资源的可用性。如预期的那样，菌落的重量和寿命随着集约型作物的比例而降低，并随着开花作物的数量而增加，但女王产量和农杆菌的出现不受景观组成的影响。与我们的预测相反，当地花卉资源的可用性也未影响菌落。带回殖民地的花粉丰富度随着开花作物的比例而降低，并随着集约型作物与当地花卉资源相互作用的比例而变化。我们的工作有助于推广对局部作物特定研究更具限制性的结论，即集约化耕作破坏了大黄蜂蜂群的发育，因此可能在这些昆虫的大规模种群减少中发挥作用。