The cultivation of mass-flowering crops (MFC) can promote pollinators by providing floral resources. However, there is missing knowledge about the effect of MFC cultivation history on bees and their pollination services in agricultural landscapes. We investigated how bee densities in oilseed rape (Brassica napus L.) (OSR) fields were affected by past (cultivation area of the preceding three years) and current MFC area coverages in the surrounding landscape. Moreover, we analyzed how insect pollination, its possible interaction with the plants` pod numbers and MFC covers influence yield components of individual OSR plants and calculated yields (t/ha). To test this, we conducted pollinator surveys and a pollinator exclusion experiment in one oilseed rape field in 17 agricultural landscapes in Germany. We found that wild bee densities were positively affected by past MFC covers and negatively impacted by current OSR covers, indicating enhanced pollinator populations due to previous MFC cultivation and contemporary pollinator dilution. In contrast, honeybees showed opposite responses to past and present MFC cultivation. Furthermore, seed weight per plant of open pollinated plants was positively correlated with past MFC covers. Pollinator exclusion decreased the seed number per pod and increased thousand-seed weight, while yields were unaffected. Pod number interacted with insect pollination in shaping yields, such that pollinator exclusion led to a steeper increase of yield with higher pod numbers. Insect pollination compensated for low pod numbers by increasing the plants` seed number per pod and ultimately yields. Our findings demonstrate a beneficial effect of high MFC covers in the past on bee densities and potentially yield components in the current year. Our study highlights the need for further research on how past and present landscape composition in terms of MFC cultivation interactively affect pollinator communities and their pollination services in agricultural landscapes.

大规模开花作物 (MFC) 的种植可以通过提供花卉资源来促进传粉媒介。然而，缺乏关于 MFC 栽培历史对蜜蜂及其在农业景观中的授粉服务的影响的知识。我们调查了油菜（欧洲油菜）中的蜜蜂密度L.) (OSR) 田地受到周围景观中过去（前三年的栽培面积）和当前 MFC 区域覆盖率的影响。此外，我们分析了昆虫授粉、其与植物豆荚数和 MFC 覆盖范围的可能相互作用如何影响单个 OSR 植物的产量成分和计算的产量 (t/ha)。为了测试这一点，我们在德国 17 个农业景观的一个油菜田中进行了传粉媒介调查和传粉媒介排除实验。我们发现野生蜜蜂密度受到过去 MFC 覆盖的积极影响，而受到当前 OSR 覆盖的负面影响，表明由于先前的 MFC 种植和当代传粉媒介稀释，传粉媒介种群增加。相比之下，蜜蜂对过去和现在的 MFC 培养表现出相反的反应。此外，开放授粉植物的单株种子重量与过去的 MFC 覆盖率呈正相关。传粉媒介排除减少了每个豆荚的种子数并增加了千粒重，而产量不受影响。豆荚数与昆虫授粉在影响产量方面相互作用，因此排除传粉媒介导致豆荚数越高产量增加幅度越大。昆虫授粉通过增加每个豆荚的植物种子数和最终产量来补偿低豆荚数。我们的研究结果表明，过去高 MFC 覆盖率对本年度的蜜蜂密度和潜在产量成分具有有益影响。