Chemical signatures of floral resource competition between honeybees and wild bees along a landuse gradient

由于蜜蜂数量多、资源利用通用性强、竞争力强，被认为对当地传粉者，特别是野生蜜蜂产生了负面影响。然而，这种影响的证据很少，因为对资源的竞争很难在移动的和长期生存的生物体中表现出来。我们将利用生物多样性探索实验室的独特优势，探索蜜蜂与它们的野生群居近亲熊蜂(Bombus spp.)之间的竞争性相互作用。首先，我们将“读取”蜜蜂和大黄蜂在花朵上的碳氢化合物沉积(“足迹”)，以评估它们之间的花卉资源重叠。这项新技术将为所有草原试验田中足够多的复制植物物种提供访问数据，以便能够在蜜蜂丰度较高的地区检测到大黄蜂从首选花朵中移开的情况。其次，我们将测量大黄蜂的健康相关特征，并分析这些特征的差异是由与蜜蜂的竞争、土地利用还是这两个因素的共同影响来解释的。第三，我们将在人工蜂箱中对大黄蜂进行实地实验，直接测试蜜蜂对大黄蜂觅食和繁殖的影响。将多重复相关方法与田间试验相结合，将得出关于蜜蜂对中欧野生传粉者的竞争影响以及与土地利用相互作用的一般性结论。

Domesticated honeybees (Apis mellifera) are suspected to have negative impacts on native pollinators, particularly wild bees, due to their large numbers, generalist resource use, and competitive strength. However, evidence for such effects is scant since competition for resources is difficult to demonstrate in mobile and long-lived organisms. We will exploit the unique advantages of the biodiversity exploratories to probe for competitive interactions between honeybees and their wild eusocial relatives, bumblebees (Bombus spp.). First, we will “read” hydrocarbon deposits (“footprints”) of honeybees and bumblebees on flowers to assess floral resource overlap between them. The novel technique will provide visitation data for sufficient replicate plant species across all grassland experimental plots so as to allow the detection of bumblebee displacement from preferred flowers in areas with high honeybee abundance. Second, we will measure fitness-related traits in bumblebees and analyze whether variation in these traits is explained by competition with honeybees, by land use or by a combined effect of these two factors. Third, we will conduct a field experiment with bumblebees in artificial hives to test directly for honeybee effects on bumblebee foraging and reproduction. The combination of multi-replicate correlative approaches with field experiments will allow general conclusions on the competitive impact of honeybees on wild pollinators in Central Europe and interactions with land use.