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

驯化蜜蜂（Apis mellifera）被怀疑对本地传粉者，特别是野生蜜蜂产生负面影响，因为它们数量众多，资源利用广泛，竞争优势强。然而，这种影响的证据很少，因为对资源的竞争很难在移动和长寿的生物体中得到证明。我们将利用生物多样性探索的独特优势来探索蜜蜂与其野生真社会亲戚大黄蜂（Bombus spp.）之间的竞争相互作用。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物（“足迹”），以评估它们之间的花卉资源重叠。该新技术将为所有草地实验地块提供足够的复制植物物种的访问数据，以便在蜜蜂丰度高的地区检测大黄蜂从首选花朵上迁移的情况。其次，我们将测量大黄蜂的适应性相关特征，并分析这些特征的变化是由与蜜蜂的竞争、土地利用还是这两个因素的综合影响来解释的。第三，我们将在人工蜂巢中对大黄蜂进行实地试验，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实地实验相结合，将对中欧蜜蜂对野生传粉媒介的竞争影响以及与土地利用的相互作用得出一般性结论。

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.