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

• Applicant: Privatdozent Dr. Thomas Eltz
• Subject Area: Ecology and Biodiversity of Plants and Ecosystems
• Term: from 2011 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 193567699

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.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1374: Biodiversity Exploratories
• Participating Person: Professor Dr. Nico Blüthgen