Abstract
Intensive beekeeping to mitigate crop pollination deficits and habitat loss may cause interspecific competition between bees. Studies show negative correlations between flower visitation of honey bees (Apis mellifera) and wild bees, but effects on the reproduction of wild bees were not proven. Likely reasons are that honey bees can hardly be excluded from controls and wild bee nests are generally difficult to detect in field experiments. The goal of this study was to investigate whether red mason bees (Osmia bicornis) compete with honey bees in cages in order to compare the reproduction of red mason bees under different honey bee densities. Three treatments were applied, each replicated in four cages of 18m³ with 38 red mason bees in all treatments and 0, 100, and 300 honey bees per treatment with 10-20% being foragers. Within the cages, the flower visitation and interspecific displacements from flowers were observed. Niche breadths and resource overlaps of both bee species were calculated, and the reproduction of red mason bees was measured. Red mason bees visited fewer flowers when honey bees were present. Niche breadth of red mason bees decreased with increasing honey bee density while resource overlaps remained constant. The reproduction of red mason bees decreased in cages with honey bees. In conclusion, our experimental results show that in small and isolated flower patches, wild bees can temporarily suffer from competition with honey bees. Further research should aim to test for competition on small and isolated flower patches in real landscapes.
Highlights
The growing demand for pollination in agriculture has raised attention (Aizen and Harder 2009) and led to a widespread use of honey bee colonies placed in fields to provide pollination service
This study investigates whether the generalist and solitary red mason bee, Osmia bicornis L., is able to compete with social honey bees in cages that represented small and isolated flower-rich habitat patches
We show that red mason bees visited fewer flowers when honey bees were present and the niche breadth of the red mason bee decreased with increasing honey bee density and niche breadth
Summary
The growing demand for pollination in agriculture has raised attention (Aizen and Harder 2009) and led to a widespread use of honey bee colonies placed in fields to provide pollination service (e.g., almonds in California). The massive expansion of flowering crops may enhance abundances of honey bees (Holzschuh et al 2011), which could be competitors for flower resources in surrounding natural habitat patches. Before or after the peak of crop flowering, honey bees might switch to forage on flowers of surrounding natural habitats. Despite recent concern over the threats posed to honey bees by diseases, the worldwide number of domesticated honey bee colonies continues to increase (Aizen and Harder 2009).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
