Red mason bees cannot compete with honey bees for floral resources in a cage experiment

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 18 m³ 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.

Fragmentation of nest and foraging habitat affects time budgets of solitary bees, their fitness and pollination services, depending on traits: Results from an individual-based model

“…As a minimum, the distribution of these traits in a community is needed to simulate realistic vegetation patches. At the same time, additional model rules may be required when bee species face different types of flowers or when the presence of other species affects foraging behaviour [80] or brood cell number [81]. A further advantage of such an attempt with real bee densities for each species separately is that it overrules the assumption that pollinator density scales negatively with body size and positively with foraging resources, which had a prominent effect on our results.…”

Complex long‐term dynamics of pollinator abundance in undisturbed Mediterranean montane habitats over two decades

“…“Pollinator decline,” however, is not necessarily synonymous with “pollination decline” (Thomson ). Failure of keystone pollinators may not cause a decay in pollination success if it is followed by shifts in the composition and abundance of remaining pollinators that eventually compensate for the loss (Pauw , Hudewenz and Klein , Hallett et al. ).…”

“…"Pollinator decline," however, is not necessarily synonymous with "pollination decline" (Thomson 2001). Failure of keystone pollinators may not cause a decay in pollination success if it is followed by shifts in the composition and abundance of remaining pollinators that eventually compensate for the loss (Pauw 2007, Hudewenz and Klein 2015, Hallett et al 2017. Pollinator and pollination declines are expected to be tightly correlated in depauperate habitats with low overall diversity such as agroecosystems, where compensatory shifts by other species are unlikely to follow the decay of key pollinators (Kremen et al 2002).…”

Trap nests for bees and wasps to analyse trophic interactions in changing environments—A systematic overview and user guide

“…In addition to interaction networks, trap nests are promising tools for long term environmental monitoring (e.g., Steffan‐Dewenter & Schiele, ), pesticide residue (Peters, Gao, & Zumkier, ) or environmental pollution assessments (Moron, Szentgyoergyi, Skorka, Potts, & Woyciechowski, ) and can be used to stock animals for manipulative experiments (e.g., Hudewenz & Klein, ). Nonscientists know various modifications of the methodological approach behind trap nests as “bee hotels” or “insect hotels.” If maintained properly and depletion of local populations due to excessive collecting is avoided, these can have great potential for environmental education (Césard, Mouret, & Vaissiere, ) and citizen science projects (Everaars et al., ).…”

“…Dewenter & Schiele, 2008), pesticide residue (Peters, Gao, & Zumkier, 2016) or environmental pollution assessments (Moron, Szentgyoergyi, Skorka, Potts, & Woyciechowski, 2014) and can be used to stock animals for manipulative experiments (e.g., Hudewenz & Klein, 2015). Nonscientists know various modifications of the methodological approach behind trap nests as "bee hotels" or "insect hotels."…”