Emerging infectious diseases (EIDs) pose a risk to human welfare, both directly and indirectly, by affecting managed livestock and wildlife that provide valuable resources and ecosystem services, ...such as the pollination of crops. Honeybees (Apis mellifera), the prevailing managed insect crop pollinator, suffer from a range of emerging and exotic high-impact pathogens, and population maintenance requires active management by beekeepers to control them. Wild pollinators such as bumblebees (Bombus spp.) are in global decline, one cause of which may be pathogen spillover from managed pollinators like honeybees or commercial colonies of bumblebees. Here we use a combination of infection experiments and landscape-scale field data to show that honeybee EIDs are indeed widespread infectious agents within the pollinator assemblage. The prevalence of deformed wing virus (DWV) and the exotic parasite Nosema ceranae in honeybees and bumblebees is linked; as honeybees have higher DWV prevalence, and sympatric bumblebees and honeybees are infected by the same DWV strains, Apis is the likely source of at least one major EID in wild pollinators. Lessons learned from vertebrates highlight the need for increased pathogen control in managed bee species to maintain wild pollinators, as declines in native pollinators may be caused by interspecies pathogen transmission originating from managed pollinators.
Growing evidence for declines in bee populations has caused great concern because of the valuable ecosystem services they provide. Neonicotinoid insecticides have been implicated in these declines ...because they occur at trace levels in the nectar and pollen of crop plants. We exposed colonies of the bumble bee Bombus terrestris in the laboratory to field-realistic levels of the neonicotinoid imidacloprid, then allowed them to develop naturally under field conditions. Treated colonies had a significantly reduced growth rate and suffered an 85% reduction in production of new queens compared with control colonies. Given the scale of use of neonicotinoids, we suggest that they may be having a considerable negative impact on wild bumble bee populations across the developed world.
Pathogens and lack of floral resources interactively impair global pollinator health. However, epidemiological and nutritional studies aimed at understanding bee declines have historically focused on ...social species, with limited evaluations of solitary bees. Here, we asked whether Crithidia bombi, a trypanosomatid gut pathogen known to infect bumble bees, could infect the solitary bees Osmia lignaria (females) and Megachile rotundata (males), and whether nutritional stress influenced infection patterns and bee survival. We found that C. bombi was able to infect both solitary bee species, with 59% of O. lignaria and 29% of M. rotundata bees experiencing pathogen replication 5–11 days following inoculation. Moreover, access to pollen resulted in O. lignaria living longer, although it did not influence M. rotundata survival. Access to pollen did not affect infection probability or resulting pathogen load in either species. Similarly, inoculating with the pathogen did not drive survival patterns in either species during the 5–11-day laboratory assays. Our results demonstrate that solitary bees can be hosts of a known bumble bee pathogen, and that access to pollen is an important contributing factor for bee survival, thus expanding our understanding of factors contributing to solitary bee health.
The aim of the study was to determine the effectiveness of the drug "Cobazin" on the productivity of bee colonies during the increase in strength (increase in the number of young bees in the bee ...colony) in spring and autumn.
Materials and methods. Control and experimental groups were formed to test "Cobazin" feed supplement. It was fed 5 times with an interval of 5 days. Bee colonies from the control group received a pure sugar solution (1:1) in the amount of 0.5 liters per bee colony, and the experimental group received a sugar solution of 0.5 liters per bee colony (1:1) with the addition of the drug "Cobazin" in the amount of 2.5 g.
Indicators characterizing the development of bee colonies were determined by a measuring frame of 5x5 cm in size, for 12 days to cover the total number of eggs laid by the queen bee during feeding. Four measurements were performed during the study. The results of the control and experimental groups were compared and the significance of the differences between them was established. There was a comparison of the difference between groups of bees both fed pure sugar syrup in a ratio of 1:1 and syrup with the addition of the drug "Cobazin".
Results. It is proved that during the feeding period the number of brood in bee colonies that received feed supplement "Cobazin" increased significantly by 76 % (71 % in the group that received only sugar solution without this drug). Live weight of queen bees in colonies that were stimulated with "Cobazin" was actually 2 % higher compared to the control group.
It was found that at the end of the bee season, bee colonies fed in May with the feed supplement "Cobazin" had significantly higher values of strength, number of sealed brood and live queen bees compared to those who received pure sugar solution. The brood in the control group was 25 % lower than in the experimental group.
Conclusions. For the first time it was proved that the use of feed supplement "Cobazin" in combination with sugar solution has a positive effect on the features that characterize the development of bee colonies (strength, number of sealed brood) and their health productivity. The positive impact is observed not only during feeding, but also in subsequent periods of colony development.
Reports of honey bee population decline has spurred many national efforts to understand the extent of the problem and to identify causative or associated factors. However, our collective ...understanding of the factors has been hampered by a lack of joined up trans-national effort. Moreover, the impacts of beekeeper knowledge and beekeeping management practices have often been overlooked, despite honey bees being a managed pollinator. Here, we established a standardised active monitoring network for 5 798 apiaries over two consecutive years to quantify honey bee colony mortality across 17 European countries. Our data demonstrate that overwinter losses ranged between 2% and 32%, and that high summer losses were likely to follow high winter losses. Multivariate Poisson regression models revealed that hobbyist beekeepers with small apiaries and little experience in beekeeping had double the winter mortality rate when compared to professional beekeepers. Furthermore, honey bees kept by professional beekeepers never showed signs of disease, unlike apiaries from hobbyist beekeepers that had symptoms of bacterial infection and heavy Varroa infestation. Our data highlight beekeeper background and apicultural practices as major drivers of honey bee colony losses. The benefits of conducting trans-national monitoring schemes and improving beekeeper training are discussed.
Large-scale losses of honey bee colonies represent a poorly understood problem of global importance. Both biotic and abiotic factors are involved in this phenomenon that is often associated with high ...loads of parasites and pathogens. A stronger impact of pathogens in honey bees exposed to neonicotinoid insecticides has been reported, but the causal link between insecticide exposure and the possible immune alteration of honey bees remains elusive. Here, we demonstrate that the neonicotinoid insecticide clothianidin negatively modulates NF-κB immune signaling in insects and adversely affects honey bee antiviral defenses controlled by this transcription factor. We have identified in insects a negative modulator of NF-κB activation, which is a leucine-rich repeat protein. Exposure to clothianidin, by enhancing the transcription of the gene encoding this inhibitor, reduces immune defenses and promotes the replication of the deformed wing virus in honey bees bearing covert infections. This honey bee immunosuppression is similarly induced by a different neonicotinoid, imidacloprid, but not by the organophosphate chlorpyriphos, which does not affect NF-κB signaling. The occurrence at sublethal doses of this insecticide-induced viral proliferation suggests that the studied neonicotinoids might have a negative effect at the field level. Our experiments uncover a further level of regulation of the immune response in insects and set the stage for studies on neural modulation of immunity in animals. Furthermore, this study has implications for the conservation of bees, as it will contribute to the definition of more appropriate guidelines for testing chronic or sublethal effects of pesticides used in agriculture.
Honey bees are a highly valued resource around the world. They are prized for their honey and wax production and depended upon for pollination of many important crops. While globally honey bee ...populations have been increasing, the rate of increase is not keeping pace with demand. Further, honey bee populations have not been increasing in all parts of the world, and have declined in many nations in Europe and in North America. Managed honey bee populations are influenced by many factors including diseases, parasites, pesticides, the environment, and socio-economic factors. These factors can act alone or in combination with each other. This review highlights the present day value of honey bees, followed by a detailed description of some of the historical and present day factors that influence honey bee populations, with particular emphasis on colony populations in Europe and the United States.
The gut microbiota can have profound effects on hosts, but the study of these relationships in humans is challenging. The specialized gut microbial community of honey bees is similar to the mammalian ...microbiota, as both are mostly composed of host-adapted, facultatively anaerobic and microaerophilic bacteria. However, the microbial community of the bee gut is far simpler than the mammalian microbiota, being dominated by only nine bacterial species clusters that are specific to bees and that are transmitted through social interactions between individuals. Recent developments, which include the discovery of extensive strain-level variation, evidence of protective and nutritional functions, and reports of eco-physiological or disease-associated perturbations to the microbial community, have drawn attention to the role of the microbiota in bee health and its potential as a model for studying the ecology and evolution of gut symbionts.
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