Mixture toxicity of tebuconazole and fluopyram to honeybee (Apis mellifera L.): Effects on survival, feeding and antioxidant defenses

Effect of carbendazim on honey bee health: Assessment of survival, pollen consumption, and gut microbiome composition

Seasonal variability in physiology and behavior affect the impact of fungicide exposure on honey bee (Apis mellifera) health

Simple SummaryPollinators adjust their foraging preference based on the pollen cues of foraging plants. Honey bees, for example, prefer to collect one type of pollen from plants that bloom at the same time. In northern China, apricot and pear trees are the two main foraging plants in the early spring. However, honey bees tend to collect pollen from apricot trees. It is interesting to understand what affects the foraging decision of honey bees regarding these two pollen types. In this study, we observed the foraging preference of Apis mellifera workers with respect to apricot and pear pollen under laboratory conditions. The effect of pollen on the development of the hypopharyngeal gland (HG) and ovary was measured. The number of visits made to apricot pollen was significantly higher than that to pear pollen. Furthermore, the response of the HG and ovary to these two pollens was different. The development of the HG was significantly affected by pollen diet treatments. However, there was no significant difference in the ovarian development of caged workers supplied with the two different pollen diets. Overall, honey bees showed a significant preference for apricot pollen over pear pollen. Compared with the ovary, the HG of honey bee workers may be more sensitive to pollen nutrition.With the availability of various plants in bloom simultaneously, honey bees prefer to collect some pollen types over others. To better understand pollen’s role as a reward for workers, we compared the digestibility and nutritional value of two pollen diets, namely, pear (Pyrus bretschneideri Rehd.) and apricot (Armeniaca sibirica L.). We investigated the visits, pollen consumption, and pollen extraction efficiency of caged Apis mellifera workers. Newly emerged workers were reared, and the effects of two pollen diets on their physiological status (the development of hypopharyngeal glands and ovaries) were compared. The choice-test experiments indicated a significant preference of A. mellifera workers for apricot pollen diets over pear pollen diets (number of bees landing, 29.5 ± 8.11 and 9.25 ± 5.10, p < 0.001 and pollen consumption, 0.052 ± 0.026 g/day and 0.033 ± 0.013 g/day, p < 0.05). Both pollen diets had comparable extraction efficiencies (67.63% for pear pollen and 67.73% for apricot pollen). Caged workers fed different pollen diets also exhibited similar ovarian development (p > 0.05). However, workers fed apricot pollen had significantly larger hypopharyngeal glands than those fed pear pollen (p < 0.001). Our results indicated that the benefits conferred to honey bees by different pollen diets may influence their foraging preference.

A combination of Tropilaelaps mercedesae and imidacloprid negatively affects survival, pollen consumption and midgut bacterial composition of honey bee

ABSTRACTHoney bees are critical pollinators in both agricultural and ecological settings. Recent declines in honey bee colonies in the United States have put increased strain on agricultural pollination. Although there are many environmental stressors implicated in honey bee disease, there has been intensifying focus on the role of microbial attacks on honey bee health. Despite the long-standing appreciation for the association of fungi of various groups with honey bees and their broader environment, the effects of these interactions on honey bee health are incompletely understood. Here, we report the discovery of colonization of the honey bee digestive tract by the environmental yeast Lachancea thermotolerans. Experimental colonization of honey bee digestive tracts by L. thermotolerans revealed that this yeast species maintains high levels in the honey bee midgut only at temperatures below the typical colony temperature. In newly eclosed bees, L. thermotolerans colonization alters the microbiome, suggesting that environmental yeasts can impact its composition. Future studies should be undertaken to better understand the role of L. thermotolerans and other environmental yeasts in honey bee health.IMPORTANCE Although many fungal species are found in association with honey bees and their broader environment, the effects of these interactions on honey bee health are largely unknown. Here, we report the discovery that a yeast commonly found in the environment can be found at high levels in honey bee digestive tracts. Experimentally feeding this yeast to honey bees showed that the yeast’s ability to maintain high levels in the digestive tract is influenced by temperature and can lead to alterations of the microbiome in young bees. These studies provide a foundation for future studies to better understand the role of environmental yeasts in honey bee health.

Pollen feeding in the honeybee (Apis mellifera) is dependent on the caste, ethotype, and dominance status of individuals. Pollen is the near-exclusive external source of lipids for the colony. Lipids from pollen are rich in polyunsaturated fatty acyl residues, which, because of their sensitivity to lipid peroxidation, have been suggested to limit the lifespan of individual bees. We here investigated whether the spectrum of phosphatidylcholine (PC), the main class of membrane-constituting lipids in insects, is indeed, connected to pollen feeding. We further studied the relationship between pollen feeding, PC spectra, and fat-body stores of vitellogenin, an indicator of potential longevity in bees. For this, we determined the pollen consumption, PC spectra, abdominal vitellogenin stores, and behavioral as well as reproductive status of individuals in queenless groups of workers. In contrast to earlier studies, we found that reproduction in workers is not universally linked to trophallactic dominance alone, but can be accompanied by strong pollen consumption. Pollen consumption seemed connected to a strong remodeling of tissue PC spectra. There was no systematic link between these spectra and trophallactic activity, but individuals with strongly deviating spectra also showed extreme behavioral profiles. Abdominal vitellogenin was strongly and positively linked to pollen-influenced PC spectra and the prevalence of polyunsaturated fatty acyl residues, contradicting the hypothesis that pollen consumption is systematically leading to a shorter lifespan in workers. Our results suggest that the association between pollen consumption, short lifespan, and functional sterility that differentiates workers from queens cannot in all cases be extended to the situation within the worker caste.

Microplastics (MPs), as an environmental contaminant, pose a significant risk to both animal and human health through the food and water supply chains. Honey, widely recognised as a safe and health‐oriented food product, may become compromised if its production process involves non‐biodegradable MPs. This study was conducted as a systematic review, using comprehensive searches of PubMed, Scopus and ScienceDirect to investigate the effects of MP on honey bee and human health, and the potential route and main species and composition of MP contamination in honey. This review highlights the impacts of MPs on honey bee health, including mortality, sucrose response, sucrose habituation, olfactory learning, memory recall, colony performance, body size and growth, gut microbiota and viral infection. From a mechanistic perspective, MPs can disrupt the equilibrium of the gut microbiota, adversely impact the function of the immune system, and undermine neural signalling pathways that are critical for learning and memory processes in honey bees. It is crucial to consider the applied aspects of these findings in beekeeping practices, including adopting sustainable practices to mitigate exposure to MPs and minimize contamination in honey production. The study also provided detailed information on honey bee contact routes with MPs, the environment (air, water, soil, pollen), and routes of exposure to MPs in beekeeping practices (plastic composition of the hive and beekeeping activities). MPs can adversely affect human health by altering energy homeostasis, causing oxidative stress, immune system deficiencies, malnutrition, reduced growth and decreased reproductive rates. Synthesis and applications. The findings of this study are highly relevant to both the beekeeping industry and public health policymakers. By identifying key contamination routes and the detrimental effects of microplastics (MPs) on honey bee health and honey quality, this research provides actionable insights for beekeepers to adopt sustainable hive management practices that minimise MP exposure. Additionally, the study underscores the need for regulatory policies to control MP pollution, ensuring the safety of honey as a food product and protecting both pollinators and human health.

Working with State and Provincial Apiary Programs to Manage Honey Bee (Apis mellifera) Health

No detectable impact of chronic oral lactic acid exposure on honey bee health: Insights from survival, lactate accumulation and head transcriptome.

Western honey bees (Apis mellifera), a cornerstone to crop pollination in the U.S., are faced with an onslaught of challenges from diseases caused by parasites, pathogens, and pests that affect this economically valuable pollinator. Natural products (NPs), produced by living organisms, including plants and microorganisms, can support health and combat disease in animals. NPs include both native extracts and individual compounds that can reduce disease impacts by supporting immunity or directly inhibiting pathogens, pests, and parasites. Herein, we describe the screening of NPs in laboratory cage studies for their effects on honey bee disease prevention and control. Depending on the expected activity of compounds, we measured varied responses, including viral levels, honey bee immune responses, and symbiotic bacteria loads. Of the NPs screened, several compounds demonstrated beneficial activities in honey bees by reducing levels of the critical honey bee virus deformed wing virus (DWV-A and-B), positively impacting the gut microbiome or stimulating honey bee immune responses. Investigations of the medicinal properties of NPs in honey bees will contribute to a better understanding of their potential to support honey bee immunity to fight off pests and pathogens and promote increased overall honey bee health. These investigations will also shed light on the ecological interactions between pollinators and specific floral food sources.

Through their pollination services, honey bees serve an essential role in sustaining the nutrition, health, and shelter of humans and other animals. Because of the demand for their pollination services, beekeepers strive to keep honey bees healthy and productive. Unfortunately, many factors commonly found throughout the USA can detract from honey bee health. For example, infections with pathogens such as viruses and Nosema spp. pose a significant threat to honey bee survival. Viruses and Nosema spp. must invade cells of their host to reproduce and complete their development. To better understand the interaction between intracellular pathogens and honey bee cells, tools are needed that allow examination of infection at fine resolution and under controlled, aseptic conditions. One tool that has been underutilized in honey bee biology is cell culture; therefore, the focus of this chapter is to discuss the technique and use of honey bee cells in culture. Infection of honey bee cells in culture with the fungal pathogen, Nosema ceranae, is used as an example to demonstrate how cell culture can be a powerful tool to explore the process of infection and the negative impact pathogens may have on honey bee biology and health.

Cadmium and lead-based nanotechnologies are increasingly used in agricultural, industrial, and biological processes; however, potential adverse effects of nanomaterials on honey bees had not been assessed. In this study, effects of exposures to sublethal concentrations of PbO and CdO nanoparticles (NPs), either separately or in combination on honey bee (Apis mellifera) workers, were assessed. Honey bee workers were orally exposed for 9days under laboratory conditions to sublethal concentrations (20% of LC50) of CdO (0.01mg/ml-) and PbO (0.65mg/ml-) NPs either separately or combined. Effects on survival, feeding rate, activity of acetylcholinesterase (AChE), and expression of selected stress-related detoxifying enzymes were quantified. Survival and feeding rates decreased particularly in bees fed sugar syrup containing CdO NPs or binary mixtures of NPs of both metal oxides. Expressions of genes involved in detoxification of xenobiotics were affected by various combinations. Expression of catalase was 13.6-fold greater in bees consumed sugar syrup diet containing binary mixture of sublethal concentrations of both CdO and PbO NPs than it was in unexposed, control bees. AChE activity in heads of honey bees was inhibited by 3.8-, 3.0-, and 2.8-fold relative to control, respectively, in response to exposure to Cd or/and Pb oxide NPs. This result indicates potential neurotoxic effects of these NPs to honey bees. CdO NPs exhibited greater potency to honey bees. Overall, sublethal concentrations of CdO or/and PbO NPs resulted in detrimental effects on honeybee workers.

Вплив препарату «Шумерське срібло» на життєздатність медоносних бджіл та вміст окремих мікроелементів в їх організмі

Simple SummaryHoney bees are key pollinators in agricultural crops. Today, honey bee colonies in decline are a global concern as a result of various stressors, including pesticides, pathogens, honey bee health, and parasites. A healthy honey bee colony refers to colonies that are not exposed to biotic and abiotic stressors. In this study, we examine how thiamethoxam (pesticide) and deformed wing virus type A (DWV-A) interact in effects on honey bee health. The results revealed that the honey bees were infected with DWV-A and were additionally exposed to thiamethoxam, showing effects that increased the mortality rate, and crippled wings in newly emerged adult honey bees. Moreover, the exposure to thiamethoxam and DWV-A injection resulted in induced expression of immune genes (hymenoptaecin gene) while downregulation of two apoptosis genes (caspase8-like, caspase9-like genes). The impact interaction of pesticide and DWV-A have on the expression of apoptosis genes can directly affect viral susceptibility in the honey bee host.Honey bees are economically important insects for crop pollination. They play a significant role as pollinators of wild plants and agricultural crops and produce economical products, such as honey, royal jelly, wax, pollen, propolis, and venom. Despite their ecological and economical importance, the global honey bee population is in decline due to factors including pathogens, parasites, intensive agriculture, and pesticides. Moreover, these factors may be interlinked and exacerbate the loss of honey bees. This study aimed to investigate the interaction between a pesticide, thiamethoxam, and deformed wing virus type A (DWV-A) to honey bees and the effects on survival rate, wing characteristics, and expression of immune and apoptosis genes in Apis mellifera. We described the potential interaction between thiamethoxam and DWV-A on honey bee wing characteristics, DWV-A loads, and the expressions of immune (defensin, abaecin, and hymenoptaecin) and apoptosis genes (buffy, apaf1, caspase3-like, caspase8-like, and caspase9-like). Honey bee larvae were fed with three different thiamethoxam doses (0.001, 1.4, and 14.3 ng/µL of the diet). Then, thiamethoxam-treated white-eyed pupae were injected with 107 copy numbers/honey bee of the DWV-A genome. The interaction between thiamethoxam and DWV-A caused a high mortality rate, crippled wings in newly emerged adult honey bees (100%), and resulted in induced expression of hymenoptaecin gene compared to the control group, while downregulation of caspase8-like, caspase9-like genes compared to the DWV injection group. Therefore, the potential interaction between thiamethoxam and DWV-A might have a deleterious effect on honey bee lifespan. The results from this study could be used as a tool to combat DWV-A infection and mitigate pesticide usage to alleviate the decrease in the honey bee population.

The use of gut bacteria isolated from Thai honey bees (Apis spp.) to control Nosema ceranae infection in the giant honey bee, Apis dorsata.