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Viruses are omnipresent, yet the knowledge on drivers of viral prevalence in wild host populations is often limited. Biotic factors, such as sympatric managed host species, as well as abiotic factors, such as climatic variables, are likely to impact viral prevalence. Managed and wild bees, which harbor several multi-host viruses with a mostly fecal-oral between-species transmission route, provide an excellent system with which to test for the impact of biotic and abiotic factors on viral prevalence in wild host populations. Here we show on a continental scale that the prevalence of three broad host viruses: the AKI-complex (Acute bee paralysis virus, Kashmir bee virus and Israeli acute paralysis virus), Deformed wing virus, and Slow bee paralysis virus in wild bee populations (bumble bees and solitary bees) is positively related to viral prevalence of sympatric honey bees as well as being impacted by climatic variables. The former highlights the need for good beekeeping practices, including Varroa destructor management to reduce honey bee viral infection and hive placement. Furthermore, we found that viral prevalence in wild bees is at its lowest at the extreme ends of both temperature and precipitation ranges. Under predicted climate change, the frequency of extremes in precipitation and temperature will continue to increase and may hence impact viral prevalence in wild bee communities., (© 2022. The Author(s).)

Beeswax foundations are a necessary material in intensive modern beekeeping. Heavy metals can accumulate in these foundations for decades, as it is a common beekeeping practice to recycle wax. Beeswax samples were analysed using GFAAS for As, Cd, Pb, and Hg concentrations during the production of beeswax foundations using casting technology with a prolonged cooling and sedimentation phase. Significant differences were determined in the concentrations of As, Cd, Pb (p<0.01, all), and Hg (p<0.05) between the three levels of wax in a double-walled steel casting container and comb foundations (CF) during the processing stage. Concentrations (mg kg-1) of the examined metals in comb foundations as the final product ranged as follows: As 0.01-0.88; Cd 1.26-3.55; Pb 82.5-171, and Hg 0.29-1.46. All examined element concentrations demonstrated similar distribution and ratio in different layers, ranging from the lowest concentrations in layers from which wax material is used for comb foundations as the final product, to the highest concentrations in sedimented layer, which represents waste. The obtained results suggest that the described method could effectively eliminate a significant amount of heavy metals from the initial material used for the production of new beeswax foundations.

Simple Summary: Diseases are a major cause of honeybee colony weakness and death. An effective and fast way to diagnose subclinical infections is by sampling and analyzing debris from hive bottom boards. Molecular tests, like PCR and qPCR can be used to identify disease-causing agents quickly. In this study, we analyzed hive debris samples from Croatian apiaries to check the presence of pathogens, such as Paenibacillus larvae, Melissococcus plutonius, Crithidia mellificae, Lotmaria passim, Vairimorpha spp. (Nosema spp.), Aethina tumida, Acute Bee Paralysis Virus (ABPV), Black Queen Cell Virus (BQCV), Deformed Wing Virus (DWV) and Sacbrood Virus (SBV). Debris samples were also examined to quantify Varroa destructor mites, and natural mite fall was observed in spring. Many honeybee colonies were infected with four to six agents, which is probably why some colonies failed to survive winter. Honeybee diseases are one of the most significant and most common causes of honeybee colonies' weakness and death. An early diagnosis of subclinical infections is necessary to implement precautionary and control measures. Sampling debris from hive bottom boards is simple, non-invasive, and cheap. In this study, we collected winter debris samples in apiaries located in the continental part of Croatia. We used molecular methods, PCR and qPCR, for the first time to analyze those samples. Laboratory results were compared with the health condition and strength of honeybee colonies at an apiary in spring. Our study successfully identified the presence and quantity of various pathogens, including the presence of Vairimorpha spp. (Nosema spp.), quintefied Paenibacillus larvae, Acute Bee Paralysis Virus (ABPV), Black Queen Cell Virus (BQCV), Deformed Wing Virus (DWV), and Sacbrood Virus (SBV). However, our analysis did not detect Melissococcus plutonius, Crithidia mellificae, Lotmaria passim, and Aethina tumida. Samples of winter debris were also examined for the presence and quantification of the V. destructor mites, and their natural mite fall was observed in spring. Honeybee colonies were simultaneously infected by an average of four to six pathogens. Some observed honeybee colonies developed characteristic symptoms, while others did not survive the winter. [ABSTRACT FROM AUTHOR]

The decline in pollinator insect abundance and diversity is increasing on a global scale. Major threats are the byproducts of numerous negative environmental pressures acting individually or in combination. They vary throughout different geographical areas, affecting the solitary bees differently. One of the most important negative pressures are the many parasites, predators and pests representing a threat to the successful reproduction of solitary bees in artificial nests. Especially vulnerable are the managed Osmia spp. bee populations reared for commercialization and trade. The primary goals of our monitoring study were: (i) to examine the presence and the prevalence of brood parasites in the various types of bees' nesting material and in semi-field rearing conditions using the nest section analyses; (ii) to determine the presence of Nosema spp. in samples of feces and homogenized bee abdomens using a multiplex PCR method; (iii) the evaluation of the survival success level and emergence mass of healthy bees at each of the four studied bee rearing locations separately, depending on different environments and on the implementation of different managing practices. We determined the presence and prevalence of nest destructor parasites and accompanying fauna. Their presence was positively correlated with bee rearing failures. The results of this study may be used as a baseline for further solitary bee nest parasites monitoring schemes. [ABSTRACT FROM AUTHOR]

To determine the presence and the prevalence of four different honeybee viruses (acute bee paralysis virus—ABPV, black queen cell virus—BQCV, chronic bee paralysis virus—CBPV, deformed wing virus—DWV) in wild bumblebees, pooled randomly selected bumblebee samples were collected from twenty-seven different locations in the territory of Croatia. All samples were prepared and examined using the RT-PCR methods for quantification of mentioned honeybee viruses. Determined prevalence (%) of identified positive viruses were in the following decreasing order: BQCV > DWV > ABPV, CBPV. Additionally, direct sequencing of samples positive for BQCV (n = 24) and DWV (n = 2) was performed, as well as a test of molecular phylogeny comparison with those available in GenBank. Selected positive field viruses' strains showed 95.7 to 100% (BQCV) and 98.09% (DWV) nucleotide identity with previously detected and deposited honeybee virus strains in the geographic areas in Croatia and neighboring Slovenia. In this article, the first detection of four honeybee viruses with genetic characterization of high diversity strains circulating in wild bumblebees in Croatia is presented. [ABSTRACT FROM AUTHOR]

Simple Summary: Various negative factors contribute to a decline in insect pollinators. The aim of this study was to assess the impact of commercial probiotic EM® PROBIOTIC FOR BEES on honey bees. The study was conducted in field and laboratory-controlled conditions. In the field, the sugar syrup with 10% of probiotic was administered by spraying or feeding the honey bee colonies in order to evaluate the colonies' strength and Nosema spp. infection levels. In the laboratory, the adult workers have been fed with sugar syrup supplemented with 2.5, 5, and 10% of EM® for bees for biochemical and immunological analyses of hemolymph, and with 5 and 10% for measuring the size of hypopharyngeal glands. It was found that following the EM® for bees administration the Nosema spp. spore counts in colonies were significantly reduced, and colonies' strength was increased. The results at the individual level showed positive physiological changes in treated groups of adult bees, but, at the same time, a higher mortality rate. Our findings indicate that the EM® for bees is a promising food additive for nosemosis combating. Therefore, additional emphasis needs to be placed on studies investigating the nutritional requirements crucial to improve and sustain honey bee colonies health. Several negative factors contribute to a decline in the number of insect pollinators. As a novel approach in therapy, we hypothesize that the EM® for bees could potentially have an important therapeutic and immunomodulatory effect on honey bee colonies. The aim of our study was to evaluate its impact on honey bees at the individual and colony level. This is the first appliance of the commercial probiotic mix EM® PROBIOTIC FOR BEES in honey bees as economically important social insects. The sugar syrup with 10% of probiotic was administered by spraying or feeding the honey bee colonies in the field conditions, in order to evaluate the infection levels with spores of Nosema spp. and colonies' strength. Moreover, in laboratory-controlled conditions, in the hoarding cages, adult workers have been fed with sugar syrup supplemented with 2.5, 5, and 10% of EM® for bees for biochemical and immunological analyses of hemolymph, and with 5 and 10% for measuring the size of hypopharyngeal glands. It was found that following the EM® for bees administration the Nosema spp. spore counts in colonies were significantly reduced, and colonies' strength was increased. The results at the individual level showed significant positive physiological changes in treated groups of adult bees, revealing at the same time a higher mortality rate when feeding sugar syrup supplemented with the probiotic. [ABSTRACT FROM AUTHOR]