Western Honey Bee Apis Mellifera Research Articles

Learning performance and GABAergic pathway link to deformed wing virus in the mushroom bodies of naturally infected honey bees.

Viral infections can be detrimental to the foraging ability of the western honey bee, Apis mellifera. The deformed wing virus (DWV) is the most common honey bee virus and has been proposed as a possible cause of learning and memory impairment. However, evidence for this phenomenon so far has come from artificially infected bees, while less is known about the implications of natural infections with the virus. Using the proboscis extension reflex (PER), we uncovered no significant association between a simple associative learning task and natural DWV load. However, when assessed through a reversal associative learning assay, bees with higher DWV load performed better in the reversal learning phase. DWV is able to replicate in the honey bee mushroom bodies, where the GABAergic signalling pathway has an antagonistic effect on associative learning but is crucial for reversal learning. Hence, we assessed the pattern of expression of several GABA-related genes in bees with different learning responses. Intriguingly, mushroom body expression of selected genes was positively correlated with DWV load, but only for bees with good reversal learning performance. We hypothesise that DWV might improve olfactory learning performance by enhancing the GABAergic inhibition of responses to unrewarded stimuli, which is consistent with the behavioural patterns that we observed. However, at higher disease burdens, which might be induced by an artificial infection or by a severe, natural Varroa infestation, this DWV-associated increase in GABA signalling could impair associative learning as previously reported by other studies.

Known and novel viruses in Belgian honey bees: yearly differences, spatial clustering, and associations with overwintering loss.

The western honey bee (Apis mellifera) is a highly effective pollinator of flowering plants, including many crops, which gives honey bees an outstanding importance both ecologically and economically. Alarmingly high annual loss rates of managed honey bee colonies are a growing concern for beekeepers and scientists and have prompted a significant research effort toward bee health. Several detrimental factors have been identified, such as varroa mite infestation and disease from various bacterial and viral agents, but annual differences are often not elucidated. In this study, we utilize the viral metagenomic survey of the EPILOBEE project, a European research program for bee health, to elaborate on the most abundant bee viruses of Flanders. We complement the existing metagenomic data with absolute viral loads and their spatial and temporal distributions. Furthermore, we identify Apis orthomyxovirus 1 as a potentially emerging pathogen, as we find evidence for its active replication honey bees.

Target and non-target effects of insecticide use during ornamental milkweed production

Abstract There are widespread public efforts to conserve wildlife in urbanized landscapes via the installation of nursery-grown plants that support Lepidoptera taxa. Insecticides are commonly used during nursery production to suppress key plant pests, and many products have extended periods of toxicity and affect a wide range of herbivore taxa. While there are plentiful toxicological data on bee species, predominantly the Western honey bee (Apis mellifera L.), little is known about how insecticides affect nonpest lepidopterans. Lepidoptera has different modes of exposure (e.g., leaf-feeding) and differences in susceptibility to insecticide target sites compared to bees. Consequently, many products compatible with bee conservation pose an uncertain risk to nonpest lepidopterans and thus may represent an under-recognized conflict with conservation efforts. Using the monarch butterfly (Danaus plexippus, L.), tropical milkweed (Asclepias curassavica, L.), and oleander aphid (Aphis nerii, Fonscolombe, 1841) system, we conducted leaf and whole-plant feeding assays to evaluate effects of acute and chronic monarch exposure to industry standard and alternative reduced-risk insecticides used during nursery production. We also evaluated the efficacy of these insecticides against their target pest, the oleander aphid. Our results indicate that insecticides used to control pests on ornamental milkweed can cause monarch larval mortality up to 4 wk after treatment application. Furthermore, the duration of aphid suppression is often shorter than the duration of adverse effects on monarchs. This study demonstrates a conflict between insect pest management and Lepidoptera conservation during ornamental plant production and has implications for the conservation value of ornamentals after retail sale.

Attractant spray enhances nesting preference and reduces macroparasite infestation of Osmia cornuta

AbstractMason bees (Osmia. spp) can provide an alternative for crop pollination management in addition to the Western honeybees (Apis mellifera). Targeted evidence‐based guidelines can improve cost‐effective management of mason bees. Here, I test the effect of an attractant spray developed in the United States for improving the nesting preference for artificial trap nests of mason bees in Belgium. More specifically, this study investigates the effect of the attractant spray on the nesting preference and nesting performance of the European orchard bee (Osmia cornuta), as well as its effect on the infestation of nest‐associated macroparasites. The number of sealed nesting cavities was twice as high in the trap nests that were treated with the attractant spray. Nesting performance expressed as number of brood cells per cavity, successful cocoon formation, adult emergence, proportion of female bees in the offspring and the number of dead larvae was not different between the treated and the untreated nests. Overall infestation of macroparasites, and infestation of drosophilid flies in particular, were both twice as high in untreated nests. This study provides evidence that the attractant spray improves nesting preference and reduces macroparasite infestation in O. cornuta. The use of this attractant can provide growers and stakeholders with an effective management strategy to prevent infestation by macroparasites and promote efficient bee breeding.

Transcriptional control of a metabolic switch regulating cellular methylation reactions is part of a common response to stress in divergent bee species.

Recent global declines in bee health have elevated the need for a more complete understanding of the cellular stress mechanisms employed by diverse bee species. We recently uncovered the biomarker lethal (2) essential for life (l(2)efl) genes as part of a shared transcriptional program in response to a number of cell stressors in the western honey bee (Apis mellifera). Here we describe another shared stress responsive gene, Glycine N-methyl transferase (Gnmt), which is known as a key metabolic switch controlling cellular methylation reactions. We observed Gnmt induction by both abiotic and biotic stressors. We also found increased levels of the GNMT reaction product sarcosine in the midgut after stress linking metabolic changes with the observed changes in gene regulation. Prior to this study, Gnmt upregulation has not previously been associated with cellular stress responses in other organisms. To determine whether this novel stress-responsive gene would behave similarly in other bee species, we first characterized the cellular response to ER stress in lab-reared adults of the solitary alfalfa leafcutting bee (Megachile rotundata) and compared with age-matched honey bees. The novel stress gene Gnmt was induced in addition to a number of canonical gene targets induced in both bee species upon UPR activation, suggesting that stress-induced regulation of cellular methylation reactions is a common feature of bees. Therefore, this study suggests that honey bee can serve as an important model for bee biology more broadly, although studies on diverse bee species will be required to fully understand global declines in bee populations.

Variation in Pesticide Toxicity in the Western Honey Bee (Apis mellifera) Associated with Consuming Phytochemically Different Monofloral Honeys.

Insecticide toxicity to insect herbivores has long been known to vary across different host plants; this phenomenon has been widely documented in both foliage-feeders and sap-feeders. Species-specific phytochemical content of hostplant tissues is assumed to determine the pattern of induction of insect enzymes that detoxify insecticides, but specific phytochemicals have rarely been linked to host plant-associated variation in pesticide toxicity. Moreover, no studies to date have examined the effects of nectar source identity and phytochemical composition on the toxicity of insecticides to pollinators. In this study, we compared LD50 values for the insecticide bifenthrin, a frequent contaminant of nectar and pollen in agroecosystems, in the western honey bee, Apis mellifera, consuming three phytochemically different monofloral honeys: Nyssa ogeche (tupelo), Robinia pseudoacacia (black locust), and Fagopyrum esculentum (buckwheat). We found that bifenthrin toxicity (LD50) values for honey bees across different honey diets is linked to their species-specific phytochemical content. The profiles of phenolic acids and flavonoids of buckwheat and locust honeys are richer than is the profile of tupelo honey, with buckwheat honey containing the highest total content of phytochemicals and associated with the highest bifenthrin LD50 in honey bees. The vector fitting in the ordination analysis revealed positive correlations between LD50 values and two honey phytochemical richness estimates, Chao1 and Abundance-based Coverage Estimator (ACE). These findings suggest unequal effects among different phytochemicals, consistent with the interpretation that certain compounds, including ones that are rare, may have a more pronounced effect in mitigating pesticide toxicity.

Development of a multiplex real-time quantitative reverse-transcription polymerase chain reaction for the detection of four bee viruses

Viruses in the families Dicistroviridae and Iflaviridae are among the main threats to western honey bees (Apis mellifera) and native bee species. Polymerase chain reaction (PCR) is the gold standard for pathogen detection in bees. However, high throughput screening for bee virus infections in singleplex PCR reactions is cumbersome and limited by the high quantities of sample RNA required. Thus, the development of a sensitive and specific multiplex PCR detection method for screening for multiple viruses simultaneously is necessary. Here, we report the development of a one-step multiplex reverse-transcription quantitative polymerase chain reaction (RT-qPCR) assay to detect four viruses commonly encountered in pollinator species. The optimized multiplex RT-qPCR protocol described in this study allows simultaneous detection of two dicistroviruses (Israeli acute paralysis virus and Black queen cell virus) and two iflaviruses (Sacbrood virus and Deformed wing virus) with high efficiency and specificity comparable to singleplex detection assays. This assay provides a broad range of detection and quantification, and the results of virus quantification in this study are similar to those performed in other studies using singleplex detection assays. This method will be particularly useful for data generation from small-bodied insect species that yield low amounts of RNA.

Apirhabdus apintestini gen. nov., sp. nov., a member of a novel genus of the family Enterobacteriaceae, isolated from the gut of the western honey bee Apis mellifera.

A Gram-negative, motile, rod-shaped bacterial strain, CA-0114T, was isolated from the midgut of a western honey bee, Apis mellifera. The isolate exhibited ≤96.43 % 16S rRNA gene sequence identity (1540 bp) to members of the families Enterobacteriaceae and Erwiniaceae. Phylogenetic trees based on genome blast distance phylogeny and concatenated protein sequences encoded by conserved genes atpD, fusA, gyrB, infB, leuS, pyrG and rpoB separated the isolate from other genera forming a distinct lineage in the Enterobacteriaceae. In both trees, the closest relatives were Tenebrionicola larvae YMB-R21T and Tenebrionibacter intestinalis BIT-L3T, which were isolated previously from Tenebrio molitor L., a plastic-eating mealworm. Digital DNA-DNA hybridization, orthologous average nucleotide identity and average amino acid identity values between strain CA-0114T and the closest related members within the Enterobacteriaceae were ≤23.1, 75.45 and 76.04 %, respectively. The complete genome of strain CA-0114T was 4 451669 bp with a G+C content of 52.12 mol%. Notably, the apparent inability of strain CA-0114T to ferment d-glucose, inositol and l-rhamnose in the API 20E system is unique among closely related members of the Enterobacteriaceae. Based on the results obtained through genotypic and phenotypic analysis, we propose that strain CA-0114T represents a novel species and genus within the family Enterobacteriaceae, for which we propose the name Apirhabdus apintestini gen. nov., sp. nov. (type strain CA-0114T=ATCC TSD-396T=DSM 116385T).

Molecular detection of Lotmaria passim in intestine of Japanese honeybees (Apis cerana japonica)

ABSTRACTCrithidia mellificae and Lotmaria passim are trypanosomatids that infect honeybees, and many studies suggest that both parasites contribute to the decline in the honeybee population. The Japanese honeybee (Apis cerana japonica) is a native honeybee that inhabits various areas of Japan and is one of the most important pollinators. Both parasites have been well studied in the western honeybee (Apis mellifera) but have been poorly investigated in A. c. japonica. The present study investigated the presence of C. mellificae and L. passim in one feral and six managed A. c. japonica colonies at three different institutes. Five out of seven colonies were polymerase chain reaction‐positive for L. passim (71.4%); however, C. mellificae was not detected. Four of the five colonies were positive in both the midgut and hindgut, but one was positive only in the hindgut. A homology search and phylogenetic tree of the glycosomal glyceraldehyde‐3‐phosphate dehydrogenase (gGAPDH) and cytochrome b (Cytb) genes obtained in this study indicated that the sequences belonged to L. passim. The results of this study emphasize concerns regarding the health of this ecologically important pollinator and the importance of further investigation of the prevalence of L. passim in A. c. japonica in a wider area of Japan.

Expression of honey bee (Apis mellifera) sterol homeostasis genes in food jelly producing glands of workers.

Adult workers of Western honey bees (Apis mellifera L.) acquire sterols from their pollen diet. These food sterols are transported by the hemolymph to peripheral tissues such as the mandibular and the hypopharyngeal glands in the worker bees' heads that secrete food jelly which is fed to developing larvae. As sterols are obligatory components of biological membranes and essential precursors for molting hormone synthesis in insects, they are indispensable to normal larval development. Thus, the study of sterol delivery to larvae is important for a full understanding of honey bee larval nutrition and development. Whereas hypopharyngeal glands only require sterols for their membrane integrity, mandibular glands add sterols, primarily 24-methylenecholesterol, to its secretion. For this, sterols must be transported through the glandular epithelial cells. We have analyzed for the first time in A. mellifera the expression of genes which are involved in intracellular movement of sterols. Mandibular and hypopharyngeal glands were dissected from newly emerged bees, 6-day-old nurse bees that feed larvae and 26-day-old forager bees. The expression of seven genes involved in intracellular sterol metabolism was measured with quantitative real-time PCR. Relative transcript abundance of sterol metabolism genes was significantly influenced by the age of workers and specific genes but not by gland type. Newly emerged bees had significantly more transcripts for six out of seven genes than older bees indicating that the bulk of the proteins needed for sterol metabolism are produced directly after emergence.

Determinants of honeybee hive survival and its implications for urban biodiversity in Toronto and Montreal: A Canadian case study

Cities are shown to provide favourable conditions for western honeybees (Apis mellifera) by protecting them from agricultural pesticides and offering a greater diversity of flora. Nevertheless, while current research primarily focuses on the causes of pollinator – and particularly honeybee – decline, including pesticide exposure, climate change, and habitat fragmentation, little attention is dedicated to urban apiculture and factors associated with the survival of honeybees within cities. Here, we analyse data from 3,697 honeybee hives in Montreal and Toronto to assess the effect of urban and environmental factors on hive survival. We find ground-level ozone concentrations, the height at which hives are located, and the number of surrounding hives to be negatively associated with hive survival, which may point towards an issue of hive saturation. Conversely, vegetation density and the COVID-19 pandemic are positively associated with the likelihood of hive survival, emphasizing the effect of urban air pollution. These findings highlight the need for urban planners to consider neighborhood-scale environmental factors to identify potential venues for enhancing honeybee survival within cities beyond existing urban beekeeping initiatives.

Biodiversity and Challenges of Honey Bee Population in Pakistan

Honey bees are important pollinators that support food security and nature’s biodiversity. They are also a source of various honey bee-derived products (api-products) used in the food, pharmaceutical, and cosmetic industries. However, various biological, chemical and physical factors threaten the population and biodiversity of feral and managed honey bees. These challenges have not been elaborated upon in the Pakistani context; therefore, this review aims to identify and describe the menaces to feral and domesticated populations of honey bees in Pakistan. Four honey bee species are reported in the country, with the Western honey bee (Apis mellifera) currently being the main domesticated species. Climate change and urbanization are altering the habitats of honey bees. Additionally, agrochemicals are extensively used to manage emerging pests, exacerbating environmental pollution. The air quality in the majority of urban areas is toxic for honey bees. Although remote forest areas can provide habitat and food for these insects, low forest cover and non-sustainable silviculture are still significant hurdles. Microplastics and antimicrobials are impacting the fitness of honey bees and also appear in their products, making it a One-Health issue. Electromagnetic signals also influence honey bee health and behavior. Overall, all these factors influence honey bee health and colony fitness, ultimately causing population declines in both managed and wild honey bees. The purpose of this information is to assist decision-makers, researchers, beekeepers and educators in comprehending the obstacles faced by the honey bee population within the context of Pakistan.

Roles of DNA Methylation in Color Alternation of Eastern Honey Bees (Apis cerana) Induced by the Royal Jelly of Western Honey Bees (Apis mellifera).

Honey bees have a very interesting phenomenon where the larval diets of two different honey bee species are exchanged, resulting in altered phenotypes, namely, a honey bee nutritional crossbreed. This is a classical epigenetic process, but its underlying mechanisms remain unclear. This study aims to investigate the contribution of DNA methylation to the phenotypic alternation of a Apis mellifera-Apis cerana nutritional crossbreed. We used a full nutritional crossbreed technique to rear A. cerana queens by feeding their larvae with A. mellifera royal-jelly-based diets in an incubator. Subsequently, we compared genome-wide methylation sequencing, body color, GC ratio, and the DMRs between the nutritional crossbreed, A. cerana queens (NQs), and control, A. cerana queens (CQs). Our results showed that the NQ's body color shifted to yellow compared to the black control queens. Genome methylation sequencing revealed that NQs had a much higher ratio of mCG than that of CQs. A total of 1020 DMGs were identified, of which 20 DMGs were enriched into key pathways for melanin synthesis, including tryptophan, tyrosine, dopamine, and phenylalanine KEGG pathways. Three key differentially methylated genes [OGDH, ALDH(NAD+) and ALDH7] showed a clear, altered DNA methylation in multiple CpG islands in NQs compared to CQs. Consequently, these findings revealed that DNA methylation participates in A. cerana-A. mellifera nutritional crossbreeding as an important epigenetic modification. This study serves as a model of cross-kingdom epigenetic mechanisms in insect body color induced by environmental factors.

Developing a method to rear Varroa destructor in vitro.

Varroa destructor is a significant mite pest of western honey bees (Apis mellifera). Developing a method to rear and maintain populations of V. destructor in vitro would provide year-round access to the mites, allowing scientists to study their biology, behavior, and control more rapidly. In this study, we determined the impact of various rearing parameters on V. destructor survival and reproduction in vitro. This was done by collecting V. destructor from colonies, placing them in gelatin capsules containing honey bee larvae, and manipulating the following conditions experimentally: rearing temperature, colony source of honey bee larva, behavioral/developmental stages of V. destructor and honey bee larva, and mite:bee larva ratio. Varroa destructor survival was significantly impacted by temperature, colony source of larvae and mite behavioral stage. In addition, V. destructor reproduction was significantly impacted by mite: larva ratio, larval developmental stage, colony source of larva, and temperature. The following conditions optimized mite survival and reproduction in vitro: using a 4:1 mite:larva ratio, beginning the study with late stage uncapped larvae, using mites collected from adult bees, maintaining the rearing temperature at 34.5° C, and screening larval colony source. Ultimately, this research can be used to improve V. destructor in vitro rearing programs.

Future range dynamics of Asian yellow-legged hornets (Vespa velutina) and their range overlap with Western honey bees (Apis mellifera) reveal major challenges for bee conservation in Europe.

The invasion of Asian yellow-legged hornets (Vespa velutina) has significantly affected Western honey bees (Apis mellifera) and apiculture in Europe. However, the range dynamics of this hornet and its range overlap with the bees under future change scenarios have not yet been clarified. Using land-use, climate, and topographical datasets, we projected the range dynamics of this hornet and Western honey bees in Europe and the future overlap of their ranges. We found that climatic factors had stronger effects on the potential ranges of the hornets compared with land-use and topographical factors. A considerable range expansion of this hornet was predicted, and an increase in the overlap between this pest and the bees was primarily caused by future decreases in temperature seasonality. Additionally, we detected future range expansions of the hornet in the UK and France; future range overlap between this pest and Western honey bees in the UK, Ireland, Portugal, and France; and future overlap between the ranges of this pest and bees but not under recent conditions was mainly projected in Germany, Denmark, and the UK. Mitigating future climate change might effectively control the proliferation of the hornets and their effects on the bees. Strategies for preventing the invasion of this pest and developing European apiculture should be developed and implemented in these regions where future range overlap between them was projected. Given that climate-change scenarios may result in uncertainty in our projections, further investigation is needed to clarify future range changes of our target species. © 2024 Society of Chemical Industry.

An Aspergillus flavus strain from bee bread of the Western honey bee (Apis mellifera) displays adaptations to distinctive features of the hive environment.

Aspergillus fungi are ubiquitous inhabitants of colonies of the western honey bee (Apis mellifera), where they interact with bees in associations ranging from parasitism to possible mutualism. Aspergillus Flavi fungi are frequently found in bee bread (pollen processed for longterm storage) and are thought to contribute to food preparation, processing, preservation, and digestion. Conditions in the hive are challenging for fungi due, in part, to xeric and acidic properties of bee bread and the omnipresence of propolis, an antimicrobial product manufactured by bees from plant resins. We used quantitative and qualitative assays to determine whether A. flavus isolated from bee bread demonstrates tolerance for hive environmental conditions in terms of temperature, pH, osmotic pressure, and propolis exposure. Comparisons made use of three strains of A. flavus: a fungal biocontrol product not known from beehives (AF36), a strain isolated from bee bread (AFBB) in hives from central Illinois, and a pathogenic strain from a honey bee colony displaying symptoms of stonebrood (AFPA). Strain AFBB displayed higher tolerance of acidic conditions, low matric potential (simulating xeric substrate), and propolis exposure than did other strains. A genomic comparison between this new strain and the reference NRRL-3357 showed that AFBB, like AF36, might be blocked from carrying out aflatoxin biosynthesis. Sequence comparisons also revealed several missense variants in genes that encode proteins regulating osmotolerance and osmotic pressure in Aspergillus spp., including SakA, SskB, GfdA, and TcsB/Sln1. Collectively, results of our laboratory assays and genetic analyses are consistent with the suggestion that the strain isolated from bee bread is adapted to the bee bread environment and may have persisted due to a coevolutionary relationship between Aspergillus and A. mellifera. This finding bolsters recent concerns about the effects of fungicide use near bee colonies and broadens the ecological importance of highly adaptable fungal strains.

The buzz within: the role of the gut microbiome in honeybee social behavior.

Gut symbionts influence the physiology and behavior of their host, but the extent to which these effects scale to social behaviors is an emerging area of research. The use of the western honeybee (Apis mellifera) as a model enables researchers to investigate the gut microbiome and behavior at several levels of social organization. Insight into gut microbial effects at the societal level is critical for our understanding of how involved microbial symbionts are in host biology. In this Commentary, we discuss recent findings in honeybee gut microbiome research and synthesize these with knowledge of the physiology and behavior of other model organisms to hypothesize how host-microbe interactions at the individual level could shape societal dynamics and evolution.

Bridging the Gap between Field Experiments and Machine Learning: The EC H2020 B-GOOD Project as a Case Study towards Automated Predictive Health Monitoring of Honey Bee Colonies.

Honey bee colonies have great societal and economic importance. The main challenge that beekeepers face is keeping bee colonies healthy under ever-changing environmental conditions. In the past two decades, beekeepers that manage colonies of Western honey bees (Apis mellifera) have become increasingly concerned by the presence of parasites and pathogens affecting the bees, the reduction in pollen and nectar availability, and the colonies' exposure to pesticides, among others. Hence, beekeepers need to know the health condition of their colonies and how to keep them alive and thriving, which creates a need for a new holistic data collection method to harmonize the flow of information from various sources that can be linked at the colony level for different health determinants, such as bee colony, environmental, socioeconomic, and genetic statuses. For this purpose, we have developed and implemented the B-GOOD (Giving Beekeeping Guidance by computational-assisted Decision Making) project as a case study to categorize the colony's health condition and find a Health Status Index (HSI). Using a 3-tier setup guided by work plans and standardized protocols, we have collected data from inside the colonies (amount of brood, disease load, honey harvest, etc.) and from their environment (floral resource availability). Most of the project's data was automatically collected by the BEEP Base Sensor System. This continuous stream of data served as the basis to determine and validate an algorithm to calculate the HSI using machine learning. In this article, we share our insights on this holistic methodology and also highlight the importance of using a standardized data language to increase the compatibility between different current and future studies. We argue that the combined management of big data will be an essential building block in the development of targeted guidance for beekeepers and for the future of sustainable beekeeping.

Molecular survey of endosymbiotic bacteria in the honeybee ectoparasite Varroa destructor in Türkiye

Varroa destructor is recognized as the predominant ectoparasite affecting Western honey bees (Apis mellifera L.) globally, representing a significant threat to the sustainability of bee colonies. The bacterial community of the digestive system and body tissues of Varroa mites has been documented in previous studies, however, the diversity and prevalence of detected endosymbiotic bacteria remain limited. In this study, the existence of four commonly found endosymbiotic bacteria including Wolbachia, Cardinium, Spiroplasma, and Rickettsia was investigated in various Varroa mite populations collected from Turkish apiaries. Almost half of the sampled population was infected with at least one endosymbiotic bacteria. Wolbachia endosymbiont was detected as the most prevalent genus, observed in six populations followed by Cardinium present in three populations. Furthermore, Spiroplasma and Rickettsia endosymbionts were each detected in one sample. To our knowledge, this study provides the first molecular characterization of Cardinium endosymbionts in V. destructor. The identity of 16S rDNA sequences of Cardinium was 98.9% of the sequence of Cardinium reported from another mite species, Brevipalpus papayensis, in the NCBI database. The study contributes new insights into the endosymbiotic bacterial community of Varroa mites. Understanding the diversity and prevalence of endosymbiotic bacteria in Varroa mites could facilitate the development of targeted management strategies to control Varroa infestations and improve honeybee health.

Impact of apitherapy on canine, equine, and chicken lymphocytes, in vitro

Apitherapy is a form of alternative medicine that utilizes products from the western honeybee (Apis mellifera), including honey, propolis, and honeybee venom, to improve the health status of human patients by altering host immunity. An added benefit of these products is that they are nutraceuticals and relatively inexpensive to aquire. Currently, little is known about the use of honeybee products in veterinary species, as well as their impact on host immunity. In the present in vitro study, honey, propolis, and honeybee venom were co-cultured with enriched canine, equine, and chicken peripheral blood lymphocytes (PBLs) with cell proliferation, cell viability/apoptosis, and cellular morphology evaluated. Concanavalin A (Con A) and dexamethasone were used as stimulatory and suppressive controls, respectively. Honeybee products’ effects on the three veterinary species varied by product and the species. Honey stimulated the PBLs proliferation in all three species but also displayed some increased cytotoxicity. Propolis stimulated proliferation in canine and equine PBLs, however, it suppressed proliferation in the chicken PBLs. Honeybee venom was the strongest PBL stimulant for all three species and in the equine, surpassed the stimulant response of Con A and yet, enhanced PBL cell viability post culture. In summary, the results of this preliminary in vitro study show that these three honeybee products do impact lymphocyte proliferation and viability in dogs, horses, and chickens, and that more research both in vitro and in vivo will be necessary to draw conclusions regarding their future use as immune stimulants or inhibitors.