Honey Bee Apis Mellifera Research Articles

On the distribution and diversity of tissue-specific somatic mutations in honey bee (Apis mellifera) drones

Somatic mutations originate from both exogenous (e.g. UV radiation, chemical agents) and endogenous (e.g., DNA replication, defective DNA repair) sources and can have significant impacts on an animal’s reproductive success. This may be especially true for haploid organisms that are susceptible to any deleterious alleles inherited from their parent and any that arise over their lifetime. Unfortunately, little is known about the rate of somatic mutation accumulation across individuals and tissues of haplodiploid animal populations, the functional processes through which they arise, and their distribution across tissues and the genome. Here, we generated short-read whole-genome sequencing data for four tissues of haploid honey bee males. We paired this with estimates of telomere length and tissue-specific DNA content to address three major questions: is there variance in somatic mutational load across haploid individuals and specific tissues therein, does increased DNA content in a tissue contribute to somatic mutational load, and does telomere length correlate with mutational load? Our results suggest that variance in somatic mutational load is better captured across individuals than across tissues, that tissue-specific DNA content is not associated with somatic mutation load, and that variance in telomere length does not correlate with somatic mutation loads across tissues. To our knowledge, this is the first observational study on somatic mutational load in Apoidea and likely Hymenoptera. It serves as a useful advent for additional studies understanding the processes through which haploids tolerate or repair somatic mutations.

Aggressive dominance of acacia floral resources by wild east African lowland honey bees

AbstractThe East African lowland honey bee (Apis mellifera scutellata) is reported as an aggressive subspecies of the Western honey bee, but few studies have investigated the impact of its aggressiveness on other insect pollinators. Observations of flower visitors to Vachellia (Acacia) etbaica and interactions between honey bees and other insects were conducted in 2022 in Mpala, Kenya. A total of 873 individual flower visitors were recorded, the most frequent being Hymenoptera, followed by Diptera and Lepidoptera. Honey bees dominated floral resources in the morning and late afternoon. When honey bees encountered other types of insects, they displaced the latter from flowers 100% of the time. This has never been observed in other Western honey bee subspecies, and we recommend further research on these taxa.

Microfungal flora of Apis mellifera anatoliaca (Hymenoptera: Apidae) and Varroa destructor (Mesostigmata: Varroidae) from the Eastern Black Sea Region and fungal vector capacity in honey bee colonies.

Honey bees have a great economic importance both in Turkey and in the world due to the products they produce and their contribution to pollination. For this reason, many microflora and microbiota studies have been conducted on bees. While these research were primarily focused on pathogen isolation, the ecological roles of non-pathogenic flora members and how they may be used are now being studied more extensively. Considering the importance of pathogens, the number of studies is expected to continue to increase. This study was carried out to determine the microfungal flora of the body surfaces and digestive tracts of dead honey bee (Apis mellifera anatoliaca) and Varroa destructor samples taken from different apiaries in the Eastern Black Sea Region of Turkey (Gümüşhane, Trabzon, Artvin and Ordu) in 2022. As a result of the study, a total of 11 different fungal species belonging to the genera Penicillium, Alternaria, Mucor, Trichoderma, Fusarium, Aspergillus and Verticillium were identified and the relationships of these fungi with bees were discussed based on the literature.

Complete genome sequence of deformed wing virus and black queen cell virus isolated from honeybees (Apis mellifera) in Argentina.

We report the complete genome sequence of deformed wing virus and black queen cell virus isolated from Argentinean's honeybees. These sequence data will be valuable for future research on the viral variants present in the country and the development of strategies to control the spread of these viruses in apiaries.

Electrostatic detection and electric signalling in plants: do flowers act as antennas?

Flying insect pollinators are electrically charged. As bumblebees (Bombus terrestris) and honeybees (Apis mellifera) are almost always positively charged, they present a static electric field that is modulated by the harmonic motion of their wings. Previous research has demonstrated that as a bee approaches a flower, there is a change in the stem potential of the plant, even before the bee lands, suggesting a capacity for flowers to sense the approaching bee through its electric field. Using a combination of laboratory and field studies, we explore the potential for flowers to act as receiving antennas for electrical signals, and to transmit these signals to neighbouring plants. Results show that flowers can detect non-contact electric stimuli, presumably by charge induction, and appear not to be tuned to a specific frequency. In the field, non-contact electric stimuli can also be detected in neighbouring flowers that did not receive the aerial stimulus. This evidence demonstrates the ability of flowers to capture local, aerial electrical signals, and the plant to then transmit signals through the soil to neighbouring plants. This work highlights the significance of environmental electric fields in pollination biology.

Effects of queen excluders on the colony dynamics of honeybees (Apis mellifera L.) under biodynamic management

The evaluation of beekeeping management practices (BMPs) is important for beekeepers worldwide because their choice affects health and survival of managed honeybee (A. mellifera L.) colonies and touches ethical and economic questions. This study focusses on queen excluders, a common hive addition in contemporary beekeeping. Its impacts are controversially discussed but have not been studied scientifically yet. Within a 4-year participatory on-farm experiment, we assessed the effects on colony dynamics in 64 hives in 8 apiaries during one season in Germany using the Liebefeld estimation method. We found no significant deviation for parameters of colony dynamics between hives managed with and without queen excluders. A qualitative decision-making tool (Pugh decision matrix) facilitated concept selection only for specific beekeepers.

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.

Comparison of pure caucasian, carniolan and native anatolian ecotype honey bee (Apis mellifera L.) colonies in the eastern anatolia region with reciprocal F1 hybrids

The aim of this study was to compare specific physiological and behavioral characteristics of A. m. caucasica, A. m. carnica, and native honeybees, as well as reciprocal crosses, within the ecological conditions of East Anatolia (Van province), Turkey. The findings revealed that native honeybees exhibited the highest average sealed brood area and the highest average number of frames with bees. In contrast, the highest average honey yield was observed in the crossbreeding of Carniolan bees with native bees. Significant differences were identified among the groups concerning brood area, the number of bee frames, aggression tendency, and honey yield. The study concluded that Carniolan and Caucasian bees exhibited suboptimal performance outside their native habitats. Nevertheless, Carniolan bees were identified as a viable option for mitigating aggression tendencies and enhancing honey yield in native bee populations.

Inadequate Pollination Is a Key Factor Determining Low Fruit-to-Flower Ratios in Avocado

Avocado is an evergreen tree that exhibits protogynous dichogamy and displays a massive flower production, characterized by a high abscission of unfertilized flowers and developing fruitlets, ultimately leading to a low final fruit set. A common practice to improve avocado pollination involves introducing honey bee (Apis mellifera L.) hives during the flowering season. To evaluate the extent of inadequate pollination in avocado, the effect of different beehive densities on the percentage of flowers receiving pollen during the female flower stage was examined for seven years in an experimental orchard located in Southern Spain. A total of 17,288 flowers were observed under the microscope for this purpose. Additionally, pollen deposition was evaluated in five “Hass” avocado commercial orchards under different management strategies situated in the Malaga province (3960 flowers). The results obtained reveal that the percentage of flowers with pollen at the end of the female stage ranged from 2.85 (0.13% fruits retained at the end of June) in orchards without honey bee hives to 4.34 (0.11% fruits retained) in orchards in which 10 beehives per ha were placed. This percentage increased significantly to 13.79 after introducing 24 honey beehives per ha (0.21% fruits retained). Furthermore, the percentage of pollinated flowers in the commercial orchards remained below 15% even in those orchards in which pollen donors and honey bee hives were present. Thus, insufficient pollination could be considered as a primary limiting factor in avocado production under Mediterranean climates. Enhancing pollinator diversity and increasing their numbers could be a viable strategy to improve the percentage of avocado flowers receiving pollen during the female stage.

Yeast communities related to honeybees: occurrence and distribution in flowers, gut mycobiota, and bee products

Honeybee (Apis mellifera) is an important agricultural pollinator and a model for sociality. In this study, a deep knowledge on yeast community characterizing the honeybees’ environmental was carried out. For this, a total of 93 samples were collected: flowers as food sources, bee gut mycobiota, and bee products (bee pollen, bee bread, propolis), and processed using culture-dependent techniques and a molecular approach for identification. The occurrence of yeast populations was quantitatively similar among flowers, bee gut mycobiota, and bee products. Overall, 27 genera and 51 species were identified. Basidiomycetes genera were predominant in the flowers while the yeast genera detected in all environments were Aureobasidium, Filobasidium, Meyerozyma, and Metschnikowia. Fermenting species belonging to the genera Debaryomyces, Saccharomyces, Starmerella, Pichia, and Lachancea occurred mainly in the gut, while most of the identified species of bee products were not found in the gut mycobiota. Five yeast species, Meyerozyma guilliermondii, Debaryomyces hansenii, Hanseniaspora uvarum, Hanseniaspora guilliermondii, and Starmerella roseus, were present in both summer and winter, thus indicating them as stable components of bee mycobiota. These findings can help understand the yeast community as a component of the bee gut microbiota and its relationship with related environments, since mycobiota characterization was still less unexplored. In addition, the gut microbiota, affecting the nutrition, endocrine signaling, immune function, and pathogen resistance of honeybees, represents a useful tool for its health evaluation and could be a possible source of functional yeasts.Key points• The stable yeast populations are represented by M. guilliermondii, D. hansenii, H. uvarum, H. guilliermondii, and S. roseus.• A. pullulans was the most abondance yeast detective in the flowers and honeybee guts.• Aureobasidium, Meyerozyma, Pichia, and Hanseniaspora are the main genera resident in gut tract.

Manipulating larval rearing media to optimise mass production of the blow fly Calliphora vicina (Diptera: Calliphoridae)

AbstractThe oviparous blow fly Calliphora vicina has shown potential as a managed pollinator to support honeybee (Apis mellifera) usage in Australian horticulture. A series of three laboratory‐based studies reared newly hatched larvae of C. vicina on meatmeal with varying amounts of either whole egg powder, whole eggs (including shells), bran flakes, brewer's yeast, fish paste or milk powder. The objective was to determine the best larval media for quick and efficient production of adult flies in a mass‐rearing environment. Pure meatmeal or meatmeal with only brewer's yeast added were the least productive media. Larvae fed meatmeal with either 10% or 20% whole dried egg powder had the fastest development to pupae, the highest pupation rate, the heaviest pupae and the highest subsequent adult eclosion. Larval media containing fish paste had the highest survival through to adult emergence (>85%) of all the media treatments, which suggests that this ingredient is of value when mass rearing C. vicina. In addition, newly hatched larvae (n = 50) were reared on varying amounts of media (i.e., 4, 2, 1, 0.5, 0.25 and 0.125 g per larvae) to determine the minimum amount of media required to produce adults. Reductions in media per larvae resulted in smaller pupae and adults that emerged with no subsequent reduction in adult eclosion, indicating the adaptability of this fly to food deprivation. Replacing whole egg powder with whole eggs reduces the costs of rearing C. vicina larvae significantly. In order to rear 1 million adult C. vicina, these studies showed that 0.5 g of media per larvae is sufficient to produce high numbers of pupae with >95% adult eclosion. Although larval development and pupation are optimal on media containing whole egg powder, its recent rapid rise in costs makes it far less economical compared with the use of discarded whole eggs from egg producers. Sourcing of seafood waste could also reduce media costs and improve production of C. vicina. The costs of each media required to realise 1 million adult C. vicina are between $540 and $1900 depending on the media ingredients.

Metagenomic analysis of the honey bee queen microbiome reveals low bacterial diversity and Caudoviricetes phages.

In eusocial insects, the health of the queens-the colony founders and sole reproductive females-is a primary determinant for colony success. Queen failure in the honey bee Apis mellifera, for example, is a major concern of beekeepers who annually suffer colony losses, necessitating a greater knowledge of queen health. Several studies on the microbiome of honey bees have characterized its diversity and shown its importance for the health of worker bees, the female non-reproductive caste. However, the microbiome of workers differs from that of queens, which, in comparison, is still poorly studied. Thus, direct investigations of the queen microbiome are required to understand colony-level microbiome assembly, functional roles, and evolution. Here, we used metagenomics to comprehensively characterize the honey bee queen microbiome. Comparing samples from different geographic locations and breeder sources, we show that the microbiome of queens is mostly shaped by the environment experienced since early life and is predicted to play roles in the breakdown of the diet and protection from pathogens and xenobiotics. We also reveal that the microbiome of queens comprises only four candidate core bacterial species, Apilactobacillus kunkeei, Lactobacillus apis, Bombella apis, and Commensalibacter sp. Interestingly, in addition to bacteria, we show that bacteriophages infect the queen microbiome, for which Lactobacillaceae are predicted to be the main reservoirs. Together, our results provide the basis to understand the honey bee colony microbiome assemblage, can guide improvements in queen-rearing processes, and highlight the importance of considering bacteriophages for queen microbiome health and microbiome homeostasis in eusocial insects.IMPORTANCEThe queen caste plays a central role in colony success in eusocial insects, as queens lay eggs and regulate colony behavior and development. Queen failure can cause colonies to collapse, which is one of the major concerns of beekeepers. Thus, understanding the biology behind the queen's health is a pressing issue. Previous studies have shown that the bee microbiome plays an important role in worker bee health, but little is known about the queen microbiome and its function in vivo. Here, we characterized the queen microbiome, identifying for the first time the present species and their putative functions. We show that the queen microbiome has predicted nutritional and protective roles in queen association and comprises only four consistently present bacterial species. Additionally, we bring to attention the spread of phages in the queen microbiome, which increased in abundance in failing queens and may impact the fate of the colony.

Nursing Honeybee Behavior and Sensorial-Related Genes Are Altered by Deformed Wing Virus Variant A.

Insect behavior is coordinated mainly by smell through the diverse odor-binding proteins (OBP) that allow them to identify and recognize their environment. Sensory information collected through smell is then analyzed and interpreted in the brain, allowing for correct insect functioning. The behavior of honeybees (Apis mellifera L.) can be affected by different pathogens, such as deformed wing virus (DWV). In particular, the DWV variant A (DWV-A) is capable of altering olfactory sensitivity and reducing the gene expression of different OBPs, including those associated with nursing behavior. The DWV is also capable of replicating itself in the sensory lobes of the brain, further compromising the processing of sensory information. This study evaluated the behavioral response of nurse honeybees exposed to a pheromone compound and the alterations in the gene expression of the pre- and post-synaptic neuronal genes neuroxins-1 and neurogilin-1 in the bee heads and OBP proteins in the antennae of nurse bees inoculated with DWV-A. The behavioral response of nurse bees exposed to the larval pheromone compound benzyl alcohol was analyzed using a Y-tube olfactometer. The viral load, the gene expression of OBP5 and OBP11 in antennae, and neuroxins-1 and neurogilin-1 in the bee heads were analyzed via qPCR. High viral loads significantly reduced the ability of 10- and 15-day-old nurse honeybees to choose the correct pheromone compound. Also, the gene expression of OBP5, OBP11, neuroxin-1, and neurogilin-1 in nurse honeybees decreased when they were highly infected with DWV-A. These results suggest that a DWV-A infection can disturb information processing and cause nursing honeybees to reduce their activity inside the hive, altering internal cohesion.

Genetic Diversity and Biological Activities of Nuclei from Swarming and Dividing of Honey Bee Apis mellifera L. Colonies

Genetic Diversity and Biological Activities of Nuclei from Swarming and Dividing of Honey Bee Apis mellifera L. Colonies

Effect of Thiacloprid Exposure on Honey Bees <i>Apis mellifera</i> F.

An evaluation of the effect of thiacloprid (21.7% SC), an N-cyanoamidine neonicotinoid exposure on honey bees Apis mellifera F. was done under field conditions. Study on foraging behaviour, mortality and food stores were carried out with 500, 325, 250, 125, 62.50, and 31.25 ppm, while 0 ppm concentration served as control. Of these, a significant effect was observed with 500 and 325 ppm as could be observed from the foraging behaviour. Thus, thiacloprid is found to be safe at lower concentrations <250 ppm.

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.

Prevalence and distribution of Varroa destructor and Nosema spp. in symptomatic honey bee colonies across the USA from 2015 to 2022

USDA-ARS Bee Research Laboratory received symptomatic honey bee (Apis mellifera L.) samples across the United States for disease diagnosis. Here, we present a retrospective study and cartography of ectoparasite Varroa destructor and intracellular microsporidia parasite Nosema spp. These two major parasites were identified in the diseased honey bee samples between 2015 and 2022. Varroa infestation level (VIL) was examined by a wash technique (Mites/100 bees) and calculated as a percentage, while Nosema infection was quantified by microscopical spore count (Million Spores/Bee). Data were analyzed by month, year, state, and by nine geographical climate regions described in the U.S. Of adult bee samples (n = 4039) that were analyzed for Varroa mite infestation, the overall VIL in the U.S. ranged between 0.4 and 30.85%, with an overall national VIL and Varroa prevalence of 8.21% and 85.14%, respectively. Overall monthly data showed VIL constantly exceeded the critical level of 4% except from June to September and reached a maximum of 15% in January and December. Nationwide, VIL significantly (p < 0.001) increased from 2015 to 2018 (1.1–4.7%), plateaued from 2018 to 2021 (4.7–4.5%), followed by a significant decrease in 2022 (3.6%). Significant VIL differences (p < 0.001) were recorded among climate regions, with the highest mite infestation levels in the Upper Midwest region (13.9%) and the lowest in the West region (5.1%). Of adult bee samples (n = 2,994) that were analyzed for Nosema infection, Nosema spore count ranged between (1–16.8) million spores per bee among states, with a national average of 6.8 and a prevalence of 99.7%. The lowest and highest Nosema loads were respectively recorded in the South region (3.1) and Upper Midwest (10.5), a significant difference (p < 0.001). No statistical differences were recorded among the six other climate regions. Overall, VIL and Nosema infection correlated significantly (p < 0.001) with a regression coefficient of (R2 = 0.6). Our data, which originated from ailing bee colonies, showed significantly higher rates of maladies compared to data from healthy colonies obtained by the USDA-APHIS National Honey Bee Survey, demonstrating the role of bee diseases caused by Varroa mite and Nosema in honey bee population declines.

The Response of the Honey Bee Gut Microbiota to Nosema ceranae Is Modulated by the Probiotic Pediococcus acidilactici and the Neonicotinoid Thiamethoxam.

The honey bee Apis mellifera is exposed to a variety of biotic and abiotic stressors, such as the highly prevalent microsporidian parasite Nosema (Vairimorpha) ceranae and neonicotinoid insecticides. Both can affect honey bee physiology and microbial gut communities, eventually reducing its lifespan. They can also have a combined effect on the insect's survival. The use of bacterial probiotics has been proposed to improve honey bee health, but their beneficial effect remains an open question. In the present study, western honey bees were experimentally infected with N. ceranae spores, chronically exposed to the neonicotinoid thiamethoxam, and/or supplied daily with the homofermentative bacterium Pediococcus acidilactici MA18/5M thought to improve the honey bees' tolerance to the parasite. Deep shotgun metagenomic sequencing allowed the response of the gut microbiota to be investigated with a taxonomic resolution at the species level. All treatments induced significant changes in honey bee gut bacterial communities. Nosema ceranae infection increased the abundance of Proteus mirabilis, Frischella perrara, and Gilliamella apicola and reduced the abundance of Bifidobacterium asteroides, Fructobacillus fructosus, and Lactobacillus spp. Supplementation with P. acidilactici overturned some of these alterations, bringing back the abundance of some altered species close to the relative abundance found in the controls. Surprisingly, the exposure to thiamethoxam also restored the relative abundance of some species modulated by N. ceranae. This study shows that stressors and probiotics may have an antagonistic impact on honey bee gut bacterial communities and that P. acidilactici may have a protective effect against the dysbiosis induced by an infection with N. ceranae.

Viruses, microsporidia and glyphosate residues in Africanized honey bees Apis mellifera, under field conditions

Bees are affected by several factors, including pathogens and pesticides, which may cause mortality and consequent population decline. Considering the ecological and economic importance of these pollinators, this study evaluated the occurrence of the microsporidia Nosema apis and Nosema ceranae, the viruses ABVP, DWV, BQCV, KBV, IAPV and CBPV and residues of the pesticides atrazine, chlorantraniliprole, deltamethrin, fipronil and glyphosate in workers from field colonies of Africanized honey bee Apis mellifera across one year. The presence of pesticide residues was also evaluated in honey and pollen samples. All tested viruses were found in the workers, with BQCV showing the highest copy number. BQCV levels were correlated with relative humidity. Nosema ceranae was the only microsporidian with higher intensities of infection during summer and autumn; seasons with high availability of food resources, which can act as dispersers of this pathogen. Small amounts of glyphosate and its metabolite were detected in the bees tested. These data show that honey bees are contaminated with pathogens and pesticides in the field and present correlative data for these threats.

Mitochondrial DNA variation in honey bee (Apis mellifera) colonies from Arkansas, U.S.

This study characterized the mitochondrial DNA (mtDNA) genetic variation in Arkansas honey bee, Apis mellifera L., by sequencing a portion of the mitochondrial cytochrome oxidase (COI-COII) intergenic region). The samples were primarily of hobbyist-managed origin (n = 180), as well as 32 feral colonies and two swarms. Of the 214 honey bee colonies and swarms sampled, 23 haplotypes were observed. The haplotypes were from the: A (African) (1.87%); C (South eastern European) (92.52%); M (Northern and Western European) (3.27%); and O (Near East and Middle East) lineages (2.34%). Six C lineage haplotypes were predominantly detected (n = 189, 88.31%), all of which are common in U.S. commercial queen breeder colonies. The remaining 27 honey bee samples represented 19 haplotypes, all of which are absent from commercial queen breeder colonies but have been observed in feral honey bee populations collected in other States. These haplotypes, particularly those from the M and O lineages, are likely hundred-year-old remnants of historical importations, surviving for generations despite the arrival of threats, such as Varroa mites. Understanding honey bee genetics and population structure are valuable for maintaining genetic diversity. Results from this study provide evidence that Arkansas honey bee populations differ from U.S. commercial queen breeder colonies. The 15 haplotypes detected in our Arkansas study absent from commercial queen breeder colonies could be important sources of genetic diversity in future honey bee breeding programs, highlighting the importance of State-level genetic surveys.