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Apis mellifera (honey bee) is supposed to be the top most beneficial insect and plays a key role in protecting biodiversity and increasing crop yields. The ectoparasite, Varroa mite causes tremendous honey bee colony losses all over the world. Among all other Varroa mite species, the Varroa destructor is a major threat to the honey bee, Apis mellifera and has detrimental impacts on honey bee colonies. It poses a severe threat to honeybee apiaries, particularly to those that grow Apis mellifera. It primarily nourishes the haemolymph of adult and brood bees, which weakens colonies, reduces brood and deforms the development of young and mature bees. In this study, we have attempted to study the species of Varroa mite affecting Apis mellifera by using the polymerase chain reaction (PCR) method. The Varroa mites used in the study were collected from honeybee apiaries throughout several regions of Lucknow, Uttar Pradesh during the spring and summer seasons. The mites from in and around various regions of Lucknow and Uttar Pradesh were isolated from the honey bee colonies and brought to the Parasitology Laboratory for further examination. The present research describes the molecular characterization of Varroa mites for species identification and their characterization. A sequence of 28sRNA gene had been used to amplify the sequence and to identify the Varroa mite species by using next-generation sequencing (NGS). This research may provide additional insights into the taxonomy of Varroa mite species and helps in understanding species identification. [ABSTRACT FROM AUTHOR]

Copyright of Tesla Revista Científica is the property of Puerto Madero Editorial Academica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Varroa destructor is an ectoparasitic mite of honeybees which vectors a range of pathogenic viruses, the most notable being Deformed wing virus (DWV). Mites parasitise bees during pupal development and male honeybees, drones, have a longer development cycle than female workers (24 versus 21 days), allow for more progeny mites to develop per foundress (1.6–2.5 compared to 0.7–1.45). How this longer exposure time influences evolution of the transmitted virus population is unknown. Using uniquely tagged viruses recovered from cDNA we investigated the replication, competition and morbidity of DWV genotypes in drones. Assays examining virus replication and morbidity revealed drones are highly susceptible to both predominant genotypes of DWV. In virus passage studies using an equimolar inocula of major DNA genotypes and their recombinants, the recombinant form dominated but did not reach 100% of the virus population within 10 passages. Using an in-silico model of the virus–mite–bee system we examined bottlenecks during virus acquisition by the mite and subsequent injection of viruses into the host, which may play a significant role in shaping virus diversity. This study furthers our understanding of the variables influencing DWV diversity changes and provides insight into areas of future research in the mite–virus–bee system. [ABSTRACT FROM AUTHOR]

Varroa destructor is one of the main causes of colony losses of the western honey bee (Apis mellifera). Many efforts exist to breed honey bees resistant to V. destructor. Varroa sensitive hygiene (VSH) is a commonly selected behavioural trait; VSH workers remove the pupae of mite infested brood cells with high efficiency, interrupting the reproduction of the mite. The cues and triggers for this behaviour are not yet fully understood. To determine what elicits this removal behaviour, we examined preselected VSH workers´ responses to four different groups of objects inserted into freshly capped cells: live mites, dead mites, odour reduced mites, and glass beads. These were also compared to control cells that were opened and closed without inserting any object. The pupae in cells containing inorganic objects (glass beads) were removed at similar rates to the control, demonstrating that an object alone does not trigger a removal response. Dead and odour reduced mites were removed at a higher frequency than control cells, but less frequently than live mites. Workers sometimes removed items resting near the top of the cell without removing the pupa. Our results demonstrate that although mite odour from dead mites triggers removal behaviour, the pupa of cells containing live mites were removed more frequently, suggesting that other cues (i.e. odour from feeding wound) or signals (i.e. pupal movement to signal distress) are important. Future research should focus on elucidating these other cues or signals from the brood and mites, as mite presence alone seems to be insufficient. [ABSTRACT FROM AUTHOR]

Echinolaelaps echidninus is a gamasid mite that is of medical and veterinary significance as parasites and vectors of disease agents, which can carry pathogens of zoonosis such as Rickettsia tsutsugamushi , Rickettsia Q fever , Rickettsia mooseri , Rickettsia pox pathogens , Corynebacterium pseudotuberculosis and Leptospira. At present, only single mitochondrial genes have been analysed for E. echidninus in the world, and no complete mitochondrial genome has been reported. However, information carried by a single gene is limited. Therefore, the complete mitochondrial genome of E. echidninus was determined for the first time by Illumina Hiseq X-Ten platform in this study. The mitochondrial genome is 15 736 bp in length and contains 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and a control region of 1561 bp in length. Codon analysis of 13 protein-coding genes revealed that UUU, UUA, AUU, AUA and AAU were the most frequently used, while cox2 had the fastest evolutionary rate and cob the slowest. Comparative analysis of genome structure and breakpoint distances of the mitochondrial genomes of 23 species in 17 genera from 10 families of Gamasida deposited in GenBank revealed a novel gene arrangement type of the E. echidninus mitochondrial genome, and different degrees of rearrangement among different taxa of Gamasida. Phylogenetic analyses of Gamasida were performed using the maximum likelihood and Bayesian inference methods. Echinolaelaps echidninus was clustered with Dermanyssoidea and formed a more supportive sister group with Varroa destructor. This study provides novel insights into rearrangement patterns and evolution of mitochondrial genomes of Gamasida. [ABSTRACT FROM AUTHOR]

Varroa-sensitive hygiene (VSH) is highly influenced by the worker bee's olfactory ability. Workers bred for VSH and non-selected control line workers were tested for differences in their speed and perception ability when presented with highly diluted stimuli. Four different substances (citral – dilution 1:1300, linalool dilution 1:1300, Varroa-parasitized brood extract, isopropanol) were used as tactile stimuli for differential conditioning with the proboscis extension response (PER). Discrimination ability and generalization were assessed. In a second set of conditioning experiments differences in sensitivity to the highly diluted citral and the Varroa-parasitized brood extract as reinforced stimuli (Cs +) were explored between workers from both lines. The worker bees were classified into three groups (Time points) depending on how long before they started correctly extending their proboscis to the Cs + , and results were examined separately for each of the two stimuli and group. While the VSH-selected line exhibited a significantly higher perception ability for the parasitized brood extract than the non-selected line, the two lines showed no differences when conditioned with the floral stimulus citral as Cs +. Furthermore, the VSH-selected line displayed a significantly higher number of worker bees that perceived the complex bouquet of the Varroa-parasitized brood extract at the earliest time grouping (Time point 1). The odds of perception at the earliest possible time point were 2.6-times higher for the VSH-selected line. Although no comparison was made between healthy and parasitized brood, the results indicate an enhanced specific sensitivity in VSH-selected workers towards chemical cues emitted by the brood, which might play a role in the detection of Varroa destructor. [ABSTRACT FROM AUTHOR]

Simple Summary: Relatively little is known about experience of beekeepers, honey bee management practices and colony loss rates in Saudi Arabia and the Middle East compared to other countries, yet beekeeping and honey production are important in the Saudi economy. Results of a survey of 109 beekeepers in Saudi Arabia conducted in 2018 are presented, from a purpose-designed questionnaire, including colony losses over 5 seasons, to help fill this knowledge gap. The participants were managing 135 to 1700 colonies and had 2 to 45 years of beekeeping experience. Most (73.1%) respondents were mainly keeping local hybrid bees, while 25.9% mainly kept the Yemeni honey bee. Most (83.5%) beekeepers reported losing colonies over the time period studied. The reported colony loss rate was significantly higher in summer than in other seasons: the overall proportion of colonies lost was 11.4% in summer 2017 and was lowest in spring 2018 (6.6%). The main reported causes of colony losses were the Varroa mite, then disease. However, the bee wolf was the major named pest. Honey produced per colony varied greatly between beekeepers rather than bee races. The results establish a benchmark for future beekeeper surveys in Saudi Arabia and other environmentally similar countries where colony losses are of interest in all seasons of the year. There is high demand for honey in Saudi Arabia, honey bees make a valuable contribution to agriculture and the economy, and therefore it is important to know levels of colony loss and potential reasons for losses. While there is much research into honey bee colony losses worldwide, little is known about colony losses in Saudi Arabia, management practices or beekeeping experience there. The aims of this work were to address this knowledge gap. Results of a survey of beekeepers in southwest Saudi Arabia conducted in summer 2018 are presented, including colony losses in five different seasons. Data collection involved face-to-face interviews, supplemented by an online survey, using a purpose-designed questionnaire. Responses were obtained from 109 beekeepers, all male, managing 135 to 1700 colonies, with 2 to 45 years of beekeeping experience. Most (73.1%) respondents mainly kept local hybrid bees, while 25.9% mainly kept Apis mellifera jemenitica. Honey yields per colony varied much more between beekeepers than between bee races. A high proportion (83.5%) of beekeepers reported losing colonies over the period studied. The reported colony loss rate was significantly higher in summer than in other seasons, but still low. The overall proportion of colonies lost was 11.4% in summer 2017 and was lowest in spring 2018 (6.6%). The main reported causes of loss were Varroa destructor and disease. Most beekeepers (88.0%) treated against the Varroa mite, although only one method was reported, tau-fluvalinate as Apistan strips, and only 41.7% used a screened bottom board. The results establish a benchmark for future beekeeper surveys in Saudi Arabia and other environmentally similar countries where colony losses are of interest in all seasons of the year. Informing and supporting Saudi beekeepers concerning Varroa monitoring and treatment and optimal hive management could result in fewer losses, higher honey yields, potential to market organic honey and a greater share of the domestic honey market. [ABSTRACT FROM AUTHOR]

Simple Summary: Mexico is an important honey producer, but not much information exists about the health of honey bees in the country. This study analyzed the sanitary status of adult honey bees in five different beekeeping regions of Mexico. Samples from hives were analyzed to identify pests, parasites, and viruses. The mite Varroa destructor was found in 83.5% of the samples, with the Pacific Coast having the highest frequency (>95%) and levels (4.5% ± 0.6). Another mite, Acarapis woodi, was found in only one sample from the Pacific Coast, whereas the fungi Nosema spp. were present in 48.5% of the samples, with the highest frequency in the Yucatan Peninsula (64.6%). For viruses, deformed wing virus (DWV) was more frequently found in the Pacific Coast region (44.7%), and Israeli acute paralysis virus (IAPV) was detected in only 3.2% of the samples. Sacbrood bee virus (SBV) was frequently found in the High Plateau region (36.4%), and the small hive beetle (SHB) was common in the Yucatan Peninsula (39.2%). This information could be useful to design disease control strategies for honey bee colonies in different regions of Mexico. Mexico is a major honey producer, but not much information exists about the health status of honey bees (Apis mellifera L.) in the country. This study was conducted to determine the sanitary status of adult honey bees in Mexico's five beekeeping regions. Samples from 369 apiaries were diagnosed to identify pathogens such as Varroa destructor, which was quantified, Acarapis woodi, Nosema spp., and five viruses. Colonies were also inspected for the presence of the small hive beetle (SHB), Aethina tumida. Varroa destructor was found in 83.5% of the apiaries, with the Pacific Coast region having the highest prevalence (>95%) and rates (4.5% ± 0.6). Acarapis woodi was detected in only one apiary from the Pacific Coast, whereas Nosema spp. were prevalent in 48.5% of the apiaries, with the highest and lowest frequencies in the Yucatan Peninsula and North regions (64.6% and 10.2%, respectively). For viruses, deformed wing virus (DWV) was detected in 26.1% of the apiaries, with the highest frequency in the Pacific Coast region (44.7%). Israeli acute paralysis virus (IAPV) was diagnosed in 3.2% of the samples and sacbrood bee virus (SBV) in 23.3% of them, with the highest frequency in the High Plateau region (36.4%). Chronic bee paralysis and Kashmir bee viruses were not detected. SHB prevalence was 25.2% nationwide, with the highest frequency in the Yucatan Peninsula (39.2%). This study shows that the most common parasites of adult honey bees in Mexico are V. destructor and Nosema spp., and that the most prevalent virus is DWV, whereas SHB is highly prevalent in the Yucatan Peninsula. This information could be useful to design disease control strategies for honey bee colonies in different regions of Mexico. [ABSTRACT FROM AUTHOR]

The European honey bee, Apis mellifera L., is the bee species with the largest geographic distribution in the world. It is considered a pollinator generalist of wild plants and agricultural crops, as well as honey bee products as honey, beeswax, and propolis. For this reason, it plays an extremely important role in the world's ecosystems, economy, and food security. However, Apis mellifera is facing population declines due to biotic and abiotic factors, such as climate change, habitat loss, agrochemical use, and emerging pests and diseases. Pests and diseases are directly associated with a phenomenon known as colony collapse disorder (CCD), which is linked with the loss of millions of bee colonies annually worldwide. One particularly important pest is the varroa mite, which is already widely distributed and is considered the major threat to apiculture. In this review, we compile documentation of the presence and distribution of pests and diseases reported to affect Apis mellifera in Mexico. Surveys demonstrate that the following pests are present: Varroa destructor, Acarapis woodi, Aethina tumida, Galleria mellonella, as well as the diseases caused by Melissococcus plutonius, Paenibacillus larvae, Vairimorpha (Nosema) apis, V. ceranae, Ascosphaera apis and several viruses. It should be noted that the distribution and presence of European bee pathogens throughout the beekeeping states of Mexico is not very well defined, due to the lack of current bee health studies in apiaries or nationwide databases to quickly update information on their distribution and incidence. [ABSTRACT FROM AUTHOR]

Beekeepers in the United States have experienced high losses of managed honey bee (Apis mellifera) colonies for more than a decade. Long-term, multi-year monitoring efforts are crucial to provide a temporal and spatial context to these losses. To document and explain these losses, the Bee Informed Partnership has conducted national surveys on managed honey bee colonies since spring 2011, continuing the work of surveys first commissioned by the Apiary Inspectors of America in spring 2007. Here we present survey results from three years – 2017–18, 2018–19, and 2019–20. Each year, colony loss rates were estimated and compared among three loss periods – summer, winter, and annual – and three beekeeping operation types based on their number of colonies managed – backyard (≤50 colonies), sideline (51-500 colonies), and commercial (>500 colonies). At the national level, we recorded the highest winter colony loss rates (37.7%) in 2018–2019, while 2019 marked the year with the highest summer losses (32.1%). As documented in past surveys, we observed that smaller scale backyard beekeepers experienced the highest winter loss rates when compared to the larger operation types. Similarly, commercial beekeepers experienced higher loss rates during the summer compared to the other operation types. Overall, our results highlight the temporal variability, specifically among loss periods and years, of colony loss rates in the United States, and suggest a strong effect of beekeeping operation size. [ABSTRACT FROM AUTHOR]

Formic acid is the main component of the ant's major weapon against enemies. Being mainly used as a chemical defense, the acid is also exploited for recruitment and trail marking. The repelling effect of the organic acid is used by some mammals and birds which rub themselves in the acid to eliminate ectoparasites. Beekeepers across the world rely on this effect to control the parasitic mite Varroa destructor. Varroa mites are considered the most destructive pest of honey bees worldwide and can lead to the loss of entire colonies. Formic acid is highly effective against Varroa mites but can also kill the honeybee queen and worker brood. Whether formic acid can also affect the behavior of honey bees is unknown. We here study the effect of formic acid on sucrose responsiveness and cognition of honey bees treated at different live stages in field-relevant doses. Both behaviors are essential for survival of the honey bee colony. Rather unexpectedly, formic acid clearly improved the learning performance of the bees in appetitive olfactory conditioning, while not affecting sucrose responsiveness. This exciting side effect of formic acid certainly deserves further detailed investigations. [ABSTRACT FROM AUTHOR]

The mite Varroa destructor is one of the greatest threats to the apiculture sector worldwide. Generation of knowledge on its behavior and of the factors that favor its development under different environmental conditions, as well as the level of influence of these factors, is essential to the development of strategies for integral management of the mite. With the objective of analyzing the interaction between the variables of Apis mellifera colony strength and the percentage of V. destructor infestation, a group of 40 beehives were monitored during two flowering seasons, spring and summer-fall, in San Luis Potosí, Mexico. The variables were analyzed using the Pearson correlation analysis as well as an analysis of variance with repeated measures in time (p = 0.05). The level of V. destructor infestation was significantly related to the quantity of honey (+0.58) and pollen (+0.62) reserves and negatively correlated with hygienic behavior (-0.65). The percentage of V. destructor infestation in spring was not significantly different from that in summer-fall, while the quantity of food (honey and pollen) reserves in spring were statistically superior as of the second half of the season. Hygienic behavior had statistical differences only at the beginning of the flowering seasons; it was superior in summerfall. However, this difference was not maintained over time. [ABSTRACT FROM AUTHOR]

Deformed wing virus (DWV) is a pathogenic virus of honey bees transmitted by the ectoparasitic mite Varroa destructor. Annual overwintering colony losses, accounting for ~25% of all colonies, are associated with high levels of Varroa‐DWV infestation. Effective miticide treatments are available to control Varroa. However, the absence of coordinated treatment means environmental transmission of mites continues unchecked. We aimed to determine whether rational, coordinated treatment is beneficial, and characterized the DWV population as an indicator of colony health.This study uses coordinated treatment of Varroa in a geographically isolated environment (Isle of Arran, Scotland) over 3 years. The study area contained 50–84 colonies managed by ~20 amateur beekeepers. Sampling and virus analysis to assess strain diversity and viral loads were conducted before and after treatments, and changes in population diversity were quantified by sequence analysis.Over the 3 years analysis of the virus population revealed that the dominant DWV variant shifted from Type A to Type B in all apiaries, regardless of mite levels or proximity to other colonies. During this period the number of managed colonies increased by 47% (57–84 colonies), but despite this, we estimate total mite numbers decreased by 58%.Synthesis and applications. In this study, the beekeepers in Arran significantly improved the number of colonies they managed, without importing any bees onto the island, indicating that an improved focus on management techniques, through the combination of a coordinated miticide programme and an improved understanding of bee diseases, could yield positive results for bee health and sustainability. [ABSTRACT FROM AUTHOR]

The purpose of the study is to determine the effect of formic acid on Varroa destructor, applied in the spring using an infrared heater in the beehive. The experiment was conducted on three biological apiaries – 1, 2 and 3, located in Veliko Tarnovo region. Two groups of bee colonies were formed – experimental and control. Each group consists of 6 bee colonies. All bee colonies are equipped with a temperature probe (for temperature measurement in °C). The bee coloniesfrom the experimental group had infrared heater in the upper part of the frames, that were not covered with bees. Each bee colony from the control and experimental groups was treated with 20 ml 60% formic acid applied on a cellulose material. The results of study show that the application of 60% formic acid together with an infrared heater in April, leads to an effective reduction of the population of the Varroa destructor mite in theapiaries. Early spring effective treatment of bee colonies against Varroa destructor would reduce bee colony losses and increase production in beekeeping. [ABSTRACT FROM AUTHOR]

Simple Summary: Globally, honey bees are exposed to many challenges, such as the Varroa destructor mite and various viruses, which lead to massive losses. It is generally believed that African honey bees are more resilient and better able to cope with these stressors. This study examined some molecular markers that may be associated with this resilience. Higher resistance to the varroa mite could be related to better olfactory sensing. Higher gene expression levels of the odorant binding protein OBP14 in the antennae of Ethiopian honey bees suggest that reproducing mites might be better detected and cleaned. Resistance or tolerance to viruses could be attributed to a better functioning antiviral RNAi system. Several genes involved in this pathway are upregulated and are positively correlated with the viral load in honey bees. Both mechanisms may contribute to the resilience of African bees to varroa infestation and viral infection. Varroa destructor mites and the viruses it vectors are two major factors leading to high losses of honey bees (Apis mellifera) colonies worldwide. However, honey bees in some African countries show resilience to varroa infestation and/or virus infections, although little is known about the mechanisms underlying this resilience. In this study, we investigated the expression profiles of some key molecular markers involved in olfactory sensing and RNA interference, as these processes may contribute to the bees' resilience to varroa infestation and virus infection, respectively. We found significantly higher gene expression of the odorant binding protein, OBP14, in the antennae of Ethiopian bees compared to Belgian bees. This result suggests the potential of OBP14 as a molecular marker of resilience to mite infestation. Scanning electron microscopy showed no significant differences in the antennal sensilla occurrence and distribution, suggesting that resilience arises from molecular processes rather than morphological adaptations. In addition, seven RNAi genes were upregulated in the Ethiopian honey bees and three of them—Dicer-Drosha, Argonaute 2, and TRBP2—were positively correlated with the viral load. We can conclude that the antiviral immune response was triggered when bees were experiencing severe viral infection and that this might contribute to the bees' resilience to viruses. [ABSTRACT FROM AUTHOR]

The majority of honeybee farms in industrialized countries currently base their Varroa destructor control programs on the use of acaricides in conjunction with other management practices. However, the outcomes of these practices are often misunderstood and have only been studied to a limited extent. Better yields are guaranteed by having hives with low infection levels in the spring. Therefore, it is crucial to understand which beekeeping practices can result in increased control effectiveness. This study aimed to analyze the potential effects of environmental factors and beekeeping practices on the dynamics of V. destructor population. Experimental evidence was obtained by interpolating percentage infestation data from diagnoses conducted on several apiaries in the Calabria region (Southern Italy) with data acquired from a questionnaire on pest control strategies. Data on climatic temperature during the different study periods were also taken into account. The study was conducted over two years and involved 84 Apis mellifera farms. For each apiary, the diagnosis of infestation was made on a minimum of 10 hives. In total, 840 samples of adult honeybees were analyzed in the field to determine the level of infestation. In 2020, 54.7% of the inspected apiaries tested positive for V. destructor, and in 2021, 50% tested positive, according to a study of the field test findings (taking into account a threshold of 3% in July). A significant effect of the number of treatments on parasite prevalence was found. The results showed a significant reduction in the infestation rate in apiaries that received more than two treatments each year. Furthermore, it was shown that management practices, such as drone brood removal and frequent queen replacement, have a statistically significant impact on the infestation rate. The analysis of the questionnaires revealed some critical issues. In particular, only 50% of the interviewed beekeepers diagnosed infestation on samples of adult bees, and only 69% practiced drug rotation. In conclusion, it is only possible to maintain the infestation rate at an acceptable threshold by implementing integrated pest management (IPM) programs and using good beekeeping practices (GBPs). [ABSTRACT FROM AUTHOR]

Simple Summary: The western honeybee (Apis mellifera L.) is one of the most valuable insect species. However, several biological stressors pose a threat to this pollinating insect. Among these, the ectoparasitic mite Varroa destructor is currently the most significant concern. In this paper, we offer an updated analysis of the literature on the use of essential oils (EO) to fight against V. destructor. Numerous aromatic plants have been subjected to EO extraction to test their varroacidal efficacy in the laboratory or in the field. The results were extremely different even when the same botanical species were used in independent studies. This is undoubtedly related to the enormous variety of methods used to assess the efficacy of acaricides and the variation in plant composition according to origin. This review, in addition to providing an overview of the results, seeks to steer the scientific community towards consistent evaluation methods by pointing out the most valuable research projects currently underway. The Varroa destructor parasite is the main obstacle to the survival of honey bee colonies. Pest control mainly involves the use of synthetic drugs which, used with the right criteria and in rotation, are able to ensure that infestation levels are kept below the damage threshold. Although these drugs are easy to use and quick to apply, they have numerous disadvantages. Their prolonged use has led to the emergence of pharmacological resistance in treated parasite populations; furthermore, the active ingredients and/or their metabolites accumulate in the beehive products with the possibility of risk for the end consumer. Moreover, the possibility of subacute and chronic toxicity phenomena for adult honeybees and their larval forms must be considered. In this scenario, eco-friendly products derived from plant species have aroused great interest over the years. In recent decades, several studies have been carried out on the acaricidal efficacy of plant essential oils (EOs). Despite the swarming of laboratory and field studies, however, few EO products have come onto the market. Laboratory studies have often yielded different results even for the same plant species. The reason for this discrepancy lies in the various study techniques employed as well as in the variability of the chemical compositions of plants. The purpose of this review is to take stock of the research on the use of EOs to control the V. destructor parasite. It begins with an extensive discussion of the characteristics, properties, and mechanisms of action of EOs, and then examines the laboratory and field tests carried out. Finally, an attempt is made to standardize the results and open up new lines of study in future. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Varroa destructor Anderson and Trueman (Acari: Varroadae), previously known as Varroa jacobsoni, is an important pest of the honeybee, Apis mellifera L. It has been causing severe damage to populations of this species worldwide in recent years. The aim of this work was the isolation and identification of the bacterial ectomicroflora of the Varroa destructor, an ectoparasite of the bee (Apis mellifera L). Samples of Varroa were collected from the location of Boumerdes (situated in northern Algeria) beehive summer debris. The ectoparasitic honeybee Varroa was disinfected with 70% ethanol and then it was spread in nutrient agar plates. For the isolation and identification of the bacteria, the macroscopic and microscopic characters were done according to Bergey's manual of systematic Bacteriology. Biochemical characteristics were tested by using API 20E galleries (Biomerieux). The experiments were performed twice. The results of the preliminary study showed that the ectoparasite harbored seven genera of bacteria: Staphylococcus sp (3), Bacillus sp (2) and Pseudomonas sp (2). The colonies of Staphylococcus are Gram positive, mobile, coccoid shaped, aero-anaerobic and with a positive catalase. Bacillus are Gram-staining-positive rods, mobile, endospore forming, aerobes or facultative anaerobic and can produce catalase and oxidase. Pseudomonas bacteria are Gram-negative, oxidase-positive, strict aerobic and nonspore forming. [ABSTRACT FROM AUTHOR]

Abstract Background Varroa destructor is the major ectoparasite of the western honey bee (Apis mellifera). Through both its parasitic life-cycle and its role as a vector of viral pathogens, it can cause major damage to honey bee colonies. The deformed wing virus (DWV) is the most common virus transmitted by this ectoparasite, and the mite is correlated to increased viral prevalence and viral loads in infested colonies. DWV variants A and B (DWV-A and DWV-B, respectively) are the two major DWV variants, and they differ both in their virulence and transmission dynamics. Methods We studied the transmission of DWV between bees, parasitic mites and their offspring by quantifying DWV loads in bees and mites collected in in vitro and in situ environments. In vitro, we artificially transmitted DWV-A to mites and quantified both DWV-A and DWV-B in mites and bees. In situ, we measured the natural presence of DWV-B in bees, mites and mites’ offspring. Results Bee and mite viral loads were correlated, and mites carrying both variants were associated with higher mortality of the infected host. Mite infestation increased the DWV-B loads and decreased the DWV-A loads in our laboratory conditions. In situ, viral quantification in the mite offspring showed that, after an initially non-infected egg stage, the DWV-B loads were more closely correlated with the foundress (mother) mites than with the bee hosts. Conclusions The association between mites and DWV-B was highlighted in this study. The parasitic history of a mite directly impacts its DWV infection potential during the rest of its life-cycle (in terms of variant and viral loads). Regarding the mite’s progeny, we hypothesize that the route of contamination is likely through the feeding site rather than by vertical transmission, although further studies are needed to confirm this hypothesis. Graphical Abstract

Among many important functions, bees play a key role in food production. Unfortunately, worldwide bee populations have been decreasing since 2007. One reason for the decrease of adult worker bees is varroosis, a parasitic disease caused by the Varroa destructor (V. destructor) mite. Varroosis can be quickly eliminated from beehives once detected. However, this requires them to be monitored continuously during periods of bee activity to ensure that V. destructor mites are detected before they spread and infest the entire beehive. To this end, the use of Internet of things (IoT) devices can significantly increase detection speed. Comprehensive solutions are required that can cover entire apiaries and prevent the disease from spreading between hives and apiaries. In this paper, we present a solution for global monitoring of apiaries and the detection of V. destructor mites in beehives. Our solution captures and processes video streams from camera-based IoT devices, analyzes those streams using edge computing, and constructs a global collection of cases within the cloud. We have designed an IoT device that monitors bees and detects V. destructor infestation via video stream analysis on a GPU-accelerated Nvidia Jetson Nano. Experimental results show that the detection process can be run in real time while maintaining similar efficacy to alternative approaches.

Varroa destructor parasitism is associated with extreme honey bee (Apis mellifera) colony losses in the northern hemisphere. Varroa destructor causes severe damage, including a decrease in bee longevity and immunosuppression, and acts as a vector for viruses, such as Deformed wing virus (DWV-A). The surveillance of viral pathogens in V. destructor samples is essential to assess risks of emerging virulent viral variants (such as VDV-1) and evaluate their impact on honey bee health. Thus, the objective of this study was to identify viral pathogens in V. destructor and honey bee samples collected in Ontario, Canada, from 2015 to 2019 with the use of metagenomics and real time PCR (qPCR). DWV-A and VDV-1 had the highest abundance of viral transcripts (7.5 log2 and 5.72 log2, respectively). Acute bee paralysis virus (ABPV) and Bee macula virus were also identified. Viral identification and quantification in V. destructor samples using metagenomics will facilitate the surveillance of viral pathogens. This surveillance technique will assist diagnostic laboratories in delivering timely and accurate diagnoses and risk assessments, which in turn will help honey bee producers to take adequate measures to mitigate the damage caused by V. destructor and associated viruses.

Honey bees (Apis mellifera) play a pivotal role in agricultural production worldwide, primarily through the provision of pollination services. But despite their importance, honey bee health continues to be threatened by many factors, including parasitization by the mite Varroa destructor, poor queen quality, and pesticide exposure. Accumulation of pesticides in the hive's comb matrix over time inevitably leads to the exposure of developing brood, including queens, to wax contaminated with multiple compounds. Here, we characterized the brain transcriptome of queens that were reared in wax contaminated with pesticides commonly found in commercial beekeeping operations including either (a) a combination of 204,000 ppb of tau-fluvalinate and 91,900 ppb of coumaphos ("FC" group), (b) a combination of 9,800 ppb of chlorpyrifos and 53,700 ppb of chlorothalonil ("CC" group), or (c) 43,000 ppb of amitraz ("A" group). Control queens were reared in pesticide-free wax. Adult queens were allowed to mate naturally before being dissected. RNA isolated from brain tissue from three individuals per treatment group was sequenced using three technical replicates per queen. Using a cutoff log2 fold-change value of 1.5, we identified 247 differentially expressed genes (DEGs) in the FC group, 244 in the CC treatment group, and 668 in the A group, when comparing each group to the control. This is the first study to examine the sublethal effects of pesticides commonly found in wax (particularly amitraz) on the queen's brain transcriptome. Future studies should further explore the relationship between our molecular findings and the queen's behavior and physiology. [ABSTRACT FROM AUTHOR]

The population decrease of bees that has been observed in recent years due to the Varroa destructor parasite may endanger the production of bee-products whose demand is on the rise. To minimize the negative effects caused by this parasite, the pesticide amitraz is commonly used by beekeepers. Based on these, the objectives of this work are to determine the toxic effects caused by amitraz and its metabolites in HepG2 cells, as well as its determination in honey samples and the study of its stability with different heat treatments commonly used in the honey industry and its relationship with the amount of 5-hydroxymethylfurfural (HMF) produced. Amitraz significantly decreased cell viability by MTT assay and total protein content (PC) assay, being more cytotoxic than its metabolites. Amitraz and its metabolites caused oxidative stress by Lipid Peroxidation (LPO) production and Reactive Oxygen Species (ROS) generation. Residues of amitraz and/or its metabolites were found in analyzed honey samples, with 2,4-Dimethylaniline (2,4-DMA) being the main metabolite confirmed by high-performance liquid chromatography-high resolution mass spectrometry (HPLC-QTOF HRMS). Amitraz and its metabolites resulted as unstable even at moderate heat treatments. Additionally, a positive correlation in terms of HMF concentration in samples and the severity of heat treatment was also observed. However, quantified amitraz and HMF were within the levels set in the regulation. [ABSTRACT FROM AUTHOR]

Simple Summary: The Varroa destructor mite is a severe problem for the development of beekeeping in many parts of the world. The presented study concerns the control of this harmful nuisance mite via a disease management protocol for the first time. Poor field conditions made it possible to evaluate the protocol's effectiveness against mites in a natural and uncontrolled way. "Personalised" (tailored) applications consist of adjusting the number of control agents with different doses of amitraz to the number of detected parasite females in a given colony, taking into account a specific brood of queen bees (sisters) with a specific brood area. We showed that the number of treatments did not affect egg laying (brood surface) by mother sisters. We confirmed that amitraz should be increased by more than the number of mites found. The best results were obtained by repeating the procedure four times. We confirmed that effectiveness depends on the degree of Varroa infestation in a given family and the treatment of mites before the procedure. This procedure enables the protocol (personalisation) to effectively control of the impact of parasites on the bee colony. In such a procedure, one of the reasons for efficacy is the genetic conditions related to the reproductive potential of queens resulting from the bee breed. Based on new research, the presented study may change the overall effects of Varroa treatment in bee colonies. The requirement for the protection of bee colonies against Varroa destructor invasions has been noted by many breeders and is included as an aspect of the development of beekeeping. This research aimed to check the effect of the development of a colony exposed to laying eggs (brood surface) by queen bees with similar chemical potential (sisters) on the effect of a preparation combating V. destructor depending on the number of mites found in a given colony. We chose this as a standard model of conduct that treats each bee colony as one organism subjected to individual parasite control. For this purpose, we created a bee colony with a mother-of-one breeding line and fertilised drones from one colony. Infection with V. destructor occurred naturally and uncontrollably. Without interfering with the colony's development, the frame insulator helped each colony's brood (mothers' reproductive potential) and the initial and final individuals from the mites themselves. The study was carried out in four species (two control species and two species with up to 20 and over 21 mites, respectively). Treatments with amitraz to combat damage were divided into four treatment subgroups: two treatments every four days or four treatments every two days. We observed the number of individuals that were protected in all subgroups in the average brood area. The reproductive potential of the sisters' mothers did not change after the treatments with amitraz, which indicated that amitraz did not affect the delegation of egg laying. The invasion rate was also tracked relative to the control group, which allowed us to conclude that a two-time treatment with amitraz reduced the frequency of mites and a four-time treatment checked the effectiveness. Tailoring the control of V. destructor in bee colonies may be an effective measure in the fight against this parasite. [ABSTRACT FROM AUTHOR]

In recent years the Varroa destructor mite has been a dominant challenge for honey bee colonies, worldwide. Varroa- sensitive hygiene, a behavioral characteristic of honey bee, involves the detection and removal of Varroa larvae from the colony. It has been exploited as a recordable trait for Varroa resistance. The sense of smell is a key element in Varroa sensitive hygiene behavior. In this scenario, NorpA2 candidate gene, a putative olfactory receptor, is associated with vision and smell in honey bee and is known as a candidate gene for Varroa sensitive hygiene. With this motivation, the main goal of the current work was to determine some single nucleotide polymorphism (SNP) markers of NorpA2 candidate gene employing PCR sequencing in a case-control approach. To this end, after the identification of resistant (RES) and susceptible (SUS) colonies according to the percentage of infections of the drone pupae to Varroa mite, a total of 10 drone pupae (5 from SUS and 5 from RES) were selected and were subjected for DNA isolation. The polymerase chain reaction (PCR) was performed based on two pairs of specific primers for the amplification of 5' untranslated region (5' UTR) and promoter regions of NorpA2 gene. After expected size bands were observed, the purification process and Sanger sequencing of the PCR products were carried out. The sequencing results were quality checked and the alignment and clustering were done using the BLAST and MAFTT software, respectively. Sequences of both UTR and promoter regions displayed multiple variations (SNP, deletion). Interestingly, the results showed the existence of three specific differences in sequence in the form of SNP (C/T) at position 308 and the form of SNP/deletion at positions 504 and 563 of the nucleotide sequence region in the promoter between the SUS and RES groups. To our knowledge, this is the first report on the identification of biomarkers to control host-mite interaction in the honey bee Apis mellifera. Further research is required for the reported SNPs to be validated as biomarkers of resistance to Varroa. [ABSTRACT FROM AUTHOR]

Beekeepers have various options to control the parasitic mite Varroa destructor in honey bee colonies, but no empirical data are available on the methods they apply in practice. We surveyed 28,409 beekeepers maintaining 507,641 colonies in 30 European countries concerning Varroa control methods. The set of 19 different Varroa diagnosis and control measures was taken from the annual COLOSS questionnaire on honey bee colony losses. The most frequent activities were monitoring of Varroa infestations, drone brood removal, various oxalic acid applications and formic acid applications. Correspondence analysis and hierarchical clustering on principal components showed that six Varroa control options (not necessarily the most used ones) significantly contribute to defining three distinctive clusters of countries in terms of Varroa control in Europe. Cluster I (eight Western European countries) is characterized by use of amitraz strips. Cluster II comprises 15 countries from Scandinavia, the Baltics, and Central-Southern Europe. This cluster is characterized by long-term formic acid treatments. Cluster III is characterized by dominant usage of amitraz fumigation and formed by seven Eastern European countries. The median number of different treatments applied per beekeeper was lowest in cluster III. Based on estimation of colony numbers in included countries, we extrapolated the proportions of colonies treated with different methods in Europe. This suggests that circa 62% of colonies in Europe are treated with amitraz, followed by oxalic acid for the next largest percentage of colonies. We discuss possible factors determining the choice of Varroa control measures in the different clusters. [ABSTRACT FROM AUTHOR]

Black queen cell virus (BQCV) is a ubiquitous honeybee virus and a significant pathogen to queen bee (Apis mellifera) larvae. However, many aspects of the virus remain poorly understood, including the transmission dynamics. In this study, we used next-generation sequencing to identify BQCV in Aedes vexans (n = 4,000) collected in 2019 and 2020 from Manitoba, Canada. We assembled de novo the nearly complete (>96%) genome sequence of the virus, which is the first available from North America and the first report of BQCV being harbored by mosquitoes. Phylogenetic tree reconstructions indicated that the genome had 95.5% sequence similarity to a BQCV isolate from Sweden. Sequences of a potential vector (Varroa destructor) and a microsporidian associated with BQCV (Nosema apis) were not identified in the mosquito samples, however, we did detect sequences of plant origin. We, therefore, hypothesize that the virus was indirectly acquired by mosquitoes foraging at the same nectar sources as honeybees. [ABSTRACT FROM AUTHOR]

Honey bees, Apis mellifera, of European origin are major pollinators of crops and wild flora. Their endemic and exported populations are threatened by a variety of abiotic and biotic factors. Among the latter, the ectoparasitic mite Varroa destructor is the most important single cause behind colony mortality. The selection of mite resistance in honey bee populations has been deemed a more sustainable solution to its control than varroacidal treatments. Because natural selection has led to the survival of some European and African honey bee populations to V. destructor infestations, harnessing its principles has recently been highlighted as a more efficient way to provide honey bee lineages that survive infestations when compared with conventional selection on resistance traits against the parasite. However, the challenges and drawbacks of harnessing natural selection to solve the varroa problem have only been minimally addressed. We argue that failing to consider these issues could lead to counterproductive results, such as increased mite virulence, loss of genetic diversity reducing host resilience, population collapses or poor acceptance by beekeepers. Therefore, it appears timely to evaluate the prospects for the success of such programmes and the qualities of the populations obtained. After reviewing the approaches proposed in the literature and their outcomes, we consider their advantages and drawbacks and propose perspectives to overcome their limitations. In these considerations, we not only reflect on the theoretical aspects of host–parasite relationships but also on the currently largely neglected practical constraints, that is, the requirements for productive beekeeping, conservation or rewilding objectives. To optimize natural selection‐based programmes towards these objectives, we suggest designs based on a combination of nature‐driven phenotypic differentiation and human‐directed selection of traits. Such a dual strategy aims at allowing field‐realistic evolutionary approaches towards the survival of V. destructor infestations and the improvement of honey bee health. [ABSTRACT FROM AUTHOR]

The global spread of the parasitic mite Varroa destructor instigated a substantial decline in both managed and feral honeybee (Apis mellifera) colonies mainly across the Northern hemisphere. In response, many beekeepers began to treat their colonies with chemical acaricides to control mite populations in managed colonies. However, some countries or beekeepers allowed their bees to develop mite-resistance by adopting a "treatment-free" approach, rather than using selective breeding programs. Yet, the distribution and proportion of beekeepers either treating or not within the United Kingdom (UK) is unknown, as it is in most Northern hemisphere countries. Therefore, the aim of this study was to conduct a beekeeper survey to determine the current treatment strategies within the UK. We gathered 2,872 beekeeper responses from an estimated 30,000 UK beekeepers belonging to 242 bee-associations in the winter of 2020/21. The survey indicated that the majority (72–79%) of UK beekeepers are still treating their bees for Varroa, typically twice-yearly using chemical-based methods. Six percent or 1,800 UK beekeepers were treatment-free for six years or more. This is reflected by our finding that 78 associations out of 242 consist of responders who entirely treated, while only four associations had more than 75% of their members that were non-treating. Overall treatment status was not affected by association currently. Using the baseline data from this survey it will be possible in the future to observer if a shift towards treatment-free beekeeping occurs or not. [ABSTRACT FROM AUTHOR]

The Varroa destructor parasite is responsible for varroasis in honeybees worldwide, the most destructive disease among parasitic diseases. Thus, different insecticides/acaricides have been widely used within beehives to control these parasitic diseases. Namely, amitraz is the most used acaricide due to its high efficacy shown against Varroa destructor. However, pesticides used for beehive treatments could be incorporated into the honey and accumulate in other hive products. Hence, honeybee health and the impairment of the quality of honey caused by pesticides have gained more attention. Amitraz and its main metabolites, N-(2,4-dimethylphenyl) formamide (2,4-DMF) and 2,4-dimethylaniline (2,4-DMA), are known to be potent neurotoxicants. In this research, the cytotoxicity of amitraz and its metabolites has been assessed by MTT and PC assays in HepG2 cells. In addition, possible target receptors by in silico strategies have been surveyed. Results showed that amitraz was more cytotoxic than its metabolites. According to the in silico ADMEt assays, amitraz and its metabolites were predicted to be compounds that are able to pass the blood–brain barrier (BBB) and induce toxicity in the central and peripheral nervous systems. The main target class predicted for amitraz was the family of A G protein-coupled receptors that comprises responses to hormones and neurotransmitters. This affects, among other things, reproduction, development, locomotion, and feeding. Furthermore, amitraz and its metabolites were predicted as active compounds interacting with diverse receptors of the Tox21-nuclear receptor signaling and stress response pathways. [ABSTRACT FROM AUTHOR]

Simple Summary: Diseases, particularly those caused by viruses, are a major cause of bee colony losses. However, little is known about the prevalence of the pathogens, particularly virus prevalence, of the honey bee in Egypt, one of the most important countries for beekeeping and agricultural production in Africa. To address this shortfall, we determined the prevalence of ten widespread bee viruses in honey bee colonies in Egypt between two major season, winter and summer, in relation to colony infestation by varroa mites. Honey bees are essential for crop and wild plant pollination. However, many countries have reported high annual colony losses caused by multiple possible stressors. Diseases, particularly those caused by viruses, are a major cause of colony losses. However, little is known about the prevalence of honey bee pathogens, particularly virus prevalence, in Egyptian honey bees. To address this shortfall, we determined the prevalence of widespread bee viruses in honey bee colonies in Egypt—whether it is affected by geography, the season, or infestation with Varroa destructor (varroa) mites. Honey bee worker samples were collected from 18 geographical regions across Egypt during two seasons: winter and summer of 2021. Three apiaries were chosen in each region, and a pooled sample of 150 worker bees was collected from five colonies in each apiary then screened by qPCR for 10 viral targets: acute bee paralysis virus (ABPV), black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus (DWV) genotypes A (DWV-A), B (DWV-B) and D (Egyptian bee virus), Israeli acute paralysis virus (IAPV), Kashmir bee virus (KBV), sacbrood virus (SBV), and slow bee paralysis virus (SBPV). Our results revealed that DWV-A was the most prevalent virus, followed by BQCV and ABPV; the DWV genotype now spreading across the world, DWV-B, was not detected. There was no difference in varroa infestation rates as well as virus prevalence between winter and summer. However, colonies infected with BQCV had a significantly higher varroa count (adjusted p < 0.05) in the winter season, indicating that there is a seasonal association between the intensity of infestation by varroa and the presence of this virus. We provide data on the current virus prevalence in Egypt, which could assist in the protection of Egypt's beekeeping industry. Moreover, our study aids in the systematic assessment of the global honey bee virome by filling a knowledge gap about the prevalence of honey bee viruses in Egypt. [ABSTRACT FROM AUTHOR]

Simple Summary: Dermacentor reticulatus is a significant parasite and vector of various pathogens which are dangerous to humans and animals. Lithium chloride is currently one of the most promising potential alternatives against Varroa destructor, a detrimental mite parasite of honeybees. Furthermore, it shows efficacy against Dermanyssus gallinae, a severe pest of poultry, in vitro. In the present study, we report for the first time that the biocidal efficacy of lithium chloride extends to D. reticulatus as well, with 100% mortality at a minimum concentration of 1.38 M and an LC50 of 0.654 M. Our results may contribute to a comprehensive understanding of the lithium ion. Dermacentor reticulatus (Fabr., 1794) (Acari: Ixodidae) is parasite that spreads many diseases which are dangerous to humans and animals. Microelement lithium was found to have promising potential against the detrimental bee pest Varroa destructor. Furthermore, its effectiveness was confirmed against Dermanyssus gallinae, a major parasite of poultry, in vitro. In the present study, we investigated whether the efficacy of lithium chloride extends to other parasitic species, such as D. reticulatus. Our results revealed, for the first time, that the effectiveness of lithium chloride extends to D. reticulatus, confirmed to have 100% mortality at a relatively high minimum concentration of 1.38 M in vitro. The 24 h and 48 h median lethal concentration (LC50) values proved to be 0.654 M and 0.481 M, respectively, for this species. Our pilot study may contribute to a better understanding of the properties of lithium ion. Furthermore, it may elicit further studies aiming to reveal whether the different environmental mineral conditions may influence the D. reticulatus population. Further studies might reveal whether lithium has any possible veterinary relevance. [ABSTRACT FROM AUTHOR]

Organisms live within cycles of birth, growth, and reproduction, but life cycles also include decline and death. Here, we focus on the process of colony decline and death in “hopelessly queenless” honey bee colonies (Apis mellifera). In addition, we tracked the parasitic mite, Varroa destructor, to understand how mite populations change during colony decline, and the implications of colony decline on mite transmission. To address these knowledge gaps, we established four hopelessly queenless colonies in observation hives and tracked their bee and mite populations until death. Hopelessly queenless colonies persisted for 2–3 months (86 ± 19 days), with a long-tailed survival distribution (50% of bees dead by day 25; 95% by day 74). In two of the four colonies, the mites outlived the bees by up to 48 h; in one colony the bees outlived the mites by 13 days; in one colony the bees and mites died simultaneously. Though we did not observe robbing in our study, colonies with fewer than 200 bees still harbored mites that could have infested robber bees. All colonies attempted to rear worker-laid drones, though survival rates for the drones were low (3.0 ± 2.1% of worker-laid drone brood were estimated to reach adulthood). Colonies did, however, maintain adult drones until colony death, despite the experiment running from September through December (past the date of typical drone eviction). This work shows that declining colonies are a viable mechanism for horizontal mite transfer in both managed and wild colonies, with potential implications for the evolution of mite virulence. [ABSTRACT FROM AUTHOR]

Deformed wing virus (DWV), notorious for its virulence in the western honey bee (Apis mellifera) when vectored by the ectoparasitic mite Varroa destructor, is also widespread among wild bumble bee species, presumably through spillover from honey bees. Experimental studies on the virulence of DWV in Bombus spp. have provided equivocal results and have until now been confined to bumble bees under laboratory conditions.Here, we inoculated commercially reared Bombus terrestris workers with DWV‐A through feeding or injection and introduced them into experimental colonies placed in the field, thus exposing them to the environment and associated stressors. We monitored the survival of inoculated worker bumble bees and quantified their viral load at 10 days post inoculation.Bombus terrestris workers injected with DWV‐A supported high viral loads and exhibited significantly reduced median survival compared to controls. Bumble bees inoculated by feeding had low or zero detectable viral loads while their mortality did not differ from the control group.Our results demonstrate that, although DWV‐A is pathogenic for commercial B. terrestris, the risks for individual fitness from spillover of DWV‐A during foraging on shared flowers appear limited.The findings of this experiment also highlight the necessity to address the potential context‐dependence of virulence when evaluating the impact of a pathogen in an alternative host. [ABSTRACT FROM AUTHOR]

[Display omitted] • Genes related to the oogenesis of V. destructor on their new host species were studied. • A. cerana and A. mellifera K1 mites exhibited a very close genetic relationship at the genome level. • A total of 121 genes with nonsynonymous high- F ST SNPs were found between the two types of mites. • The transcriptomes of the two types of mites differentiated as early as 1 h post-infestation. • Nine genes carrying nonsynonymous high- F ST SNPs were associated with oogenesis on the new host. Host shift of parasites may have devastating effects on the novel hosts. One remarkable example is that of the ectoparasitic mite Varroa destructor , which has shifted its host from Eastern honey bees (Apis cerana) to Western honey bees (Apis mellifera) and posed a global threat to apiculture. To identify the genetic factors underlying the reproduction of host-shifted V. destructor on the new host. Genome sequencing was conducted to construct the phylogeny of the host-shifted and non-shifted mites and to screen for genomic signatures that differentiated them. Artificial infestation experiment was conducted to compare the reproductive difference between the mites, and transcriptome sequencing was conducted to find differentially expressed genes (DEGs) during the reproduction process. The host-shifted and non-shifted V. destructor mites constituted two genetically distinct lineages, with 15,362 high- F ST SNPs identified between them. Oogenesis was upregulated in host-shifted mites on the new host A. mellifera relative to non-shifted mites. The transcriptomes of the host-shifted and non-shifted mites differed significantly as early as 1h post-infestation. The DEGs were associated with nine genes carrying nonsynonymous high- F ST SNPs, including mGluR2-like , Lamb2-like and Vitellogenin 6-like , which were also differentially expressed, and eIF4G , CG5800 , Dap160 and Sas10 , which were located in the center of the networks regulating the DEGs based on protein-protein interaction analysis. The annotated functions of these genes were all associated with oogenesis. These genes appear to be the key genetic determinants of the oogenesis of host-shifted mites on the new host. Further study of these candidate genes will help elucidate the key mechanism underlying the success of host shifts of V. destructor. [ABSTRACT FROM AUTHOR]

Landscapes can affect parasite epidemiology in wild and agricultural animals. Honey bees are threatened by loss of floral resources and by parasites, principally the mite Varroa destructor and the viruses it vectors. Existing mite control relies heavily on chemical treatments that can adversely affect bees. Alternative, pesticide-free control methods are needed to mitigate infestation with these ectoparasites. Many flowering plants provide nectar and pollen that confer resistance to parasites. Enrichment of landscapes with antiparasitic floral resources could therefore provide a sustainable means of parasite control in pollinators. Floral rewards of Asteraceae plants can reduce parasitic infection in diverse bee species, including honey and bumble bees. Here, we tested the effects of sunflower (Helianthus annuus) cropland and pollen supplementation on honey bee resistance to macro- and microparasites. Although sunflower had nonsignificant effects on microparasites, We found that increased sunflower pollen availability correlated with reduced Varroa mite infestation in landscapes and pollen-supplemented colonies. At the landscape level, each doubling of sunflower crop area was associated with a 28% reduction in mite infestation. In field trials, late-summer supplementation of colonies with sunflower pollen reduced mite infestation by 2.75-fold relative to artificial pollen. United States sunflower crop acreage has declined by 2% per year since 1980, however, suggesting reduced availability of this floral resource. Although further research is needed to determine whether the observed effects represent direct inhibition of mite fecundity or mite-limiting reductions in honey bee brood-rearing, our findings suggest the potential for sunflower plantings or pollen supplements to counteract a major driver of honey bee losses worldwide. [ABSTRACT FROM AUTHOR]

Several resistance traits have been proposed to select honey bees (Apis mellifera L.) that can survive in the presence of parasitic mite Varroa destructor (Anderson and Trueman) and enable a more sustainable apiculture. The interest for uncapping-recapping has recently increased following its identification in several naturally surviving honey bee populations, yet the utility of this trait for human-mediated selection is poorly known. Here, we evaluated the repeatability of recapping and its correlations with mite infestation levels, and assessed the expression of the trait in the often neglected drone brood. We also calculated correlations between recapping, mite infertility, and mite fecundity, expressed either at the level of individual brood cells or of the whole colony. Recapping measured in worker brood showed moderate repeatability (ranging between 0.30 and 0.46). Depending on sample, recapping slightly correlated negatively with colony infestation values. Recapping was also measured in drone brood, with values often comparable to recapping in worker brood, but no significant correlations were obtained between castes. At cell level, recapped cells in drone brood (but not in workers) were significantly less infested than nonrecapped cells, whereas in workers (but not in drones), recapped cells hosted mites with significantly lower fecundity. At colony level, with a few exceptions, recapping did not significantly correlate with mite infertility and fecundity, caste, sample, or number of infested cells considered. These results indicate limited possibilities of impeding mite reproduction and possibly mite infestation of honey bee colonies by recapping, which would need to be confirmed on larger, different populations. [ABSTRACT FROM AUTHOR]

Propolis contains substances with antibacterial, antiviral, antioxidant, and immune-stimulatory action and is used in the defense of the colony against microorganisms and parasites. The present study is a systematic review of the use of propolis in bee health and in prevention against the main bee pathogens. A search was performed in databases from 01/01/2009 to 30/04/2020. After applying the criteria, 23 articles were included in the review that investigated the use of propolis to prevent the ectoparasite Varroa destructor, the microsporidium Nosema ceranae, the bacterium Paenibacillus larvae, and the fungus Ascosphaera apis. Of these, nine manuscripts reported the bactericidal effect of propolis against P. larvae (39.13%), and two of these studies simultaneously investigated the fungus A. apis. In total, eight were conducted in vitro and one in the field. Six articles related propolis to acaricidal effect in combating the parasite V. destructor (26.08%), four of which were in vitro and two field experiments. Five studies related propolis to combat the microsporidium N. ceranae (21.73%), all of which were carried out in vitro. Two articles were found (one in vitro and the other in the field) that generically related the importance of the physicochemical composition of propolis to bee immunology and defense against its main pathogens. One study investigated the fungal effect of propolis on the pathogen A. apis in a field experiment. In conclusion, scientific production on this subject is sparse, warranting further research in the field to examine the effects of propolis on bee health. [ABSTRACT FROM AUTHOR]

Varroa destructor is a parasitic mite responsible for the loss of honey bee (Apis mellifera) colonies. This study aimed to find a promising marker in honey for the bee colony infestation level using fluorescence spectroscopy and biochemical analyses. We examined whether the parameters of the honey samples' fluorescence spectra and biochemical parameters, both related to proteins and phenolics, may be connected with the level of honey bee colonies' infestation. The infestation level was highly positively correlated with the catalase activity in honey (r = 0.936). Additionally, the infestation level was positively correlated with the phenolic spectral component (r = 0.656), which was tentatively related to the phenolics in honey. No correlation was found between the diastase activity in honey and the colonies' infestation level. The results indicate that the catalase activity in honey and the PFC1 spectral component may be reliable markers for the V. destructor infestation level of the colonies. The obtained data may be related to the honey yield obtained from the apiaries. [ABSTRACT FROM AUTHOR]

Developing effective and sustainable green solutions for managing arthropod pests and vectors is a timely challenge. The present review is dedicated to mites and ticks (Acari), species which represent a burden for human and animal health. The focus is on hard ticks (Ixodidae), primarily belonging to the genera Haemaphysalis spp., Hyalomma spp., and Rhipicephalus spp., house dust mites Dermatophagoides spp., stored-product mites Tyrophagus putrescentiae and Acarus siro , various strains of the itch mite Sarcoptes scabiei , the poultry red mite Dermanyssus gallinae , and the main ectoparasitic mite of honeybees Varroa destructor. We overviewed all the nano- and microemulsions and capsules loaded with essential oils, plant extracts, and/or singular compounds applied as toxicant or repellent treatments to manage such pests. Additionally, we explored current knowledge about the effectiveness of metal nanoparticles obtained through green synthesis routes by exploiting phytochemicals in botanical extracts. For all the products, we reported their mean particle size, tested formulation, efficacy, and when available, mode of action, comparison with synthetic acaricides, and non-target effects. Future challenges involve the need to improve the synthesis technologies and storage conditions of the different formulations; scaling up the production is necessary too to achieve lower prices and wider distribution. Notably, research on S. scabiei and V. destructor is required, as these species are extremely overlooked when compared to hard ticks and other mites. [Display omitted] • Nano- and microformulation of botanicals can boost acaricidal efficacy. • Botanical-based nano- and microformulations were mostly tested on hard ticks. • Other medical-veterinary relevant Acari may benefit this expertise. • Nano/microformulations may help in Varroa destructor management. • Synthesis routes and storage improvements are crucial for formulation efficacy. [ABSTRACT FROM AUTHOR]

The honeybee has a significant impact on ecosystem stability, biodiversity conservation, and pollinating crops. However, during the past few years, there has been a sharp reduction in both the honeybee population and their colonies. It has been found that the parasitic mite Varroa destructor is responsible for the decline in honeybee colonies around the world, which in turn immensely affects the economic growth of a country. To investigate how the dynamics of a system is influenced by the growth of honeybees and the parasitism of mites, we study a nonlinear honeybee-mite population model in a discrete-time setup. We observe that an increase in the value of the queen's egg-laying rate drives the system towards chaos. However, chaos can be controlled as well if the parasite attachment effect is increased. The intrinsic dynamical properties of the proposed system are investigated with the simultaneous variation of the queen's egg-laying rate and the mite's parasite attachment effect by constructing several largest Lyapunov exponent and isoperiodic diagrams. The investigation reveals the existence of several periodic structures in the quasiperiodic and chaotic regimes of the parameter plane, including Arnold tongues, saddle area, spring area, connected shrimp-shaped structure, and connected saddle area. We also find the appearance of a novel 'jellyfish'-shaped periodic structure. One of the most fascinating findings of this study is the appearance of Arnold tongues along the inner boundary region of another Arnold tongue. In addition, this work also reveals different types of multistability, e.g., the coexistence of two, three, and even four attractors. What is more interesting is that the current analysis unveils the coexistence of five attractors as well, more specifically, four different periodic attractors coexist with the trivial fixed point attractor, which is quite rare in ecological systems. The structures of the basins of these coexisting attractors are either smooth or very complex in nature. Furthermore, the present study also discloses the fact that variation in the initial condition of the system can significantly change the appearance of the periodic structures in the parameter plane. • A discrete-time honeybee-mite population model is investigated in a parameter plane. • An array of Arnold tongues appears along the inner boundary of another Arnold tongue. • A new kind of 'jellyfish'-shaped periodic structure is visualized. • The coexistence of two, three, four, and five different attractors is observed. • The appearance of periodic structures may vary depending on the initial states. [ABSTRACT FROM AUTHOR]

The greater wax moth Galleria mellonella is a cosmopolitan pest of hives of the western honey bee Apis mellifera , where it remains exposed to varroicides applied by beekeepers in past decades as pest management chemicals for control of Varroa destructor , a devastating ectoparasite of bees. The prolonged presence of coumaphos residues, an organophosphate varroicide, in beeswax may be responsible for current levels of tolerance exhibited by G. mellonella , a non-target species that infests beehives. In this study, a field-collected strain of waxworms exhibited a higher LC 50 value for coumaphos than that of a laboratory strain that had not been continuously exposed to coumaphos residues at field concentrations. Despite its higher tolerance for coumaphos, the field strain experienced growth inhibition at ecologically relevant concentration of coumaphos. Moreover, at low environmental concentrations that did not alter growth, detoxification gene expression levels were substantially altered. RNA-Seq analysis revealed 1181 and 658 differentially expressed genes in fat body and midgut, respectively, with 378 and 186 of those genes upregulated. This large-scale upregulation encompassed 21 genes encoding cytochrome P450 monooxygenases (CYPs), 13 encoding UDP-glycosyltransferases (UGTs), 5 encoding glutathione-S-transferases (GSTs), 2 encoding carboxylesterases (COEs), and 2 encoding ABC transporters (ABCs) in either tissue. Expression analysis of 13 selected candidate detoxification genes by RT-qPCR was consistent with their expression from RNA-Seq data. In sum, our results indicate that long-lasting pesticide residues in beeswax from past Varroa mite management may continue to act as selective agents on detoxification systems of hive residents other than the initial target species and that multiple resistance mechanisms to these chemicals may coexist within the beehive fauna. [Display omitted] • The coumaphos LC 50 for a waxworm field strain exceeded that of a laboratory strain. • Waxworm relative growth rates were reduced by coumaphos at a high concentration. • RNA-Seq showed 378 and 186 upregulated genes in fatbody and midgut, respectively. • RT-qPCR analysis confirmed expression patterns revealed by RNA-Seq. [ABSTRACT FROM AUTHOR]

In recent years, honey bee colony losses in the Republic of Kosovo remained largely unknown. From 2019 to 2021, 81 apiaries with different disease suspicions were investigated in the framework of honey bee disease passive surveillance. Fifty-nine of the eighty-one apiaries were tested for Vairimorpha ceranae, Vairimorpha apis, trypanosomatids Lotmaria passim, and Crithidia mellificae. All samples were positive for V. ceranae (100%) whereas L. passim was found with a lower frequency (11.9%). V. apis and C. mellificae were not found. Thirteen of the eighty-one apiaries were tested for seven viruses (ABPV, CBPV, DWV, BQCV, SBV, IAPV, KBV) and five of them were found (ABPV, CBPV, DWV, BQCV, SBV). The most frequently detected viruses in honey bees and Varroa mites were DWV (100%) followed by BQCV, ABPV, SBV, and CBPV (92.3%, 69.2%, 30.8%, and 7.7%, respectively). Varroa mite samples had different degrees of co-infection by viruses. Nine of the eighty-one apiaries consisted of brood combs with larvae, eight of them were AFB positive, ERIC I genotype, and one EFB positive. This paper represents the first molecular investigation (PCR) and detection of the honey bee viruses ABPV, CBPV, DWV, BQCV, and SBV as well as V. ceranae, L. passim, and M. plutonius in the Republic of Kosovo.

The most significant ectoparasitic mite of honeybees, Varroa destructor, has a detrimental effect on bee health and honey output. The principal strategy used by the control programs is the application of synthetic acaricides. All of this has resulted in drug resistance, which is now a major worry for beekeeping. As a result, research on alternate products and techniques for mite management is now required. The aim of this study was to determine whether essential oils (EOs) extracted from botanical species of Lamiacae, typical of the Calabria region of Southern Italy, could reduce the population of the mite V. destructor. Among the best-known genera of the Lamiaceae family are oregano, rosemary and thyme, whose EOs were employed in this study. By steam distillation, the EOs were extracted from Origanum vulgare subsp. viridulum (Martrin-Donos) Nyman, Thymus capitatus Hoffmanns. and Link, Thymus longicaulis C.Presl and Salvia rosmarinus Schleid. plant species harvested directly on the Calabrian territory in their balsamic time. Each EO went to the test in vitro (contact toxicity) against V. destructor. Fifty adult female mites, five for each EO and the positive and negative control, were used in each experimental replicate. The positive controls comprised five individuals treated to Amitraz dilute in acetone, and the negative controls included five individuals exposed to acetone alone. To create the working solution to be tested (50 μL/tube), the EOs were diluted (0.5 mg/mL, 1 mg/mL, 2 mg/mL and 4 mg/mL) in HPLC-grade acetone. After 1 h of exposure, mite mortality was manually assessed. Origanum vulgare subsp. viridulum, Thymus capitatus and Thymus longicaulis were the EOs with the highest levels of efficiency at 2 mg/mL, neutralizing (dead + inactivated), 94%, 92% and 94% of parasites, respectively. Salvia rosmarinus EO gave a lower efficacy, resulting in a percentage of 38%. Interestingly, no adverse effects were highlighted in toxicity tests on honeybees. These results show that these OEs of the Lamiaceae family have antiparasitic action on V. destructor. Therefore, they could be used, individually or combined, to exploit the synergistic effect for a more sustainable control of this parasite mite in honeybee farms.

Varroa destructor is a cosmopolitan pest and leading cause of colony loss of the European honey bee. Historically described as a competent vector of honey bee viruses, this arthropod vector is the cause of a global pandemic of Deformed wing virus, now endemic in honeybee populations in all Varroa-infested regions. Our work shows that viral spread is driven by Varroa actively switching from one adult bee to another as they feed. Assays using fluorescent microspheres were used to indicate the movement of fluids in both directions between host and vector when Varroa feed. Therefore, Varroa could be in either an infectious or naïve state dependent upon the disease status of their host. We tested this and confirmed that the relative risk of a Varroa feeding depended on their previous host's infectiousness. Varroa exhibit remarkable heterogeneity in their host-switching behavior, with some Varroa infrequently switching while others switch at least daily. As a result, relatively few of the most active Varroa parasitize the majority of bees. This multiple-feeding behavior has analogs in vectorial capacity models of other systems, where promiscuous feeding by individual vectors is a leading driver of vectorial capacity. We propose that the honeybee-Varroa relationship offers a unique opportunity to apply principles of vectorial capacity to a social organism, as virus transmission is both vectored and occurs through multiple host-to-host routes common to a crowded society. Author summary: Varroa destructor is an ectoparasitic mite implicated in historical colony losses of the managed honey bee Apis mellifera and is responsible for the global pandemic of Deformed wing virus (DWV). Varroa has long been described as a competent vector of DWV, but surprisingly little is known about its feeding and subsequent vectoring of viruses on adult honey bees. Through a series of experiments, we found Varroa actively switch from one adult bee host to another to feed. Mites exhibit a large degree of heterogeneity in their host-switching behavior, with some mites switching frequently and others not nearly at all. Our results mirror an observation in other vector-host-pathogen relationships: a relatively small number of mites contributed to a majority of parasitized hosts. These high-frequency biters are most likely to not only transmit, but also acquire infectious pathogens as they switch from host to host. The ability to parasitize and infect multiple adult bees provides the best explanation to date for the maintenance and subsequent host-to-host spread of viruses among the long-lived worker bees common in these crowded and vulnerable colony populations. [ABSTRACT FROM AUTHOR]