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Simple Summary: A major threat to honey bees is the Varroa destructor mite, a parasite that feeds on bee fat bodies and transmits viruses, leading to significant colony losses. Detecting the level of Varroa infestation in the apiary is crucial for defining appropriate intervention strategies and preventing irreparable damage to the colonies. Traditional methods based on manual counting are time-consuming and require meticulous attention. In this study, we tested an AI-based portable scanner for Varroa destructor detection. The device operates through image analysis of a sticky sheet placed under the beehive for several days, capturing the Varroa mites that naturally fall. Over 17 weeks, the scanner was tested with sheets from five beehives each week, assessing the accuracy, reliability, and speed of the method compared to conventional human visual inspection. Results show that the system can consistently repeat measurements with high precision, with an error rate in detecting Varroa mites consistently below 1% when there are more than 10 mites per sheet. Given its repeatability and reliability, the device can be considered a valuable tool for beekeepers and scientists, offering the opportunity to monitor many beehives in a short time. Beekeeping is a crucial agricultural practice that significantly enhances environmental health and food production through effective pollination by honey bees. However, honey bees face numerous threats, including exotic parasites, large-scale transportation, and common agricultural practices that may increase the risk of parasite and pathogen transmission. A major threat is the Varroa destructor mite, which feeds on honey bee fat bodies and transmits viruses, leading to significant colony losses. Detecting the parasite and defining the intervention thresholds for effective treatment is a difficult and time-consuming task; different detection methods exist, but they are mainly based on human eye observations, resulting in low accuracy. This study introduces a digital portable scanner coupled with an AI algorithm (BeeVS) used to detect Varroa mites. The device works through image analysis of a sticky sheet previously placed under the beehive for some days, intercepting the Varroa mites that naturally fall. In this study, the scanner was tested for 17 weeks, receiving sheets from 5 beehives every week, and checking the accuracy, reliability, and speed of the method compared to conventional human visual inspection. The results highlighted the high repeatability of the measurements (R2 ≥ 0.998) and the high accuracy of the BeeVS device; when at least 10 mites per sheet were present, the device showed a cumulative percentage error below 1%, compared to approximately 20% for human visual observation. Given its repeatability and reliability, the device can be considered a valid tool for beekeepers and scientists, offering the opportunity to monitor many beehives in a short time, unlike visual counting, which is done on a sample basis. [ABSTRACT FROM AUTHOR]

Olfaction mediated by the antennae is a vital sensory modality for arthropods and could be applied as a tool in pest control. The ectoparasitic mite Varroa destructor poses a significant threat to the health of the honey bee Apis mellifera worldwide and has garnered global attention. To better understand the chemical ecology of this host–parasite relationship, we collected and characterized the volatile organic compounds (VOCs) from V. destructor and used electroantennography (EAG) to record the responses of honey bee (A. c. cerana and A. m. ligustica) antennae to the different VOCs. Fifteen VOCs were detected from V. destructor using gas chromatography–mass spectrometry (GC-MS), which mainly contained ethyl palmitate, followed by isoamyl alcohol, nonanal, and ethyl oleate. The EAGs for ethyl palmitate were higher at the lowest stimulus loading (5 μg/μL in liquid paraffin) in A. c. cerana compared to A. m. ligustica, suggesting that A. c. cerana may have acute sensitivity to low concentrations of some VOCs from V. destructor. After exposure to ethyl palmitate for 1 h, the relative expression levels of AcerCSP1 and AcerOBP21 in A. c. cerana significantly increased, as well as the level of AmelCSP1 in A. m. ligustica, while AmelOBP8 showed no significant changes. The results indicate that the EAG response was influenced by the VOC composition and concentration. A. c. cerana tended to be more responsive than A. m. ligustica to the VOCs of V. destructor. Our findings offer a deeper understanding of how bees recognize V. destructor, potentially using ethyl palmitate as a chemical cue. [ABSTRACT FROM AUTHOR]

Simple Summary: One of the main culprits of honey bee colony losses is the parasitic mite, Varroa destructor, which is primarily controlled with acaricides, which lose efficacy due to resistance and can contaminate honey. An alternative is to breed bees that are resistant to Varroa, which was conducted in this study by bidirectional selection for mite fall to obtain colonies with low (resistant) or high (susceptible) Varroa population growth (LVG and HVG, respectively). Selection for three generations resulted in greatly reduced Varroa population growth in LVG compared to HVG colonies. In addition, Varroa infestation rates of bees were lower in LVG colonies, and they had lower Deformed Wing Virus (DWV) infection levels. Survival of Varroa-parasitized bees was higher for LVG bees compared to HVG bees, which may help explain why colony winter survivorship was higher for LVG colonies than for HVG colonies. Selecting colonies of bees for LVG resulted in better individual and colony bee health, demonstrating its effectiveness as a means of breeding for controlling Varroa mites. Honey bee (Apis mellifera) population declines have been associated with the parasitic mite, Varroa destructor, which is currently primarily controlled by the use of acaricides. An alternative is to breed for resistance to Varroa, which was conducted in this study by bidirectional selection for mite fall to obtain colonies with low (resistant) or high (susceptible) Varroa population growth (LVG and HVG, respectively). Selection for three generations resulted in approx. 90% lower Varroa population growth in LVG than in HVG colonies. In addition, late summer Varroa infestation rates of brood and adults were both significantly lower in LVG colonies (p < 0.01), which was also significantly associated with lower Deformed Wing Virus (DWV) infection levels (p < 0.01). Survival of Varroa-parasitized bees was almost 50% higher for LVG bees compared to HVG bees (p < 0.01). Also, colony winter survivorship was significantly higher for LVG colonies than for HVG colonies (p < 0.05). However, the higher colony populations observed for LVG colonies were not significantly different from those of HVG colonies. Overall, individual and colony health was improved by selecting colonies for LVG, demonstrating its effectiveness as a means of breeding for controlling Varroa populations in honey bee colonies. [ABSTRACT FROM AUTHOR]

This study examined the conditions and factors affecting honey production in Hungary from the perspective of Hungarian beekeepers. Due to the scarcity of research on Hungary, this study can be considered a missing piece. The survey was based on a questionnaire survey (N = 632). Basic statistical tools (frequencies, means) were used to describe the data. To assess differences between some categorical variables, cross-stability was assessed using chi-square tests, and non-parametric tests were used. Based on the study results, the study population has an average of 101 colonies per beekeeper. Beekeepers with a low number of colonies are mainly hobby beekeepers for whom non-economic goals are a priority. The average honey yield is 40 kg per bee colony, with a wide variation between counties. The primary function of beekeeping is production and selling, followed by the importance of pollinating crops and other plants, maintaining natural landscapes and habitats, and conserving plant biodiversity. Around 80% of beekeepers keep bees primarily for income, which is consistent with production and selling as their primary activity. The main problems identified are bee mite infestation (Varroa destructor Anderson and Trueman), bee poisoning from pesticides, Nosema (Nosema apis Zander; Nosema ceranae Huang) infection, problems with sales and profitability, and lack of bee pastures. [ABSTRACT FROM AUTHOR]

The ectoparasitic mite Varroa destructor is well known for transmitting a number of viruses that can contribute to the collapse of honeybee colonies. To date, the many control measures put in place to limit the spread of V. destructor have yielded no satisfactory results. This is challenging because the effect of the parasite on honeybee colonies is becoming notorious. This has weakened the beekeeping industry and reduced pollination services, which may contribute to global food insecurity in the future. Therefore, it is necessary to put in place possible control measures and outline sustainable approaches to mitigate research efforts against the Varroa destructor. Extensive research to elaborate on the best possible solution has revealed that the selective breeding of naturally occurring V. destructor immune-related traits of honeybee strains is sustainable. Since the Integrated Pest Management approach was introduced, while still being very unreliable, there are open questions as to what control strategy could be considered effective. After cross-examination of existing strategies, a more practical way could be the adoption of an integrated approach. This approach should involve the association of selective breeding of honeybee colonies with V. destructor immune-related traits and the application of soft chemical treatment. [ABSTRACT FROM AUTHOR]

Simple Summary: The mite Varroa destructor is the most damaging parasite of honey bees (Apis mellifera) worldwide. When necessary, mite control is mainly accomplished with acaricides. Optimal parasite control is achieved when the acaricide is applied during times of little or no brood in honey bee colonies, which varies by region. Therefore, in this study we analyzed the population dynamics of the mite in honey bee colonies established in a temperate semi-arid climate in Mexico by periodically sampling brood and adult bees, as well as by counting mites falling to the bottom board of hives over 10 months. We also measured brood and adult bee populations and food stores. It was found that the sampling period influences the population of V. destructor in the colonies. The mite population increased by 26% in the 10 months of sampling. It was observed that as the worker brood population increased, the mite infestation rate in adult bees decreased, and the opposite occurred when the amount of brood in the colonies was reduced. Monitoring V. destructor populations by recording fallen mites is more reliable than determining mite infestation rates in adult bees and brood. The best period to apply an acaricide treatment in the region of study is between November and December. This study aimed to analyze the population dynamics of the mite Varroa destructor in honey bee (Apis mellifera) colonies in a temperate semi-arid climate in Mexico. Ten colonies homogeneous in population, food stores, and levels of mite infestation were used. The mite infestation rate in brood and adult bees, total number of mites, daily mite fall, brood and adult bee population, and food stores were determined periodically for 10 months. There was a significant effect (p < 0.05) of sampling period on the population of V. destructor in adult bees, brood, total mite population, and daily fallen mites. The total mite population increased by 26% on average per colony. The increase in brood amount reduced the mite infestation rate in adult bees, and the opposite occurred when the brood decreased. Monitoring V. destructor populations by recording fallen mites is more reliable than determining mite infestation rates in bees, as mite fall has a dynamic pattern similar to that of the total mite population. The best period to apply an acaricide treatment in the region of study is between November and December because most mites were in the phoretic phase, since there was less brood in the colonies compared to other times. [ABSTRACT FROM AUTHOR]

Simple Summary: Varroa destructor is a significant global honey bee parasite and the primary threat to bee health. Due to its latent lifestyle, detecting the mite in a brood requires invasive techniques. Enhancing detection methods is critical for advanced research on mite population dynamics, spread, selection efforts, and control methodologies. In this study, we employed infrared thermal imaging, a less-explored technique in apicultural studies, to detect parasitism in Apis mellifera broods. Our findings indicate that handheld infrared thermal cameras can generate adequately detailed heat maps of the hive. These maps distinctly separate cells containing honey, pollen, and brood, with stable, reproducible temperature measurements observable in late autumn. Notably, mite parasitism induces a sustained temperature increase in developing honey bee pupae, consistently detected regardless of mite numbers in the cell. This study reveals an advanced thermoregulatory behavior in the honey bee colony, manifesting as a social fever phenomenon. Further research is necessary to explore the health benefits of this behavior for bees and the negative effects on the mite. Our method, combined with the development of AI-based image evaluation software, could provide beekeepers and researchers with a valuable tool for Varroa research and bee biological studies. The Varroa destructor is the most significant bee parasite and the greatest threat to bee health all around the world. Due to its hidden lifestyle, detection within the brood cell is only possible through invasive techniques. Enhancing detection methods is essential for advancing research on population dynamics, spread, selection efforts, and control methodologies against the mite. In our study, we employed infrared imaging to measure the thermal differences in parasite and intact Apis mellifera worker broods. Experiments were conducted over two years at the MATE Kaposvár Campus in Hungary involving five beehives in 2022 and five beehives in 2023. A FLIR E5-XT WIFI handheld infrared camera was used to create a heat map of capped brood frames. Our results indicate that the resolution of these cameras is sufficient to provide detailed IR images of a bee colony, making them suitable to detect temperature differences in intact and Varroa parasitized capped brood cells. Mite parasitism causes a time-dependent and sustained temperature increase in developing bee pupae, observable regardless of mite number. Our work demonstrates two different heating patterns: hotspot heating and heating cells that are responsible for the elevated temperature of the Varroa-infested cells as a social fever response by the worker bees. Based on our results, future research combined with AI-based image evaluation software could offer beekeepers and researchers practical and valuable tools for high-throughput, non-invasive Varroa detection in the field. [ABSTRACT FROM AUTHOR]

Deformed wing virus (DWV) is known as one of the main viruses that affect honeybees' health all around the world. The virus has two widespread genotypes, DWV-A and DWV-B (VDV-1), transmitted mainly by V. destructor mites. In this study, we collected honeycombs with covered broods from 73 apiaries in eight Lithuanian regions and initially investigated the prevalence of V. destructor mites. Mites were collected from May to the end of July in 2021 from 124 hives. The prevalence of V. destructor infestations in beehives reached 30% and 63% in investigated apiaries. The presence of DWV-A and DWV-B pathogens in mites and broods was examined by RT-qPCR targeting the CRPV-capsid region. The molecular characterization of the virus in mite samples was based on sequence analysis of the RNA-dependent RNA polymerase (RdRp) region. In addition, leader polypeptide (LP), structural protein (Vp3), Helicase, and RdRp genes were used for phylogenetic characterization of dual infection. The prevalences of DWV-B in mites and broods were 56.5% and 31.5%, respectively, while DWV-A was detected in 12.9% of mite samples and 24.7% of brood samples. Some of the examined mite samples harboured dual virus infections. Our findings showed that bee colonies from the same apiary were not always infected by the same viruses. Some bee colonies were virus-free, while others were highly infected. Phylogenetic analysis of 21 sequences demonstrated the presence of highly variable DWV-B and DWV-A genotypes in Lithuania and possible recombinant variants of the virus. This study represents the first molecular characterization of mite-borne pathogens hosted by honeybees (Apis mellifera) in Lithuania. [ABSTRACT FROM AUTHOR]

Simple Summary: Economically, Varroa destructor is the most important parasite to honey bees. There are many ways to deal with it, including pharmaceutical and biotechnological treatments. However, the mite has become resistant to many synthetic pesticides. There is little research on its response to organic acids. This report examines the question of whether it could become resistant to oxalic acid. The review uses literature from the past 30 years, and calculates and reviews the annual median efficacy for different application methods. If an efficacy of 70% or more is achieved, it can be concluded that the organism is not resistant. There is no evidence of resistance development, despite some outliers, which can be explained by the studies. Further tests are required to confirm the results. As Varroa destructor is one of the most important pathogens of Apis mellifera, there are numerous treatment methods, including pharmaceutical and biotechnological approaches. However, the rapid development of resistance to synthetic acaricides by Varroa destructor has become a significant concern. To date, there have been no investigations into the development of resistance to organic acids. This review examines the potential risk of oxalic acid resistance development by evaluating literature sources from the past 30 years following the PRISMA 2020 guidelines. Median annual efficacies are calculated and reviewed over time for several application methods. An efficacy higher than 70% is determined as not resistant. Independent of the method of application, no resistance development can be observed, although there are some outliers of the annual median. These outliers can be explained by brood status or study setting. However, the result is limited by the low number of efficacy values, and further standardised studies are needed. [ABSTRACT FROM AUTHOR]

Winter is the season of main concern for beekeepers since the temperature, humidity, and potential infection from mites and other diseases may lead the colony to death. As a consequence, beekeepers perform invasive checks on the colonies, exposing them to further harm. This paper proposes a novel design of an instrumented beehive involving color cameras placed inside the beehive and at the bottom of it, paving the way for new frontiers in beehive monitoring. The overall acquisition system is described focusing on design choices towards an effective solution for internal, contactless, and stress-free beehive monitoring. To validate our approach, we conducted an experimental campaign in 2023 and analyzed the collected images with YOLOv8 to understand if the proposed solution can be useful for beekeepers and what kind of information can be derived from this kind of monitoring, including the presence of Varroa destructor mites inside the beehive. We experimentally found that the observation point inside the beehive is the most challenging due to the frequent movements of the bees and the difficulties related to obtaining in-focus images. However, from these images, it is possible to find Varroa destructor mites. On the other hand, the observation point at the bottom of the beehive showed great potential for understanding the overall activity of the colony. [ABSTRACT FROM AUTHOR]

Simple Summary: Honeybees are vital pollinators, essential for maintaining ecosystems and biodiversity, but there is rising concern about the health of managed honey bee colonies, especially in heavily human-influenced ecosystems. Multiple factors contribute to this decline, including environmental conditions, forage quality, and pesticide use. These elements have a complex effect on the health and nutritional status of honeybee colonies and influence their response to disease and various stressors. In this study, the authors propose a new approach to assess colony health by correlating common measures of colony strength such as honey and pollen reserves, the number of bees, and brood with hemolymph proteins, common bee pathogens (Varroa destructor and Nosema spp.), and essential trace elements (iron, zinc, and copper). Significant correlations were found between hemolymph proteins and colony performance measures, and between V. destructor and hemolymph proteins and iron content. In conclusion, this study confirms the need for a more holistic approach to honeybee health considering all the relevant aspects and critical points that may affect colony survival. Environment, forage quality, management practices, pathogens, and pesticides influence honeybee responses to stressors. This study proposes an innovative approach to assess colony health and performance using molecular diagnostic tools by correlating hemolymph proteins with common measures of colony strength, prevalent honeybee pathogens (Varroa destructor and Nosema spp.), and essential trace elements (iron, zinc and copper). Colonies were selected from four apiaries located in different environmental and foraging conditions in the province of Bologna (Italy). Hemolymph samples were taken from June to October 2019. The Varroa infestation of the colonies was estimated by assessing the natural mortality of the mites, while the bees were tested for Nosema spp. spores using a microscopic method. Hemolymph proteins were quantified and separated using SDS-PAGE, and colony performance was assessed by determining adult bees, total brood, honey, and pollen reserves. The biomarkers measured proved to be useful for monitoring changes in performance and trophic conditions during summer and early autumn. Significant correlations were found between hemolymph proteins and colony performance measures. A positive correlation between pollen reserves, vitellogenin, and hexamerin 70a highlights the importance of these proteins for successful overwintering. In October, Varroa infestation was negatively correlated with total proteins, vitellogenin, apolipophorin II, transferrin, and hexamerin 70a, with negative implications for overwintering; furthermore, Varroa infestation was also negatively correlated with iron content, potentially affecting iron homeostasis. [ABSTRACT FROM AUTHOR]

Simple Summary: There is a global need for targeted, environmentally friendly, sustainable alternatives to pesticides. In the apicultural industry, the parasitic mite Varroa destructor poses a serious threat to honey bee health. Like many other agricultural pests, Varroa are primarily managed via pesticides. Whilst these pesticides can effectively control mites, they can also harm bee health, contaminate bee products and pose toxicity risks to beekeepers during application. As a first step to assessing public support for a new biotechnology that could provide a non-toxic alternative to pesticides, beekeepers' perspectives on a novel Varroa control method designed to inhibit protein production, called RNA interference (RNAi), were investigated. The majority of beekeepers surveyed were open to using RNAi treatments against Varroa, particularly as it provided a non-toxic alternative to current pesticide options. The major concerns raised were the unknown long-term effects of the RNAi treatment on bee health, potential effects on non-target species that interact with beehives and concern that an uninformed public that might prevent them from accessing a new tool to combat Varroa. Surveys such as ours can inform scientists and regulatory authorities on how best to introduce novel biotechnologies for commercial use. Current Varroa mite management strategies rely heavily on the use of pesticides, adversely affecting honey bee health and leaving toxic residues in hive products. To explore the likelihood of RNAi technology being utilised as an alternative control method for pests like Varroa, the opinions of beekeepers on the use of this new biotechnology were obtained using a mixed-methodology approach. In-person surveys and focus groups using the Q method were conducted to discover the willingness of beekeepers to utilise Varroa-targeting RNAi treatments in their hives, and to gain feedback to inform decisions before the implementation of this new technology. Overall, the beekeepers saw potential in RNAi being used to control Varroa in their hives and were eager to have access to an alternative to pesticide treatments. Participants raised concerns about unknown long-term effects on bees and other non-target species, and the potential of an uninformed public preventing them from accessing a new Varroa treatment. While further research and discussion is needed before RNAi treatments for Varroa become commercially available, RNAi technology presents a promising, species-specific and non-toxic solution for Varroa management. [ABSTRACT FROM AUTHOR]

Varroa mites, scientifically identified as Varroa destructor, pose a significant threat to beekeeping and cause one of the most destructive diseases affecting honey bee populations. These parasites attach to bees, feeding on their fat tissue, weakening their immune systems, reducing their lifespans, and even causing colony collapse. They also feed during the pre-imaginal stages of the honey bee in brood cells. Given the critical role of honey bees in pollination and the global food supply, controlling Varroa mites is imperative. One of the most common methods used to evaluate the level of Varroa mite infestation in a bee colony is to count all the mites that fall onto sticky boards placed at the bottom of a colony. However, this is usually a manual process that takes a considerable amount of time. This work proposes a deep learning approach for locating and counting Varroa mites using images of the sticky boards taken by smartphone cameras. To this end, a new realistic dataset has been built: it includes images containing numerous artifacts and blurred parts, which makes the task challenging. After testing various architectures (mainly based on two-stage detectors with feature pyramid networks), combination of hyperparameters and some image enhancement techniques, we have obtained a system that achieves a mean average precision (mAP) metric of 0.9073 on the validation set. [ABSTRACT FROM AUTHOR]

Simple Summary: Since the mid-20th century, the parasitic Varroa mite has become a major threat for honey bee health worldwide. However, mature female mites are only able to reproduce in the honey bee colony's brood cells, which are the hexagonal wax cells in which early bee larvae and pupae develop. By abundantly feeding on the larvae and pupae's fat body tissues and hemolymph, the mites weaken the bees and act as an important vector for many honey bee viruses. Worldwide, distinct natural mite-surviving colonies have already been observed, which often show a range of Varroa resistance traits suppressing the mite's population growth. One such trait is characterized by the suppression of mite reproduction in the brood cells of the developing bees. However, accounting for this trait in selection programs to improve resilience is hard, as the trait is labor- and time-intensive to evaluate. In this study, we propose an alternative, more holistic way of evaluating this Varroa resistance trait, reducing labor without impairing precision, which ultimately allows more colonies to be included in honey bee selection or breeding programs. The mechanisms of action behind decreased mite reproduction (DMR) are still unknown, but current hypotheses state that DMR is the result of brood-intrinsic and/or external disturbances in the V. destructor—honey bee pupa signal interactions. For accurate and precise DMR phenotyping, sufficient single infested honey bee brood cells are required (e.g., 35), which requires extensive labor and time and may exclude many samples not reaching the threshold. We defined a new comprehensive trait called the 'mean V. destructor reproduction rate' (mVR), which describes the mean number of offspring mites per infested cell in the sample while compensating for the reduced number of offspring with increasing multiple infested cells. We found a significant correlation between mVR and DMR, allowing for an estimation of DMR based on the mVR only. When the mVR was calculated with 10 infested cells, we found an average variation in mVR of 16.8%. For the same variation in DMR determination, 40 single infested cells are required. This broader look at V. destructor resistance phenotyping can improve the applicability and effectiveness of traits related to V. destructor reproduction in honey bee breeding programs. [ABSTRACT FROM AUTHOR]

The grooming behavior of honeybees serves as a crucial auto-protective mechanism against Varroa mite infestations. Compared to Apis mellifera, Apis cerana demonstrates more effective grooming behavior in removing Varroa mites from the bodies of infested bees. However, the underlying mechanisms regulating grooming behavior remain elusive. In this study, we evaluated the efficacy of the auto-grooming behavior between A. cerana and A. mellifera and employed RNA-sequencing technology to identify differentially expressed genes (DEGs) in bee brains with varying degrees of grooming behavior intensity. We observed that A. cerana exhibited a higher frequency of mite removal between day 5 and day 15 compared to A. mellifera, with day-9 bees showing the highest frequency of mite removal in A. cerana. RNA-sequencing results revealed the differential expression of the HTR2A and SLC17A8 genes in A. cerana and the CCKAR and TpnC47D genes in A. mellifera. Subsequent homology analysis identified the HTR2A gene and SLC17A8 gene of A. cerana as homologous to the HTR2A gene and SLC17A7 gene of A. mellifera. These DEGs are annotated in the neuroactive ligand–receptor interaction pathway, the glutamatergic synaptic pathway, and the calcium signaling pathway. Moreover, CCKAR, TpnC47D, HTR2A, and SLC17A7 may be closely related to the auto-grooming behavior of A. mellifera, conferring resistance against Varroa infestation. Our results further explain the relationship between honeybee grooming behavior and brain function at the molecular level and provide a reference basis for further studies of the mechanism of honeybee grooming behavior. [ABSTRACT FROM AUTHOR]

Honey bees are crucial for ecosystem pollination and honey production, yet the Varroa destructor mite hinders their productivity and health. Efforts to manage Varroa mites with synthetic pesticides have had limited success, highlighting the need for naturally derived acaricides as a primary option. However, the acaricidal efficacy of essential oils from Salvia officinalis L. (sage), Cannabis sativa (hemp), and Laurus nobilis (laurel) remains to be fully understood. This study aims to investigate the acaricidal efficacy of these three essential oils at varying concentrations and their impact on honey production, focusing on the efficient reduction in Varroa mites. The sugar roll method was employed to assess Varroa mite infestation levels, while GC-MS analysis was utilized to verify the composition of the essential oils. Honey production measurements were also performed. The efficacy rates (%) at concentrations of 15%, 10%, and 5% for hemp oil were 95.4% ± 0.30%, 85.71% ± 0.85%, and 64.48% ± 0.26%, respectively; for sage oil, they were 81.08% ± 0.57%, 69.42% ± 1.72%, and 50.35% ± 0.70%; and for laurel oil, they were 68.96% ± 0.34%, 54.66% ± 0.37%, and 33.58% ± 0.30%, respectively. Key compounds identified include trans-caryophyllene, α-pinene, and viridiflorol in hemp oil; myrcene, limonene, and β-caryophyllene in sage oil; and phytol, β-myrcene, and n-heneicosane in laurel oil. The overall findings indicate that hemp oil is highly effective in controlling Varroa mites. However, further research is needed to evaluate its potential side effects on bees to ensure its sustainability and safety. [ABSTRACT FROM AUTHOR]

In recent years, the global reduction in populations of the Apis mellifera species has generated a worrying deterioration in the production of essential foods for human consumption. This phenomenon threatens food security, as it reduces the pollination of vital crops, negatively affecting the health and stability of ecosystems. The three main factors generating the loss of the bee population are industrial agriculture, climate changes, and infectious diseases, mainly those of parasitic origin, such as the Varroa destructor mite. This article proposes an IoT system that uses accessible, efficient, low-cost devices for beekeepers in developing countries to monitor hives based on temperature, humidity, C O 2 , and TVOC. The proposed solution incorporates nine-feature aggregation as a data preprocessing strategy to reduce redundancy and efficiently manage data storage on hardware with limited capabilities, which, combined with a machine learning model, improves mite detection. Finally, an evaluation of the energy consumption of the solution in each of its nodes, an analysis of the data traffic injected into the network, an assessment of the energy consumption of each implemented classification model, and, finally, a validation of the solution with experts is presented. [ABSTRACT FROM AUTHOR]

The incessant threat posed by the Varroa destructor mite to bee colonies has spurred extensive research into control strategies. One of these strategies involves ultraviolet radiation, aiming to harness the damaging effects that this type of radiation induces in arthropods. This study focuses on investigating the potential influence of near ultraviolet (UVA) radiation on the surface damage incurred by Varroa destructor. To address this inquiry, multiple specimens were continuously irradiated with UVA while digital holograms were recorded. To assess surface damage, these holographic records were processed and analyzed. It was found that exposure to radiation induces subtle swelling, around a few tenths of micrometers, which is more pronounced around the anal shield and genital shield of the mite. These alterations could impact the health and viability of this parasitic mite. This is the first time that the measurement and quantification of this superficial damage is reported, contributing to the understanding of the impact of UVA irradiation on the external structure of the mite. [ABSTRACT FROM AUTHOR]

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

Simple Summary: Honeybees (Apis mellifera) are crucial for our ecosystem, but they face various threats. This study investigates the detection of a new mite species emerging in Korean honeybees, Carpoglyphus lactis. Using the polymerase chain reaction method to amplify the Cytochrome c oxidase subunit 1 gene region, we examined the presence of C. lactis in honeybee colonies across nine provinces of the Republic of Korea. We found C. lactis in eight provinces in ROK, particularly during winter. This is the first identification of C. lactis in Korean honeybees. Identifying new threats is essential for beekeepers and researchers. Understanding the prevalence of C. lactis mite species and its impact on honeybee health will help develop strategies to protect bee populations. Apis mellifera, especially weak ones, are highly vulnerable to Carpoglyphus lactis mites, which can rapidly infest and consume stored pollen, leading to weakened colonies and potential colony collapse. This study aimed to ascertain and investigate the prevalence of this mite in honeybee colonies across nine provinces in the Republic of Korea (ROK). A total of 615 honeybee colony samples were collected from 66 apiaries during the spring and 58 apiaries during the summer of 2023. A 1242 bp segment of the Cytochrome c oxidase subunit 1 (COI) gene was amplified using the polymerase chain reaction method. The detection levels of C. lactis in the honeybees were compared between winter and summer. Based on the COI sequence analysis, the nucleotide sequence similarity of C. lactis mites isolated in the ROK with those from China (NC048990.1) was found to be 99.5%, and with those from the United Kingdom (KY922482.1) was 99.3%. This study is the first report of C. lactis in Korean apiaries. The findings of this study demonstrate a significantly higher detection rate in winter, which is 4.1 times greater than that in summer (p < 0.001). Furthermore, the results underscore the usefulness of molecular diagnostic techniques for detecting C. lactis mites. [ABSTRACT FROM AUTHOR]

The presence of the Varroa destructor mite requires the use of acaricide treatments for honeybee colonies. Amitraz is one of the most common acaricide-active ingredients used by beekeepers. Certain Varroa mite populations have developed resistance to amitraz, thereby leading to a loss in the efficacy of amitraz-based treatments. Two products, Apivar and Supatraz, were applied in the same apiary in France to evaluate their efficacy. Both treatments are amitraz-based but have different galenics. Thanks to field data, a dynamic model was used to simulate the actions of Apivar and Supatraz on the mite population. We considered two parameters to compare the products as follows: the daily mortality rate and the treatment duration. In the field, the percentage of the efficacy of the two products was not significantly different, but Supatraz kills mites faster and decreases 90% of the mite infestation in 28.4 days compared with 50.9 days when using Apivar. Through modeling, we showed the daily impact of the two different products on mite population. Supatraz has a higher daily mortality rate during the first two weeks than Apivar. Supatraz requires a lower efficacy (% of varroa mites killed during all the treatment) to stabilize the varroa mite population due to its faster release of active ingredients than Apivar, thereby needing a shorter period to achieve the same result. Depending on the model, Supatraz conserves effective efficacy when used against moderately resistant mites (with mite mortality being 40–70% at the LC90) but not against highly resistant mites (with mite mortality being <40% at the LC90). These results show that the comparison of the efficacy of the two products with different characteristics (duration of treatment and daily mortality rate) should be analyzed with caution. [ABSTRACT FROM AUTHOR]

Simple Summary: Apis mellifera is a managed pollinator that experiences cycles of extreme losses at the population level. Several culprits have been associated with these mass losses. Most notably, the parasitic mite Varroa destructor is a consistent suspect in periodic mass losses of honey bee colonies. Our team performed diagnostic screening of pathogens and parasites in operations that experienced extreme losses during the winter of 2023. The direct cost to replace lost colonies and the immediate economic harm imparted from severe losses are described. United States commercial beekeepers prepare honey bee colonies for almond pollination in California each year in late January to early February. This represents the largest managed pollination event in the world and involves more than half of all U.S. honey bee colonies. In winter 2023, numerous colonies in Florida, which were graded as suitable for almonds (larger than ten frames of bees), dwindled suddenly or altogether died within several weeks, just prior to movement for almonds. The timing of these losses and the resulting morbidity caused severe economic harm to affected operations. This study reports interviews with affected stakeholders, their economic harm, and analyses of pathogens and parasites found in their colonies. [ABSTRACT FROM AUTHOR]

Simple Summary: The aim of the study was to evaluate the viral load in honey bee colonies after adopting two brood interruption techniques that are used to control varroa mite. We evaluated the efficacy of two integrated pest management (IPM) strategies, "Queen Caging" (QC) and "Trapping Comb" (TC) procedures, in conjunction with an oxalic acid treatment, to control varroa infestations and consequently lower the viral loads of Deformed Wing Virus (DWV) and Acute Bee Paralysis Virus (ABPV). Two distinct apiaries in Slovenia and Italy, each with a different climate, served as the research sites. In the experiment, the adult bee viral load, mite fall, colony strength, and acaricide efficiency were assessed. The study indicated that the TC approach might be more successful in lowering viral loads. Our results also showed that the acaricidal efficacy of the applied IPM protocols is high. Our study is the first attempt to assess viral infections in honey bees after IPM adoption. The results show the potential advantages of using targeted varroa treatments in combination with brood interruption strategies to manage honey bee viruses vectored by varroa mite. Honey bee viruses in combination with varroa mite are very damaging for honey bee colonies worldwide. There are no effective methods to control the viral load in honey bee colonies except regular and effective control of mites. Integrated Pest Management strategies are required to effectively control mites with veterinary medicines based on organic compounds. We evaluated the effect of two brood interruption techniques, queen caging (QC) and trapping comb (TC), followed by an oxalic acid treatment, on the mite fall, colony strength, and viral load of Deformed Wing Virus (DWV) and Acute Bee Paralysis Virus (ABPV). In this paper, we report the data obtained in two experimental sites, in Slovenia and Italy, in terms of the varroacide efficacy, colony strength, and viral load. The number of adult bees after the adoption of the two techniques showed similar decreasing trends in both locations. The viral load of Acute Bee Paralysis Virus did not show any significant reduction after 25 days, reported as the number of Real-Time PCR cycles needed to detect the virus. The viral load of DWV also did not show a significant reduction after 25 days. The acaricidal efficacy of the applied protocols was high in both experimental groups and in both apiaries. Both the queen caging and trapping comb techniques, followed by an oxalic acid treatment, can be considered effective varroa treatment strategies, but further studies should be carried out to evaluate the long-term effects on viral loads to plan the Integrated Pest Management strategy with the right timing before wintering. [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. [ABSTRACT FROM AUTHOR]

Simple Summary: Varroa destructor is an ectoparasitic mite that affects honey bee colonies and it is considered one of the most important causes of honey bee losses. Botanical origins have emerged as natural alternative acaricides to diminish the population levels of Varroa mites. Propolis is a natural product, consisting of a complex mixture of resinous substances collected by honey bees from different plant sources. In this study, we investigated the effect of propolis, collected by native Algerian honey bees, on V. destructor by a spraying method. The results indicated that propolis extracts at 10% are effective in killing Varroa mites and are harmless for honey bees. Propolis extracts could be used in honey bee colonies by spraying to control Varroa mite infestations, and further investigations are required for a better understanding of the mechanism(s) of this acaricide activity. Varroa destructor is an ectoparasitic mite and is considered one of the most important causes of honey bee population loss. In the last years, substances of botanical origin have emerged as natural alternatives to diminish the mite population levels. Propolis is a natural product and is used by honey bees for multiple tasks, including protection from pathogens and parasites, and varroacidal activity of propolis extracts has been shown. In this study, we investigated the potential of propolis, collected by native Algerian honey bee subspecies (Apis mellifera intermissa and A. m. sahariensis) in different locations in Algeria and extracted by ultrasound, to control mites of V. destructor and tested the safety for the honey bees. The most important results were that the best propolis extracts at 10% killed 100% of the Varroa mites within 3–4 h in a Petri dish assay. In addition, when we sprayed A. m. intermissa bees infested with Varroa mites with a 10% concentration in a mini-hive setup, we scored a high mite mortality of 85–87% with the best propolis extracts, and importantly, there was no mortality in the bees. Our data demonstrated that propolis extracts in Algeria could be used in honey bee colonies by spraying against Varroa mite infestations, which may develop as an easy method for local beekeepers to control Varroa in their hives. Further research should investigate the mechanism of action. [ABSTRACT FROM AUTHOR]

Simple Summary: Varroa destructor is a parasitic mite of honey bees that causes several injuries to colonies. The emergence of resistant populations of mites to traditional chemical acaricides has decreased their effectiveness and has made the control of this pathogen extremely difficult. The aim of this study was to evaluate the efficacy of postbiotics from beehives, and their combinations with other organic compounds, against V. destructor. Four species of lactic acid bacteria were obtained and tested by exposing mites to each species in a postbiotic format (preparations of inanimate microorganisms and/or their components that confer a health benefit to the host). Three species decreased the viability of mites regarding the control group, and those were further tested together as a single postbiotic product (POS). Later, the effect of the postbiotic product and its combination with oxalic acid and oregano essential oil was tested in eight groups: Control, POS, Oregano, Oxalic, POS/Oregano, POS/Oxalic, Oregano/Oxalic, POS/Oregano/Oxalic. All the products decreased the viability of the mites, and the most effective were the oxalic acid combinations, with significant differences for each product alone. These results show that oxalic acid combinations with postbiotics and essential oils could be an important tool for the treatment of V. destructor. The Varroa destructor mite infests Apis mellifera colonies and causes significant harm. Traditional treatments have become less effective because of mite resistance development and can also generate residues inside beehives. This study aimed to gauge the efficacy of a beehive-derived postbiotic in reducing V. destructor viability and to explore its synergies with organic compounds. Four lactic acid bacteria (LAB) species, Leuconostoc mesenteroides, Lactobacillus helsingborgensis, Bacillus velezensis, and Apilactobacillus kunkeei, were isolated and tested in a postbiotic form (preparations of inanimate microorganisms and/or their components) via bioassays. L. mesenteroides, L. helsingborgensis, and B. velezensis notably reduced the mite viability compared to the control, and they were further tested together as a single postbiotic product (POS). Further bioassays were performed to assess the impact of the POS and its combinations with oxalic acid and oregano essential oil. The simple products and combinations (POS/Oregano, POS/Oxalic, Oregano/Oxalic, and POS/Oregano/Oxalic) decreased the mite viability. The most effective were the oxalic acid combinations (POS/Oregano/Oxalic, Oxalic/Oregano, POS/Oxalic), showing significant improvements compared to the individual products. These findings highlight the potential of combining organic products as a vital strategy for controlling V. destructor infection. This study suggests that these combinations could serve as essential tools for combating the impact of mites on bee colonies. [ABSTRACT FROM AUTHOR]

Simple Summary: Essential oils (EOs) have been shown to possess several pharmacological properties, among which we can mention antibacterial, antiviral and acaricidal effects. The latter activity is particularly interesting in beekeeping for the control of Varroa destructor parasitosis. This research aimed to verify the acaricidal potential of four botanical species belonging to the Lamiaceae family. Specifically, the species tested were Calamintha sylvatica, Calamintha nepeta, Lavandula austroapennina and Mentha piperita. The evaluation was conducted by means of residual contact toxicity tests by diluting the EOs in Acetone to achieve concentrations of 2, 1 and 0.5 mg/mL. At the highest concentration, the tests returned a neutralization percentage of 52% for Calamintha nepeta, 60% for Calamintha sylvatica, 80% for Lavandula austroapennina and 68% for Mentha piperita. Varroa destructor is currently considered the parasite that causes the greatest damage and economic losses to honeybee farms. Its presence is often associated with that of viral and bacterial pathogens, which ultimately leads to colony collapse. Careful control of the parasitic load is therefore necessary to avoid the onset of these events. Although chemical treatments are often in easily and quickly administered formulations, in recent years, there have been increasingly frequent reports of the onset of drug resistance phenomena, which must lead to reconsidering their use. Furthermore, chemical compounds can easily accumulate in the food matrices of the hive, with possible risks for the final consumer. In such a condition, it is imperative to find alternative treatment solutions. Essential oils (EOs) prove to be promising candidates due to their good efficacy and good environmental biodegradability. In this study, the acaricidal efficacy of the EOs of Calamintha sylvatica Bromf., Calamintha nepeta Savi, Lavandula austroapennina N.G. Passal. Tundis & Upson and Mentha piperita L., extracted from botanical species belonging to the Lamiaceae family, was evaluated. The test chosen for the evaluation was residual toxicity by contact. The examined EOs were diluted in Acetone to a concentration of 2, 1 and 0.5 mg/mL. At the highest concentration, the EOs demonstrated an acaricidal activity equal to 52% for C. nepeta, 60% for C. sylvatica, 80% for L. austroapennina and 68% for M. piperita. Of the EOs tested, therefore, Lavender proves to be a good candidate for subsequent evaluations in semi-field and field studies. [ABSTRACT FROM AUTHOR]

Varroa destructor infestation is a major factor leading to the global decline of honeybee populations. Monitoring the level of Varroa mite infestation in order to take timely control measures is crucial for the protection of bee colonies. Machine vision systems can achieve non-invasive Varroa mite detection on bee colonies, but it is challenged by two factors: the complex dynamic scenes of honeybees and small-scale and limited data on Varroa destructor. We design a convolutional neural network integrated with machine vision to solve these problems. To address the first challenge, we separate the image of the honeybee from its surroundings using a segmentation network, and the object-detection network YOLOX detects Varroa mites within the segmented regions. This collaboration between segmentation and object detection allows for more precise detection and reduces false positives. To handle the second challenge, we add a Coordinate Attention (CA) mechanism in YOLOX to extract a more discriminative representation of Varroa destructor and improve the confidence loss function to alleviate the problem of class imbalance. The experimental results in the bee farm showed that the evaluation metrics of our model are better than other models. Our network's detection value for the percentage of honeybees infested with Varroa mites is 1.13%, which is the closest to the true value of 1.19% among all the detection values. [ABSTRACT FROM AUTHOR]

The deformed wing virus (DWV) belongs to the genus Iflavirus and the family Iflaviridae within the order Picornavirales. It is an important pathogen of the Western honey bee, Apis mellifera, causing major losses among honey bee colonies in association with the ectoparasitic mite Varroa destructor. Although DWV is one of the best-studied insect viruses, the mechanisms of viral replication and polyprotein processing have been poorly studied in the past. We investigated the processing of the protease-polymerase region at the C-terminus of the polyprotein in more detail using recombinant expression, novel serological reagents, and virus clone mutagenesis. Edman degradation of purified maturated polypeptides uncovered the C- and N-termini of the mature 3C-like (3CL) protease and RNA-dependent RNA polymerase (3DL, RdRp), respectively. Autocatalytic processing of the recombinant DWV 3CL protease occurred at P1 Q2118 and P1′ G2119 (KPQ/GST) as well as P1 Q2393 and P1′ S2394 (HAQ/SPS) cleavage sites. New monoclonal antibodies (Mab) detected the mature 3CL protease with an apparent molecular mass of 32 kDa, mature 3DL with an apparent molecular mass of 55 kDa as well as a dominant 3CDL precursor of 90 kDa in DWV infected honey bee pupae. The observed pattern corresponds well to data obtained via recombinant expression and N-terminal sequencing. Finally, we were able to show that 3CL protease activity and availability of the specific protease cleavage sites are essential for viral replication, protein synthesis, and establishment of infection using our molecular clone of DWV-A. [ABSTRACT FROM AUTHOR]

Simple Summary: Varroa destructor salivary secretion plays a vital role in mite–bee interactions. In this study, we found that the salivary cystatin gene was highly expressed in mites during the reproductive phase when they fed on pupal bees. Injection of prokaryotic-expressed cystatin into white-eyed pupal bees downregulated the metabolism of carbohydrates, fatty acids, and amino acids, and ATP production, which caused the pupal bees to fail to emerge and decreased the weight of newly emerged bees. Downregulation could save nutrients and energy for V. destructor to maximize its reproduction potential, implying that Varroa destructor could manipulate the metabolism of host bees through the injected salivary secretion. These results provide new insights into mite–bee interactions, providing a basis for Varroa destructor control in apiculture. Varroa destructor injects a salivary secretion into honeybees during their feeding process. The salivary secretion plays a vital role in mite–bee interactions and is the main cause of honeybee illness. To determine the biological function of cystatin-L2-like, one of the components of V. destructor salivary secretion, its gene expression in mites during the reproductive phase and dispersal phase was quantified using RT-qPCR, respectively. Moreover, the E. coli-expressed and -purified cystatin was injected into the white-eyed honeybee pupae, and its effects on the survival, the weight of the newly emerged bee, and the transcriptome were determined. The results showed that cystatin was significantly upregulated in mites during the reproductive phase. Cystatin significantly shortened the lifespan of pupae and decreased the weight of the newly emerged bees. Transcriptome sequencing showed that cystatin upregulated 1496 genes and downregulated 1483 genes in pupae. These genes were mainly enriched in ATP synthesis, the mitochondrial respiratory chain, and cuticle structure and function. Cystatin comprehensively downregulated the metabolism of carbohydrates, fatty acids, and amino acids, and energy production in the pupae. The downregulation of metabolic activity could save more nutrients and energy for V. destructor, helping it to maximize its reproduction potential, implying that the mite could manipulate the metabolism of host bees through the injected salivary secretion. The results provide new insights into mite–bee interactions, providing a basis for related studies and applications. [ABSTRACT FROM AUTHOR]

Simple Summary: Varroa destructor acariasis is currently the main threat to the health and survival of honeybee colonies. Chemicals are often used to control this parasitosis. However, overuse and misuse over the years has allowed the mite to acquire resistance to synthetic active ingredients. In this scenario, it is vital to search for alternative therapeutic solutions. Essential oils (EOs) are a promising therapeutic choice, as they have a complex chemical composition, making them unlikely to be prone to the development of resistance. In addition, they are easily degraded in the environment and have a low toxicity for humans, characteristics that make them particularly attractive. In this research study, four EOs from the Lamiaceae family, isolated from botanical species native to the Calabria region, Southern Italy, were tested in contact toxicity tests against V. destructor. Origanum vulgare subsp. viridulum, Thymus capitatus and Thymus longicaulis, used at 2 mg/mL, were found to have a high level of efficacy, neutralizing (dead + inactivated) 94%, 92% and 94% of parasites, respectively. These EOs could be chosen and tested in subsequent in vivo studies. 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. [ABSTRACT FROM AUTHOR]

The Varroa destructor mite is a devastating parasite of honey bees; however the negative effects of varroa parasitism are exacerbated by its role as an efficient vector of the honey bee pathogen, Deformed wing virus (DWV). While no direct treatment for DWV infection is available for beekeepers to use on their hives, RNA interference (RNAi) has been widely explored as a possible biopesticide approach for a range of pests and pathogens. This study tested the effectiveness of three DWV-specific dsRNA sequences to lower DWV loads and symptoms in honey bees reared from larvae in laboratory mini-hives containing bees and varroa. The effects of DWV-dsRNA treatment on bees parasitised and non-parasitised by varroa mites during development were investigated. Additionally, the impact of DWV-dsRNA on viral loads and gene expression in brood-parasitising mites was assessed using RNA-sequencing. Bees parasitised during development had significantly higher DWV levels compared to non-parasitised bees. However, DWV-dsRNA did not significantly reduce DWV loads or symptoms in mini-hive reared bees, possibly due to sequence divergence between the DWV variants present in bees and varroa and the specific DWV-dsRNA sequences used. Varroa mites from DWV-dsRNA treated mini-hives did not show evidence of an elevated RNAi response or significant difference in DWV levels. Overall, our findings show that RNAi is not always successful, and multiple factors including pathogen diversity and transmission route may impact its efficiency. [ABSTRACT FROM AUTHOR]

Simple Summary: Beekeeping is an important economic activity but the sector suffers from both technical and economic problems. One of the main threats affecting honey bees is the Varroa destructor mite. To improve beekeeping farm sustainability, low-environmental-impact control of this mite is recommended. This paper examines different methods applied for the control of Varroa on Italian beekeeping farms both in terms of operations carried out in apiaries and net income, focusing on biotechniques. First, our analyses provide a detailed overview of each biotechnique and the organic and conventional treatments used to fight Varroa. Then, by highlighting the higher net income of farms applying biotechniques, we show that a trade-off need not be made between sustainable techniques and farm profitability. It is possible to achieve a long-term reduction in Varroa infestation while obtaining zero-residue bee products and respecting environmental and human health in compliance with European and national regulations and guidance. Beekeeping faces several challenges, such as the Varroa mite. Few studies have measured the economic performance of farms in relation to the practices used for Varroa control. Our study analyzed various biotechniques (total brood removal, TBR; queen caging, QC; royal cell insertion, CI) and other methods (chemical treatments, CT; thymol use, THY) adopted by Italian beekeepers to show whether the adoption of biotechniques leads to farm profitability or a necessary trade-off between sustainability and profitability. Beekeepers were interviewed about the methods and operations conducted on their farms. The net incomes (NIs) of the farms were calculated and inter- and intrafarm comparisons were performed. A detailed schema of each practice was designed. The net income derived from TBR was the highest in eight out of the nine case studies, followed by CI and then QC. The NI calculated for farms using CT was lower than that for farms using other methods in two of the case studies. We also analyzed different biotechniques applied by the same farm and found that the NI resulting from TBR was higher than that achieved from the use of QC and CI. Our study suggests that use of biotechniques represents a long-term sustainable solution for reducing the level of Varroa infestation, which affects farm net income. [ABSTRACT FROM AUTHOR]

Simple Summary: Varroa destructor, a parasitic mite, has significantly impacted Irish beekeeping, causing alarming colony losses and threatening the native honeybee subspecies, Apis mellifera mellifera. While Irish beekeepers are crucial for controlling this parasite, they lack supportive infrastructure. This creates a unique opening for national programmes promoting sustainable beekeeping practices for varroa control. Reports indicate that an increasing number of local beekeepers are successfully managing colonies without treatments, suggesting potential for varroa-resistant stock development through selective breeding. Our survey examined beekeepers' views on sustainable practices and varroa resistance. The results underline Irish beekeepers' hobbyist nature and their preference for the native honey bee subspecies. Some control varroa without treatment, achieving comparable survival rates. Most prefer varroa-resistant lines of native origin, with little openness to non-Irish strains. A strong willingness to engage in a national breeding programme appears evident. These insights offer Ireland an opportunity to establish a large-scale sustainable beekeeping strategy for safeguarding native honeybees and local biodiversity. Beekeeping in Ireland has been strongly impacted by the parasitic mite Varroa destructor, whose introduction caused alarming honeybee colony losses. If unmitigated, these losses could lead to the disappearance of the native honeybee subspecies, Apis mellifera mellifera, with severe consequences for local biodiversity. Although beekeepers play a pivotal role in mitigating this crisis, beekeeping in Ireland is less intensive compared to other European regions, lacking significant infrastructure or support. These circumstances offer a unique opportunity for the development of national programmes that promote sustainable beekeeping practices for varroa control. Notably, local accounts highlight an increasing number of beekeepers successfully managing colonies in the absence of treatments, indicating a potential avenue for developing varroa-resistant stocks through selection of local colonies. Through a survey, we explored beekeeper's opinions and attitudes towards future national projects focused on the development of sustainable beekeeping practices and selection for varroa resistance. The findings confirm the hobbyist nature of Irish beekeepers and their preference for the native honey bee. Some beekeepers were reported to be effectively controlling varroa without treatment, yielding comparable survivals to those using treatments. The majority expressed preference towards a varroa-resistant line if it were of native origin; a few were open to importing non-Irish lines. Overall, a strong willingness to participate in a national breeding programme was expressed. These findings highlight a prime opportunity for Ireland to establish a community-driven strategy based on sustainable beekeeping practices for safeguarding native honeybees and local biodiversity. [ABSTRACT FROM AUTHOR]

Simple Summary: Deformed wing virus (DWV) is a major honey bee pathogen found throughout the world. DWV, in association with the varroa mite, causes wing deformity, a shortened abdomen, and neurological impairments, leading to the mortality of millions of honey bee colonies worldwide. At least 12 ant species have been shown to harbor DWV, including the red imported fire ant, one of the most invasive and detrimental pests in the world. To date, there have been no reports in the literature of DWV causing symptoms in ants. In this study, we observed the classic honey-bee-like symptoms of deformed wings in laboratory and field colonies of the red imported fire ants and verified the presence and replication of DWV. This is the first report of the co-occurrence of DWV-like symptoms and DWV in ants. However, more research is needed to determine whether DWV is indeed the causative agent of DW syndrome in S. invicta. Deformed wing virus (DWV), a major honey bee pathogen, is a generalist insect virus detected in diverse insect phyla, including numerous ant genera. Its clinical symptoms have only been reported in honey bees, bumble bees, and wasps. DWV is a quasispecies virus with three main variants, which, in association with the ectoparasitic mite, Varroa destructor, causes wing deformity, shortened abdomens, neurological impairments, and colony mortality in honey bees. The red imported fire ant, Solenopsis invicta Buren, is one of the most-invasive and detrimental pests in the world. In this study, we report the co-occurrence of DWV-like symptoms in S. invicta and DWV for the first time and provide molecular evidence of viral replication in S. invicta. Some alates in 17 of 23 (74%) lab colonies and 9 of 14 (64%) field colonies displayed deformed wings (DWs), ranging from a single crumpled wing tip to twisted, shriveled wings. Numerous symptomatic alates also exhibited altered locomotion ranging from an altered gait to the inability to walk. Deformed wings may prevent S. invicta alates from reproducing since mating only occurs during a nuptial flight. The results from conventional RT-PCR and Sanger sequencing confirmed the presence of DWV-A, and viral replication of DWV was confirmed using a modified strand-specific RT-PCR. Our results suggest that S. invicta can potentially be an alternative and reservoir host for DWV. However, further research is needed to determine whether DWV is the infectious agent that causes the DW syndrome in S. invicta. [ABSTRACT FROM AUTHOR]

Simple Summary: Ectoparasitic mite Varroa destructor with its associated viruses is a common global threat to the health of honey bee colonies. If colonies are not treated, the vast majority die in a 3-year period. Existing acaricides used for treatment are becoming less effective, and new approaches to honey bee protection are required. A reliable method is to create a broodless condition in a colony by preventing the queen from laying eggs, and after 25 days all mites will be exposed to the treatment with organic acids or essential oils. The focus of our study, performed on 178 colonies in six Mediterranean countries, was to compare different periods of queen caging on honey production, colony development, and the effect of treatment. Queen caging had no negative effect on colony strength before the wintering period, while it affected honey production; colonies in which queens were caged two weeks before the main summer nectar flow produced significantly less honey. However, tested colonies ten weeks after the treatment had significantly lower infestation with V. destructor mites. This study shows that caging the queen with subsequent oxalic acid treatment 25 days after caging is an efficient method to control V. destructor infestation, while the starting point of queen caging in relation to the main summer nectar flow affects honey production. In this study, we investigated the effect of queen caging on honey bee colonies' post-treatment development and the optimal timing of method application on honey production during the main summer nectar flow. We conducted the study in nine apiaries (N = 9) across six Mediterranean countries, with a total of 178 colonies. The colonies were divided into three test groups: QC1, QC2, and C. The QC1 group involved queens caged for a total of 28 days before the expected harvesting day. In the QC2 group, queens were caged for 28 days, but only 14 days before the expected harvesting day. The C group consisted of queens that were not caged, and the colonies received common local treatments. In both the QC1 and QC2 groups, the colonies were treated with a 4.2% oxalic acid (OA) solution by trickling after the queen release. Our findings revealed no significant adverse effects (p > 0.05) on colony strength at the end of the study resulting from queen caging. However, significantly lower amounts of honey were extracted from the QC1 group compared to both the QC2 group (p = 0.001) and the C group (p = 0.009). Although there were no initial differences in Varroa destructor infestation between the groups, ten weeks later, a significantly higher infestation was detected in the C group compared to both the QC1 group (p < 0.01) and the QC2 group (p = 0.003). Overall, our study demonstrates that queen caging, in combination with the use of OA, is an effective treatment for controlling V. destructor. However, the timing of caging plays a crucial role in honey production outcomes. [ABSTRACT FROM AUTHOR]

Simple Summary: Honey bees (Apis mellifera) that play vital roles in pollination and ecosystem maintenance, face severe threats from the ectoparasite, Varroa destructor. Existing control techniques, including mechanical, chemical, and organic, have had adverse effects on honey bees. Therefore, finding an easy, effective, affordable, and safe method is crucial. Essential oils (EOs) and their major components emerge as potential candidates due to their higher efficiency, biodegradability, and selectivity. However, evaluating composition variability, as well as their efficiency and safety in honey bee species, is essential. In this study, we assessed the efficiency of essential oil and their components against Varroa mites while studying the safety for honey bees. Eucalyptus globulus, Rosemary officinalis, Trachyspermum ammi (Ethiopian and Indian varieties), alongside their major components and a 1:1 mixture, were assessed for their acaricidal activity. All the samples exhibited acaricidal activity, with T. ammi, thymol, and the 1:1 mixture of thymol and carvacrol showing the highest efficiency against V. destructor. Importantly, the EOs and their major components showed selectivity and did not affect the honey bees' learning and memory. In conclusion, our findings highlight the potential of T. ammi and the 1:1 mixture of thymol and carvacrol as candidates for Varroa control, suggesting further study at the colony level. The honey bee (Apis mellifera) faces a significant threat from Varroa destructor, causing the losses of millions of colonies worldwide. While synthetic acaricides are widely used to control Varroa infestations, excessive application has led to resistant strains and poses side effects on the host. Consequently, there is an urgent need for a new acaricide that is both effective and affordable, yet safe to use on bees. One potential source of these acaricides is essential oils (EOs) and their constituents. This study evaluated the acaricidal properties of four essential oils (Eucalyptus globulus, Rosemary officinalis, Trachyspermum ammi (Ethiopian and Indian varieties), their constituents and mixture of constituents against V. destructor through the complete exposure method. Our finding showed that a 1:1 mixture of thymol and carvacrol (4 h-LC50 = 42 μg/mL), thymol (4 h-LC50 = 71 μg/mL), and T. ammi oil (4 h-LC50 = 81–98 μg/mL) were the most toxic test samples against V. destructor. Honey bee behavior and selectivity were also assessed with one additional EO Thymus schimperi, indicating that T. schimperi, T. ammi, and their components were selective and did not affect the learning and memory of bees. In conclusion, the thymol and carvacrol (1:1) mixture was shown to be a promising replacement for synthetic acaricides, being three times more toxic than a commercial acaricide, fluvalinate (4 h-LC50 = 143 μg/mL). [ABSTRACT FROM AUTHOR]

Beekeepers can use a variety of treatments against Varroa destructor, the parasitic mite of Apis mellifera. However, sustainable and easy-to-use solutions are still scarce, considering the complexity of reaching the parasite alone. Current treatments involve soft acaricides, although their mechanism of action is not well understood. We investigated the effects of organic acids such as tartaric, lactic, formic, and citric acids on the attachment abilities of V. destructor under laboratory conditions. Preventing parasites from gripping or holding on to their hosts is a crucial target for mite control strategies. We challenged grip skills through the Rotavar setup after the direct application of acids to mites' arolia. We also tested the potential for mites to fall off honeybees after bee treatment. We found that tartaric, citric, and lactic acids were good candidates to impair the attachment of V. destructor twenty-four hours post-treatment. However, lactic acid remained the only candidate at a reasonable concentration to destabilise mites after the honey bee's treatment without reducing their lifespan. While we conducted these experiments under artificial conditions, our results improved our comprehension of the organic acids' potential impact on V. destructor. They can also help with the development of new methods for hive application for beekeepers worldwide. [ABSTRACT FROM AUTHOR]

Varroa destructor, a major ectoparasite of the Western honey bee Apis mellifera, is a widespread pest that damages colonies in the Northern Hemisphere. Throughout their lifecycle, V. destructor females feed on almost every developmental stage of their host, from the last larval instar to the adult. The parasite is thought to feed on hemolymph and fat body, although its exact diet and nutritional requirements are poorly known. Using artificial Parafilm™ dummies, we explored the nutrition of V. destructor females and assessed their survival when fed on hemolymph from bee larvae, pupae, or adults. We compared the results with mites fed on synthetic solutions or filtered larval hemolymph. The results showed that the parasites could survive for several days or weeks on different diets. Bee larval hemolymph yielded the highest survival rates, and filtered larval plasma was sufficient to maintain the mites for 14 days or more. This cell-free solution therefore theoretically contains all the necessary nutrients for mite survival. Because some bee proteins are known to be hijacked without being digested by the parasite, we decided to run a proteomic analysis of larval honey bee plasma to highlight the most common proteins in our samples. A list of 54 proteins was compiled, including several energy metabolism proteins such as Vitellogenin, Hexamerin, or Transferrins. These molecules represent key nutrient candidates that could be crucial for V. destructor survival. [ABSTRACT FROM AUTHOR]

Simple Summary: Honey bees are important for ecosystems and crops, but their populations are declining due to threats such as residues from veterinary and phytosanitary treatments. These residues accumulate in honeycomb wax, posing a risk to bees. Moreover, the constant recycling of old wax worsens the issue as new residues accumulate. To address this, a study explored using methanol extraction to decontaminate the wax. Now, we have assessed the acceptance of decontaminated wax by bees for building new honeycombs. The results showed that bees accepted it, albeit with a slight delay compared to commercial wax. Therefore, using decontaminated wax may be a viable solution to mitigate hazards from high residue levels. Honey bees face serious threats. These include the presence of the Varroa destructor mite in hives, which requires the use of acaricides to control. The constant recycling of old wax exacerbates the problem, and results in the accumulation of residues in the beeswax, which is a problem for the viability of the colony. The same happens with the accumulation of phytosanitary residues. In a previous study, we implemented an efficient wax decontamination method using a batch methanol extraction method. The present study evaluates the acceptance of the decontaminated wax by the bees for comb building, brood, honey and pollen containment. The results show a slight delay in the start of comb building and small changes were observed in the pharmacopoeia of the decontaminated wax compared to the original commercial wax. The slight delay in the acceptance of the decontaminated wax could be due to the loss of some components, such as honey residues, which usually appear in the wax. The addition of bee-attractive substances to the manufacturing process could help to mitigate the delay. The results suggest that the use of decontaminated wax is a good alternative to reduce the concentration of residues in hives. [ABSTRACT FROM AUTHOR]

Bees play a critical role in pollination and food production, so their preservation is essential, particularly highlighting the importance of detecting diseases in bees early. The Varroa destructor mite is the primary factor contributing to increased viral infections that can lead to hive mortality. This study presents an innovative method for identifying Varroa destructors in honey bees using multichannel Legendre–Fourier moments. The descriptors derived from this approach possess distinctive characteristics, such as rotation and scale invariance, and noise resistance, allowing the representation of digital images with minimal descriptors. This characteristic is advantageous when analyzing images of living organisms that are not in a static posture. The proposal evaluates the algorithm's efficiency using different color models, and to enhance its capacity, a subdivision of the VarroaDataset is used. This enhancement allows the algorithm to process additional information about the color and shape of the bee's legs, wings, eyes, and mouth. To demonstrate the advantages of our approach, we compare it with other deep learning methods, in semantic segmentation techniques, such as DeepLabV3, and object detection techniques, such as YOLOv5. The results suggest that our proposal offers a promising means for the early detection of the Varroa destructor mite, which could be an essential pillar in the preservation of bees and, therefore, in food production. [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]

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]

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]

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]