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Six Corsican essential oils (EOs) from Humulus lupulus were studied for their activity against Varroa destructor adults and Apis mellifera pupae. The GC/MS analysis of EOs showed that the major compounds of all accessions were α-Humulene, Myrcene, α-Selinene, β-Selinene, (E)-β-Farnesene, and (E)-β-Caryophyllene. Bioassays showed that EOs from each accession acted as toxins and repellents against V. destructor adults, with lower toxicity towards A. mellifera pupae. In terms of efficacy against V. destructor adults, Smaragd 2020 oil displayed the highest performance, with LC50 and LC90 values of 2.33 and 7.83 µL/L air, respectively. Meanwhile, Smaragd 2019 and Tettnanger EOs showed moderate toxicity, with LC50 values of 3.101 and 3.66 µL/L air, along with LC90 values of 11.67 and 19.89µL/L air, respectively. The oils from Biguglia and Ajaccio were strongly repellent to Varroa adults. At the lowest concentration (2 µL/mL), these EOs exhibited percentage of repellence greater than 70% after 2h exposure, with RC50 values of 1.66 and 1.26 µL/L air, respectively. Concerning their insecticidal effects, EOs demonstrate reduced toxicity towards bee pupae when compared to Varroa mites. Notably, Ajaccio stands out for inducing lower mortality among bee pupae, with a selectivity ratio below 2 and LC50 of 11.25 µL/L air. [ABSTRACT FROM AUTHOR]

BACKGROUND: The parasitic mite, Varroa destructor has posed a threat to the health and survival of European honey bees, Apis mellifera worldwide. There is a prevailing belief that small comb cells could provide a management tool against Varroa mites. However, the hypothesis that smaller cells can impede Varroa reproduction has not been fully tested. Here, we tested this hypothesis under laboratory conditions by using two distinct Varroa in vitro rearing systems: one involved gelatin capsules of different sizes, specifically size 00 (0.95 mL) versus size 1 (0.48 mL), and the second consisted of brood comb cells drawn on 3D printed foundations with varying cell sizes, ranging from 5.0 mm to 7.0 mm at 0.5 mm intervals. RESULTS: The results showed that mother mites in size 00 cells had significantly lower fecundity and fertility compared to those in size 1 cells. Interestingly, the reproductive suppression in larger cells could be reversed by adding an extra worker larva. Similarly, gonopore size of mother mites was smaller in size 00 cells, but restored with another host larva. Furthermore, both the fecundity and fertility of mother mites decreased linearly with the size of brood comb cells. CONCLUSIONS: Our results suggest that the reproduction of V. destructor is hindered by larger cells, possibly because larger brood cells disperse or weaken host volatile chemical cues that are crucial for Varroa reproduction. The insights derived from this study are expected to hold significant implications for the implementation of Varroa management programs. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Tropilaelaps spp. are invasive mites that cause severe disease in Apis mellifera colonies. The UK has deployed an elaborate surveillance system that seeks to detect these mites early in any invasion to allow the best opportunity to eradicate any incursion. Effective field and laboratory protocols, capable of reliably detecting low numbers of mites, are key to the success of any intervention. Here we compared the efficacy of established field monitoring using brood removal with an uncapping fork, and brood 'bump' methods with novel methods for Tropilaelaps detection modified from Varroa monitoring schemes. In addition, we monitored the efficacy of the laboratory method for screening for mites in hive debris by floating mites in ethanol. Our results clearly indicated that novel methods such as uncapping infested brood with tweezers, catching mite drop using sticky traps and rolling adult bees in icing sugar were all significantly more likely to detect Tropilaelaps than existing methods such as using an uncapping fork on infested brood, or the brood 'bump' method. Existing laboratory protocols that sieved hive debris and then floated the mite containing layer failed to detect Tropilaelaps mites and new efficacious protocols were developed. Our results demonstrated that the national surveillance protocols for Tropilaelaps mite detection required modification to improve the early detection of this damaging invasive mite. [ABSTRACT FROM AUTHOR]

Varroa destructor is the main health problem in the honey bee colonies. Regular monitoring of the Varroa load plays an essential role in determining the right time for treatment of the colony and evaluating the effectiveness of the treatment method. This research aimed at comparative evaluation of the efficacy of alcohol wash and powdered sugar methods to dislodge the Varroa mite from the adult bees' body. Our findings revealed that wash the bees with 75% ethanol dislodged 81.14±3.56% of the mites from their body. In contrast, powdered sugar could dislodge only 54.53±3.56% of the mites from the body of the bees. Therefore, alcohol wash method is more accurate for determining the infestation intensity of the adult honey bees to the Varroa mite. [ABSTRACT FROM AUTHOR]

Honey bees (Apis mellifera L.) are the premier agricultural pollinators with direct ecological value and are key to some agro-economies. Major factors have negatively impacted honey bee health in the past 2 decades with Varroa (Varroa destructor Anderson and Trueman) infestation rising as a principal predictor of colony mortality. A key strategy deployed in Varroa management is breeding for resistant honey bee populations that can maintain comparable levels of productivity as nonresistant populations. In this study, we examine one such population, Hilo honey bees, within the context of a common garden contrast with a commercial population in a stationary honey production operation. We compare colony survival, health, yield, and profit outcomes to show how this specific breeding population retains a profit value in honey production operations while maintaining higher survival and lower Varroa infestation levels than the commercial population. This information can be used by commercial beekeepers to make best management practice decisions and inspire further work examining what trade-offs, if any, are present in this Varroa- resistant population. [ABSTRACT FROM AUTHOR]

Varroa mite infestation poses a severe threat to honeybee colonies globally. This study investigates the feasibility of utilizing the HS-Cam and machine learning techniques for Varroa mite counting. The methodology involves image acquisition, dimensionality reduction through Principal Component Analysis (PCA), and machine learning-based segmentation and classification algorithms. Specifically, a k-Nearest Neighbors (kNNs) model distinguishes Varroa mites from other objects in the images, while a Support Vector Machine (SVM) classifier enhances shape detection. The final phase integrates a dedicated counting algorithm, leveraging outputs from the SVM classifier to quantify Varroa mite populations in hyperspectral images. The preliminary results demonstrate segmentation accuracy exceeding 99% and an average precision of 0.9983 and recall of 0.9947 across all the classes. The results obtained from our machine learning-based approach for Varroa mite counting were compared against ground-truth labels obtained through manual counting, demonstrating a high degree of agreement between the automated counting and manual ground truth. Despite working with a limited dataset, the HS-Cam showcases its potential for Varroa counting, delivering superior performance compared to traditional RGB images. Future research directions include validating the proposed hyperspectral imaging methodology with a more extensive and diverse dataset. Additionally, the effectiveness of using a near-infrared (NIR) excitation source for Varroa detection will be explored, along with assessing smartphone integration feasibility. [ABSTRACT FROM AUTHOR]

Objective: to characterize honey bee (Apis mellifera) production systems in the municipality of Hopelchén, Campeche, Mexico. Design/methodology/approach: the sample was made up by 10% of the beekeepers in Holpechén, identified through the snowball method. A semi-structured questionnaire was designed with 94 questions grouped into five sections (general information, structure of the systems, product trade, technologies used, and decision making). The questionnaire was applied through the technique of interviewing those responsible for the 118 beekeeping production systems. The information obtained with the questionnaires was analyzed with descriptive statistics. Results: beekeeping is an important productive activity in the region of Los Chenes and La Montaña in Hopelchén, which are undergoing the process of generational replacement and are currently maintained by young adult producers who are younger than 45 years old. They own 55 hives on average per producer, which are located at a distance of 7.7 km from their households. The main technology is the use of sugar for feed, by 50% of producers, followed by the diagnosis of Varroa infestation and determination of moisture with 35 and 21.5% of beekeepers. Limitations on study/implications: the limited access to regions with beekeeping potential, as well as the lack of monitoring by outside staff, does not ease open-mindedness of beekeepers toward researchers. Findings/conclusions: the characterization of beekeeping production systems with high potential allows proposing improvement strategies to promote the development of small-scale producers. [ABSTRACT FROM AUTHOR]

Varroa mites, notorious for parasitizing honeybees, are generally classified as Varroidae. Their extremely modified morphologies and behaviors have led to debates regarding their phylogenetic position and classification as an independent family. In this study, two different datasets were employed to reconstruct the phylogenies of Varroa mites and related Laelapidae species: (1) 9257 bp from the whole 13 mitochondrial protein-coding genes of 24 taxa, (2) 3158 bp from 113 taxa using Sanger sequencing of four nuclear loci. Both mitochondrial and nuclear analyses consistently place Varroa mites within the Laelapidae. Here we propose to place Varroa mites in the subfamily Varroinae stat. nov., which represents a highly morphologically adapted group within the Laelapidae. Ancestral state reconstructions reveal that bee-associated lifestyles evolved independently at least three times within Laelapidae, with most phoretic traits originating from free-living ancestors. Our revised classification and evolutionary analyses will provide new insight into understanding the Varroa mites. [ABSTRACT FROM AUTHOR]

A sustainable solution to the global threat of the Varroa destructor mite is the selection of varroa‐resistant honey bee (Apis mellifera) colonies. Both "mite non‐reproduction" (MNR) and "varroa sensitive hygiene" (VSH) appear to be promising selection traits for achieving the goal of a resistant honey bee. MNR describes colonies that have a high number of non‐reproductive mites (no offspring, no males, or delayed development of mite offspring). High numbers of non‐reproductive mites have been observed in selected colonies, but the mechanism behind this trait has not yet been identified. The specialized hygienic behavior of selected honey bees, called VSH, is the removal of varroa‐infested brood. These traits were thought to be linked by VSH bees preferentially removing reproductive varroa females leaving only non‐reproductive mites behind in cells and thus creating colonies with high levels of MNR. To further investigate this link, we used an experimental setup and data sets from a four‐year selection project designed to breed for MNR and VSH colonies. In addition, we sought to answer the question of whether non‐reproductive mites are a direct consequence of worker removal behavior. To test this, we artificially induced removal behavior, and after providing the mite with enough time to re‐enter another cell, we opened all capped cells, relocated the mites, and evaluated their reproduction. As shown in previous studies and in this study, VSH had no effect on MNR levels. Also, the induced removal behavior did not lead to non‐reproduction in the subsequent reproductive cycle post interruption. We thus concluded that breeding for non‐reproductive mites does not automatically breed for VSH behavior and worker removal behavior does not cause subsequent reproductive failure of the mites forced to flee and find a new cell for reproduction. [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: Increasing honey bee resilience against the parasitic mite Varroa destructor, while respecting sustainability, may be achieved by enriching natural mite resistance traits in the breeding population. Some of these traits are linked to specific variants in the honey bee genome, which can be pinpointed and characterized with high-throughput molecular lab tests. Breeding by focusing on these genomic variants is thus more efficient and less time-consuming. However, when evaluating the link between a specific varroa resistance trait outcome and its associated variants in the genome, different contributions of the variants may be observed between honey bee races. It is hypothesized that these observations evolve from different linkages between the trait-causing genes and the genomic variants. Therefore, we evaluated the presence of genomic variants associated with a varroa resistance trait in different honey bee samples across the European continent. We observed significant differences in the presence of the genomic variants in the considered honey bee races, which underpin our hypothesis of linkage dissimilarities. This study shows that determining the honey bee race prior to using the genomic variants associated with varroa resistance for selective breeding is of utmost importance. Implementation of marker-assisted selection (MAS) in modern beekeeping would improve sustainability, especially in breeding programs aiming for resilience against the parasitic mite Varroa destructor. Selecting honey bee colonies for natural resistance traits, such as brood-intrinsic suppression of varroa mite reproduction, reduces the use of chemical acaricides while respecting local adaptation. In 2019, eight genomic variants associated with varroa non-reproduction in drone brood were discovered in a single colony from the Amsterdam Water Dune population in the Netherlands. Recently, a new study tested the applicability of these eight genetic variants for the same phenotype on a population-wide scale in Flanders, Belgium. As the properties of some variants varied between the two studies, one hypothesized that the difference in genetic ancestry of the sampled colonies may underly these contribution shifts. In order to frame this, we determined the allele frequencies of the eight genetic variants in more than 360 Apis mellifera colonies across the European continent and found that variant type allele frequencies of these variants are primarily related to the A. mellifera subspecies or phylogenetic honey bee lineage. Our results confirm that population-specific genetic markers should always be evaluated in a new population prior to using them in MAS programs. [ABSTRACT FROM AUTHOR]

Simple Summary: Our study addresses the growing number of reports of Varroa mite resistance to amitraz, which is vital for beekeepers in managing this destructive pest. Recently, beekee-pers in France and the United States have reported the diminishing effectiveness of amitraz treatments, threatening their ability to control Varroa infestations. We collected data from French apiaries in 2020 and 2021, examining the field effectiveness of amitraz treatments and conducting laboratory sensitivity tests to the pesticide. Additionally, we genotyped 240 Varroa mites from different regions in France, focusing on a specific genetic marker previously linked to amitraz resistance. Our findings revealed regional occurrences of resistance, but the decrease in treatment efficacy was less severe compared to resistance against other pesticides. Notably, our genetic analysis suggested that the previously identified genetic marker may not directly cause amitraz resistance. These findings underscore the urgent need for ongoing monitoring and the development of new strategies to manage Varroa mites, ensuring the sustainability of beekeeping. By understanding and addressing resistance, we can maintain amitraz as a reliable tool to protect bee colonies, which are crucial due to the essential pollination services they provide. Resistance against amitraz in Varroa mite populations has become a subject of interest in recent years due to the increasing reports of the reduced field efficacy of amitraz treatments, especially from some beekeepers in France and the United States. The loss of amitraz as a reliable tool to effectively reduce Varroa mite infestation in the field could severely worsen the position of beekeepers in the fight to keep Varroa infestation rates in their colonies at low levels. In this publication, we present data from French apiaries, collected in the years 2020 and 2021. These data include the field efficacy of an authorized amitraz-based Varroa treatment (Apivar® ,Véto-pharma, France) and the results of laboratory sensitivity assays of Varroa mites exposed to the reference LC90 concentration of amitraz. In addition, a total of 240 Varroa mites from Eastern, Central, and Southern regions in France that were previously classified as either "sensitive" or "resistant" to amitraz in a laboratory sensitivity assay were genotyped. The genetic analyses of mite samples are focused on the β-adrenergic-like octopamine receptor, which is considered as the main target site for amitraz in Varroa mites. Special attention was paid to a single-nucleotide polymorphism (SNP) at position 260 of the ORβ-2R-L gene that was previously associated to amitraz resistance in French Varroa mites, Varroa. Our findings confirm that amitraz resistance occurs in patches or "islands of resistance", with a less severe reduction in treatment efficacy compared to pyrethroid resistance or coumaphos resistance in Varroa mites. The results of our genetic analyses of Varroa mites call into question the hypothesis of the SNP at position 260 of the ORβ-2R-L gene being directly responsible for amitraz resistance development. [ABSTRACT FROM AUTHOR]

Simple Summary: In addition to invaluable ecosystem services, beekeeping offers opportunities for job creation, income generation and food security. Beekeepers have been experiencing economic losses due to high rates of honey bee colony losses driven by various factors worldwide. We conducted this study using the COLOSS monitoring survey tools for the first time in Ethiopia to assess honey bee colony loss rates, annual colony development, beekeeping practices, and to determine the role of management practices (varroa monitoring, varroa treatment, colony splitting, feed supplementation, use of natural comb, and purchase of beeswax from external sources), as well as region, on colony losses. For this, data were collected by interviewing beekeepers from two major beekeeping regions in the country—Oromia and Tigray. Our results showed a high rate of colony losses in Ethiopia, which significantly varied between the regions. The main drivers of honey bee colony losses are related to natural disasters (particularly war), beekeeping husbandry practices, and pest management. Therefore, it is important to promote the capacity of smallholder beekeepers to implement improved beekeeping practices such as feed supplementation, queen replacement and pest management that would lead to reduced losses, increased profitability, and improved food security and livelihood. The COLOSS research association has been assessing honey bee colony losses, associated risk factors and management, focusing on Western countries but with a progressive international expansion. Here, we report the first survey on the loss rates of colonies in 2022/2023 in Ethiopia using COLOSS monitoring survey tools. A face-to-face interview questionnaire survey was conducted on 64 beekeepers selected from Oromia and Tigray regions. This covered 1713 honey bee colonies distributed in 68 apiaries. The percentages of colonies lost were significantly different between Oromia (24.1%) and Tigray (66.4%) regions. Colony losses were attributed as unsolvable queen problems (8% in Oromia; 10% in Tigray), natural disaster (32%; 82%), and empty hives or dead colonies (60%; 8%). The loss rate was significantly affected by queen replacement (p < 0.0001), use of natural comb (p < 0.0001), feed supplementation (p < 0.0001), region (p < 0.0001), varroa treatment (p < 0.0001), colony splitting (p < 0.01), and merging (p < 0.01). Beekeepers in Oromia managed more colonies and implemented improved practices compared to those in Tigray. However, all beekeepers in Oromia detected at least some bees with signs of deformed wing virus, compared to 76% of beekeepers in Tigray. In conclusion, the colony loss rate was significantly different between Oromia and Tigray regions due to differences in natural disasters, management, environment and health factors. [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]

It has been demonstrated that fatty acids esters play an important role in the caste selection Varroa mites. However, there may be another mechanism of attraction in the preferred host location. We hypothesize that it may be due to differential respiration rates between larvae, but no investigations have been reported. This research was developed to determine if there is a measurable level and significant difference in honey bee caste respiration that may be exploited by Varroa mites in choice selection. In this study, we measured the respiration of all stages of the Western honey bee Apis mellifera, L. castes to determine the rate of continuous respiration. An assay was conducted using a portable photosynthesis system for gas exchange and chlorophyll fluorescence measurement (Li-Core LI-6400XT) to measure the respiration rate. In this study, a comparative analysis resulted in respiration levels that indicated a significant difference in the CO2 levels of adult worker (777.0 ± 0.002 μg CO2 g insect-1 min-1) and drone (375.5 µg CO2) honey bees. The comparison of worker (5.59 ± 0.002 μg CO2 g insect-1 min-1) and drone (7.20 ± 0.002 μg CO2 g insect-1 min-1) pupae showed no significant difference in the respiration levels; however, there was a noticeable difference in respiration levels of the worker (6.33 ± 0.002 μg CO2 g insect-1 min-1) and drone (10.07 ± 0.002 μg CO2 g insect-1 min-1) larvae. Future research will utilize the knowledge obtained to examine the mite's attraction to the honey bee castes in host location. This information is a crucial step for the advancement of research studies and the development of management protocols for Varroa. [ABSTRACT FROM AUTHOR]

Honey bees (Apis mellifera) are exposed to multiple stressors such as pesticides, lack of forage, and diseases. It is therefore a long-standing aim to develop robust and meaningful indicators of bee vitality to assist beekeepers While established indicators often focus on expected colony winter mortality based on adult bee abundance and honey reserves at the beginning of the winter, it would be useful to have indicators that allow detection of stress effects earlier in the year to allow for adaptive management. We used the established honey bee simulation model BEEHAVE to explore the potential of different indicators such as population size, number of capped brood cells, flight activity, abundance of Varroa mites, honey stores and a brood-bee ratio. We implemented two types of stressors in our simulations: 1) parasite pressure, i.e. sub-optimal Varroa treatment by the beekeeper (hereafter referred as Biotic stress) and 2) temporal forage gaps in spring and autumn (hereafter referred as Environmental stress). Neither stressor type could be detected by bee abundance or honey reserves at the end of the first year. However, all response variables used in this study did reveal early warning signals during the course of the year. The most reliable and useful measures seem to be related to brood and the abundance of Varroa mites at the end of the year. However, while in the model we have full access to time series of variables from stressed and unstressed colonies, knowledge of these variables in the field is challenging. We discuss how our findings can nevertheless be used to develop practical early warning indicators. As a next step in the interactive development of such indicators we suggest empirical studies on the importance of the number of capped brood cells at certain times of the year on bee population vitality. [ABSTRACT FROM AUTHOR]

The survival of the honey bee (Apis mellifera), which has a crucial role in pollination and ecosystem maintenance, is threatened by many pathogens, including parasites, bacteria, fungi and viruses. The ectoparasite Varroa destructor is considered the major cause of the worldwide decline in honey bee colony health. Although several synthetic acaricides are available to control Varroa infestations, resistant mites and side effects on bees have been documented. The development of natural alternatives for mite control is therefore encouraged. The study aims at exploring the effects of cinnamon and oregano essential oils (EOs) and of a mixed fruit cocktail juice on mite infestation levels and bee colony health. A multi-method study including hive inspection, mite count, molecular detection of fungal, bacterial and viral pathogens, analysis of defensin-1, hymenoptaecin and vitellogenin immune gene expression, colony density and honey production data, was conducted in a 20-hive experimental apiary. The colonies were divided into five groups: four treatment groups and one control group. The treatment groups were fed on a sugar syrup supplemented with cinnamon EO, oregano EO, a 1:1 mixture of both EOs, or a juice cocktail. An unsupplemented syrup was, instead, used to feed the control group. While V. destructor affected all the colonies throughout the study, no differences in mite infestation levels, population density and honey yield were observed between treatment and control groups. An overexpression of vitellogenin was instead found in all EO-treated groups, even though a significant difference was only found in the group treated with the 1:1 EO mixture. Viral (DWV, CBPV and BQCV), fungal (Nosema ceranae) and bacterial (Melissococcus plutonius) pathogens from both symptomatic and asymptomatic colonies were detected. [ABSTRACT FROM AUTHOR]

Honey bees use grooming to defend against the devastating parasite Varroa destructor Anderson and Trueman. We observed the grooming responses of individual bees from colonies previously chosen for high- and low-grooming behavior using a combination of mite mortality and mite damage. Our aim was to gain insight into specific aspects of grooming behavior to compare if high-grooming bees could discriminate between a standardized stimulus (chalk dust) and a stimulus of live Varroa mites and if bees from high-grooming colonies had greater sensitivity across different body regions than bees from low-grooming colonies. We hypothesized that individuals from high-grooming colonies would be more sensitive to both stimuli than bees from low-grooming colonies across different body regions and that bees would have a greater response to Varroa than a standardized irritant (chalk dust). Individuals from high-grooming colonies responded with longer bouts of intense grooming when either stimulus was applied to the head or thorax, compared to sham-stimulated controls, while bees from low-grooming colonies showed no differences between stimulated and sham-stimulated bees. Further, high-grooming bees from colonies with high mite damage exhibited greater grooming to Varroa than high-grooming colonies with only moderate mite damage rates. This study provides new insights into Varroa -specific aspects of grooming, showing that although a standardized stimulus (chalk dust) may be used to assess general grooming ability in individual bee grooming assays, it does not capture the same range of responses as a stimulus of Varroa. Thus, continuing to use Varroa mites in grooming assays should help select colonies with more precise sensitivity to Varroa. [ABSTRACT FROM AUTHOR]

Honey bee parasites remain a critical challenge to management and conservation. Because managed honey bees are maintained in colonies kept in apiaries across landscapes, the study of honey bee parasites allows the investigation of spatial principles in parasite ecology and evolution. We used a controlled field experiment to study the relationship between population growth rate and virulence (colony survival) of the parasite Varroa destructor (Anderson and Trueman). We used a nested design of 10 patches (apiaries) of 14 colonies to examine the spatial scale at which Varroa population growth matters for colony survival. We tracked Varroa population size and colony survival across a full year and found that Varroa populations that grow faster in their host colonies during the spring and summer led to larger Varroa populations across the whole apiary (patch) and higher rates of neighboring colony loss. Crucially, this increased colony loss risk manifested at the patch scale, with mortality risk being related to spatial adjacency to colonies with fast-growing Varroa strains rather than with Varroa growth rate in the colony itself. Thus, within-colony population growth predicts whole-apiary virulence, demonstrating the need to consider multiple scales when investigating parasite growth-virulence relationships. [ABSTRACT FROM AUTHOR]

Despite the use of various integrated pest management strategies to control the honey bee mite, Varroa destructor , varroosis remains the most important threat to honey bee colony health in many countries. In Canada, ineffective varroa control is linked to high winter colony losses and new treatment options, such as a summer treatment, are greatly needed. In this study, a total of 135 colonies located in 6 apiaries were submitted to one of these 3 varroa treatment strategies: (i) an Apivar® fall treatment followed by an oxalic acid (OA) treatment by dripping method; (ii) same as in (i) with a summer treatment consisting of formic acid (Formic Pro™); and (iii) same as in (i) with a summer treatment consisting of slow-release OA/glycerin pads (total of 27 g of OA/colony). Treatment efficacy and their effects on colony performance, mortality, varroa population, and the abundance of 6 viruses (acute bee paralysis virus [ABPV], black queen cell virus [BQCV], deformed wing virus variant A [DWV-A], deformed wing virus variant B [DWV-B], Israeli acute paralysis virus [IAPV], and Kashmir bee virus [KBV]) were assessed. We show that a strategy with a Formic Pro summer treatment tended to reduce the varroa infestation rate to below the economic fall threshold of 15 daily varroa drop, which reduced colony mortality significantly but did not reduce the prevalence or viral load of the 6 tested viruses at the colony level. A strategy with glycerin/OA pads reduced hive weight gain and the varroa infestation rate, but not below the fall threshold. A high prevalence of DWV-B was measured in all groups, which could be related to colony mortality. [ABSTRACT FROM AUTHOR]

Management, brood nest structure and factors associated with varroa mite infestation were studied in 60 apiaries of Africanized honey bees in the northwest region of the Central Valley of Costa Rica. Apiaries were monitored two times. The first monitoring was taken forward during the rainy season between May and November 2019. The second monitoring during the dry season between February and March 2020. Information about the beekeepers, apiaries and management was collected through a survey. Amount of open and capped brood, honey and pollen were measured in the field. The infestation rate of varroa (IRV) was quantified using standard laboratory methods. A determination of multi-residue pesticides in bee bread was made through GC–MS/MS and LC–MS/MS techniques. According to the results, most of the beekeepers produce honey (96.7%), participate in training activities (82.2%), and change the bee queens annually (70%). The first monitoring was characterized by a lower amount of capped brood and honey reserves compared to the second one. IRV was significantly higher in the first monitoring (6.0 ± 0.4) in comparison with the second one (3.0 ± 0.3) (U Mann–Whitney p < 0.001). The maximum value for the first monitoring exceeds 40%, while this value was close to 25% in the second monitoring. Mite infestation exposed significant differences in relation to the variables associated to the beekeeper's management, i.e., change of bee queen (p = 0.002) or when beekeepers monitor varroa mites (p = 0.004). Additionally, the IRV had inverse correlations (p < 0.01) with the number of comb sides with capped brood (Spearman's rho coefficient = − 0.190), and honey reserves (Spearman's rho coefficient = − 0.168). Furthermore, 23 of 60 bee bread samples presented one to five pesticide residues, being the most frequent antifungal agrochemicals. [ABSTRACT FROM AUTHOR]

Parasitoses can destroy Apis mellifera hives. Bee biology and physiology determine distribution and abundance of their parasites; however, geographic and environmental factors constrain the frequency and intensity of interaction. This census evaluated the occurrence of Varroa destructor and Nosema spp. in temperate and semiarid ecoregions at Michoacán. Samples were collected from 54 hives from the temperate ecoregion and 50 from the semiarid ecoregion. Varroa destructor was in 18.5% of colonies in the temperate ecoregion, with average infestation of 0.5% and was in 94% in the semiarid ecoregion, average of 5.0%. Nosema spp. was in 43.4% of colonies at the temperate ecoregion, with an average of 24,383,019 spores per bee, and 19.1% of colonies at the semiarid ecoregion with an average of 433,333.33 spores per bee. V. destructor was more in the semiarid ecoregion. Nosema spp. was more in the temperate ecoregion, an inverse pattern of infestation. Los parásitos pueden destruir las colmenas de Apis mellifera. La biología y fisiología de la abeja determina la distribución y abundancia de sus parásitos; sin embargo los factores geográficos y ambientales limitan la frecuencia e intensidad de la interacción. Este censo evaluó la ocurrencia de Varroa destructor y Nosema spp. en ecorregiones templadas y semiáridas de Michoacán. Las muestras fueron colectadas de 54 colmenas en la ecorregión templada y de 50 en la ecorregión semiárida. Varroa destructor estuvo en 18.5% de las colonias en la ecorregión templada, con un promedio de infestación de 0.5% y de 94% en la ecorregión semiárida, con un promedio de 5.0%. Nosema spp. fue de 43.4% de las colonias en la ecorregión templada, con un promedio de 24,383,019 esporas por abeja, y 19.1% de colonias en la ecorregión semiárida con un promedio de 433,333.33 esporas por abeja. V. destructor fue mayor en la ecorregión semiárida. Nosema spp. fue mayor en la ecorregión templada, un patrón inverso de infestación. [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]

Varroa destructor mite poses a serious problem for the future of bee populations around the world. Today, there are many commercial drugs with the same and different active ingredients on the market to chemically control over of Varroa destructor. More frequent chemical applications for against Varroa destructor increases stress resilience, colony losses, loss of yield and residue problems in bee products. The scope of this project is aimed to determine the appropriate control method of Varroa by investigating the efficiency values of the evaporation and dropping methods of Oxalic acid. Experimental area were chosen three different apiaries. 28 colonies were determined in each apiary and equalization studies (area with brood, number of bees with bees, age of queen bees, honey, pollen, etc.) were carried out in these colonies. The determined colonies were randomly divided into 4 groups as 7 colonies. The first group is the control group, the second group is applying 2 g of oxalic acid by vaporizing, the third group is 4% oxalic acid 5 ml of sugar syrup (1:1) is dropped between the frames, and in the fourth group, the fight against a drug that is determined by the beekeeper in the market without interfering with the beekeeper. In order to evaluate the data, samples were taken for four periods, before and after spraying in spring and autumn. While the varroa measurements in the group of syrup, vapor and spraying were found to be statistically less than the control group, the syrup, vapor and spraying groups were statistically similar in terms of varroa measurements. Oxalic acid syrup application showed higher efficiency in spring and autumn than vapor application. There is no statistically difference between both two-application method reveals that it can be used as an effective and safe alternative to chemical control against varroa.

The ectoparasitic mite, Varroa destructor is the most serious widespread pest of managed honeybees (Apis mellifera). Several acaricide products, which include essential oils, have been proposed for mite control. In this study, we aimed to apply atmospheric-pressure plasma to modify a cardboard piece surface in order to prolong the delivery of essential oils for controlling Varroa in honeybee colonies. Absorption capacity, release rates and evaporation rates of essential oils were determined. Cardboard piece showed a higher absorption capacity of cinnamon compared to citronella and clove. Surface modification of cardboard pieces using argon plasma at different gas flow rates and treatment durations, significantly affected the absorption of clove oil. Additionally, the release rate of cinnamon, citronella and clove was significantly enhanced after argon plasma treatments. Evaporation of cinnamon was dramatically increased by plasma treatment at 6-h of incubation. The highest evaporation rate was obtained by plasma-treated cardboard piece at a gas flow rate of 0.5 Lpm for 60 s (0.2175 ± 0.0148 μl/g•h). Efficiency of plasma-treated cardboard piece, impregnated with essential oils, was also investigated for Varroa control in honeybee colonies. In the first experiment, formic acid 65% (v/v) showed the highest efficiency of 90.60% and 81.59% with the percent of mite infestation was 0.23 ± 0.13% and 0.47 ± 0.19% at 21 and 35 days, respectively after treatment. The efficacy of cardamon oil (5% (v/v)) delivered using plasma-treated cardboard pieces was 57.71% (0.70 ± 0.16% of mite infestation) at day 21 of experiment. However, the delivery of cardamon oil at the concentration of 1% and 5% (v/v) by untreated cardboard piece had 16.93% and 24.05% of efficacy to control mites. In the 2nd experiment, the application of plasma-treated cardboard pieces impregnated with 5% (v/v) clove oil induced a 38.10% reduction in the population of Varroa mites followed by 5% (v/v) of cardamon with 30% efficiency. Although, the infestation rate of Varroa in colonies was not significant different between treatments, essential oils delivered using plasma-treated cardboard pieces tended to decrease Varroa population in the treated colonies. Hence, atmospheric-pressure plasma for the modification of other materials, should be further investigated to provide alternative control treatment applications against honeybee mites. [ABSTRACT FROM AUTHOR]

Background: Ecto-parasite, varroa mite, (Varroa destructor), is the primary pest affecting the apiculture sector globally in various regions. Aim: This study examined the toxicity of nine essential oils to Apis mellifera L. and the acaricidal impact of those oils against V. destructor. Methods: The acaricidal effects of nine essential oils, extracted from plant materials were used. In the screening experiment, 10 mg of the active ingredients of the plant material extracts were prepared in an alcohol solution with concentrations of 5%, 10%, and 15%. For each type of plant extract, five female V. destructor were transferred to a Petri dish with five worker bees incubated at 70% humidity and 33°--34° for 2 days, for each treatment four replicates were used compared to the control. Forty-eight hours following treatment, the number of dead and live mites was counted to determine the mortality rate. In the second assay experiment, the best five essential oils of the previous experiment were selected to re-assess their effectiveness on varroa mites and honeybee workers by using a concentration of 15%. Five females of V. destructor were transferred to a Petri dish with 10 adult bees and treated with the solution of the selected oils. Five replicates and control treatments were taken for each sample simultaneously. Dead and live bees were counted for each replicate at 48 hours after treatment. Results: There were no significant differences between the concentrations used of each oil on the rate of death of mites, and its effectiveness ranged between 70.0% and 53.3% compared to the control groups. In addition, the best oil used was bitter melon, with a death rate of 80% at a concentration of 15%, while peppermint oil showed the lowest death rate of 45% at a concentration of (5%). However, all these treatments were statistically highly significant compared with the natural death rate in control (2%). In the second test, the results of the statistical analysis indicated that there were highly significant differences (P0.05 <0.0001) in the average numbers of dead varroa mites compared to the control when using a 15% concentration of five selected oils. On the other hand, there was no statistically significant difference in the honey bee workers' mortality rate between the treatment and control groups (P0.05 <0.3390), and it was relatively low for all treatments except the basil oil, where the bee mortality rate was 16% compared to the control (10%). Conclusion: It is clear from this experiment that bitter melon oil can be used to control varroa mites and it can be considered safe for honey bees as well as for the environment. [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]

Deformed wing virus (DWV) is a resurgent insect pathogen of honeybees that is efficiently transmitted by vectors and through host social contact. Continual transmission of DWV between hosts and vectors is required to maintain the pathogen within the population, and this vector–host–pathogen system offers unique disease transmission dynamics for pathogen maintenance between vectors and a social host. In a series of experiments, we measured vector–vector, host–host and host–vector transmission routes and show how these maintain DWV in honeybee populations. We found co-infestations on shared hosts allowed for movement of DWV from mite to mite. Additionally, two social behaviours of the honeybee, trophallaxis and cannibalization of pupae, provide routes for horizontal transmission from bee to bee. Circulation of the virus solely among hosts through communicable modes provides a reservoir of DWV for naïve Varroa to acquire and subsequently vector the pathogen. Our findings illustrate the importance of community transmission between hosts and vector transmission. We use these results to highlight the key avenues used by DWV during maintenance and infection and point to similarities with a handful of other infectious diseases of zoonotic and medical importance. [ABSTRACT FROM AUTHOR]

Honeybees play a major role in crop pollination, which supports the agricultural economy and international food supply. The colony health of honeybees is threatened by the parasitic mite Varroa destructor, which inflicts physical injury on the hosts and serves as the vector for variable viruses. Recently, it shows that V. destructor may also transmit bacteria through the feeding wound, yet it remains unclear whether the invading bacteria can exhibit pathogenicity to the honeybees. Here, we incidentally isolate Enterococcus faecalis, one of the most abundant bacteria in Varroa mites, from dead bees during our routine generation of microbiota-free bees in the lab. In vivo tests show that E. faecalis is only pathogenic in Apis mellifera but not in Apis cerana. The expression of antimicrobial peptide genes is elevated following infection in A. cerana. The gene-based molecular evolution analysis identifies positive selection of genes encoding Späetzle 4 (Spz4) in A. cerana, a signaling protein in the Toll pathway. The amino acid sites under positive selection are related to structural changes in Spz4 protein, suggesting improvement of immunity in A. cerana. The knock-down of Spz4 in A. cerana significantly reduces the survival rates under E. faecalis challenge and the expression of antimicrobial peptide genes. Our results indicate that bacteria associated with Varroa mites are pathogenic to adult bees, and the positively selected gene Spz4 in A. cerana is crucial in response to this mite-related pathogen. Author summary: Multiple factors contribute to the decline of honeybee colonies, including climate change, the spread of pests and pathogens, and pesticide use. Varroa mites and the viruses they carry pose a severe threat to honeybee health. However, it is still unknown whether the bacteria from Varroa mites are also responsible for the death of worker bees. Indeed, these bacterial pathogens were underestimated since infected adult workers tend to abandon their hives. Here, we characterized the virulence of E. faecalis strains isolated from the gut of A. mellifera originating from mite-infected hives. Our results indicate that E. faecalis, an opportunistic pathogen of many plants and animals, poses a significant threat to A. mellifera but not A. cerana. Infection of E. faecalis stimulates the Toll signaling pathway and the downstream expression of AMPs in A. cerana. Specifically, Spz4 protein has been selected in a relatively longer evolutionary process in A. cerana, and is the key mechanism of A. cerana to defend against E. faecalis. Our results suggest that eastern and western honeybees may possess different innate immune responses against the V. destructor-associated bacterial pathogens. [ABSTRACT FROM AUTHOR]

Background: Primary key pest affecting the apiculture business in many areas of the globe is the ecto parasite Varroa mite (Varroa destructor), recently, bee lice have become a considerable bee pest. Aim: In this study, the ecto parasites that infest honey bees, were investigated during the spring of 2013. Methods: A total of 66 apiaries were investigated from different geographical regions in Libya: 34 apiaries from the southern region, 21 apiaries from the north-eastern region, and 11 apiaries from the north-western region. Three bee colonies were randomly chosen from each apiary (316 colonies). From each colony, 300 worker bees were taken as samples, put in container filled with 100 ml of alcohol, and transported to the Honey bee Laboratory--Plant Protection Department at the University of Tripoli's. The parasites were separated from the bees and identified, and the infestation rates were calculated. Results: The study of the parasite distribution clearly showed that Varroa mites were present in all regions. However, the degree of mite density varies not only between apiaries but also between colonies in the same apiary, while the bee louse, Barulla coeca, was detected in 23.1% and 5.8% of apiaries in the western region and southern region of Libya, respectively. On the other hand, all the inspected apiaries in the northern region were not infested. Conclusion: Lack of knowledge about honey bee parasites, poor management practices, and the lack of proper distance between hives of migrated apiaries have been attributed as the possible reason for the spread of these two parasites, especially the Varroa mites in the country. [ABSTRACT FROM AUTHOR]

Surveys were conducted in Malatya and Elazığ provinces of Eastern Türkiye between 2018–2019 to detect the presence and distribution of Deformed wing virus (DWV), Acute bee paralysis virus (ABPV) and Black queen cell virus (BQCV) infecting honey bees and Varroa mites. Thirty Varroa mites feeding on honey bees and 147 honey bees were collected from twenty-five apiaries of Malatya and fifteen apiaries of Elazığ. The collected samples were subjected to reverse transcriptase-polymerase chain reaction. All tested viruses were found to be present in the samples singly or as mixed infections. The prevalence of the viruses were 23.81%, 12.93%, and 10.20% for DWV, ABPV and BQCV, respectively. Five out of thirty Varroa mites tested for the viruses were found to be infected only with DWV. Randomly chosen sequences of each detected virus’s partial polyprotein gene region were registered in GenBank under the accession numbers OP805878, OP805879, OP805880, OP805887, OP805888, OP805889, OP805890, OP805891 (DWV), OP805881, OP805882, OP805883, OP805884 (ABPV) and OP805885, OP805886 (BQCV). The phylogenetic tree of the viral isolates were compared with the world isolates. DWV isolates were found to be closely related to the UK, Lebanon, Türkiye, France, Germany and Israel isolates, whereas ABPV isolates were related to Türkiye, South Africa, Slovenia, Serbia, France, Hungary, Syria and USA isolates and BQCV isolates were related to China, South Korea, Czech Republic, France, Hungary, Poland, South Africa, Australia and Sweden isolates. The presence of DWV, ABPV and BQCV infections in Malatya and Elazığ provinces of Türkiye is revealed for the first time in this study.

A significant amount of researcher and practitioner effort has focused on developing new chemical controls for the parasitic Varroa destructor mite in beekeeping. One outcome of that has been the development and testing of "glycerol–oxalic acid" mixtures to place in colonies for extended periods of time, an off-label use of the otherwise legal miticide oxalic acid. The majority of circulated work on this approach was led by practitioners and published in nonacademic journals, highlighting a lack of effective partnership between practitioners and scientists and a possible failure of the extension mandate in beekeeping in the United States. Here, we summarize the practitioner-led studies we could locate and partner with a commercial beekeeper in the Southeast of the United States to test the "shop towel–oxalic acid–glycerol" delivery system developed by those practitioners. Our study, using 129 commercial colonies between honey flows in 2017 split into 4 treatment groups, showed no effectiveness in reducing Varroa parasitism in colonies exposed to oxalic acid–glycerol shop towels. We highlight the discrepancy between our results and those circulated by practitioners, at least for the Southeast, and the failure of extension to support practitioners engaged in research. [ABSTRACT FROM AUTHOR]

The varroa mite (Varroa destructor) is the most economically important parasitic pest of honey bees (Apis mellifera) that causes global colony decline and loss. Since its first detection in Ethiopia in 2010, little is known about the current infestation levels and contributing factors to the mite's distribution across the country. In this study, we conducted a large‐scale assessment of varroa prevalence and infestation levels in managed colonies across three potential beekeeping regions of Ethiopia; Oromia, Amhara and Southern Nations, Nationalities and Peoples Region (SNNPR). A total of 360 samples from 39 apiaries were collected following standard protocols and the mite prevalence and infestation levels were determined using the established method of varroa research. Overall, 89% of sampled colonies were infested by the mite, with varying prevalence rates across the regions: 95.8% in Oromia, 85.2% in Amhara and 71.9% in SNNPR, indicating the widespread nature of the parasite throughout the country. The varroa infestation levels were lower in local hives (2.6 ± 5.9) than in frame hives (5.0 ± 0.9), and significantly higher in brood bees (5.6 ± 0.8) than in adult bees (1.93 ± 0.17) (p < 0.001). Possible factors contributing to the varied mite prevalence and infestation levels in the country include differences in agro‐ecology, beekeeping practices, host age preference and the nature of bee hives. Therefore, our study provides insights into the current status of varroa prevalence and associated factors across regions in Ethiopia. Further investigation is required to explore the probable impact of the parasite on the health and productivity of local honey bees, in order to design future monitoring strategies. [ABSTRACT FROM AUTHOR]

Understanding the ecological and evolutionary processes that drive host–pathogen interactions is critical for combating epidemics and conserving species. The Varroa destructor mite and deformed wing virus (DWV) are two synergistic threats to Western honeybee (Apis mellifera) populations across the globe. Distinct honeybee populations have been found to self-sustain despite Varroa infestations, including colonies within the Arnot Forest outside Ithaca, NY, USA. We hypothesized that in these bee populations, DWV has been selected to produce an avirulent infection phenotype, allowing for the persistence of both host and disease-causing agents. To investigate this, we assessed the titre of viruses in bees from the Arnot Forest and managed apiaries, and assessed genomic variation and virulence differences between DWV isolates. Across groups, we found viral abundance was similar, but DWV genotypes were distinct. We also found that infections with isolates from the Arnot Forest resulted in higher survival and lower rates of symptomatic deformed wings, compared to analogous isolates from managed colonies, providing preliminary evidence to support the hypothesis of adaptive decreased viral virulence. Overall, this multi-level investigation of virus genotype and phenotype indicates that host ecological context can be a significant driver of viral evolution and host–pathogen interactions in honeybees. [ABSTRACT FROM AUTHOR]

Simple Summary: Varroa is a parasite of honeybees and is one of the main problems that beekeeping faces worldwide: it affects honey production and is involved in colony losses reported in some parts of the world. The objective of this study was to assess the effect of honeybee genetic origin, climate type and the interactions between these two variables on the prevalence and infestation levels of Varroa in a large population of 1134 colonies. The morphotype, haplotype and climate type of each colony were determined. The results indicate that the climate has an effect on the prevalence and infestation levels of Varroa: both were higher in the temperate sub-humid climate than in the semi-warm climate and the warm sub-humid climate. The morphotype has no effect: there were no differences between Africanized, European and Hybrid honeybees for the prevalence and infestations levels of Varroa. The haplotype has an effect on prevalence but not on infestation levels, and the African haplotype has a higher prevalence than the European haplotype, but no differences were found between the two haplotypes for infestation levels of Varroa. Correlations between Varroa infestation levels and mean annual temperature, mean annual precipitation, winter precipitation and the Lang index were found. The objective of this study was to evaluate the effect of honeybee genetic origin, climate type and the interactions between these variables on the prevalence and infestation levels of Varroa in a large population of honeybee colonies (n = 1134). For each colony, the morphotype, haplotype and climate type were determined. No differences between the Africanized, European and Hybrid morphotypes were found for the prevalence and infestation levels of Varroa (p > 0.05). Differences between honeybee haplotypes were found for the prevalence of Varroa (p < 0.05), and the prevalence was higher in the African haplotype than in the European haplotype. No differences between honeybee haplotypes were found for the infestation levels of Varroa (p > 0.05). Differences were found between climate type for the prevalence and infestation levels of Varroa (p < 0.05): the temperate sub-humid climate had a higher prevalence and higher infestation levels than the semi-warm climate and the warm sub-humid climate. Correlations between the infestation levels of Varroa and mean annual temperature, mean annual precipitation, winter precipitation and Lang index were found. [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: 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]

The COLOSS research association has been assessing honey bee colony losses, associated risk factors and management, focusing on Western countries but with a progressive international expansion. Here, we report the first survey on the loss rates of colonies in 2022/2023 in Ethiopia using COLOSS monitoring survey tools. A face-to-face interview questionnaire survey was conducted on 64 beekeepers selected from Oromia and Tigray regions. This covered 1713 honey bee colonies distributed in 68 apiaries. The percentages of colonies lost were significantly different between Oromia (24.1%) and Tigray (66.4%) regions. Colony losses were attributed as unsolvable queen problems (8% in Oromia; 10% in Tigray), natural disaster (32%; 82%), and empty hives or dead colonies (60%; 8%). The loss rate was significantly affected by queen replacement (p < 0.0001), use of natural comb (p < 0.0001), feed supplementation (p < 0.0001), region (p < 0.0001), varroa treatment (p < 0.0001), colony splitting (p < 0.01), and merging (p < 0.01). Beekeepers in Oromia managed more colonies and implemented improved practices compared to those in Tigray. However, all beekeepers in Oromia detected at least some bees with signs of deformed wing virus, compared to 76% of beekeepers in Tigray. In conclusion, the colony loss rate was significantly different between Oromia and Tigray regions due to differences in natural disasters, management, environment and health factors.

The number of managed honeybee colonies in New Zealand has increased dramatically, due largely to increasing high-value mānuka honey exports. Pollination also represents an important part of the apicultural sector, providing critical services to the horticultural and arable crop industries. A survey of winter colony losses has been conducted annually since 2015. Using data from the 2021 wave of the survey, we derive a model to estimate the financial cost of winter colony loss to New Zealand commercial beekeepers in that year. We estimate that winter colony losses conservatively cost commercial beekeepers $24,181,835 in 2021, which amounts to $38.04 per managed colony. This equates to 9.2% of the value of honey yields for commercial beekeepers who produce honey and between 10.6% and 60.5% of the value of contracts for beekeepers who provide pollination services. These substantial costs pose a risk to the profitability of beekeeping. [ABSTRACT FROM AUTHOR]

BACKGROUND: The parasitic mite, Varroa destructor (Anderson and Trueman), is a leading cause of honey bee colony losses around the world. Application of miticides such as amitraz are often the primary method of Varroa control in commercial beekeeping operations in the United States. It is likely that excessive and exclusive amitraz application has led to the development of amitraz resistance in Varroa. A mutation of tyrosine at amino acid position 215 to histidine (Y215H) in the β2‐octopamine receptor was identified in putatively amitraz‐resistant Varroa in the United States. This research investigated the presence of the Y215H mutation in quantitatively confirmed amitraz‐resistant Varroa from the United States. RESULTS: There was a strong association of susceptible and resistant phenotypes with the corresponding susceptible and resistant genotypes respectively, and vice versa. The resistance bioassay may understate resistance levels because of the influence of environmental conditions on the outcome of the test, whereby Varroa with an amitraz‐resistant genotype may appear with a susceptible phenotype. CONCLUSION: Confirmation of the Y215H mutation in the β2‐octopamine receptor of amitraz‐resistant Varroa encourages the development and validation of low‐cost, high‐throughput genotyping protocols to assess amitraz resistance. Resistance monitoring via genotyping will allow for large‐scale passive monitoring to accurately determine the prevalence of amitraz resistance rather than directed sampling of apiaries with known resistance issues. Genotyping of Varroa for amitraz resistance early in the beekeeping season may predict late‐season resistance at the colony level and provide beekeepers with enough time to develop an effective Varroa management strategy. © 2023 Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

Varroa mites are serious pests of European honeybees (Apis mellifera). For detection of Varroa mite, a new molecular LAMP-based assay has been developed, which retains the body of the mite intact for morphological identification. Six novel Varroa LAMP primers were designed from existing DNA sequences of the COI locus to target V. destructor and V. jacobsoni, providing the ability to tell them apart from other non-target beehive associated mite and insect species. This LAMP assay is specific in detecting these Varroa species and has been tested on specimens originating from multiple countries. It produces amplification of V. destructor and V. jacobsoni in 16 ± 3.4 min with an anneal derivative of 78 ± 0.5 °C whilst another Varroa species,V. underwoodi, showed late amplification. A gBlock gene fragment, used here as a positive control has a different anneal derivative of 80 °C. Three non-destructive DNA extraction methods (HotShot, QuickExtract and Xtract) were tested and found to be suitable for use in the field. The LAMP assay was sensitive to very low levels of Varroa DNA, down to 0.24 picogram (~ 1 × 10 copies/µL of Varroa gBlock). This is a new molecular tool for rapid and accurate detection and identification of Varroa mites for pest management, in areas where these mites do not occur. [ABSTRACT FROM AUTHOR]

Placing honey bee colonies in cold storage has been proposed as a way to induce a pause in brood production as part of a Varroa mite treatment plan. Here, we exposed colonies to combinations of with or without an October cold storage period and with or without a subsequent miticide application. We then measured the effects of those treatments on colony-level variables (i.e. colony size, Varroa infestation level, survivorship and hive weight and temperature) and pooled individual-level variables that are associated with nutritional and stress responses. Colonies were assessed before and after cold storage, and again post winter, for a total duration of about 5 months, and the experiment was repeated. Brood levels were significantly lower after cold storage, and hive temperatures indicated that most or all brood had emerged after about two weeks in cold storage. However, Varroa levels at the end of the experiments in February were not significantly different among treatment groups. Colonies kept outside (not subjected to cold storage) and treated with a miticide had higher survivorship on average than any other treatment group, but no other group comparisons were significant, and long-term impact of cold storage on adult bee populations and on colony thermoregulation was low. The bee forage environment was also very different between the 2 years of the study, as rainfall and bee forage availability were much higher the second year. Colonies were over 2.5 times larger on average the second year compared to the first, both in terms of adult bee mass and brood area, and expression levels of nutrition and stress response genes were also significantly higher the second year. The results indicate that limited cold storage would likely have little long-term impact on most colony and individual measures of health, but for such a strategy to succeed levels of stressors, such as Varroa, may also need to be low. [ABSTRACT FROM AUTHOR]

Domesticated honeybees and wild bees are some of the most important beneficial insects for human and environmental health, but infectious diseases pose a serious risk to these pollinators, particularly following the emergence of the ectoparasitic mite Varroa destructor as a viral vector. The acquisition of this novel viral vector from the Asian honeybee Apis ceranae has fundamentally changed viral epidemiology in its new host, the western honeybee A. mellifera. While the recently discovered Lake Sinai Viruses (LSV) have been associated with weak honeybee colonies, they have not been associated with vector‐borne transmission. By combining a large‐scale multi‐year survey of LSV in Chinese A. mellifera and A. cerana honeybee colonies with globally available LSV‐sequence data, we investigate the global epidemiology of this virus. We find that globally distributed LSV is a highly diverse multi‐strain virus, which is predominantly associated with the western honeybee A. mellifera. In contrast to the vector‐borne deformed wing virus, LSV is not an emerging disease. Instead, demographic reconstruction and strong global and local population structure indicates that it is a highly variable multi‐strain virus in a stable association with its main host, the western honeybee. Prevalence patterns in China suggest a potential role for migratory beekeeping in the spread of this pathogen, demonstrating the potential for disease transmission with the man‐made transport of beneficial insects. [ABSTRACT FROM AUTHOR]

The honey bee is responsible for pollination of a large proportion of crop plants, but the health of honey bee populations has been challenged by the parasitic mite Varroa destructor. Mite infestation is the main cause of colony losses during the winter months, which causes significant economic challenges in apiculture. Treatments have been developed to control the spread of varroa. However, many of these treatments are no longer effective due to acaricide resistance. In a search of varroa-active compounds, we tested the effect of dialkoxybenzenes on the mite. A structure–activity relationship revealed that 1-allyloxy-4-propoxybenzene is most active of a series of dialkoxybenzenes tested. We found that three compounds (1-allyloxy-4-propoxybenzene, 1,4-diallyloxybenzene and 1,4-dipropoxybenzene) cause paralysis and death of adult varroa mites, whereas the previously discovered compound, 1,3-diethoxybenzene, which alters host choice of adult mites in certain conditions, did not cause paralysis. Since paralysis can be caused by inhibition of acetylcholinesterase (AChE), a ubiquitous enzyme in the nervous system of animals, we tested dialkoxybenzenes on human, honey bee and varroa AChE. These tests revealed that 1-allyloxy-4-propoxybenzene had no effects on AChE, which leads us to conclude that 1-allyloxy-4-propoxybenzene does not exert its paralytic effect on mites through AChE. In addition to paralysis, the most active compounds affected the ability of the mites to find and remain at the abdomen of host bees provided during assays. A test of 1-allyloxy-4-propoxybenzene in the field, during the autumn of 2019 in two locations, showed that this compound has promise in the treatment of varroa infestations. [ABSTRACT FROM AUTHOR]

The European honey bee, Apis mellifera is the most important social insect among the primary pollinators of crops providing sustainability to the ecosystem. The gradual decrease in populations of honey bees as a result of an ectoparasitic infestation by the Varroa (Acari) mite is a significant concern for beekeepers worldwide. In this context, the present work in this study was designed with the main objective to understand the morphology and ultra-structure of the Varroa mite, the results of which may give some insights into its management and control. To conduct this study, honey bee colonies from apiaries located in, and nearby regions of Lucknow district, Uttar Pradesh were selected for collection of test populations. Light Microscopy was used for morphological identification, and Scanning Electron Microscopy (SEM) was used to evaluate the ultrastructure of the collected Varroa mite specimens. Light and scanning electron microscopy showed numerous structures which were optimized for ectoparasitism. The adult mite was flattened, had a dorsal shield having a dome-shaped appearance, and a flat ventral surface composed of numerous plates. Mouthparts appeared to be well-modified and used to feed the bee hemolymph. The morphology of the mite revealed four pairs of legs along with the presence of irregular setae throughout its body. This preliminary investigation revealed the presence of one of the most damaging genera of mites viz., Varroa mite on honey bees in the selected colonies of the study area. The study of the morphology and ultrastructure of the mite provides additional insights into the taxonomy of the parasite as well as provides information for future parasite management. [ABSTRACT FROM AUTHOR]