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Background: Deformed wing virus (DWV) is a major honey bee pathogen that is actively transmitted by the parasitic mite Varroa destructor and plays a primary role in Apis mellifera winter colony losses. Despite intense investigation on this pollinator, which has a unique environmental and economic importance, the mechanisms underlying the molecular interactions between DWV and honey bees are still poorly understood. Here, we report on a group of honey bee proteins, identified by mass spectrometry, that specifically co-immunoprecipitate with DWV virus particles. Results: Most of the proteins identified are involved in fundamental metabolic pathways. Among the co-immunoprecipitated proteins, one of the most interesting was arginine kinase (ArgK), a conserved protein playing multiple roles both in physiological and pathological processes and stress response in general. Here, we investigated in more detail the relationship between DWV and this protein. We found that argK RNA level positively correlates with DWV load in field-collected honey bee larvae and adults and significantly increases in adults upon DWV injection in controlled laboratory conditions, indicating that the argK gene was upregulated by DWV infection. Silencing argK gene expression in vitro, using RNAi, resulted in reduced DWV viral load, thus confirming that argK upregulation facilitates DWV infection, likely through interfering with the delicate balance between metabolism and immunity. Conclusions: In summary, these data indicate that DWV modulates the host ArgK through transcriptional regulation and cooptation to enhance its fitness in honey bees. Our findings open novel perspectives on possible new therapies for DWV control by targeting specific host proteins. [ABSTRACT FROM AUTHOR]

A survey was conducted of microbes and arthropods associated with Varroa destructor (Acari: Varroidae) mites (hereafter, Varroa) collected from honey bee colonies in Maryland, USA. Live Varroa were challenged with samples of both microbes and arthropods and assessed for their potential as biocontrol agents against the mites. To our knowledge, this is the first survey of natural enemies of Varroa conducted in North American honey bee colonies. The survey revealed 21 fungi, 25 bacteria, one nematode, and 8 arthropod species associated with Varroa in honey bee colonies, and from challenge assays using 11 of these, including 4 species of fungi, 2 species of bacteria, a parasitic nematode, 2 insects (Hemiptera and Hymenoptera), and 2 arachnids (Pseudoscorpiones) were capable of killing Varroa. This assemblage of Varroa natural enemies was similar to taxa identified from surveys conducted elsewhere globally, suggesting there is a core assemblage of organisms capable of killing Varroa that are best suited to tolerate the sometimes-hostile abiotic and biotic conditions of the hive environment. Generally, entomopathogenic fungi and bacteria assessed in our study showed the highest efficacy against Varroa, and for some, efficacy was comparable to that determined by other researchers, suggesting entomopathogenic fungi and bacteria appear to be the most promising candidates for development into commercially viable varroicides. A novel parasitic nematode identified from our survey killed greater than 90% of infected hosts. In addition, the behaviours of some arthropods toward Varroa observed in our study were indicative of predation on the mites. [ABSTRACT FROM AUTHOR]

BACKGROUND: The acaricide amitraz is now used intensively in many regions to control the honey bee parasite, Varroa destructor, because of the reduced efficacy of pyrethroids and coumaphos caused by resistance evolution. The continued application of amitraz in recent years exerts a very high selection pressure on mites, favouring the evolution of resistance to this acaricide. Mutations N87S and Y215H in the β2‐adrenergic‐like octopamine receptor (Octβ2R), target site of amitraz, have been already associated with resistance to amitraz in France and the USA, respectively. RESULTS: A new mutation (F290L) in the Octβ2R of V. destructor has been found in mites from Spanish apiaries. The frequency of L290 mutated alleles in colonies increased after consecutive treatments with amitraz. In a field trial, mites from colonies with higher frequency of L290 mutated allele took longer to die compared with those carrying a higher proportion of the wild‐type allele. Lower susceptibility to amitraz was found in apiaries with a high frequency of homozygous mutants. CONCLUSION: Our data indicate the association of the F290L mutation in the octopamine receptor with resistance to amitraz in Spanish populations of V. destructor. Determining the frequency of mutant mites in apiaries may be important for predicting the efficacy of amitraz treatment in the field and would help design appropriate resistance management. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

ABSTRACT Honeybees, Apis mellifera, have experienced the full impacts of globalisation, including the recent invasion by the parasitic mite Varroa destructor, now one of the main causes of colony losses worldwide. The strong selection pressure it exerts has led some colonies to develop defence strategies conferring some degree of resistance to the parasite. Assuming these traits are partly heritable, selective breeding of naturally resistant bees could be a sustainable strategy for fighting infestations. To characterise the genetic determinism of varroa resistance, we conducted the largest genome wide association study performed to date on whole genome sequencing of more than 1500 colonies on multiple phenotypes linked to varroa resistance of honeybees. To take into account some genetic diversity of honeybees, colonies belonging to different ancestries representing the main honeybee subspecies in Western Europe were included and analysed both as separate populations and combined in a meta‐analysis. The results show that varroa resistance is substantially heritable and polygenic: while 60 significant associations were identified, none explain a substantial part of the trait genetic variance. Overall our study highlights that genomic selection for varroa resistance is promising but that it will not be based on managing a few strong effect mutations and rather use approaches that leverage the genome wide diversity of honeybee populations. From a broader perspective, these results point the way towards understanding the genetic adaptation of eusocial insects to parasite load. [ABSTRACT FROM AUTHOR]

The nutritional physiology of parasites is often overlooked although it is at the basis of host-parasite interactions. In the case of Varroa destructor, one of the major pests of the Western honey bee Apis mellifera, the nature of molecules and tissues ingested by the parasite is still not completely understood. Here, the V. destructor feeding biology was explored through artificial feeding, dissection of the mite's gut and proteomic analyses. More specifically, the proteome of guts extracted from starved mites and honey bee-fed mites was compared to highlight both the parasite proteins likely involved in food processing and the honey bee proteins actually ingested by the mite. We could identify 25 V. destructor candidate proteins likely involved in the parasite digestion. As the host developmental stages infested by the mite are diverse, we also focused on the identity and on the origin of honey bee proteins ingested by the mite when it feeds on larvae, pupae or adults. We highlighted profiles of consumed honey bee proteins and their variations throughout the V. destructor life cycle. These variations matched the ones observed in the honey bee hemolymph, showing that this tissue is an important part of the mite's diet. Based on the variations of abundance of the most consumed honey bee proteins and on their functions, the potential implication of these key candidate nutrients in V. destructor reproduction is also discussed. Author summary: Varroa destructor is one of the major parasitic pests in modern beekeeping worldwide. Since it shifted host from Eastern to Western honey bees, it was shown to weaken colonies by feeding on both immature and adult stages while transmitting several deadly viruses in the process. Nutrition, an overlooked aspect of parasite biology, is thus a key to comprehend the V. destructor life cycle and its impacts on its honey bee host. We explored the feeding physiology of this ectoparasite by analysing the protein content of its isolated gut to compare it with the protein composition of the honey bee tissues ingested. We highlighted several mite proteins probably involved in digestion and many honey bee derived proteins acquired during the feeding. Honey bee hemolymph is an important part of the mite's diet although the diet could vary throughout the cycle, especially when mites feed on adult bees. The abundance of the most regularly ingested honey bee proteins such as Vitellogenin or Hexamerin varies throughout the bee development and could directly impact the parasite physiology. The analysis and identification of key proteins required for the mite's survival and reproduction will pave the way for the development of more specific control strategies. [ABSTRACT FROM AUTHOR]

Honey bees, Apis mellifera L. (Hymenoptera: Apidae), are the most important pollinators of agricultural products and plants in the natural environment. Honeybees are an important ecosystem component due to their role in nature and agricultural production. Bacterial, fungal, viral, and parasitic factors in bee farms are among the most important causes of honey bee colony losses. Honey bee diseases (bacterial, fungal and viral) and parasites are among the most important factors limiting beekeeping development and production efficiency in Türkiye. In addition to diseases caused by bacterial and fungal agents, diseases caused by viral agents are very diverse. Viruses, especially mixed infections, cause colony losses and are the most important factors in the decline of honey bee colonies. In this study the presence and prevalence of honey bee pathogens (Varroa destructor, Nosema ceranae, Paenibacillus larvae, and nine viruses) in suspicious samples with colony losses were investigated in Sivas province. For this purpose, microscopic, microbiological, and molecular methods were investigated on larvae and adult bee. The results showed that the most common viral pathogens in samples from Sivas province were Deformed Wing Virus (70%), Apis mellifera Filamentous Virus (60%), Black Queen Cell Virus (60%), Sacbrood Virus (55%) and Varroa destructor virus-1 (40%), respectively. In some samples, it was observed that there was a double (17.5%), triple (30%), quadruple (22.5%), or even quintuple (17.5%) association of viral agents. The viral infection/varroa coexistence rate was determined to be 50%. It was determined that 22.5% of the samples examined contained Nosema spores, while 12.5% were positive for P. larvae. Revealing the distribution of bee diseases will help beekeepers in disease-fighting and taking measures. This study showed the presence of the AmFV and the Varroa destructor virüs-1 in the Sivas province of Türkiye for the first time. [ABSTRACT FROM AUTHOR]

Varroa mite threatens honey bees worldwide by affecting larvae and adults and causing viral diseases associated with colony collapse. This study investigates its prevalence and infestation level, and morphometric traits in Southern Sudanese (SS) and Northern Sudanese (NS) phytogeographical zones of Burkina Faso. We visited 238 hives from 48 apiaries in 9 provinces. Phoretic varroa mites were detected through a 70% alcohol wash on approximately 300 worker bees. Once in the laboratory, 7 morphometric characters were measured on 1 to 10 varroa mites per hive. According to these measurements, the mites were identified as Varroa destructor,Anderson & Trueman, 2000. Data analysis reveals that 91.6% of colonies of the whole sample are infested with varroa. In NS zone, the provinces of Bazega and Zoundweogo show high infestation level (5.93% and 7.18% respectively), while in the SS zone, Nahouri and Ziro exhibit the highest level (8.19% and 9.00%) respectively. In terms of body length and body width (BL and BW), varroa mites from SS zone display averages of 1176.04 ± 40.1 µm and 1765.14 ± 49.2 µm, while those from the NS zone have average values of 1167.44 ± 40.8 µm and 1755.36 ± 53.42 µm. These morphological differences are statistically significant (P ≤ 0.05), highlighting variability that may result from local adaptations or genetic variations. The morphological diversity of this parasite has implications for its biology, dispersion, and virulence towards bees. Future studies should explore genetic factors influencing parasitic dynamics and bee resistance for effective management strategies. [ABSTRACT FROM AUTHOR]

The Tropilaelaps spp. (Mesostigmata: Laelapidae), an ectoparasitic mite originally associated with such Asian giant honey bees as Apis dorsata, A. breviligula and A. laboriosa, has increasingly become a focus of global concern due to its severe effects on Western honey bee colonies (Apis mellifera) and its recent geographic expansion. This study documents the first reported presence of Tropilaelaps mercedesae in Western Georgia's Samegrelo-Zemo Svaneti region, specifically in seven honey bee colonies (A. mellifera caucasica) from three apiaries. We conducted brood sample inspections, DNA barcoding and morphological measurements to confirm mite identification. Our findings revealed high infestation rates of T. mercedesae, co-infestation with Varroa destructor and notable mite reproductive success. These results underscore the threat posed by T. mercedesae to Georgian apiculture and highlight the potential for further spread across Europe. Immediate action and vigilant monitoring by national and international authorities are crucial to mitigate the impact on beekeeping and agriculture. [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]

Apis florea is a wild honeybee native to Asia that is currently spreading throughout the countries of the Middle East and East Africa, including Saudi Arabia. The spread of these honeybees raises questions regarding their pathogens, pests, and the diseases they may harbor. This is the first study of the prevalence of A. florea pathogens in Saudi Arabia. Samples from three different locations were diagnosed to identify six honeybee viruses: acute bee paralysis virus (ABPV), chronic bee paralysis virus (CBPV), black queen cell virus (BQCV), deformed wing virus type A (DWV-A), deformed wing virus type B (DWV-B), and sacbrood virus (SBV); two microsporidian gut parasites, Nosema apis and Nosema ceranae; one fungi, Ascosphaera apis; two bacterial pathogens, Paenibacillus larvae and Melissococcus plutonius; and the ectoparasites Euvarroa sinhai and Varroa destructor. In this study, ABPV, CBPV, BQCV, DWV-A, N. apis, N. ceranae, and M. plutonius were detected in A. florea, while DWV-B, SBV, A. apis, P. larvae, E. sinhai, and V. destructor were absent. The findings of this study represent the initial contribution to understanding the presence of pathogens in the A. florea honeybee in Saudi Arabia. However, further research is necessary to develop sustainable strategies for the beekeeping industry and awareness of pathogens that cause diseases in the country. [ABSTRACT FROM AUTHOR]

Background: The Western honey bee, Apis mellifera, is an economically important pollinator, as well as a tractable species for studying the behavioral intricacies of eusociality. Honey bees are currently being challenged by multiple biotic and environmental stressors, many of which act concomitantly to affect colony health and productivity. For instance, developmental stress can lead workers to become precocious foragers and to leave the hive prematurely. Precocious foragers have decreased flight time and lower foraging efficiency, which can ultimately lower colony productivity and even lead to colony collapse. Materials and methods: In this study, we tested the hypothesis that stress during pupal development can cause young workers to exit the hive prematurely before they are physically able to fly. This premature exiting behavior results in death outside the hive soon thereafter. To determine how various stressors may lead bees to perform this behavior, we subjected workers during the last pupal stage to either cold stress (26 °C for 24 h), heat stress (39 °C for 24 h), or Varroa destructor mite parasitization, and compared the rate of premature hive exits between stressed bees and their respective control counterparts. Upon emergence, we individually tagged focal bees in all treatment groups and introduced them to a common observation hive. We then followed tagged bees over time and monitored their survivorship, as well as their likelihood of performing the premature hive exiting behavior. We also dissected the hypopharyngeal glands of all treatment and control bees sampled. Results: We found that significantly more bees in all three treatment groups exited the hive prematurely compared to their control counterparts. Bees in all treatment groups also had significantly smaller hypopharyngeal glands than control bees. Conclusions: Our results suggest that premature hive exiting behavior is driven by stress and is potentially a form of accelerated age polyethism that leads to premature death. [ABSTRACT FROM AUTHOR]

Lactic acid is an alternative treatment to hard chemicals against Varroa destructor, the parasitic mite of the Western honey bee Apis mellifera. This soft acaricide is used only for small apiaries due to its laborious administration. However, the mode of action of this honey bee medication remains unknown. Previous studies showed that a direct contact between the arolia of V. destructor and lactic acid altered their morphology and led to an impairment of grip. Yet, there is no evidence for the way of action of lactic acid in a realistic in-hive scenario, i.e. after an indirect exposure of the mite through honey bees. We investigated the nature of lactic acid activity in the hive treatment context. The local and/or systemic way of action of this honey bee treatment against V. destructor was studied through a behavioural and toxicological approach at the individual level. On one hand, we confirmed the altered morphology for the arolia of mites and studied the evolution of the process over time. On the other hand, we found that haemolymph contaminated with lactic acid did not kill the feeding parasitic mite. These findings support a local mode of action. In order to unravel the sequence of events leading to the local contact between the acid and the mite on bees, we also documented the olfactory valence of lactic acid for A. mellifera and V. destructor. This work provides a new comprehension of lactic acid activity against the parasitic mite through honey bee exposure and gives new opportunities for control strategies against V. destructor. [ABSTRACT FROM AUTHOR]

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: Owing to its systemic mode‐of‐action and ease of application, lithium chloride (LiCl) is an ideal varroacide for the control of Varroa destructor infestations in honey bee colonies. To better understand how LiCl functions within a colony, we screened different parts of honey bee anatomy for lithium accumulation. We wanted to elucidate the time‐dependent effects of LiCl on V. destructor and its metabolism within honey bees when they were fed continuous LiCl treatments, as well as evaluate potential adverse effects such as accumulation in the hypopharyngeal glands of nurse bees, which could negatively impact queens and larvae. RESULTS: Cage experiments reveal rapid acaricidal onset, with >95% mite mortality within 48 h of treatment. Bee hemolymph analysis supports these observations, showing a rapid increase in lithium concentration within 12 h of treatment, followed by stabilization at a constant level. Lithium accumulates in the rectum of caged bees (≤475.5 mg kg−1 after 7 days of feeding 50 mm LiCl), reflecting the bees' metabolic and excretion process. Despite concerns about potential accumulation in hypopharyngeal glands, low lithium levels of only 0.52 mg kg−1 suggest minimal risk to the queen and 1st‐ and 2nd‐instar larvae. Cessation of LiCl treatment results in a rapid decline in mite mortality in the first 5 days, which increases again thereafter, resulting in mite mortality of 77–90% after 10 days. CONCLUSION: These findings help optimize LiCl application in colonies to achieve high Varroa mortality without unwanted adverse effects and provide important baseline data for future registration. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [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]

A survey conducted as part of the National Honey Bee Survey from 2013 to 2020 quantified the managed honey bee hives on Guam, sampled accessible wild-living colonies, and described associated diseases and pests. During this period the number of managed bee colonies increased from 20 to 121 which was associated with the formation of the Guam Beekeepers Association. Managed Apis mellifera colonies on Guam had significantly fewer parasites and diseases than reported in the USA. The Varroa mite, Varroa destructor, was detected in 2014 in a wild-living colony in southern Guam. The greater banded hornet, Vespa tropica, was first observed on Guam in 2016, with honey bee depredations observed in 2017. Nosema ceranae was initially detected in wild-living and managed colonies in 2013 and has been consistently observed since that time with little apparent effect on colony health as there have been no recorded colony losses in apiaries. No small hive beetle, Aethina tumida, Tropilaelaps mite, Tropilaelaps spp, American foulbrood, Paenibacillus larvae, European foulbrood, Melissococcus plutonius, chalkbrood, Ascosphaera sp. and 11 additional viral diseases of the 22 known to infest honey bees, including deformed wing virus, were observed. [ABSTRACT FROM AUTHOR]

This study was undertaken to determine whether there was any correlation between the level of Varroa destructor infestation in honey bee samples collected from the Ankara region of Türkiye and the antioxidant contents of honey samples from those colonies. In terms of the severity of V. destructor infestation, the average percentage of infested bees in the first group was 16.06 ± 1.2%, the average percentage in the second group was 7.27 ± 0.71%, and the average in the third group was 1.69 ± 0.46%. Statistically significant differences were found between all honey samples collected from the three groups in terms of total phenolic contents and DPPH values. The total flavonoid levels in the honey samples taken from the third group were significantly higher than the values determined in the samples taken from the other two groups, while the ABTS and FRAP levels in honey samples from the first group were significantly higher than the values determined in samples from the other two groups. It was concluded that the total phenolic substances, total flavonoid contents, and DPPH, ABTS, and FRAP values of honey samples collected from these honey bee colonies changed in direct proportion to the severity of V. destructor infestation. [ABSTRACT FROM AUTHOR]

Varroa mite, Varroa destructor Anderson and Trueman (Acari: Varroidae), causes severe damage to honeybee colonies and facilitates the transmission of several bee viruses, such as deformed wing virus (DWV), which causes wing deformity in newly molted bees. In Japan, western honeybees Apis mellifera Linnaeus (Hymenoptera: Apidae) are reared for both honey production and pollination and are infested with Varroa mites. Detailed surveillance of bee viruses in both A. melliferra and V. destructor has not been conducted in Japan. We surveyed eight major bee viruses in A. mellifera and Varroa mites from Japanese apiaries. DWV is the predominant virus in both A. mellifera and V. destructor in Japan. Two strains of the virus, DWV-A and DWV-B, are considered virulent in honeybees, but only DWV-A was detected in this study. The DWV levels in honeybees were strongly correlated with the Varroa infestation rate. We also detected other viruses in both the bees and mites, such as black queen cell and Lake Sinai viruses, but at much lower infection rates than DWV. Infection rates of these viruses were higher in colonies that did not contain Varroa mites than in Varroa-infested bee colonies. Therefore, Varroa mites in Japanese apiaries could be associated with DWV transmission, but they may rarely be associated with the transmission of other viruses. [ABSTRACT FROM AUTHOR]

Abstract The ectoparasitic mite Varroa destructor remains a great threat for the beekeeping industry, for example contributing to excessive winter colony loss in Canada. For decades, beekeepers have sequentially used the registered synthetic varroacides tau-fluvalinate, coumaphos, amitraz, and flumethrin, leading to the risk of resistance evolution in the mites. In addition to the widespread resistance to coumaphos and pyrethroids, a decline in amitraz efficacy has recently been reported in numerous beekeeping regions in Canada. The goals of this study were to assess the evolution of resistance to amitraz in Canadian mite populations and to evaluate the presence and incidence of mutations previously associated with resistance to amitraz and pyrethroids in V. destructor. Our bioassay results confirmed the presence of amitraz-resistant mites in the population of Alberta. These phenotypic results were complemented by targeted genotyping of the octopamine receptor gene Octβ2R which revealed the presence of the mutation Y215H in 90% of tested apiaries with local allele frequencies ranging from 5 to 95%. The phenotypic resistance showed a significant correlation with the presence of this mutation across apiaries. In parallel, the L925I and L925M mutations in the voltage-gated sodium channel were identified in 100% of the tested apiaries with frequencies ranging from 33 to 97%, suggesting that resistance to pyrethroids remains widespread. These results support the notion that the practice of relying on a single treatment for a prolonged period can increase rates of resistance to current varroacides. Our findings suggest the need for large-scale resistance monitoring via genotyping to provide timely information to beekeepers and regulators. This will enable them to make an effective management plan, including rotation of available treatments to suppress or at least delay the evolution of resistance in V. destructor populations.

Abstract Background The Western honey bee, Apis mellifera, is an economically important pollinator, as well as a tractable species for studying the behavioral intricacies of eusociality. Honey bees are currently being challenged by multiple biotic and environmental stressors, many of which act concomitantly to affect colony health and productivity. For instance, developmental stress can lead workers to become precocious foragers and to leave the hive prematurely. Precocious foragers have decreased flight time and lower foraging efficiency, which can ultimately lower colony productivity and even lead to colony collapse. Materials and methods In this study, we tested the hypothesis that stress during pupal development can cause young workers to exit the hive prematurely before they are physically able to fly. This premature exiting behavior results in death outside the hive soon thereafter. To determine how various stressors may lead bees to perform this behavior, we subjected workers during the last pupal stage to either cold stress (26 °C for 24 h), heat stress (39 °C for 24 h), or Varroa destructor mite parasitization, and compared the rate of premature hive exits between stressed bees and their respective control counterparts. Upon emergence, we individually tagged focal bees in all treatment groups and introduced them to a common observation hive. We then followed tagged bees over time and monitored their survivorship, as well as their likelihood of performing the premature hive exiting behavior. We also dissected the hypopharyngeal glands of all treatment and control bees sampled. Results We found that significantly more bees in all three treatment groups exited the hive prematurely compared to their control counterparts. Bees in all treatment groups also had significantly smaller hypopharyngeal glands than control bees. Conclusions Our results suggest that premature hive exiting behavior is driven by stress and is potentially a form of accelerated age polyethism that leads to premature death.

Varroa species, commonly known as the honey bee mites, poses a significant challenge to the worldwide beekeeping industry. The aim of this study was to investigate the effect of haplotype variation on morphology of Varroa destructor. Forty-one apiaries across Bingol province (Türkiye) and its districts were visited using random sampling to examine 2440 honey bee colonies. Adult Varroa spp mites were collected from each apiary and morphometrically analysed at species level, resulting in seven mites being used to represent each apiary. Length measurements were taken of six morphometric parameters of 287 adult Varroa spp. isolates under a stereo microscope, including body length, body width, genital shield length, genital shield width, anal shield length and anal shield width. In order to analyze genetic diversity, genomic DNA was isolated from a total of 82 individual Varroa spp. isolates, and specific primers were used to amplify the mitochondrial cytochrome oxidase subunite 1 (mt-CO1) gene fragment (376 bp) by PCR followed by DNA sequence analysis. Morphometric analysis revealed that the adult Varroa spp isolates had a body width of 1691.10 ± 06.55 μm and a body length of 1125.69 ± 06.62 μm, with no significant differences between apiaries. These findings indicate that all the isolates were morphometrically identified as V. destructor. Moreover, all the sequences were highly similar to the Korean (K) haplotype of V. destructor. Six haplotypes (Hap01-Hap06) of V. destructor were identified via haplotype analysis. The haplotype groups exhibited low nucleotide diversity and were separated by 1–3 point mutations. There was no significant difference in body widths between Hap01 and other haplotypes. However, Hap03 had significantly higher body widths than Hap04 and Hap05. This indicates that haplotype differences may have an effect on morphological parameters in Varroa species. [ABSTRACT FROM AUTHOR]

Abstract Varroa destructor is one of the greatest threats to Apis mellifera worldwide and if left untreated will kill a colony in less than three years. A Varroa-resistant population from Gotland, Sweden, has managed to survive for 25 years with little to no Varroa treatment by reducing the mite’s reproductive success. The underlying mechanisms of this trait is currently not known, though previous research indicates that it is the honey bee brood, and not adult bee influence, that contributes to this phenotype. As the mite’s own reproduction is synchronized with the brood’s development though the interception of brood pheromones, it is possible that a change in pheromone profile would disrupt the mite’s reproductive timing. To investigate this, we characterized the brood ester pheromone (BEP) profile of our resistant Gotland population compared to a non-resistant control. This was done by extracting and analyzing key cuticular compounds of the BEP using gas chromatography. A significant difference was found immediately after brood capping, indicating a divergence in their pheromonal production at this time point. This is an important step to understanding the mechanisms of the Gotland population’s Varroa-resistance and contributes to our global understanding of Varroa destructor infestation and survival.

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.

The western honey bee (Apis mellifera) is severely impacted by the parasitic Tropilaelaps mercedesae mite, which has the capacity to outcompete Varroa destructor mites (the current leading cause of colony losses) and more rapidly overwhelm colonies. While T. mercedesae is native to Asia, it has recently expanded its geographic range and has the potential to devastate beekeeping worldwide if introduced to new regions. Our research exploited the dependence of T. mercedesae on developing honey bees (brood) by combining a cultural technique (brood break) with U.S. registered chemical products (oxalic acid or formic acid) to manage T. mercedesae infestation. To evaluate this approach, we compared four treatment groups: (1) Brood Break; (2) Brood Break + Formic Acid (FormicPro®); (3) Brood Break + Oxalic Acid dribble (Api-Bioxal®); and (4) untreated Control. We found that the mite infestation rate of worker brood in Control colonies rose from 0.4 to 15.25% over 60 days, whereas all other treatment groups had infestation rates under 0.11% on Day 60. Mite fall assessments showed similar results, whereby Control colonies had 15.48 mites fall per 24 h on day 60 compared to less than 0.2 mites for any other treatment group. Evaluation of colony strength revealed that Brood Break + Formic Acid colonies had slightly reduced adult honey bee populations. No treatment eliminated all mites, so additional measures may be needed to eradicate T. mercedesae if detected in countries that do not currently have T. mercedesae. [ABSTRACT FROM AUTHOR]

Deformed wing virus (DWV), which is an important honey bee virus transmitted by Varroa destructor (V. destructor) , causes colony losses in honey bee colonies. This study aimed to investigate the prevalence and genetic diversity of DWV in honey bees in Türkiye and to determine the role of V. destructor in the transmission of the genetic variants of DWV. Honey bee samples were collected from 62 apiaries, by simple random sampling, during March 2022 and April 2023. The presence of V. destructor in collected bee samples was examined using a stereo microscope. Real-time RT-PCR was used for the detection of DWV-A and DWV-B (Varroa destructor virus-1 (VDV-1)) viruses. Genetic characterisation of the positive samples was conducted by sequencing polyprotein genomic region. Considering the V. destructor infestation rate of 3% as relevant, out of the 62 apiaries examined, 17 (27.4%) were positive. However, DWV-A and VDV-1 specific RNA was not detected in V. destructor samples. VDV-1 specific RNA was detected in 6.5% (4/62) of the apiaries, whereas DWV-A was not detected in the sampled apiaries. Phylogenetic analysis showed that isolates detected in this study were located in a separate cluster from previously characterised DWV-A and VDV-1 isolates. According to RDP4 and GARD analyses, DWV-VDV-1 recombination breakpoints were detected in field isolates. To the best our knowledge, this is the first report of the presence of VDV-1-DWV recombinants in Türkiye. Further studies are needed to determine the impact of VDV-1-DWV recombinants and their virological and antigenic properties. [ABSTRACT FROM AUTHOR]

The honey bee ectoparasite Varroa destructor is the main cause of honey bee colony losses worldwide. Over the last decades, several projects have focused on improving the robustness of Apis mellifera against this parasitic mite. Selection traits, such as mite non-reproduction (MNR) and Varroa sensitive hygiene (VSH), are favored selection factors in Varroa resistance projects. VSH is a trait where adult honey bees remove the Varroa-infested brood. During this process, the female mites are arrested in their reproductive cycle leading to a reduction of the Varroa population within the bee colony. From 2019 to 2022, 1402 queens were instrumentally inseminated with single or multiple drones in a breeding program. Colonies headed by these queens were established annually, and the MNR and VSH levels were analyzed. VSH was evaluated in response to cells artificially infested with Varroa, and colonies with high VSH values were used to generate our selected VSH stock. Despite crossing high VSH drones and queens, we measured a remarkable heterogeneity of MNR and VSH in the next generation(s), most likely due to the well-described, high recombination rate in the honey bee genome. When assessed multiple times in the same colony, great variance between measurements was observed. Detailed evaluations of daughter colonies are thus required if selection programs want to breed colonies with reliable VSH traits. This constant need to evaluate all offspring to ensure the desirable resistance traits are present results in high workloads and great expenses in selection programs. Furthermore, such large-scale breeding programs are inefficient due to high fluctuations between measurements and generations, indicating we need to develop new approaches and improved methods for assessing Varroa resistance. [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]

Most published data on mite infestation rates in semi-arid regions have been collected over only 3 or 4 months during a specific period of the year. Therefore, the aim of this study was to observe parasite-host dynamics of hygienic and non-hygienic Africanized bee colonies considering environmental factors that may influence Varroa destructor mite infestation rates in a semi-arid region. To this end, the brood puncture method was applied to 37 colonies, forming two groups, namely G1, encompassing 16 hygienic colonies, and G2, comprising 21 non-hygienic colonies. After forming the groups, 300 worker bees from each colony were examined monthly for mite infestations and the data were correlated with climatological records. The monthly infestation average was considered low, below 10%, except in November, when it reached 12.19% ± 6.45. No statistically significant difference was observed for inter-group infestation rates (P > 0.05). When mite infestation rates were associated with climatic variables, they were linked to colony losses (32%) due to swarming. No significant correlations between hygienic behaviour and parasite infestation rates were noted. Nonetheless, these results support the idea that there is no need to apply acaricides for V. destructor control in Brazil. [ABSTRACT FROM AUTHOR]

We collected 56 specimens of Laelaps chini from the endemic Hengduan Mountain rat species (Eothenomys miletus) and obtained the first complete mitochondrial genome of L. chini by next-generation sequencing (NGS). The L. chini mitogenome is 16,507 bp in size and contains 37 genes and a control region of 2380 bp in length. The L. chini mitogenome has a high AT content and a compact arrangement with four overlapping regions ranging from 1 to 2 bp and 16 spacer regions ranging from 1 to 48 bp. We analyzed 13 protein-coding genes of L. chini mitogenome and found that protein-coding genes in the L. chini mitogenome preferred codons ending in A/U and codon usage pattern was mainly influenced by natural selection. Cox1 has the slowest evolution rate and cox3 has the fastest evolution rate. We combined the mitochondrial genome of eight species of gamasid mites in the superfamily Dermanyssoidea from Genbank and the L. chini mitochondrial genome to analyze its rearrangement patterns and breakpoint numbers. We found that the L. chini mitogenome showed a novel arrangement pattern and nine species of gamasid mites in the superfamily Dermanyssoidea, which have been sequenced complete mitochondrial genomes to date, all showed different degrees of rearrangement. Laelaps chini, Echinolaelaps echidninus and Echinolaelaps fukinenensis were closely related species based on genetic distance and phylogenetic analyses. Notably they are clustered with Varroa destructor of the family Varroidae, suggesting that the family Varroidae is more closely related to the family Laelapidae, but more data are needed to test whether Varroa can be classified under the family Laelapidae. The L. chini mitogenome is the first complete mitochondrial genome for the genus Laelaps, and contributes to further exploration of the mitochondrial gene rearrangements and phylogeny for the superfamily Dermanyssoidea. [ABSTRACT FROM AUTHOR]

The combined effects of mite infestation and viral transmission can lead to a rapid decline in colony health. There is growing concern about the decline of Western honey bees (Apis mellifera) caused by an emerging pathogen, Tropilaelaps mercedesae. So far, it is unclear whether T. mercedesae transmits viruses and which viruses might facilitate increased transmission. Here, we found that T. mercedesae harbored six common honey bee viruses. Furthermore, viral proliferation analysis by RT-qPCR showed that viral loads in T. mercedesae was higher than in A. mellifera, especially for deformed wing virus (DWV). Subsequently, we verified that DWV can be transferred between A. mellifera and T. mercedesae during the mite parasitism process by employing an infectious clone of DWV with Green fluorescent protein (GFP). Our findings not only contribute to the understanding of the bee-mite-virus interplay but also highlight the potential role of T. mercedesae as a vector for DWV, similar to Varroa destructor. Due to their ability to transmit viral infections, coupled with their direct parasitic effects, more research is needed for effective management strategies to protect honey bees and ensure the sustainability of apiculture and agriculture. [ABSTRACT FROM AUTHOR]

Despite the major role that insect pollinators play in crop production, agricultural intensification drives them into decline. Various conservation measures have been developed to mitigate the negative effects of agriculture on insect pollinators.In a novel comparison of the efficacy of three conservation measures on honeybee colony growth, we monitored experimental honeybee colonies in 16 landscapes that comprised orthogonal gradients of organic agriculture, annual flower strips and perennial semi‐natural habitats. Using structural equation modelling, we assessed the effects of conservation measures on the prevalence of 11 parasites, Varroa destructor loads and their collective impact on colony growth.Increasing area coverage of perennial semi‐natural habitat related to higher V. destructor load and indirectly to lower colony growth.Increasing area of annual flower strips was associated with lower V. destructor load and indirectly with higher colony growth.Increasing area of organic farming related to lower parasite richness and also directly to improved colony growth.Synthesis and applications: Landscape features can affect pollinators directly through the provision of food resources and indirectly through modulation of parasite prevalence. To promote honeybee colony health in agro‐ecosystems, our results suggest that organic agriculture and annual flower strips should be prioritized conservation measures. Landscape management should consider the merits and demerits of different measures to sustain healthy populations of pollinators in agro‐ecosystems. [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]

BACKGROUND: The Varroa mite (Varroa destructor) is considered to be the greatest threat to apiculture worldwide. RNA interference (RNAi) using double‐stranded RNA (dsRNA) as a gene silencing mechanism has emerged as a next‐generation strategy for mite control. RESULTS: We explored the impact of a dsRNA biopesticide, named vadescana, designed to silence the calmodulin gene in Varroa, on mite fitness in mini‐hives housed in a laboratory. Two dosages were tested: 2 g/L dsRNA and 8 g/L dsRNA. Vadescana appeared to have no effect on mite survival, however, mite fertility was substantially reduced. The majority of foundress mites exposed to vadescana failed to produce any offspring. No dose‐dependent effect of vadescana was observed, as both the low and high doses inhibited mite reproduction equally well in the mini‐hives and neither dose impacted pupal survival of the honey bee. Approximately 95% of bee pupae were alive at uncapping across all treatment groups. CONCLUSION: These findings suggest that vadescana has significant potential as an effective alternative to conventional methods for Varroa control, with broader implications for the utilization of RNAi as a next‐generation tool in the management of pest species. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [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]

The most devastating pest to honey bees (Apis mellifera) worldwide is the parasitic mite Varroa destructor. The development of miticide-resistant mite populations has been a major driver of colony loss in many countries. We investigated the threat Varroa poses to honey bee populations in New Zealand and tested the effectiveness of the two most popular chemical treatments used by beekeepers. Colony losses reported by New Zealand beekeepers have risen over five consecutive years from 2017 to 2021, as have the proportion of losses attributed to Varroa, with this parasite found to be the main driver of colony loss in 2021. Varroa resistance to miticide treatments flumethrin and amitraz was tested. The concentration of flumethrin required to kill 50% of the mites (LC50) was 156 µg/g, 26 times greater than the adjusted LC50 value of 6 µg/g observed in a trial also conducted in New Zealand in 2003, indicating evidence of developing mite resistance to flumethrin in New Zealand. Molecular analyses searching for mutations in the Varroa genome known to be associated with flumethrin resistance found no evidence of such mutations, suggesting that any extant resistance to flumethrin has evolved independently in New Zealand. No evidence of resistance to amitraz was found, as the LC50 value of 12 µg/g was lower than what was observed in the 2003 trial (141 µg/g). Further development of integrated pest management, such as with gene-silencing RNA interference (RNAi) and selective breeding of Varroa-resistant bees, is needed to effectively manage a parasite that threatens global agriculture. [ABSTRACT FROM AUTHOR]

We investigated the application of queen caging to prevent autumn brood rearing. In comparative experiments, cages equipped with queen excluders on both sides were used. Only cages of the experimental group were supplied with comb sections. Survival of queens and the influence of various factors on brood rearing in cages and in the nest after the queen had been released were compared. The factors included the position of caged queens in the nest (in the middle or in the periphery), comb sections with empty or honey-filled cells, or with drone cells. The queens did not perish in cages supplied with a worker comb section, but 8% of them perished in cages without it. One queen perished in the cage with drone comb section. The number of colonies rearing brood and the brood area in the nest was higher than those in the cage. There was no correlation between the position of the caged queen in the nest and brood production in the cage and later in the nest. Comb section fullness had no impact on brood rearing in the cage. In cages with a drone comb section, no brood was observed besides eggs, but the total brood area (including eggs) did not differ from the worker comb section group in cages and later in the nest. Caging of the queens on an empty worker comb section for 21 days supports their survival and enables the beekeeper to carry out successful Varroa control earlier in autumn. [ABSTRACT FROM AUTHOR]

The ectoparasitic mite Varroa destructor has become a major worldwide pest of the honey bees (Apis mellifera L). Intensive use of chemical acaricides has led to the development of acaricide resistance in mites, thereby reducing the efficacy of acaricides and causing contamination of hive products. Thus, natural products such as essential oils can become an important alternative to synthetic chemicals in controlling Varroa mites. In this study, essential oil from Thymus schimperi grown in the Ethiopian highland was investigated for its chemical composition and toxicity against Varroa mites through complete exposure tests. Hydrodistillation of T. schimperi leaves yielded a pale yellow essential oil (0.8% v/w) with a strong and pleasant odor. Analyzed by GC-MS, 29 compounds, comprising 96.67% of the oil, were identified. Carvacrol (34.84%), thymol (23.03%), and p-cymene (14.20%) were found to be the main constituents. In the toxicity assay, T. schimperi essential oil showed high acaricidal activity against Varroa mites, with a 4 h-LC50 value of 109.16 µg/ml (5.46 mg oil/l air volume). Among the main constituents, thymol and carvacrol induced high toxicity to Varroa mites, with 4 h-LC50 values of 70.71 µg/ml (3.54 mg thymol/l air volume) and 106.10 µg/ml (5.31 mg carvacrol/l air volume), respectively. However, p-cymene was less effective in toxicity testing (4 h-LC50 > 5000 µg/ml). The results show for the first time that the essential oil of Thymus schimperi and its two main constituents, thymol and carvacrol, are highly acaricidal and can be used to control Varroa mite infestations. [ABSTRACT FROM AUTHOR]

The honey bee (Apis mellifera) parasitic mite, Varroa destructor, is considered one of the main causes of colony losses in European honey bee (EHB) populations around the world. However, some EHB and Africanized honey bee (AHB) populations (derived from the African subspecies A. m. scutellata) that inhabit tropical and subtropical regions of the Americas, have survived varroa mite infestations in the absence of acaricide treatments. It is conceivable to expect that these honey bee populations, which have been subjected to natural selection over decades, would have developed resistance against V. destructor or possess pre-existing adaptations that allow them to survive mite parasitism. Here, we present a comprehensive literature review describing the spread of V. destructor and the honey bee populations occurring in Latin America (LA), and summarize the evidence of resistance of those populations to V. destructor. We also analyze reports describing the potential mechanisms of mite resistance and how they operate in those honey bee populations. Studies of a few EHB, as well as of numerous AHB populations exhibiting resistance to V. destructor in LA, unveil the existence of evolutionary adaptations that restrain V. destructor population growth and provide insight into the current host-parasite relationship. This review supports the notion that selective breeding of local honey bee populations from LA could be a viable strategy to manage varroa mite infestations in colonies. [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]

We present a one-year-long multi-sensor dataset collected from honey bee colonies (Apis mellifera) with rich phenotypic measurements. Data were collected non-stop from April 2020 to April 2021 from 53 hives located at two apiaries in Québec, Canada. The sensor data included audio features, temperature, and relative humidity. The phenotypic measurements contained beehive population, number of brood cells (eggs, larva and pupa), Varroa destructor infestation levels, defensive and hygienic behaviors, honey yield, and winter mortality. Our study is amongst the first to combine a wide variety of phenotypic trait measurements annotated by apicultural science experts with multi-sensor data, which facilitate a broader scope of analysis. We first summarize the data collection procedure, sensor data pre-processing steps, and data composition. We then provide an overview of the phenotypic data distribution as well as a visualization of the sensor data patterns. Lastly, we showcase several hive monitoring applications based on sensor data analysis and machine learning, such as winter mortality prediction, hive population estimation, and the presence of an active and laying queen. [ABSTRACT FROM AUTHOR]

Varroa destructor is a dangerous pest directly for beekeeping and indirectly for crops that require insect pollination. In recent years, the application of chemical pesticides has led to the occurrence of mite resistance and contamination of hive products. Plant extracts are considered as a suitable alternative to chemical acaricides for the Varroa mite control. Therefore, the present study aimed to investigate the acaricidal and insecticidal activity of extract of Prangos ferulacea plant against the Varroa mite and its host in the honey bee colonies in the climatic conditions of Kurdistan province from 2022 to 2024. The P. ferulacea plant was collected in June 2022 from different regions of Kurdistan province in the flowering stage, extracted and then its chemical compounds were identified using GC-MS. The present study was conducted in the form of a factorial experiment based on a completely random basic design with four treatments and seven replications. Before conducting the bioassay experiments, the experimental colonies were homogenized in terms of queen age, population (adults and brood), and honey storage. Also, the initial infestation rate of colonies with Varroa mites was evaluated for adult and brood. The results showed that the extract of 50% of P. ferulacea was relatively favorable acaricidal properties. So that, there was no significant difference with oxalic acid and Apistan treatments in terms of mite mortality percentage in the first time of spraying. Also, the result showed that the bee's mortality percentage was not more than 7% in any of the times of spraying with the 50% extract of the P. ferulacea, and there was observed a significant difference compared to the oxalic acid and Apistan treatments in terms of bee's mortality percentage (P<0.01). The queen superseding was not observed in any of the experimental treatments. According to the findings of the present research, the concentration of 50% of the extract P. ferulaceous can be suggested as a suitable alternative to synthetic acaricides and organic acids to control the Varroa mite in honey bee colonies. [ABSTRACT FROM AUTHOR]