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Xie Y, Su X, Wei R, Cao L, Zheng H. The Braconid Syntretomorpha szaboi Papp Is Posing a Great Threat to the Eastern Honeybee, Apis cerana. Pathogens 2024; 13:422. [PMID: 38787274 PMCID: PMC11124228 DOI: 10.3390/pathogens13050422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/10/2024] [Accepted: 05/15/2024] [Indexed: 05/25/2024] Open
Abstract
The expansion of pathogen distribution may result in a new threat to the host. The braconid Syntretomorpha szaboi Papp is an obligate parasite that targets Apis cerana, the Eastern honeybee, engaging in endoparasitism by ovipositing eggs inside the host bee. Although S. szaboi has been documented in India and in various regions across China, its epidemiological data are notably lacking. In this study, we summarized the distribution of S. szaboi based on the available literature and described the symptoms of infested honeybee workers. We also investigated the infestation rate in 36 apiaries in Zhejiang Province, China, after a new occurrence of the parasite was reported in these regions in 2020. A rapid increase in infestation rate was found from the year 2021 to 2022, reaching 53.88% at the colony level of the sampled colonies in the Jinhua and Wenzhou apiaries. The infestation rate at an individual level in positive colonies reached an average of 26%. A monthly survey showed high seasonal variation in S. szaboi infestation, with the peak occurring from May to August. These results suggest that S. szaboi poses a great threat to A. cerana. Further research is needed to elucidate its epidemiology and pathology and to develop disease prevention and control strategies.
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Affiliation(s)
- Yanling Xie
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; (Y.X.); (R.W.)
| | - Xiaoling Su
- Jinhua Academy of Agricultural Sciences, Jinhua 321017, China;
| | - Ruike Wei
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; (Y.X.); (R.W.)
| | - Lianfei Cao
- Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China;
| | - Huoqing Zheng
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; (Y.X.); (R.W.)
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Lin Z, Shen S, Wang K, Ji T. Biotic and abiotic stresses on honeybee health. Integr Zool 2024; 19:442-457. [PMID: 37427560 DOI: 10.1111/1749-4877.12752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Honeybees are the most critical pollinators providing key ecosystem services that underpin crop production and sustainable agriculture. Amidst a backdrop of rapid global change, this eusocial insect encounters a succession of stressors during nesting, foraging, and pollination. Ectoparasitic mites, together with vectored viruses, have been recognized as central biotic threats to honeybee health, while the spread of invasive giant hornets and small hive beetles also increasingly threatens colonies worldwide. Cocktails of agrochemicals, including acaricides used for mite treatment, and other pollutants of the environment have been widely documented to affect bee health in various ways. Additionally, expanding urbanization, climate change, and agricultural intensification often result in the destruction or fragmentation of flower-rich bee habitats. The anthropogenic pressures exerted by beekeeping management practices affect the natural selection and evolution of honeybees, and colony translocations facilitate alien species invasion and disease transmission. In this review, the multiple biotic and abiotic threats and their interactions that potentially undermine bee colony health are discussed, while taking into consideration the sensitivity, large foraging area, dense network among related nestmates, and social behaviors of honeybees.
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Affiliation(s)
- Zheguang Lin
- Apicultural Research Institute, College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Siyi Shen
- Apicultural Research Institute, College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Kang Wang
- Apicultural Research Institute, College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Ting Ji
- Apicultural Research Institute, College of Animal Science and Technology, Yangzhou University, Yangzhou, China
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Huang Q, Evans JD. Host switch by honey bee parasitic mites leads to symbiont diversification. J Invertebr Pathol 2024; 203:108068. [PMID: 38272108 DOI: 10.1016/j.jip.2024.108068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/03/2024] [Accepted: 01/22/2024] [Indexed: 01/27/2024]
Abstract
Host-parasite co-evolution is a reciprocal genetic change; however, the parasite may switch to a novel host, deviating from conventional co-evolution. Varroa destructor is a native parasite of the honey bee Apis cerana, and the mite has established infestation in another honey bee, Apis mellifera, causing colony failure. When mites switched to the novel host, they formed a distinct population from mites that remained on the native host. Consequently, this led to divergence in the microbiota associated with mites in two host populations. The microbes were conserved at the species level reflected by alpha diversity, with substantial relative abundance variance. Microbes found in mites were distinct from the bee microbiota. They mainly were pathogenic with antibiotic resistance, while a few bacterial taxa were previously found in honey bees, including Klebsiella pneumoniae and Pseudomanas aeruginosa. These symbionts may transfer between the mites and honey bees.
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Affiliation(s)
- Qiang Huang
- Honeybee Research Institute, Jiangxi Agricultural University, Zhimin Ave. 1101, Nanchang 330045, China.
| | - Jay D Evans
- USDA-ARS Bee Research Laboratory, BARC-East Building 306, Beltsville, MD 20705, USA
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Reyes-Quintana M, Goodwin PH, Correa-Benítez A, Pelaez-Hernández R, Guzman-Novoa E. Genetic variability of the honey bee mite, Varroa destructor, from a humid continental climatic region of Canada, and temperate and tropical climatic regions of Mexico. EXPERIMENTAL & APPLIED ACAROLOGY 2023; 91:541-559. [PMID: 37884811 DOI: 10.1007/s10493-023-00848-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/28/2023] [Indexed: 10/28/2023]
Abstract
Varroa destructor is a damaging mite of Western honey bees (Apis mellifera). Genetic variability of the mite in different regions of the world could be related to the movement of infested bees or other factors, such as climate. In this study, V. destructor samples were collected from tropical and temperate climate regions of Mexico, and a humid continental climate region of Canada. COX-1 AFLPs showed that all the mites were the Korean haplotype. Four microsatellites revealed nine haplogroups from the continental climate region of Canada, compared to three haplogroups from the tropical and temperate climate regions of Mexico. CytII-ATP sequences showed seven haplogroups from the humid continental climate region vs. two haplogroups from the temperate region and one haplogroup from the tropical region. CytB sequences revealed seven haplogroups from Canada vs. three from Mexico. A comparison of the cytB sequences of the samples from Canada and Mexico to those from a worldwide collection showed that one sequence, designated the cytB1 type, predominated, comprising 57% of the 86 sequences; it clustered with similar sequences that comprised 80% of the sequences, designated family A. CytB1 was predominant in Mexico, but not in Canada. The other 20% of sequences were in families B and C, and all those samples originated from East and Southeast Asia. The microsatellite, cytII-ATP, and cytB markers, all showed higher variability in mites collected in Canada than in Mexico, which could be related to the cooler climate or an earlier invasion and/or multiple mite invasions in Canada.
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Affiliation(s)
- Mariana Reyes-Quintana
- School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Paul H Goodwin
- School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Adriana Correa-Benítez
- Departamento de Medicina y Zootecnia en Abejas, FMVZ, UNAM, Ciudad Universitaria, 04510, Mexico, Mexico
| | - Roberto Pelaez-Hernández
- Departamento de Medicina y Zootecnia en Abejas, FMVZ, UNAM, Ciudad Universitaria, 04510, Mexico, Mexico
| | - Ernesto Guzman-Novoa
- School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada.
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Lin Z, Zhang N, Wang Z, Zhuang M, Wang Q, Niu D, Page P, Wang K, Niu Q, Ji T. Acute and chronic viruses mediated by an ectoparasite targeting different developmental stages of honeybee ( Apis mellifera and Apis cerana) brood. Front Vet Sci 2022; 9:951159. [PMID: 36277062 PMCID: PMC9583130 DOI: 10.3389/fvets.2022.951159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 09/19/2022] [Indexed: 11/04/2022] Open
Abstract
The health of the western honeybee, Apis mellifera, the most crucial pollinator, has been challenged globally over the past decades. An ectoparasitic mite, Varroa destructor, together with the viruses it vectored, is generally regarded as the vital pathogenic agent. Although the poor health status of A. mellifera compared to its eastern counterpart, Apis cerana, has been broadly identified, the underlying mechanism remains poorly understood and comparison between susceptible and resistant hosts will potentially ameliorate this predicament. Here, we investigated the impacts of two widespread viruses—deformed wing virus type A (DWV-A) and Israeli acute paralysis virus (IAPV), mediated by V. destructor mite, on the capped developing honeybee brood, in the absence of adult workers, of A. mellifera and A. cerana, with positive and negative controls. Our results demonstrated that the endogenous viruses imposed limited damage on the hosts even if the brood was wounded. In contrast, the exogenous viruses introduced by ectoparasites triggered variable mortality of the infested brood between host species. Intriguingly, death causes of both honeybee species presented a similar trend: the acute IAPV generally causes morbidity and mortality of late larvae, while the chronic DWV-A typically leads to brood mortality during and after pupation. Notably, the susceptible immature A. cerana individuals, supported by higher observed mortality and a lower virus tolerance, serve the interests of the colony and foster the overall survival of a resistant honeybee superorganism. These results improve our understanding of the interactions between viruses carried by ectoparasites and their developing hosts, and the novel insight of weak individuals fostering strong colonies may promote breeding efforts to mitigate the indefensible colony losses globally.
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Affiliation(s)
- Zheguang Lin
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Nan Zhang
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Zhi Wang
- Apiculture Science Institute of Jilin Province, Jilin, China
| | | | - Qi Wang
- Apiculture Science Institute of Jilin Province, Jilin, China,College of Forestry, Beihua University, Jilin, China
| | - Defang Niu
- College of Food Science and Technology, Jiangsu Agri-animal Husbandry Vocational College, Taizhou, China
| | - Paul Page
- Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Kang Wang
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Qingsheng Niu
- Apiculture Science Institute of Jilin Province, Jilin, China,Qingsheng Niu
| | - Ting Ji
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China,*Correspondence: Ting Ji
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Zheng H, Wang S, Wu Y, Zou S, Dietemann V, Neumann P, Chen Y, Li-Byarlay H, Pirk C, Evans J, Hu F, Feng Y. Genomic signatures underlying the oogenesis of the ectoparasitic mite Varroa destructor on its new host Apis mellifera. J Adv Res 2022; 44:1-11. [PMID: 36725182 PMCID: PMC9936524 DOI: 10.1016/j.jare.2022.04.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 02/04/2023] Open
Abstract
INTRODUCTION Host shift of parasites may have devastating effects on the novel hosts. One remarkable example is that of the ectoparasitic mite Varroa destructor, which has shifted its host from Eastern honey bees (Apis cerana) to Western honey bees (Apis mellifera) and posed a global threat to apiculture. OBJECTIVES To identify the genetic factors underlying the reproduction of host-shifted V. destructor on the new host. METHODS Genome sequencing was conducted to construct the phylogeny of the host-shifted and non-shifted mites and to screen for genomic signatures that differentiated them. Artificial infestation experiment was conducted to compare the reproductive difference between the mites, and transcriptome sequencing was conducted to find differentially expressed genes (DEGs) during the reproduction process. RESULTS The host-shifted and non-shifted V. destructor mites constituted two genetically distinct lineages, with 15,362 high-FST SNPs identified between them. Oogenesis was upregulated in host-shifted mites on the new host A. mellifera relative to non-shifted mites. The transcriptomes of the host-shifted and non-shifted mites differed significantly as early as 1h post-infestation. The DEGs were associated with nine genes carrying nonsynonymous high-FST SNPs, including mGluR2-like, Lamb2-like and Vitellogenin 6-like, which were also differentially expressed, and eIF4G, CG5800, Dap160 and Sas10, which were located in the center of the networks regulating the DEGs based on protein-protein interaction analysis. CONCLUSIONS The annotated functions of these genes were all associated with oogenesis. These genes appear to be the key genetic determinants of the oogenesis of host-shifted mites on the new host. Further study of these candidate genes will help elucidate the key mechanism underlying the success of host shifts of V. destructor.
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Affiliation(s)
- Huoqing Zheng
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Shuai Wang
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Yuqi Wu
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Shengmei Zou
- Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Institute for Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Vincent Dietemann
- Swiss Bee Research Center, Agroscope, Bern, Switzerland; Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Peter Neumann
- Swiss Bee Research Center, Agroscope, Bern, Switzerland; Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Yanping Chen
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA
| | - Hongmei Li-Byarlay
- Agricultural Research and Development Program, Central State University, Wilberforce, OH 45384, USA; Department of Agricultural and Life Science, Central State University, Wilberforce, OH 45384, USA
| | - Christian Pirk
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Jay Evans
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA
| | - Fuliang Hu
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Ye Feng
- Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Institute for Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
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Molecular Detection and Differentiation of Arthropod, Fungal, Protozoan, Bacterial and Viral Pathogens of Honeybees. Vet Sci 2022; 9:vetsci9050221. [PMID: 35622749 PMCID: PMC9145064 DOI: 10.3390/vetsci9050221] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 02/01/2023] Open
Abstract
The honeybee Apis mellifera is highly appreciated worldwide because of its products, but also as it is a pollinator of crops and wild plants. The beehive is vulnerable to infections due to arthropods, fungi, protozoa, bacteria and/or viruses that manage to by-pass the individual and social immune mechanisms of bees. Due to the close proximity of bees in the beehive and their foraging habits, infections easily spread within and between beehives. Moreover, international trade of bees has caused the global spread of infections, several of which result in significant losses for apiculture. Only in a few cases can infections be diagnosed with the naked eye, by direct observation of the pathogen in the case of some arthropods, or by pathogen-associated distinctive traits. Development of molecular methods based on the amplification and analysis of one or more genes or genomic segments has brought significant progress to the study of bee pathogens, allowing for: (i) the precise and sensitive identification of the infectious agent; (ii) the analysis of co-infections; (iii) the description of novel species; (iv) associations between geno- and pheno-types and (v) population structure studies. Sequencing of bee pathogen genomes has allowed for the identification of new molecular targets and the development of specific genotypification strategies.
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Techer MA, Roberts JMK, Cartwright RA, Mikheyev AS. The first steps toward a global pandemic: Reconstructing the demographic history of parasite host switches in its native range. Mol Ecol 2022; 31:1358-1374. [PMID: 34882860 PMCID: PMC11105409 DOI: 10.1111/mec.16322] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 11/23/2021] [Accepted: 11/29/2021] [Indexed: 12/14/2022]
Abstract
Host switching allows parasites to expand their niches. However, successful switching may require suites of adaptations and also may decrease performance on the old host. As a result, reductions in gene flow accompany many host switches, driving speciation. Because host switches tend to be rapid, it is difficult to study them in real-time, and their demographic parameters remain poorly understood. As a result, fundamental factors that control subsequent parasite evolution, such as the size of the switching population or the extent of immigration from the original host, remain largely unknown. To shed light on the host switching process, we explored how host switches occur in independent host shifts by two ectoparasitic honey bee mites (Varroa destructor and V. jacobsoni). Both switched to the western honey bee (Apis mellifera) after being brought into contact with their ancestral host (Apis cerana), ~70 and ~12 years ago, respectively. Varroa destructor subsequently caused worldwide collapses of honey bee populations. Using whole-genome sequencing on 63 mites collected in their native ranges from both the ancestral and novel hosts, we were able to reconstruct the known temporal dynamics of the switch. We further found multiple previously undiscovered mitochondrial lineages on the novel host, along with the genetic equivalent of tens of individuals that were involved in the initial host switch. Despite being greatly reduced, some gene flow remains between mites adapted to different hosts. Our findings suggest that while reproductive isolation may facilitate the fixation of traits beneficial for exploiting the new host, ongoing genetic exchange may allow genetic amelioration of inbreeding effects.
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Affiliation(s)
- Maeva A Techer
- Okinawa Institute of Science and Technology, Okinawa, Japan
| | - John M K Roberts
- Commonwealth Scientific & Industrial Research Organisation, Canberra, Australian Capital Territory, Australia
| | - Reed A Cartwright
- The Biodesign Institute, Arizona State University, Tempe, Arizona, USA
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Alexander S Mikheyev
- Okinawa Institute of Science and Technology, Okinawa, Japan
- Australian National University, Canberra, Australian Capital Territory, Australia
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Bai WF, Lin ZG, Yan WY, Zhang LZ, Evans JD, Huang Q. Haplotype Analysis of Varroa destructor and Deformed Wing Virus Using Long Reads. FRONTIERS IN INSECT SCIENCE 2021; 1:756886. [PMID: 38468896 PMCID: PMC10926369 DOI: 10.3389/finsc.2021.756886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 11/03/2021] [Indexed: 03/13/2024]
Abstract
As a phoretic parasite and virus vector, the mite Varroa destructor and the associated Deformed wing virus (DWV) form a lethal combination to the honey bee, Apis mellifera. Routine acaricide treatment has been reported to reduce the diversity of mites and select for tolerance against these treatments. Further, different DWV strains face selective pressures when transmitted via mites. In this study, the haplotypes of Varroa mites and associated DWV variants were quantified using long reads. A single haplotype dominated the mite mitochondrial gene cytochrome oxidase subunit I, reflecting an ancient bottleneck. However, highly polymorphic genes were present across the mite genome, suggesting the diversity of mites could be actively maintained at a regional level. DWV detected in both mites and honey bees show a dominant variant with only a few low-frequency alternate haplotypes. The relative abundances of DWV haplotypes isolated from honey bees and mites were highly consistent, suggesting that some variants are favored by ongoing selection.
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Affiliation(s)
- Wen Feng Bai
- Honeybee Research Institute, Jiangxi Agricultural University, Nanchang, China
- Jiangxi Province Key Laboratory of Honeybee Biology and Beekeeping, Jiangxi Agricultural University, Nanchang, China
| | - Zhe Guang Lin
- Apicultural Research Institute, College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Wei Yu Yan
- Honeybee Research Institute, Jiangxi Agricultural University, Nanchang, China
- Jiangxi Province Key Laboratory of Honeybee Biology and Beekeeping, Jiangxi Agricultural University, Nanchang, China
| | - Li Zhen Zhang
- Honeybee Research Institute, Jiangxi Agricultural University, Nanchang, China
- Jiangxi Province Key Laboratory of Honeybee Biology and Beekeeping, Jiangxi Agricultural University, Nanchang, China
| | - Jay D. Evans
- United States Department of Agriculture - Agricultural Research Service (USDA-ARS) Bee Research Laboratory, Beltsville, MD, United States
| | - Qiang Huang
- Honeybee Research Institute, Jiangxi Agricultural University, Nanchang, China
- Jiangxi Province Key Laboratory of Honeybee Biology and Beekeeping, Jiangxi Agricultural University, Nanchang, China
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Chen G, Wang S, Jia S, Feng Y, Hu F, Chen Y, Zheng H. A New Strain of Virus Discovered in China Specific to the Parasitic Mite Varroa destructor Poses a Potential Threat to Honey Bees. Viruses 2021; 13:679. [PMID: 33920919 PMCID: PMC8071286 DOI: 10.3390/v13040679] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/25/2021] [Accepted: 04/08/2021] [Indexed: 11/17/2022] Open
Abstract
The ectoparasitic mite, Varroa destructor, feeds directly on honey bees and serves as a vector for transmitting viruses among them. The Varroa mite causes relatively little damage to its natural host, the Eastern honey bee (Apis cerana) but it is the most devastating pest for the Western honey bee (Apis mellifera). Using Illumina HiSeq sequencing technology, we conducted a metatranscriptome analysis of the microbial community associated with Varroa mites. This study led to the identification of a new Chinese strain of Varroa destructor virus-2 (VDV-2), which is a member of the Iflaviridae family and was previously reported to be specific to Varroa mites. A subsequent epidemiological investigation of Chinese strain of VDV-2 (VDV-2-China) showed that the virus was highly prevalent among Varroa populations and was not identified in any of the adult workers from both A. mellifera and A.cerana colonies distributed in six provinces in China, clearly indicating that VDV-2-China is predominantly a Varroa-adapted virus. While A. mellifera worker pupae exposed to less than two Varroa mites tested negative for VDV-2-China, VDV-2-China was detected in 12.5% of the A. mellifera worker pupae that were parasitized by more than 10 Varroa mites, bringing into play the possibility of a new scenario where VDV-2 could be transmitted to the honey bees during heavy Varroa infestations. Bioassay for the VDV-2-China infectivity showed that A. cerana was not a permissive host for VDV-2-China, yet A. mellifera could be a biological host that supports VDV-2-China's replication. The different replication dynamics of the virus between the two host species reflect their variation in terms of susceptibility to the virus infection, posing a potential threat to the health of the Western honey bee. The information gained from this study contributes to the knowledge concerning genetic variabilities and evolutionary dynamics of Varroa-borne viruses, thereby enhancing our understanding of underlying molecular mechanisms governing honey bee Varroosis.
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Affiliation(s)
- Gongwen Chen
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; (G.C.); (S.W.); (S.J.); (F.H.)
| | - Shuai Wang
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; (G.C.); (S.W.); (S.J.); (F.H.)
| | - Shuo Jia
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; (G.C.); (S.W.); (S.J.); (F.H.)
| | - Ye Feng
- Insitutute for Translational Medicine, Zhejiang University School of Medicine, Hangzhou 310058, China;
| | - Fuliang Hu
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; (G.C.); (S.W.); (S.J.); (F.H.)
| | - Yanping Chen
- USDA-ARS Bee Research Laboratory, Beltsville, MD 20705, USA
| | - Huoqing Zheng
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; (G.C.); (S.W.); (S.J.); (F.H.)
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