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Oddie MAY, Lanz S, Dahle B, Yañez O, Neumann P. Virus infections in honeybee colonies naturally surviving ectoparasitic mite vectors. PLoS One 2023; 18:e0289883. [PMID: 38100484 PMCID: PMC10723705 DOI: 10.1371/journal.pone.0289883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 07/27/2023] [Indexed: 12/17/2023] Open
Abstract
Western honeybee populations, Apis mellifera, in Europe have been known to survive infestations of the ectoparasitic mite, Varroa destructor, by means of natural selection. Proposed mechanisms in literature have been focused on the management of this parasite, however literature remains scare on the differences in viral ecology between colonies that have adapted to V. destructor and those that are consistently treated for it. Samples were collected from both a mite-surviving and a sympatric mite-susceptible honeybee population in Norway. The prevalence and abundances of 10 viruses, vectored by the parasite or not, were investigated in adult host workers and pupae as well as in V. destructor mites. Here we show that the mite-vectored Deformed wing virus (DWV-A) is often lower in both abundance and prevalence in the mite-surviving population in tandem with lower phoretic mite infestations compared to the mite susceptible population. However, the non-mite-vectored Black queen cell virus (BQCV), had both a higher abundance and prevalence in the mite-surviving population compared to the susceptible population. The data therefore suggest that general adaptations to virus infections may be unlikely to explain colony survival. Instead, mechanisms suppressing mite reproduction and therefore the impact seem to be more important.
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Affiliation(s)
| | - Sandra Lanz
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Bjørn Dahle
- Norwegian Beekeepers Association, Dyrskuev, Kløfta, Norway
| | - Orlando Yañez
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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2
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Lu RX, Bhatia S, Simone-Finstrom M, Rueppell O. Quantitative trait loci mapping for survival of virus infection and virus levels in honey bees. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2023; 116:105534. [PMID: 38036199 DOI: 10.1016/j.meegid.2023.105534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/22/2023] [Accepted: 11/25/2023] [Indexed: 12/02/2023]
Abstract
Israeli acute paralysis virus (IAPV) is a highly virulent, Varroa-vectored virus that is of global concern for honey bee health. Little is known about the genetic basis of honey bees to withstand infection with IAPV or other viruses. We set up and analyzed a backcross between preselected honey bee colonies of low and high IAPV susceptibility to identify quantitative trait loci (QTL) associated with IAPV susceptibility. Experimentally inoculated adult worker bees were surveyed for survival and selectively sampled for QTL analysis based on SNPs identified by whole-genome resequencing and composite interval mapping. Additionally, natural titers of other viruses were quantified in the abdomen of these workers via qPCR and also used for QTL mapping. In addition to the full dataset, we analyzed distinct subpopulations of susceptible and non-susceptible workers separately. These subpopulations are distinguished by a single, suggestive QTL on chromosome 6, but we identified numerous other QTL for different abdominal virus titers, particularly in the subpopulation that was not susceptible to IAPV. The pronounced QTL differences between the susceptible and non-susceptible subpopulations indicate either an interaction between IAPV infection and the bees' interaction with other viruses or heterogeneity among workers of a single cohort that manifests itself as IAPV susceptibility and results in distinct subgroups that differ in their interaction with other viruses. Furthermore, our results indicate that low susceptibility of honey bees to viruses can be caused by both, virus tolerance and virus resistance. QTL were partially overlapping among different viruses, indicating a mixture of shared and specific processes that control viruses. Some functional candidate genes are located in the QTL intervals, but their genomic co-localization with numerous genes of unknown function delegates any definite characterization of the underlying molecular mechanisms to future studies.
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Affiliation(s)
- Robert X Lu
- Department of Biological Sciences, University of Alberta, 116 Street & 85 Avenue, Edmonton, Alberta, T6G 2E9, Canada
| | - Shilpi Bhatia
- Department of Biology, North Carolina Agricultural and Technical State University, 1601 E Market Street, Greensboro, NC 27411, USA
| | - Michael Simone-Finstrom
- USDA-ARS Honey Bee Breeding, Genetics and Physiology Research Laboratory, 1157 Ben Hur Road, Baton Rouge, LA 70820, USA
| | - Olav Rueppell
- Department of Biological Sciences, University of Alberta, 116 Street & 85 Avenue, Edmonton, Alberta, T6G 2E9, Canada; Department of Biology, University of North Carolina at Greensboro, 321 McIver Street, Greensboro, NC 27412, USA.
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3
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Dickey M, Whilden M, Ellis JT, Rangel J. A preliminary survey reveals that common viruses are found at low titers in a wild population of honey bees (Apis mellifera). JOURNAL OF INSECT SCIENCE (ONLINE) 2023; 23:26. [PMID: 38098224 PMCID: PMC10721442 DOI: 10.1093/jisesa/iead117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 08/22/2023] [Accepted: 11/29/2023] [Indexed: 12/18/2023]
Abstract
A major threat to honey bee (Apis mellifera Linnaeus, Hymenoptera: Apidae) health continues to be parasitism by the mite Varroa destructor, which has been linked to high colony losses worldwide. Besides feeding on developing and adult bees, Varroa is also a prolific vector of honey bee-associated viruses. Because they live in unmanaged conditions, wild honey bee colonies are not treated against Varroa, which has enabled the natural selection of more mite-tolerant bees. To date, few studies have explored the prevalence of viruses in unmanaged colonies. The Welder Wildlife Refuge (WWR) in Texas is a unique site to study the viral landscape of unmanaged honey bees in the United States. The goals of this study were to identify and quantify viruses in wild colonies at the WWR, to examine changes in the prevalence of viruses in these colonies over time, and to compare the presence and titers of viruses between wild colonies at the WWR and those from the nearest managed apiary. We collected bees from colonies at the WWR in 2013, 2016, and 2021, and analyzed selected viruses for their presence and titers via quantitative polymerase chain reaction. In 2021, we also sampled bees from the nearest managed apiary for comparison. We found low average virus titers in all wild colonies sampled, and no difference in virus titers between colonies at the WWR and those from the managed apiary. Our study indicates that virus titers in wild colonies at the WWR are similar to those found in nearby colonies, and that these titers fluctuate over time.
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Affiliation(s)
- Myra Dickey
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Mckaela Whilden
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | | | - Juliana Rangel
- Department of Entomology, Texas A&M University, College Station, TX, USA
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Ray AM, Gordon EC, Seeley TD, Rasgon JL, Grozinger CM. Signatures of adaptive decreased virulence of deformed wing virus in an isolated population of wild honeybees ( Apis mellifera). Proc Biol Sci 2023; 290:20231965. [PMID: 37876196 PMCID: PMC10598435 DOI: 10.1098/rspb.2023.1965] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 09/28/2023] [Indexed: 10/26/2023] Open
Abstract
Understanding the ecological and evolutionary processes that drive host-pathogen interactions is critical for combating epidemics and conserving species. The Varroa destructor mite and deformed wing virus (DWV) are two synergistic threats to Western honeybee (Apis mellifera) populations across the globe. Distinct honeybee populations have been found to self-sustain despite Varroa infestations, including colonies within the Arnot Forest outside Ithaca, NY, USA. We hypothesized that in these bee populations, DWV has been selected to produce an avirulent infection phenotype, allowing for the persistence of both host and disease-causing agents. To investigate this, we assessed the titre of viruses in bees from the Arnot Forest and managed apiaries, and assessed genomic variation and virulence differences between DWV isolates. Across groups, we found viral abundance was similar, but DWV genotypes were distinct. We also found that infections with isolates from the Arnot Forest resulted in higher survival and lower rates of symptomatic deformed wings, compared to analogous isolates from managed colonies, providing preliminary evidence to support the hypothesis of adaptive decreased viral virulence. Overall, this multi-level investigation of virus genotype and phenotype indicates that host ecological context can be a significant driver of viral evolution and host-pathogen interactions in honeybees.
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Affiliation(s)
- Allyson M. Ray
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802-1503, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37240-0002, USA
| | - Emma C. Gordon
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802-1503, USA
| | - Thomas D. Seeley
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14850, USA
| | - Jason L. Rasgon
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802-1503, USA
| | - Christina M. Grozinger
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802-1503, USA
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Piou V, Vilarem C, Blanchard S, Strub JM, Bertile F, Bocquet M, Arafah K, Bulet P, Vétillard A. Honey Bee Larval Hemolymph as a Source of Key Nutrients and Proteins Offers a Promising Medium for Varroa destructor Artificial Rearing. Int J Mol Sci 2023; 24:12443. [PMID: 37569818 PMCID: PMC10419257 DOI: 10.3390/ijms241512443] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/13/2023] Open
Abstract
Varroa destructor, a major ectoparasite of the Western honey bee Apis mellifera, is a widespread pest that damages colonies in the Northern Hemisphere. Throughout their lifecycle, V. destructor females feed on almost every developmental stage of their host, from the last larval instar to the adult. The parasite is thought to feed on hemolymph and fat body, although its exact diet and nutritional requirements are poorly known. Using artificial Parafilm™ dummies, we explored the nutrition of V. destructor females and assessed their survival when fed on hemolymph from bee larvae, pupae, or adults. We compared the results with mites fed on synthetic solutions or filtered larval hemolymph. The results showed that the parasites could survive for several days or weeks on different diets. Bee larval hemolymph yielded the highest survival rates, and filtered larval plasma was sufficient to maintain the mites for 14 days or more. This cell-free solution therefore theoretically contains all the necessary nutrients for mite survival. Because some bee proteins are known to be hijacked without being digested by the parasite, we decided to run a proteomic analysis of larval honey bee plasma to highlight the most common proteins in our samples. A list of 54 proteins was compiled, including several energy metabolism proteins such as Vitellogenin, Hexamerin, or Transferrins. These molecules represent key nutrient candidates that could be crucial for V. destructor survival.
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Affiliation(s)
- Vincent Piou
- Laboratoire Evolution et Diversité Biologique, UMR5174, CNRS-Université de Toulouse III-IRD—Université Paul Sabatier, 31077 Toulouse, France; (V.P.); (S.B.)
| | - Caroline Vilarem
- Laboratoire Evolution et Diversité Biologique, UMR5174, CNRS-Université de Toulouse III-IRD—Université Paul Sabatier, 31077 Toulouse, France; (V.P.); (S.B.)
- M2i Biocontrol–Entreprise SAS, 46140 Parnac, France
| | - Solène Blanchard
- Laboratoire Evolution et Diversité Biologique, UMR5174, CNRS-Université de Toulouse III-IRD—Université Paul Sabatier, 31077 Toulouse, France; (V.P.); (S.B.)
| | - Jean-Marc Strub
- Laboratoire de Spectrométrie de Masse Bio-Organique, Département des Sciences Analytiques, Institut Pluridisciplinaire Hubert Curien, UMR 7178 (CNRS-UdS), 67037 Strasbourg, France (F.B.)
| | - Fabrice Bertile
- Laboratoire de Spectrométrie de Masse Bio-Organique, Département des Sciences Analytiques, Institut Pluridisciplinaire Hubert Curien, UMR 7178 (CNRS-UdS), 67037 Strasbourg, France (F.B.)
| | | | - Karim Arafah
- Plateforme BioPark d’Archamps, 74160 Archamps, France
| | - Philippe Bulet
- Plateforme BioPark d’Archamps, 74160 Archamps, France
- Institute pour l’Avancée des Biosciences, CR Université Grenoble Alpes, Inserm U1209, CNRS UMR 5309, 38000 Grenoble, France
| | - Angélique Vétillard
- Laboratoire Evolution et Diversité Biologique, UMR5174, CNRS-Université de Toulouse III-IRD—Université Paul Sabatier, 31077 Toulouse, France; (V.P.); (S.B.)
- Conservatoire National des Arts et Métiers (CNAM), Unité Métabiot, 22440 Ploufragan, France
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Gebremedhn H, Claeys Bouuaert D, Asperges M, Amssalu B, De Smet L, de Graaf DC. Expression of Molecular Markers of Resilience against Varroa destructor and Bee Viruses in Ethiopian Honey Bees ( Apis mellifera simensis) Focussing on Olfactory Sensing and the RNA Interference Machinery. INSECTS 2023; 14:insects14050436. [PMID: 37233064 DOI: 10.3390/insects14050436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/26/2023] [Accepted: 05/01/2023] [Indexed: 05/27/2023]
Abstract
Varroa destructor mites and the viruses it vectors are two major factors leading to high losses of honey bees (Apis mellifera) colonies worldwide. However, honey bees in some African countries show resilience to varroa infestation and/or virus infections, although little is known about the mechanisms underlying this resilience. In this study, we investigated the expression profiles of some key molecular markers involved in olfactory sensing and RNA interference, as these processes may contribute to the bees' resilience to varroa infestation and virus infection, respectively. We found significantly higher gene expression of the odorant binding protein, OBP14, in the antennae of Ethiopian bees compared to Belgian bees. This result suggests the potential of OBP14 as a molecular marker of resilience to mite infestation. Scanning electron microscopy showed no significant differences in the antennal sensilla occurrence and distribution, suggesting that resilience arises from molecular processes rather than morphological adaptations. In addition, seven RNAi genes were upregulated in the Ethiopian honey bees and three of them-Dicer-Drosha, Argonaute 2, and TRBP2-were positively correlated with the viral load. We can conclude that the antiviral immune response was triggered when bees were experiencing severe viral infection and that this might contribute to the bees' resilience to viruses.
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Affiliation(s)
- Haftom Gebremedhn
- Laboratory of Molecular Entomology and Bee Pathology, Ghent University, 9000 Ghent, Belgium
- Tigray Agricultural Research Institute, Mekelle P.O. Box 492, Ethiopia
| | - David Claeys Bouuaert
- Laboratory of Molecular Entomology and Bee Pathology, Ghent University, 9000 Ghent, Belgium
| | - Michel Asperges
- Centrum Voor Milieukunde, University of Hasselt, 3590 Diepenbeek, Belgium
| | | | - Lina De Smet
- Laboratory of Molecular Entomology and Bee Pathology, Ghent University, 9000 Ghent, Belgium
| | - Dirk C de Graaf
- Laboratory of Molecular Entomology and Bee Pathology, Ghent University, 9000 Ghent, Belgium
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7
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Virus Prevalence in Egg Samples Collected from Naturally Selected and Traditionally Managed Honey Bee Colonies across Europe. Viruses 2022; 14:v14112442. [PMID: 36366540 PMCID: PMC9692946 DOI: 10.3390/v14112442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 10/29/2022] [Accepted: 11/02/2022] [Indexed: 11/06/2022] Open
Abstract
Monitoring virus infections can be an important selection tool in honey bee breeding. A recent study pointed towards an association between the virus-free status of eggs and an increased virus resistance to deformed wing virus (DWV) at the colony level. In this study, eggs from both naturally surviving and traditionally managed colonies from across Europe were screened for the prevalence of different viruses. Screenings were performed using the phenotyping protocol of the 'suppressed in ovo virus infection' trait but with qPCR instead of end-point PCR and a primer set that covers all DWV genotypes. Of the 213 screened samples, 109 were infected with DWV, 54 were infected with black queen cell virus (BQCV), 3 were infected with the sacbrood virus, and 2 were infected with the acute bee paralyses virus. It was demonstrated that incidences of the vertical transmission of DWV were more frequent in naturally surviving than in traditionally managed colonies, although the virus loads in the eggs remained the same. When comparing virus infections with queen age, older queens showed significantly lower infection loads of DWV in both traditionally managed and naturally surviving colonies, as well as reduced DWV infection frequencies in traditionally managed colonies. We determined that the detection frequencies of DWV and BQCV in honey bee eggs were lower in samples obtained in the spring than in those collected in the summer, indicating that vertical transmission may be lower in spring. Together, these patterns in vertical transmission show that honey bee queens have the potential to reduce the degree of vertical transmission over time.
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8
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Penn HJ, Simone-Finstrom MD, de Guzman LI, Tokarz PG, Dickens R. Viral species differentially influence macronutrient preferences based on honey bee genotype. Biol Open 2022; 11:276570. [PMID: 36082847 PMCID: PMC9548382 DOI: 10.1242/bio.059039] [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: 10/28/2021] [Accepted: 09/05/2022] [Indexed: 11/30/2022] Open
Abstract
Food quantity and macronutrients contribute to honey bee health and colony survival by mediating immune responses. We determined if this held true for bees injected with chronic bee paralysis virus (CBPV) and deformed wing virus (DWV), two common honey bee ssRNA viruses. Pollen-substitute diet and syrup consumption rates and macronutrient preferences of two Varroa-resistant stocks (Pol-Line and Russian bees) were compared to Varroa-susceptible Italian bees. Bee stocks varied in consumption, where Italian bees consumed more than Pol-Line and Russian bees. However, the protein: lipid (P:L) ratios of diet consumed by the Italian and Russian bees was greater than that of the Pol-Line bees. Treatment had different effects on consumption based on the virus injected. CBPV was positively correlated with syrup consumption, while DWV was not correlated with consumption. P:L ratios of consumed diet were significantly impacted by the interaction of bee stock and treatment, with the trends differing between CBPV and DWV. Variation in macronutrient preferences based on viral species may indicate differences in energetic costs associated with immune responses to infections impacting different systems. Further, virus species interacted with bee genotype, indicating different mechanisms of viral resistance or tolerance among honey bee genotypes.
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Affiliation(s)
- Hannah J Penn
- USDA ARS Sugarcane Research Unit, 5883 Usda Rd., Houma, LA, USA 70360
| | - Michael D Simone-Finstrom
- USDA ARS Honey Bee Breeding, Genetics and Physiology Laboratory, 1157 Ben Hur Rd., Baton Rouge, LA, USA 70820
| | - Lilia I de Guzman
- USDA ARS Honey Bee Breeding, Genetics and Physiology Laboratory, 1157 Ben Hur Rd., Baton Rouge, LA, USA 70820
| | - Philip G Tokarz
- USDA ARS Honey Bee Breeding, Genetics and Physiology Laboratory, 1157 Ben Hur Rd., Baton Rouge, LA, USA 70820
| | - Rachel Dickens
- USDA ARS Honey Bee Breeding, Genetics and Physiology Laboratory, 1157 Ben Hur Rd., Baton Rouge, LA, USA 70820
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Penn HJ, Simone-Finstrom MD, Chen Y, Healy KB. Honey Bee Genetic Stock Determines Deformed Wing Virus Symptom Severity but not Viral Load or Dissemination Following Pupal Exposure. Front Genet 2022; 13:909392. [PMID: 35719388 PMCID: PMC9204523 DOI: 10.3389/fgene.2022.909392] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 04/22/2022] [Indexed: 12/15/2022] Open
Abstract
Honey bees exposed to Varroa mites incur substantial physical damage in addition to potential exposure to vectored viruses such as Deformed wing virus (DWV) that exists as three master variants (DWV-A, DWV-B, and DWV-C) and recombinants. Although mite-resistant bees have been primarily bred to mitigate the impacts of Varroa mites, mite resistance may be associated with increased tolerance or resistance to the vectored viruses. The goal of our study is to determine if five honey bee stocks (Carniolan, Italian, Pol-Line, Russian, and Saskatraz) differ in their resistance or tolerance to DWV based on prior breeding for mite resistance. We injected white-eyed pupae with a sublethal dose (105) of DWV or exposed them to mites and then evaluated DWV levels and dissemination and morphological symptoms upon adult emergence. While we found no evidence of DWV resistance across stocks (i.e., similar rates of viral replication and dissemination), we observed that some stocks exhibited reduced symptom severity suggestive of differential tolerance. However, DWV tolerance was not consistent across mite-resistant stocks as Russian bees were most tolerant, while Pol-Line exhibited the most severe symptoms. DWV variants A and B exhibited differential dissemination patterns that interacted significantly with the treatment group but not bee stock. Furthermore, elevated DWV-B levels reduced adult emergence time, while both DWV variants were associated with symptom likelihood and severity. These data indicate that the genetic differences underlying bee resistance to Varroa mites are not necessarily correlated with DWV tolerance and may interact differentially with DWV variants, highlighting the need for further work on mechanisms of tolerance and bee stock–specific physiological interactions with pathogen variants.
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Affiliation(s)
- Hannah J. Penn
- United States Department of Agriculture, Agricultural Research Service, Sugarcane Research Unit, Houma, LA, United States
- *Correspondence: Hannah J. Penn, ; Michael D. Simone-Finstrom,
| | - Michael D. Simone-Finstrom
- United States Department of Agriculture, Agricultural Research Service, Honey Bee Breeding, Genetics and Physiology Research Unit, Baton Rouge, LA, United States
- *Correspondence: Hannah J. Penn, ; Michael D. Simone-Finstrom,
| | - Yanping Chen
- United States Department of Agriculture, Agricultural Research Service, Bee Research Laboratory, Beltsville, MD, United States
| | - Kristen B. Healy
- Department of Entomology, Louisiana State University and AgCenter, Baton Rouge, LA, United States
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A derived honey bee stock confers resistance to Varroa destructor and associated viral transmission. Sci Rep 2022; 12:4852. [PMID: 35393440 PMCID: PMC8989980 DOI: 10.1038/s41598-022-08643-w] [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: 10/28/2021] [Accepted: 02/23/2022] [Indexed: 12/11/2022] Open
Abstract
The ectoparasite Varroa destructor is the greatest threat to managed honey bee (Apis mellifera) colonies globally. Despite significant efforts, novel treatments to control the mite and its vectored pathogens have shown limited efficacy, as the host remains naïve. A prospective solution lies in the development of Varroa-resistant honey bee stocks, but a paucity of rigorous selection data restricts widespread adoption. Here, we characterise the parasite and viral dynamics of a Varroa-resistant honey bee stock, designated ‘Pol-line’, using a large-scale longitudinal study. Results demonstrate markedly reduced Varroa levels in this stock, diminished titres of three major viruses (DWV-A, DWV-B, and CBPV), and a two-fold increase in survival. Levels of a fourth virus that is not associated with Varroa—BQCV—do not differ between stocks, supporting a disruption of the transmission pathway. Further, we show that when decoupled from the influence of Varroa levels, viral titres do not constitute strong independent predictors of colony mortality risk. These findings highlight the need for a reassessment of Varroa etiology, and suggest that derived stocks represent a tractable solution to the Varroa pandemic.
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11
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Thaduri S, Marupakula S, Terenius O, Onorati P, Tellgren-Roth C, Locke B, de Miranda JR. Global similarity, and some key differences, in the metagenomes of Swedish varroa-surviving and varroa-susceptible honeybees. Sci Rep 2021; 11:23214. [PMID: 34853367 PMCID: PMC8636477 DOI: 10.1038/s41598-021-02652-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 11/12/2021] [Indexed: 11/08/2022] Open
Abstract
There is increasing evidence that honeybees (Apis mellifera L.) can adapt naturally to survive Varroa destructor, the primary cause of colony mortality world-wide. Most of the adaptive traits of naturally varroa-surviving honeybees concern varroa reproduction. Here we investigate whether factors in the honeybee metagenome also contribute to this survival. The quantitative and qualitative composition of the bacterial and viral metagenome fluctuated greatly during the active season, but with little overall difference between varroa-surviving and varroa-susceptible colonies. The main exceptions were Bartonella apis and sacbrood virus, particularly during early spring and autumn. Bombella apis was also strongly associated with early and late season, though equally for all colonies. All three affect colony protein management and metabolism. Lake Sinai virus was more abundant in varroa-surviving colonies during the summer. Lake Sinai virus and deformed wing virus also showed a tendency towards seasonal genetic change, but without any distinction between varroa-surviving and varroa-susceptible colonies. Whether the changes in these taxa contribute to survival or reflect demographic differences between the colonies (or both) remains unclear.
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Affiliation(s)
- Srinivas Thaduri
- Department of Ecology, Swedish University of Agricultural Sciences, 750-07, Uppsala, Sweden
| | - Srisailam Marupakula
- Department of Forestry Mycology and Plant Pathology, Swedish University of Agricultural Sciences, 750-07, Uppsala, Sweden
| | - Olle Terenius
- Department of Cellular and Molecular Biology, BioMedical Centre, Uppsala University, Husargatan 3, 751-24, Uppsala, Sweden
| | - Piero Onorati
- Department of Ecology, Swedish University of Agricultural Sciences, 750-07, Uppsala, Sweden
| | | | - Barbara Locke
- Department of Ecology, Swedish University of Agricultural Sciences, 750-07, Uppsala, Sweden
| | - Joachim R de Miranda
- Department of Ecology, Swedish University of Agricultural Sciences, 750-07, Uppsala, Sweden.
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12
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Penn HJ, Simone-Finstrom M, Lang S, Chen J, Healy K. Host Genotype and Tissue Type Determine DWV Infection Intensity. FRONTIERS IN INSECT SCIENCE 2021; 1:756690. [PMID: 38468897 PMCID: PMC10926404 DOI: 10.3389/finsc.2021.756690] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 10/12/2021] [Indexed: 03/13/2024]
Abstract
Varroa mite-vectored viruses such as Deformed wing virus (DWV) are of great concern for honey bee health as they can cause disease in individuals and increase colony mortality. Two genotypes of DWV (A and B) are prevalent in the United States and may have differential virulence and pathogenicity. Honey bee genetic stocks bred to resist Varroa mites also exhibit differential infection responses to the Varroa mite-vectored viruses. The goal of this project was to determine if interactions between host genotype could influence the overall infection levels and dissemination of DWV within honey bees. To do this, we injected DWV isolated from symptomatic adult bees into mite-free, newly emerged adult bees from five genetic stocks with varying levels of resistance to Varroa mites. We measured DWV-A and DWV-B dissemination among tissues chosen based on relevance to general health outcomes for 10 days. Injury from sham injections did not increase DWV-A levels but did increase DWV-B infections. DWV injection increased both DWV-A and DWV-B levels over time with significant host stock interactions. While we did not observe any differences in viral dissemination among host stocks, we found differences in virus genotype dissemination to different body parts. DWV-A exhibited the highest initial levels in heads and legs while the highest initial levels of DWV-B were found in heads and abdomens. These interactions underscore the need to evaluate viral genotype and tissue specificity in conjunction with host genotype, particularly when the host has been selected for traits relative to virus-vector and virus resistance.
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Affiliation(s)
- Hannah J. Penn
- United States Department of Agriculture (USDA) Agricultural Research Service (ARS), Sugarcane Research Unit, Houma, LA, United States
| | - Michael Simone-Finstrom
- United States Department of Agriculture (USDA) Agricultural Research Service (ARS), Honey Bee Breeding, Genetics and Physiology Research Laboratory, Baton Rouge, LA, United States
| | - Sarah Lang
- United States Department of Agriculture (USDA) Agricultural Research Service (ARS), Honey Bee Breeding, Genetics and Physiology Research Laboratory, Baton Rouge, LA, United States
| | - Judy Chen
- United States Department of Agriculture (USDA) Agricultural Research Service (ARS), Bee Research Laboratory, Beltsville, MD, United States
| | - Kristen Healy
- Department of Entomology, Louisiana State University Agriculture Center, Baton Rouge, LA, United States
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Field evaluation of Varroa-resistance traits in surviving Apis mellifera colonies in Argentina. Parasitol Res 2021; 120:4013-4021. [PMID: 34635942 DOI: 10.1007/s00436-021-07337-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 09/29/2021] [Indexed: 10/20/2022]
Abstract
Varroa destructor is one of the most important sanitary threats for the beekeeping industry and so far disease control is based mainly on chemical treatment. However, a long-term solution may arise from studying natural surviving colonies of Apis mellifera. We compared the Varroa infestation rate in six commercial colonies that received annual treatment against mites and six non-treated colonies that survived in absence of any treatment for the last 6 years. In addition, we evaluated two potential mechanisms that might be involved in colony survival: hygienic (HYG) and Varroa-sensitive hygiene behavior (VSH) by means of pin-killed and mite artificial infestation, respectively. HYG and VSH were negatively correlated with mite infestation independently of the colony group (treated or non-treated). Furthermore, colonies expressing high levels of pupae removal (≥ 80%) showed higher %HYG and lower mite infestation compared to colonies showing low pupae removal (< 80%). The analysis of reproductive status of mites from the non-removed infested cells evidenced that more infertile mites are found in colonies with more than 80% of pupae removal. To study non-treated colonies that survive for several years, it is a suitable approach for identifying the underlying mechanisms related to Varroa-resistance.
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14
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Weaver DB, Cantarel BL, Elsik CG, Boncristiani DL, Evans JD. Multi-tiered analyses of honey bees that resist or succumb to parasitic mites and viruses. BMC Genomics 2021; 22:720. [PMID: 34610790 PMCID: PMC8493683 DOI: 10.1186/s12864-021-08032-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 09/16/2021] [Indexed: 12/13/2022] Open
Abstract
Background Varroa destructor mites, and the numerous viruses they vector to their honey bee hosts, are among the most serious threats to honey bee populations, causing mortality and morbidity to both the individual honey bee and colony, the negative effects of which convey to the pollination services provided by honey bees worldwide. Here we use a combination of targeted assays and deep RNA sequencing to determine host and microbial changes in resistant and susceptible honey bee lineages. We focus on three study sets. The first involves field sampling of sympatric western bees, some derived from resistant stock and some from stock susceptible to mites. The second experiment contrasts three colonies more deeply, two from susceptible stock from the southeastern U.S. and one from mite-resistant bee stock from Eastern Texas. Finally, to decouple the effects of mites from those of the viruses they vector, we experimentally expose honey bees to DWV in the laboratory, measuring viral growth and host responses. Results We find strong differences between resistant and susceptible bees in terms of both viral loads and bee gene expression. Interestingly, lineages of bees with naturally low levels of the mite-vectored Deformed wing virus, also carried lower levels of viruses not vectored by mites. By mapping gene expression results against current ontologies and other studies, we describe the impacts of mite parasitism, as well as viruses on bee health against two genetic backgrounds. We identify numerous genes and processes seen in other studies of stress and disease in honey bee colonies, alongside novel genes and new patterns of expression. Conclusions We provide evidence that honey bees surviving in the face of parasitic mites do so through their abilities to resist the presence of devastating viruses vectored by these mites. In all cases, the most divergence between stocks was seen when bees were exposed to live mites or viruses, suggesting that gene activation, rather than constitutive expression, is key for these interactions. By revealing responses to viral infection and mite parasitism in different lineages, our data identify candidate proteins for the evolution of mite tolerance and virus resistance. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-08032-z.
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Affiliation(s)
| | - Brandi L Cantarel
- Bioinformatics Core Facility, Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Christine G Elsik
- University of Missouri, Division of Animal Sciences, Division of Plant Sciences & Technology, and Institute for Data Science and Informatics, Columbia, MO, USA
| | | | - Jay D Evans
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA.
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15
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Brettell LE, Martin SJ, Riegler M, Cook JM. Vulnerability of island insect pollinator communities to pathogens. J Invertebr Pathol 2021; 186:107670. [PMID: 34560107 DOI: 10.1016/j.jip.2021.107670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/26/2021] [Accepted: 09/14/2021] [Indexed: 10/20/2022]
Abstract
Island ecosystems, which often contain undescribed insects and small populations of single island endemics, are at risk from diverse threats. The spread of pathogens is a major factor affecting not just pollinator species themselves, but also posing significant knock-on effects to often fragile island ecosystems through disruption of pollination networks. Insects are vulnerable to diverse pathogens and these can be introduced to islands in a number of ways, e.g. via the introduction of infected managed pollinator hosts (e.g. honey bees and their viruses, in particular Deformed wing virus), long-range migrants (e.g. monarch butterflies and their protozoan parasite, Ophryocystit elektroscirrha) and invasive species (e.g. social wasps are common invaders and are frequently infected with multi-host viruses such as Kashmir bee virus and Moku virus). Furthermore, these introductions can negatively affect island ecosystems through outcompeting native taxa for resources. As such, the greatest threat to island pollinator communities is not one particular pathogen, but the combination of pathogens and introduced and invasive insects that will likely carry them.
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Affiliation(s)
- Laura E Brettell
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia; Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place L3 5QA, UK.
| | - Stephen J Martin
- School of Environment and life Sciences, University of Salford, Manchester M5 4WT, UK
| | - Markus Riegler
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - James M Cook
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
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16
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Grindrod I, Martin SJ. Parallel evolution of Varroa resistance in honey bees: a common mechanism across continents? Proc Biol Sci 2021; 288:20211375. [PMID: 34344183 PMCID: PMC8334839 DOI: 10.1098/rspb.2021.1375] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 07/12/2021] [Indexed: 12/17/2022] Open
Abstract
The near-globally distributed ecto-parasitic mite of the Apis mellifera honeybee, Varroa destructor, has formed a lethal association with Deformed wing virus, a once rare and benign RNA virus. In concert, the two have killed millions of wild and managed colonies, particularly across the Northern Hemisphere, forcing the need for regular acaricide application to ensure colony survival. However, despite the short association (in evolutionary terms), a small but increasing number of A. mellifera populations across the globe have been surviving many years without any mite control methods. This long-term survival, or Varroa resistance, is consistently associated with the same suite of traits (recapping, brood removal and reduced mite reproduction) irrespective of location. Here we conduct an analysis of data extracted from 60 papers to illustrate how these traits connect together to explain decades of mite resistance data. We have potentially a unified understanding of natural Varroa resistance that will help the global industry achieve widespread miticide-free beekeeping and indicate how different honeybee populations across four continents have resolved a recent threat using the same suite of behaviours.
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Affiliation(s)
- Isobel Grindrod
- School of Environment and Life Sciences, University of Salford, Manchester M5 4WT, UK
| | - Stephen J. Martin
- School of Environment and Life Sciences, University of Salford, Manchester M5 4WT, UK
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Locke B, Thaduri S, Stephan JG, Low M, Blacquière T, Dahle B, Le Conte Y, Neumann P, de Miranda JR. Adapted tolerance to virus infections in four geographically distinct Varroa destructor-resistant honeybee populations. Sci Rep 2021; 11:12359. [PMID: 34117296 PMCID: PMC8196020 DOI: 10.1038/s41598-021-91686-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/28/2021] [Indexed: 11/22/2022] Open
Abstract
The ectoparasitic mite, Varroa destructor, is unarguably the leading cause of honeybee (Apis mellifera) mortality worldwide through its role as a vector for lethal viruses, in particular, strains of the Deformed wing virus (DWV) and Acute bee paralysis virus (ABPV) complexes. Several honeybee populations across Europe have well-documented adaptations of mite-resistant traits but little is known about host adaptations towards the virus infections vectored by the mite. The aim of this study was to assess and compare the possible contribution of adapted virus tolerance and/or resistance to the enhanced survival of four well-documented mite-resistant honeybee populations from Norway, Sweden, The Netherlands and France, in relation to unselected mite-susceptible honeybees. Caged adult bees and laboratory reared larvae, from colonies of these four populations, were inoculated with DWV and ABPV in a series of feeding infection experiments, while control groups received virus-free food. Virus infections were monitored using RT-qPCR assays in individuals sampled over a time course. In both adults and larvae the DWV and ABPV infection dynamics were nearly identical in all groups, but all mite-resistant honeybee populations had significantly higher survival rates compared to the mite-susceptible honeybees. These results suggest that adapted virus tolerance is an important component of survival mechanisms.
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Affiliation(s)
- Barbara Locke
- Department of Ecology, Swedish Species Information Centre, Swedish University of Agricultural Sciences, Uppsala, Sweden.
| | - Srinivas Thaduri
- Department of Ecology, Swedish Species Information Centre, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jörg G Stephan
- Department of Ecology, Swedish Species Information Centre, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Matthew Low
- Department of Ecology, Swedish Species Information Centre, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Tjeerd Blacquière
- Bio-Interaction and Plant Health, Wageningen University and Research, Wageningen, The Netherlands
| | - Bjørn Dahle
- Department of Animal and Aquacultural Sciences, Norwegian University of Sciences, Kløfta, Ås, Norway
| | - Yves Le Conte
- Abeilles et Environnement, French National Institute for Agricultural Research, Avignon, France
| | - Peter Neumann
- Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Agroscope, Swiss Bee Research Center, Bern, Switzerland
| | - Joachim R de Miranda
- Department of Ecology, Swedish Species Information Centre, Swedish University of Agricultural Sciences, Uppsala, Sweden
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18
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The Gut Microbiota Can Provide Viral Tolerance in the Honey Bee. Microorganisms 2021; 9:microorganisms9040871. [PMID: 33920692 PMCID: PMC8072606 DOI: 10.3390/microorganisms9040871] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/14/2021] [Accepted: 04/16/2021] [Indexed: 01/26/2023] Open
Abstract
Adult honey bees host a remarkably consistent gut microbial community that is thought to benefit host health and provide protection against parasites and pathogens. Currently, however, we lack experimental evidence for the causal role of the gut microbiota in protecting the Western honey bees (Apis mellifera) against their viral pathogens. Here we set out to fill this knowledge gap by investigating how the gut microbiota modulates the virulence of a major honey bee viral pathogen, deformed wing virus (DWV). We found that, upon oral virus exposure, honey bee survival was significantly increased in bees with an experimentally established normal gut microbiota compared to control bees with a perturbed (dysbiotic) gut microbiota. Interestingly, viral titers were similar in bees with normal gut microbiota and dysbiotic bees, pointing to higher viral tolerance in bees with normal gut microbiota. Taken together, our results provide evidence for a positive role of the gut microbiota for honey bee fitness upon viral infection. We hypothesize that environmental stressors altering honey bee gut microbiota composition, e.g., antibiotics in beekeeping or pesticides in modern agriculture, could interact synergistically with pathogens, leading to negative effects on honey bee health and the epidemiology and impact of their viruses.
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19
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Hinshaw C, Evans KC, Rosa C, López-Uribe MM. The Role of Pathogen Dynamics and Immune Gene Expression in the Survival of Feral Honey Bees. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2020.594263] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Studies of the ecoimmunology of feral organisms can provide valuable insight into how host–pathogen dynamics change as organisms transition from human-managed conditions back into the wild. Honey bees (Apis mellifera Linnaeus) offer an ideal system to investigate these questions as colonies of these social insects often escape management and establish in the wild. While managed honey bee colonies have low probability of survival in the absence of disease treatments, feral colonies commonly survive in the wild, where pathogen pressures are expected to be higher due to the absence of disease treatments. Here, we investigate the role of pathogen infections [Deformed wing virus (DWV), Black queen cell virus (BQCV), and Nosema ceranae] and immune gene expression (defensin-1, hymenoptaecin, pgrp-lc, pgrp-s2, argonaute-2, vago) in the survival of feral and managed honey bee colonies. We surveyed a total of 25 pairs of feral and managed colonies over a 2-year period (2017–2018), recorded overwintering survival, and measured pathogen levels and immune gene expression using quantitative polymerase chain reaction (qPCR). Our results showed that feral colonies had higher levels of DWV but it was variable over time compared to managed colonies. Higher pathogen levels were associated with increased immune gene expression, with feral colonies showing higher expression in five out of the six examined immune genes for at least one sampling period. Further analysis revealed that differential expression of the genes hymenoptaecin and vago increased the odds of overwintering survival in managed and feral colonies. Our results revealed that feral colonies express immune genes at higher levels in response to high pathogen burdens, providing evidence for the role of feralization in altering pathogen landscapes and host immune responses.
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20
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Bhatia S, Baral SS, Vega Melendez C, Amiri E, Rueppell O. Comparing Survival of Israeli Acute Paralysis Virus Infection among Stocks of U.S. Honey Bees. INSECTS 2021; 12:insects12010060. [PMID: 33445412 PMCID: PMC7827508 DOI: 10.3390/insects12010060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 12/21/2022]
Abstract
Simple Summary Honey bees and other pollinators are threatened by numerous stressors, including virus infections. Currently, no effective treatments are available, stressing the importance of natural defenses. These defenses may be enhanced through selective breeding. This study sought to evaluate the potential for breeding, while also testing a few potential mechanisms of natural immune responses and assessing how widespread viruses are in commercial honey bee queens in the U.S. We identified significant differences in survival of virus infection among and within U.S honey bee stocks, indicating that selective breeding may be able to decrease the virus susceptibility of honey bees. Survival differences may be related to differences in the natural immune system of honey bees and could relate to how much virus stress bees have experienced in the past. Abstract Among numerous viruses that infect honey bees (Apis mellifera), Israeli acute paralysis virus (IAPV) can be linked to severe honey bee health problems. Breeding for virus resistance may improve honey bee health. To evaluate the potential for this approach, we compared the survival of IAPV infection among stocks from the U.S. We complemented the survival analysis with a survey of existing viruses in these stocks and assessing constitutive and induced expression of immune genes. Worker offspring from selected queens in a common apiary were inoculated with IAPV by topical applications after emergence to assess subsequent survival. Differences among stocks were small compared to variation within stocks, indicating the potential for improving honey bee survival of virus infections in all stocks. A positive relation between worker survival and virus load among stocks further suggested that honey bees may be able to adapt to better cope with viruses, while our molecular studies indicate that toll-6 may be related to survival differences among virus-infected worker bees. Together, these findings highlight the importance of viruses in queen breeding operations and provide a promising starting point for the quest to improve honey bee health by selectively breeding stock to be better able to survive virus infections.
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Affiliation(s)
- Shilpi Bhatia
- Department of Biology, University of North Carolina Greensboro, 321 McIver Street, Greensboro, NC 27403, USA; (S.B.); (S.S.B.); (C.V.M.); (E.A.)
- Department of Applied Science & Technology, North Carolina Agricultural & Technical University, 1601 E Market Street, Greensboro, NC 27411, USA
| | - Saman S. Baral
- Department of Biology, University of North Carolina Greensboro, 321 McIver Street, Greensboro, NC 27403, USA; (S.B.); (S.S.B.); (C.V.M.); (E.A.)
| | - Carlos Vega Melendez
- Department of Biology, University of North Carolina Greensboro, 321 McIver Street, Greensboro, NC 27403, USA; (S.B.); (S.S.B.); (C.V.M.); (E.A.)
- US Dairy Forage Research Center, USDA-ARS, 1925 Linden Drive, Madison, WI 53706, USA
| | - Esmaeil Amiri
- Department of Biology, University of North Carolina Greensboro, 321 McIver Street, Greensboro, NC 27403, USA; (S.B.); (S.S.B.); (C.V.M.); (E.A.)
| | - Olav Rueppell
- Department of Biology, University of North Carolina Greensboro, 321 McIver Street, Greensboro, NC 27403, USA; (S.B.); (S.S.B.); (C.V.M.); (E.A.)
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
- Correspondence: ; Tel.: +1-336-2022349
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21
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Bartlett LJ, Boots M, Brosi BJ, de Roode JC, Delaplane KS, Hernandez CA, Wilfert L. Persistent effects of management history on honeybee colony virus abundances. J Invertebr Pathol 2020; 179:107520. [PMID: 33359478 DOI: 10.1016/j.jip.2020.107520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 12/09/2020] [Accepted: 12/12/2020] [Indexed: 10/22/2022]
Abstract
Infectious diseases are a major threat to both managed and wild pollinators. One key question is how the movement or transplantation of honeybee colonies under different management regimes affects honeybee disease epidemiology. We opportunistically examined any persistent effect of colony management history following relocation by characterising the virus abundances of honeybee colonies from three management histories, representing different management histories: feral, low-intensity management, and high-intensity "industrial" management. The colonies had been maintained for one year under the same approximate 'common garden' condition. Colonies in this observational study differed in their virus abundances according to management history, with the feral population history showing qualitatively different viral abundance patterns compared to colonies from the two managed population management histories; for example, higher abundance of sacbrood virus but lower abundances of various paralysis viruses. Colonies from the high-intensity management history exhibited higher viral abundances for all viruses than colonies from the low-intensity management history. Our results provide evidence that management history has persistent impacts on honeybee disease epidemiology, suggesting that apicultural intensification could be majorly impacting on pollinator health, justifying much more substantial investigation.
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Affiliation(s)
- Lewis J Bartlett
- Centre for Ecology and Conservation, University of Exeter, TR10 9FE, UK; Department of Biology, Emory University, Atlanta, GA 30322, USA; Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA 30602, USA.
| | - Michael Boots
- Centre for Ecology and Conservation, University of Exeter, TR10 9FE, UK; Department of Integrative Biology, University of California, Berkeley, CA, 94720, USA
| | - Berry J Brosi
- Department of Environmental Sciences, Emory University, Atlanta, GA 30322, USA
| | | | - Keith S Delaplane
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Catherine A Hernandez
- Department of Integrative Biology, University of California, Berkeley, CA, 94720, USA
| | - Lena Wilfert
- Centre for Ecology and Conservation, University of Exeter, TR10 9FE, UK; Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm D-89069, Germany
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Guichard M, Dietemann V, Neuditschko M, Dainat B. Advances and perspectives in selecting resistance traits against the parasitic mite Varroa destructor in honey bees. Genet Sel Evol 2020; 52:71. [PMID: 33246402 PMCID: PMC7694340 DOI: 10.1186/s12711-020-00591-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 11/13/2020] [Indexed: 01/01/2023] Open
Abstract
Background In spite of the implementation of control strategies in honey bee (Apis mellifera) keeping, the invasive parasitic mite Varroa destructor remains one of the main causes of colony losses in numerous countries. Therefore, this parasite represents a serious threat to beekeeping and agro-ecosystems that benefit from the pollination services provided by honey bees. To maintain their stocks, beekeepers have to treat their colonies with acaricides every year. Selecting lineages that are resistant to infestations is deemed to be a more sustainable approach. Review Over the last three decades, numerous selection programs have been initiated to improve the host–parasite relationship and to support honey bee survival in the presence of the parasite without the need for acaricide treatments. Although resistance traits have been included in the selection strategy of honey bees, it has not been possible to globally solve the V. destructor problem. In this study, we review the literature on the reasons that have potentially limited the success of such selection programs. We compile the available information to assess the relevance of selected traits and the potential environmental effects that distort trait expression and colony survival. Limitations to the implementation of these traits in the field are also discussed. Conclusions Improving our knowledge of the mechanisms underlying resistance to V. destructor to increase trait relevance, optimizing selection programs to reduce environmental effects, and communicating selection outcomes are all crucial to efforts aiming at establishing a balanced relationship between the invasive parasite and its new host.
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Affiliation(s)
- Matthieu Guichard
- Agroscope, Swiss Bee Research Centre, Schwarzenburgstrasse 161, 3003, Bern, Switzerland.
| | - Vincent Dietemann
- Agroscope, Swiss Bee Research Centre, Schwarzenburgstrasse 161, 3003, Bern, Switzerland.,Department of Ecology and Evolution, Biophore, UNIL-Sorge, University of Lausanne, 1015, Lausanne, Switzerland
| | - Markus Neuditschko
- Agroscope, Swiss Bee Research Centre, Schwarzenburgstrasse 161, 3003, Bern, Switzerland
| | - Benjamin Dainat
- Agroscope, Swiss Bee Research Centre, Schwarzenburgstrasse 161, 3003, Bern, Switzerland
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Metagenomic Approach with the NetoVIR Enrichment Protocol Reveals Virus Diversity within Ethiopian Honey Bees ( Apis mellifera simensis). Viruses 2020; 12:v12111218. [PMID: 33121140 PMCID: PMC7692050 DOI: 10.3390/v12111218] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/21/2020] [Accepted: 10/23/2020] [Indexed: 12/12/2022] Open
Abstract
Metagenomics studies have accelerated the discovery of novel or divergent viruses of the honey bee. However, most of these studies predominantly focused on RNA viruses, and many suffer from the relatively low abundance of viral nucleic acids in the samples (i.e., compared to that of the host). Here, we explored the virome of the Ethiopian honey bee, Apis mellifera simensis, using an unbiased metagenomic approach in which the next-generation sequencing step was preceded by an enrichment protocol for viral particles. Our study revealed five well-known bee viruses and 25 atypical virus species, most of which have never been found in A. mellifera before. The viruses belong to Iflaviridae, Dicistroviridae, Secoviridae, Partitiviridae, Parvoviridae, Potyviridae, and taxonomically unclassified families. Fifteen of these atypical viruses were most likely plant-specific, and the remaining ten were presumed to be insect-specific. Apis mellifera filamentous virus (AmFV) was found in one sampling site out of 10. Two samples contained high read counts of a virus similar to Diatraea saccharales densovirus (DsDNV), which is a virus that causes high mortality in the sugarcane borer. AmFV and the DsDNV-like virus were the only DNA viruses found. Three viruses that primarily infect Drosophila spp. were also discovered: La Jolla virus (LJV), Kilifi virus (KiV), and Thika virus. Our study suggests that phoretic varroa mites are involved in the transmission of LJV and KiV and that both viruses replicate in mites and adult bees. We also found an overwhelming dominance of the deformed wing virus type B variant, which fits well with the apparently harmless infestation by Varroa destructor. It was suggested that Ethiopian bees have developed tolerance against virus infections as the result of natural selection.
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Varroa destructor: how does it harm Apis mellifera honey bees and what can be done about it? Emerg Top Life Sci 2020; 4:45-57. [PMID: 32537655 PMCID: PMC7326341 DOI: 10.1042/etls20190125] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 05/27/2020] [Accepted: 05/27/2020] [Indexed: 12/23/2022]
Abstract
Since its migration from the Asian honey bee (Apis cerana) to the European honey bee (Apis mellifera), the ectoparasitic mite Varroa destructor has emerged as a major issue for beekeeping worldwide. Due to a short history of coevolution, the host–parasite relationship between A. mellifera and V. destructor is unbalanced, with honey bees suffering infestation effects at the individual, colony and population levels. Several control solutions have been developed to tackle the colony and production losses due to Varroa, but the burden caused by the mite in combination with other biotic and abiotic factors continues to increase, weakening the beekeeping industry. In this synthetic review, we highlight the main advances made between 2015 and 2020 on V. destructor biology and its impact on the health of the honey bee, A. mellifera. We also describe the main control solutions that are currently available to fight the mite and place a special focus on new methodological developments, which point to integrated pest management strategies for the control of Varroa in honey bee colonies.
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Erez T, Chejanovsky N. Infection of a Lepidopteran Cell Line with Deformed Wing Virus. Viruses 2020; 12:E739. [PMID: 32659903 PMCID: PMC7412015 DOI: 10.3390/v12070739] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/02/2020] [Accepted: 07/07/2020] [Indexed: 12/19/2022] Open
Abstract
Many attempts to develop a reliable cell cultured-based system to study honey bee virus infections have encountered substantial difficulties. We investigated the ability of a cell line from a heterologous insect to sustain infection by a honey bee virus. For this purpose, we infected the Lepidopteran hemocytic cell line (P1) with Deformed wing virus (DWV). The genomic copies of DWV increased upon infection, as monitored by quantitative RT-PCR. Moreover, a tagged-primer-based RT-PCR analysis showed the presence of DWV negative-sense RNA in the cells, indicating virus replication. However, the DWV from infected cells was mildly infectious to P1 cells. Similar results were obtained when the virus was injected into Apis mellifera pupae. Thus, though the virus yields from the infected cells appeared to be very low, we show for the first time that DWV can replicate in a heterologous cell line. Given the availability of many other insect cell lines, our study paves the way for future exploration in this direction. In the absence of adequate A. mellifera cell lines, exploring the ability of alternative cell lines to enable honey bee virus infections could provide the means to study and understand the viral infectious cycle at the cellular level and facilitate obtaining purified isolates of these viruses.
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Affiliation(s)
| | - Nor Chejanovsky
- Department of Entomology Institute of Plant Protection, Agricultural Research Organization, Rishon Lezion 7528809, Israel;
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26
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Eliash N, Mikheyev A. Varroa mite evolution: a neglected aspect of worldwide bee collapses? CURRENT OPINION IN INSECT SCIENCE 2020; 39:21-26. [PMID: 32088383 DOI: 10.1016/j.cois.2019.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 11/14/2019] [Accepted: 11/18/2019] [Indexed: 06/10/2023]
Abstract
While ectoparasitic Varroa mites cause minimal damage to their co-evolved ancestral host, the eastern honey bee (Apis cerana), they devastate their novel host, the western honey bee (Apis mellifera). Over several decades, the host switch caused worldwide population collapses, threatening global food security. Varroa management strategies have focused on breeding bees for tolerance. But, can Varroa overcome these counter-adaptations in a classic coevolutionary arms race? Despite increasing evidence for Varroa genetic diversity and evolvability, this eventuality has largely been neglected. We therefore suggest a more holistic paradigm for studying this host-parasite interaction, one in which 'Varroa-tolerant' bee traits should be viewed as a shared phenotype resulting from Varroa and honey bee interaction.
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Affiliation(s)
- Nurit Eliash
- Institute of Plant Protection, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel; Ecology and Evolution Unit, Okinawa Institute of Science and Technology, Onna-son, Okinawa, Japan
| | - Alexander Mikheyev
- Ecology and Evolution Unit, Okinawa Institute of Science and Technology, Onna-son, Okinawa, Japan; Research School of Biology, Australian National University, Canberra, ACT, Australia.
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27
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Yañez O, Piot N, Dalmon A, de Miranda JR, Chantawannakul P, Panziera D, Amiri E, Smagghe G, Schroeder D, Chejanovsky N. Bee Viruses: Routes of Infection in Hymenoptera. Front Microbiol 2020; 11:943. [PMID: 32547504 PMCID: PMC7270585 DOI: 10.3389/fmicb.2020.00943] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 04/20/2020] [Indexed: 11/13/2022] Open
Abstract
Numerous studies have recently reported on the discovery of bee viruses in different arthropod species and their possible transmission routes, vastly increasing our understanding of these viruses and their distribution. Here, we review the current literature on the recent advances in understanding the transmission of viruses, both on the presence of bee viruses in Apis and non-Apis bee species and on the discovery of previously unknown bee viruses. The natural transmission of bee viruses will be discussed among different bee species and other insects. Finally, the research potential of in vivo (host organisms) and in vitro (cell lines) serial passages of bee viruses is discussed, from the perspective of the host-virus landscape changes and potential transmission routes for emerging bee virus infections.
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Affiliation(s)
- Orlando Yañez
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Agroscope, Swiss Bee Research Centre, Bern, Switzerland
| | - Niels Piot
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Anne Dalmon
- INRAE, Unité de Recherche Abeilles et Environnement, Avignon, France
| | | | - Panuwan Chantawannakul
- Environmental Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
| | - Delphine Panziera
- General Zoology, Institute for Biology, Martin-Luther-University of Halle-Wittenberg, Halle (Saale), Germany
- Halle-Jena-Leipzig, German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany
| | - Esmaeil Amiri
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, United States
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, United States
| | - Guy Smagghe
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Declan Schroeder
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, United States
- School of Biological Sciences, University of Reading, Reading, United Kingdom
| | - Nor Chejanovsky
- Entomology Department, Institute of Plant Protection, The Volcani Center, Rishon LeZion, Israel
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28
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Roberts JMK, Simbiken N, Dale C, Armstrong J, Anderson DL. Tolerance of Honey Bees to Varroa Mite in the Absence of Deformed Wing Virus. Viruses 2020; 12:E575. [PMID: 32456246 PMCID: PMC7290856 DOI: 10.3390/v12050575] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 12/31/2022] Open
Abstract
The global spread of the parasitic mite Varroa destructor has emphasized the significance of viruses as pathogens of honey bee (Apis mellifera) populations. In particular, the association of deformed wing virus (DWV) with V. destructor and its devastating effect on honey bee colonies has led to that virus now becoming one of the most well-studied insect viruses. However, there has been no opportunity to examine the effects of Varroa mites without the influence of DWV. In Papua New Guinea (PNG), the sister species, V. jacobsoni, has emerged through a host-shift to reproduce on the local A. mellifera population. After initial colony losses, beekeepers have maintained colonies without chemicals for more than a decade, suggesting that this bee population has an unknown mite tolerance mechanism. Using high throughput sequencing (HTS) and target PCR detection, we investigated whether the viral landscape of the PNG honey bee population is the underlying factor responsible for mite tolerance. We found A. mellifera and A. cerana from PNG and nearby Solomon Islands were predominantly infected by sacbrood virus (SBV), black queen cell virus (BQCV) and Lake Sinai viruses (LSV), with no evidence for any DWV strains. V. jacobsoni was infected by several viral homologs to recently discovered V. destructor viruses, but Varroa jacobsoni rhabdovirus-1 (ARV-1 homolog) was the only virus detected in both mites and honey bees. We conclude from these findings that A. mellifera in PNG may tolerate V. jacobsoni because the damage from parasitism is significantly reduced without DWV. This study also provides further evidence that DWV does not exist as a covert infection in all honey bee populations, and remaining free of this serious viral pathogen can have important implications for bee health outcomes in the face of Varroa.
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Affiliation(s)
- John M. K. Roberts
- Commonwealth Scientific and Industrial Research Organisation, Canberra 2601, Australia;
| | - Nelson Simbiken
- Coffee Industry Corporation Ltd., Goroka 441, Papua New Guinea;
| | - Chris Dale
- Department of Agriculture, Water and the Environment, Canberra 2601, Australia;
| | - Joel Armstrong
- Commonwealth Scientific and Industrial Research Organisation, Canberra 2601, Australia;
| | - Denis L. Anderson
- Research and Development Division, Abu Dhabi Agriculture & Food Safety Authority, Al Ain, UAE;
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29
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van Alphen JJM, Fernhout BJ. Natural selection, selective breeding, and the evolution of resistance of honeybees ( Apis mellifera) against Varroa. ZOOLOGICAL LETTERS 2020; 6:6. [PMID: 32467772 PMCID: PMC7236208 DOI: 10.1186/s40851-020-00158-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 04/03/2020] [Indexed: 05/21/2023]
Abstract
We examine evidence for natural selection resulting in Apis mellifera becoming tolerant or resistant to Varroa mites in different bee populations. We discuss traits implicated in Varroa resistance and how they can be measured. We show that some of the measurements used are ambiguous, as they measure a combination of traits. In addition to behavioural traits, such as removal of infested pupae, grooming to remove mites from bees or larval odours, small colony size, frequent swarming, and smaller brood cell size may also help to reduce reproductive rates of Varroa. Finally, bees may be tolerant of high Varroa infections when they are resistant or tolerant to viruses implicated in colony collapse. We provide evidence that honeybees are an extremely outbreeding species. Mating structure is important for how natural selection operates. Evidence for successful natural selection of resistance traits against Varroa comes from South Africa and from Africanized honeybees in South America. Initially, Varroa was present in high densities and killed about 30% of the colonies, but soon after its spread, numbers per hive decreased and colonies survived without treatment. This shows that natural selection can result in resistance in large panmictic populations when a large proportion of the population survives the initial Varroa invasion. Natural selection in Europe and North America has not resulted in large-scale resistance. Upon arrival of Varroa, the frequency of traits to counter mites and associated viruses in European honey bees was low. This forced beekeepers to protect bees by chemical treatment, hampering natural selection. In a Swedish experiment on natural selection in an isolated mating population, only 7% of the colonies survived, resulting in strong inbreeding. Other experiments with untreated, surviving colonies failed because outbreeding counteracted the effects of selection. If loss of genetic variation is prevented, colony level selection in closed mating populations can proceed more easily, as natural selection is not counteracted by the dispersal of resistance genes. In large panmictic populations, selective breeding can be used to increase the level of resistance to a threshold level at which natural selection can be expected to take over.
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Affiliation(s)
- Jacques J. M. van Alphen
- Naturalis Biodiversity Centre, 2333 CR Leiden, The Netherlands
- Arista Bee Research Foundation, Nachtegaal 2, 5831 WL Boxmeer, The Netherlands
| | - Bart Jan Fernhout
- Arista Bee Research Foundation, Nachtegaal 2, 5831 WL Boxmeer, The Netherlands
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30
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López-Uribe MM, Ricigliano VA, Simone-Finstrom M. Defining Pollinator Health: A Holistic Approach Based on Ecological, Genetic, and Physiological Factors. Annu Rev Anim Biosci 2019; 8:269-294. [PMID: 31618045 DOI: 10.1146/annurev-animal-020518-115045] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Evidence for global bee population declines has catalyzed a rapidly evolving area of research that aims to identify the causal factors and to effectively assess the status of pollinator populations. The term pollinator health emerged through efforts to understand causes of bee decline and colony losses, but it lacks a formal definition. In this review, we propose a definition for pollinator health and synthesize the available literature on the application of standardized biomarkers to assess health at the individual, colony, and population levels. We focus on biomarkers in honey bees, a model species, but extrapolate the potential application of these approaches to monitor the health status of wild bee populations. Biomarker-guided health measures can inform beekeeper management decisions, wild bee conservation efforts, and environmental policies. We conclude by addressing challenges to pollinator health from a One Health perspective that emphasizes the interplay between environmental quality and human, animal, and bee health.
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Affiliation(s)
- Margarita M López-Uribe
- Department of Entomology, Center for Pollinator Research, Pennsylvania State University, University Park, Pennsylvania 16802, USA;
| | - Vincent A Ricigliano
- Honey Bee Breeding, Genetics and Physiology Research, USDA-ARS, Baton Rouge, Louisiana 70820, USA; ,
| | - Michael Simone-Finstrom
- Honey Bee Breeding, Genetics and Physiology Research, USDA-ARS, Baton Rouge, Louisiana 70820, USA; ,
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