The genetic diversity of Varroa destructor (Anderson &Trueman)is limited outside its natural range due to population bottlenecks and its propensity to inbreed.In light of the arms race between V.destructor and its...The genetic diversity of Varroa destructor (Anderson &Trueman)is limited outside its natural range due to population bottlenecks and its propensity to inbreed.In light of the arms race between V.destructor and its honeybee (Apis mellifera L.)host, any mechanism enhancing population admixture of the mite may be favored.One way that admixture can occur is when two genetically dissimilar mites coinvade a brood cell, with the progeny of the foundresses admixing.We determined the relatedness of 393 pairs of V.destructor foundresses,each pair collected from a single bee brood cell (n =five colonies).We used six microsatellites to identify the genotypes of mites coinvading a cell and calculated the frequency of pairs with different or the same genotypes.We found no deviation from random coinvasion,but the frequency of cells infested by mites with different genotypes was high.This rate of recombination,coupled with a high transmission rate of mites,homogenized the allelic pool of mites within the apiary.展开更多
Apis mellifera syriaca exhibits a high degree of tolerance to pests and pathogens including varroa mites. This native honey bee subspecies of Jordan expresses behavioral adaptations to high temperature and dry seasons...Apis mellifera syriaca exhibits a high degree of tolerance to pests and pathogens including varroa mites. This native honey bee subspecies of Jordan expresses behavioral adaptations to high temperature and dry seasons typical of the region. However, persistent honey bee imports of commercial breeder lines are endangering local honey bee population. This study reports the use of next-generation sequencing （NGS） technology to study the A. m. syriaca genome and to identify genetic factors possibly contributing toward mite resistance and other favorable traits. We obtained a total of 46.2 million raw reads by applying the NGS to sequence A. m. syriaca and used extensive bioinformatics approach to identify several candidate genes for Varroa mite resistance, behavioral and immune responses char- acteristic for these bees. As a part of characterizing the functional regulation of molecular genetic pathway, we have mapped the pathway genes potentially involved using information from Drosophila melanogaster and present possible functional changes implicated in responses to Varroa destructor mite infestation toward this. We performed in-depth functional annotation methods to identify -600 candidates that are relevant, genes involved in pathways such as microbial recognition and phagocytosis, peptidoglycan recognition protein family, Gram negative binding protein family, phagocytosis receptors, serpins, Toll signaling pathway, Imd pathway, Tnf, JAK-STAT and MAPK pathway, heamatopioesis and cellular response pathways, antiviral, RNAi pathway, stress factors, etc. were selected. Finally, we have cataloged function-specific polymorphisms between A. mellifera and A. m. syriaca that could give better understanding of varroa mite resistance mechanisms and assist in breeding. We have identified immune related embryonic development （Cactus, Relish, dorsal, Ank2, baz）, Varroa hygiene （NorpA2, Zasp, LanA, gasp, impl3） and Varroa resistance （Pug, pcmt, elk, elf3-s10, Dscam2, Dhc64C, gro, futsch） functional variations genes between A. mellifera and A. m. syriaca that could be used to develop an effective molecular tool for bee conservation and breeding programs to improve locally adapted strains such as syriaca and utilize their advantageous traits for the benefit of apiculture industry.展开更多
Background:Climate change creates opportune conditions that favour the spread of pests and diseases outside their known active range.Modelling climate change scenarios is oftentimes useful tool to assess the climate a...Background:Climate change creates opportune conditions that favour the spread of pests and diseases outside their known active range.Modelling climate change scenarios is oftentimes useful tool to assess the climate analogues to unveil the potential risk of spreading suitability conditions for pests and diseases and hence allows development of appropriate responses to address the impending challenge.In the current study,we modelled the impact of climate change on the distribution of Varroa destructor,a parasitic mite that attacks all life forms of honey bees and remains a significant threat to their survival and productivity of bee products in Tanzania and elsewhere.Methods:The data about the presence of V.destructor were collected in eight regions of Tanzania selected in consideration of several factors including potentials for beekeeping activities,elevation(highlands vs.lowlands)and differences in climatic conditions.A total of 19 bioclimatic datasets covering the entire country were used for developing climate scenarios of mid-century 2055 and late-century 2085 for both rcp4.5 and rcp8.5.We thereafter modelled the current and future risk distribution of V.destructor using MaxEnt.Results:The results indicated a model performance of AUC=0.85,with mean diurnal range in temperature(Bio2,43.9%),mean temperature(Bio1,20.6%)and mean annual rainfall(Bio12,11.7%)as the important variables.Future risk projections indicated mixed responses of the potential risk of spreads of V.destructor,exhibiting both decrease and increases in the mid-century 2055 and late-century 2085 on different sites.Overall,there is a general decline of highly suitable areas of V.destructor in mid-and late-century across all scenarios(rcp4.5 and rcp8.5).The moderately suitable areas indicated a mixed response in mid-century with decline(under rcp4.5)and increase(under rcp8.5)and consistent increase in late century.The marginally suitable areas show a decline in mid-century and increase in late-century.Our results suggest that the climate change will continue to significantly affect the distribution and risks spread of V.destructor in Tanzania.The suitability range of V.destructor will shift where highly suitable areas will be diminishing to the advantage of the honey bees’populations,but increase of moderately suitable sites indicates an expansion to new areas.The late century projections show the increased risks due to surge in the moderate and marginal suitability which means expansion in the areas where V.destructor will operate Conclusion:The current and predicted areas of habitat suitability for V.destructor’s host provides information useful for beekeeping stakeholders in Tanzania to consider the impending risks and allow adequate interventions to address challenges facing honey bees and the beekeeping industry.We recommend further studies on understanding the severity of V.destructor in health and stability of the honey bees in Tanzania.This will provide a better picture on how the country will need to monitor and reduce the risks associated with the increase of V.destructor activities as triggered by climate change.The loss of honey bees’colonies and its subsequent impact in bees’products production and pollination effect have both ecological and economic implications that need to have prioritization by the stakeholders in the country to address the challenge of spreading V.destructor.展开更多
The Varroa mite,(Varroa destructor),is the worst threat to honey bee health worldwide.To explore the possibility of using RNA interference to control this pest, we determined the effects of knocking down various genes...The Varroa mite,(Varroa destructor),is the worst threat to honey bee health worldwide.To explore the possibility of using RNA interference to control this pest, we determined the effects of knocking down various genes on Varroa mite survival and reproduction.Double-stranded RNA (dsRNA)of six candidate genes (Da,Pros26S,RpL8, RpL11,RpPO and RpS13)were synthesized and each injected into Varroa mites,then mite survival and reproduction were assessed.Injection of dsRNA for Da (Daughterless)and Pros26S (Gene for proteasome 26S subunit adenosine triphosphatase)caused a significant reduction in mite survival,with 3.57%±1.94% and 30.03%±11.43% mites surviving at 72 h post-inj ection (hpi),respectively.Control mites injected with green fluorescent protein (GFP)-dsRNA showed survival rates of 81.95%±5.03% and 82.36 ±2.81%,respectively. Injections of dsRNA for four other genes (RpL8,RpL11,RpPO and RpS13)did not affect survival significantly,enabling us to assess their effect on Varroa mite reproduction.The number of female offspring per mite was significantly reduced for mites injected with dsRNA of each of these four genes compared to their GFP-dsRNA controls.Knockdown of the target genes was verified by real-time polymerase chain reaction for two genes important for reproduction (RpL8,RpL11)and one gene important for survival (Pros26S). In conclusion,through RNA interference,we have discovered two genes important for mite survival and four genes important for mite reproduction.These genes could be explored as possible targets for the control of Varroa destructor in the future.展开更多
The objective of the study was to establish the effect of formic acid on varroa(Varroa destructor),inside the capped brood cells,artificially decapped.The experiments were carried out in 2017-2018 on honeybee colonies...The objective of the study was to establish the effect of formic acid on varroa(Varroa destructor),inside the capped brood cells,artificially decapped.The experiments were carried out in 2017-2018 on honeybee colonies infested with varroa(V.destructor),in a research apiary belonging to the Institute for Beekeeping Research and Development in Bucharest.The decapping method in the present researches used the decapping fork to scrape the capped comb,without affecting the brood,in order to open it for an effective treatment.The combined treatment method was applied on honeybee colonies as a whole,as well as on brood combs,without bees,put in a special treatment box.The researches were focused on establishing the mortality level of various stages of varroa in artificially decapped brood,in normal colony and separately,as well as to make observations on the effect of formic acid on viability of capped bee brood,artificially decapped.The results show a high mortality of varroa,especially the protonymphs and deutonymphs stages(over 80%).The main conclusion is that the brood decapping method combined with formic acid treatment could be a useful technique to control varroa infestation,both in brood and honeybees,shortening strongly the treatment duration as compared to the usual treatments,increasing the efficacy of treatment by cutting the life cycle of varroa in brood.展开更多
文摘The genetic diversity of Varroa destructor (Anderson &Trueman)is limited outside its natural range due to population bottlenecks and its propensity to inbreed.In light of the arms race between V.destructor and its honeybee (Apis mellifera L.)host, any mechanism enhancing population admixture of the mite may be favored.One way that admixture can occur is when two genetically dissimilar mites coinvade a brood cell, with the progeny of the foundresses admixing.We determined the relatedness of 393 pairs of V.destructor foundresses,each pair collected from a single bee brood cell (n =five colonies).We used six microsatellites to identify the genotypes of mites coinvading a cell and calculated the frequency of pairs with different or the same genotypes.We found no deviation from random coinvasion,but the frequency of cells infested by mites with different genotypes was high.This rate of recombination,coupled with a high transmission rate of mites,homogenized the allelic pool of mites within the apiary.
文摘Apis mellifera syriaca exhibits a high degree of tolerance to pests and pathogens including varroa mites. This native honey bee subspecies of Jordan expresses behavioral adaptations to high temperature and dry seasons typical of the region. However, persistent honey bee imports of commercial breeder lines are endangering local honey bee population. This study reports the use of next-generation sequencing （NGS） technology to study the A. m. syriaca genome and to identify genetic factors possibly contributing toward mite resistance and other favorable traits. We obtained a total of 46.2 million raw reads by applying the NGS to sequence A. m. syriaca and used extensive bioinformatics approach to identify several candidate genes for Varroa mite resistance, behavioral and immune responses char- acteristic for these bees. As a part of characterizing the functional regulation of molecular genetic pathway, we have mapped the pathway genes potentially involved using information from Drosophila melanogaster and present possible functional changes implicated in responses to Varroa destructor mite infestation toward this. We performed in-depth functional annotation methods to identify -600 candidates that are relevant, genes involved in pathways such as microbial recognition and phagocytosis, peptidoglycan recognition protein family, Gram negative binding protein family, phagocytosis receptors, serpins, Toll signaling pathway, Imd pathway, Tnf, JAK-STAT and MAPK pathway, heamatopioesis and cellular response pathways, antiviral, RNAi pathway, stress factors, etc. were selected. Finally, we have cataloged function-specific polymorphisms between A. mellifera and A. m. syriaca that could give better understanding of varroa mite resistance mechanisms and assist in breeding. We have identified immune related embryonic development （Cactus, Relish, dorsal, Ank2, baz）, Varroa hygiene （NorpA2, Zasp, LanA, gasp, impl3） and Varroa resistance （Pug, pcmt, elk, elf3-s10, Dscam2, Dhc64C, gro, futsch） functional variations genes between A. mellifera and A. m. syriaca that could be used to develop an effective molecular tool for bee conservation and breeding programs to improve locally adapted strains such as syriaca and utilize their advantageous traits for the benefit of apiculture industry.
文摘Background:Climate change creates opportune conditions that favour the spread of pests and diseases outside their known active range.Modelling climate change scenarios is oftentimes useful tool to assess the climate analogues to unveil the potential risk of spreading suitability conditions for pests and diseases and hence allows development of appropriate responses to address the impending challenge.In the current study,we modelled the impact of climate change on the distribution of Varroa destructor,a parasitic mite that attacks all life forms of honey bees and remains a significant threat to their survival and productivity of bee products in Tanzania and elsewhere.Methods:The data about the presence of V.destructor were collected in eight regions of Tanzania selected in consideration of several factors including potentials for beekeeping activities,elevation(highlands vs.lowlands)and differences in climatic conditions.A total of 19 bioclimatic datasets covering the entire country were used for developing climate scenarios of mid-century 2055 and late-century 2085 for both rcp4.5 and rcp8.5.We thereafter modelled the current and future risk distribution of V.destructor using MaxEnt.Results:The results indicated a model performance of AUC=0.85,with mean diurnal range in temperature(Bio2,43.9%),mean temperature(Bio1,20.6%)and mean annual rainfall(Bio12,11.7%)as the important variables.Future risk projections indicated mixed responses of the potential risk of spreads of V.destructor,exhibiting both decrease and increases in the mid-century 2055 and late-century 2085 on different sites.Overall,there is a general decline of highly suitable areas of V.destructor in mid-and late-century across all scenarios(rcp4.5 and rcp8.5).The moderately suitable areas indicated a mixed response in mid-century with decline(under rcp4.5)and increase(under rcp8.5)and consistent increase in late century.The marginally suitable areas show a decline in mid-century and increase in late-century.Our results suggest that the climate change will continue to significantly affect the distribution and risks spread of V.destructor in Tanzania.The suitability range of V.destructor will shift where highly suitable areas will be diminishing to the advantage of the honey bees’populations,but increase of moderately suitable sites indicates an expansion to new areas.The late century projections show the increased risks due to surge in the moderate and marginal suitability which means expansion in the areas where V.destructor will operate Conclusion:The current and predicted areas of habitat suitability for V.destructor’s host provides information useful for beekeeping stakeholders in Tanzania to consider the impending risks and allow adequate interventions to address challenges facing honey bees and the beekeeping industry.We recommend further studies on understanding the severity of V.destructor in health and stability of the honey bees in Tanzania.This will provide a better picture on how the country will need to monitor and reduce the risks associated with the increase of V.destructor activities as triggered by climate change.The loss of honey bees’colonies and its subsequent impact in bees’products production and pollination effect have both ecological and economic implications that need to have prioritization by the stakeholders in the country to address the challenge of spreading V.destructor.
基金the Almond Board of California,the Foundation for the Preservation of Honey Bees, the National Honey Board,the Michigan State University GREEEN Program,Michigan Beekeepers Association, all to ZYH,and National Natural Science Foundation of China (#31302040,#31660633)General Project of Jiangxi Provincial Department of Education (#GJJ14153)a fellowship from the China Scholarship Council (#201406825006)(to XB).
文摘The Varroa mite,(Varroa destructor),is the worst threat to honey bee health worldwide.To explore the possibility of using RNA interference to control this pest, we determined the effects of knocking down various genes on Varroa mite survival and reproduction.Double-stranded RNA (dsRNA)of six candidate genes (Da,Pros26S,RpL8, RpL11,RpPO and RpS13)were synthesized and each injected into Varroa mites,then mite survival and reproduction were assessed.Injection of dsRNA for Da (Daughterless)and Pros26S (Gene for proteasome 26S subunit adenosine triphosphatase)caused a significant reduction in mite survival,with 3.57%±1.94% and 30.03%±11.43% mites surviving at 72 h post-inj ection (hpi),respectively.Control mites injected with green fluorescent protein (GFP)-dsRNA showed survival rates of 81.95%±5.03% and 82.36 ±2.81%,respectively. Injections of dsRNA for four other genes (RpL8,RpL11,RpPO and RpS13)did not affect survival significantly,enabling us to assess their effect on Varroa mite reproduction.The number of female offspring per mite was significantly reduced for mites injected with dsRNA of each of these four genes compared to their GFP-dsRNA controls.Knockdown of the target genes was verified by real-time polymerase chain reaction for two genes important for reproduction (RpL8,RpL11)and one gene important for survival (Pros26S). In conclusion,through RNA interference,we have discovered two genes important for mite survival and four genes important for mite reproduction.These genes could be explored as possible targets for the control of Varroa destructor in the future.
文摘The objective of the study was to establish the effect of formic acid on varroa(Varroa destructor),inside the capped brood cells,artificially decapped.The experiments were carried out in 2017-2018 on honeybee colonies infested with varroa(V.destructor),in a research apiary belonging to the Institute for Beekeeping Research and Development in Bucharest.The decapping method in the present researches used the decapping fork to scrape the capped comb,without affecting the brood,in order to open it for an effective treatment.The combined treatment method was applied on honeybee colonies as a whole,as well as on brood combs,without bees,put in a special treatment box.The researches were focused on establishing the mortality level of various stages of varroa in artificially decapped brood,in normal colony and separately,as well as to make observations on the effect of formic acid on viability of capped bee brood,artificially decapped.The results show a high mortality of varroa,especially the protonymphs and deutonymphs stages(over 80%).The main conclusion is that the brood decapping method combined with formic acid treatment could be a useful technique to control varroa infestation,both in brood and honeybees,shortening strongly the treatment duration as compared to the usual treatments,increasing the efficacy of treatment by cutting the life cycle of varroa in brood.
