The potato rot nematode(Ditylenchus destructor) is a very economically important nematode in agronomic and horticultural plants worldwide. In this study, 43 populations of D. destructor were collected from different h...The potato rot nematode(Ditylenchus destructor) is a very economically important nematode in agronomic and horticultural plants worldwide. In this study, 43 populations of D. destructor were collected from different hosts across China, including 37 populations from Chinese herbal medicine plants. Obtained sequences of ITS-rDNA and D2–D3of 28S-rDNA genes of D. destructor were compared and analyzed. Nine types of significant length variations in ITS sequences were observed among all populations. The differences in ITS1 length were mainly caused by the presence of repetitive elements with substantial base substitutions. Reconstructions of ITS1 secondary structures showed that the minisatellites formed a stem structure. Ten haplotypes were observed in all populations based on mutations and variations of helix H9. Among them, 3 known haplotypes(A–C) were found in 7 populations isolated from potato,sweet potato, and Codonopsis pilosula, and 7 unique haplotypes were found in other 36 populations collected from C. pilosula and Angelica sinensis compared with 7 haplotypes(A–G) according to Subbotin' system. These unique haplotypes were different from haplotypes A–G, and we named them as haplotypes H–N. The present results showed that a total of 14 haplotypes(A–N) of ITS-rDNA have been found in D. destructor. Phylogenetic analyses of ITSrDNA and D2–D3 showed that all populations of D. destructor were clustered into two major clades: one clade only containing haplotype A from sweet potato and the other containing haplotypes B–N from other plants. For further verification, PCR-ITS-RFLP profiles were conducted on 7 new haplotypes. Collectively, our study suggests that D. destructor populations on Chinese medicinal materials are very different from those on other hosts and this work provides a paradigm for relevant researches.展开更多
Given recent higher declines in managed Apis mellifera honeybees,which are the most commonly managed bee species around the world(Garibaldi et al.2013),numerous health threats involved in the losses have been received...Given recent higher declines in managed Apis mellifera honeybees,which are the most commonly managed bee species around the world(Garibaldi et al.2013),numerous health threats involved in the losses have been received great attention.To date,Varroa destructor mite infestation has become the biggest challenge in commercial beekeeping,which is considered as a thorn stuck in the throat of beekeepers.The Varroa mite threatens bee health by absorbing the fat body and hemolymph of immature and mature bees(Ramsey et al.2019).Varroa mite infestation during the development of worker bees was found to reduce birth weight,influence water content and protein level in hemolymph of newly emerged worker bees,decrease flight performance of drones,change gene expression patterns related to immune system of honeybees,and result in honeybee colony losses(Duay et al.2002;Bowen-Walker and Gunn 2010;Zhang et al.2010;Annoscia et al.2012;Dooremalen et al.2013;Locke 2016).The Varroa mite,as an ectoparasite of the honeybee,prefers living in the sealed brood cells(Bogdanov 2006).Thus,bees are more likely to become hosts of mites in the pupal stage.In this study,we systematically investigated the current impacts of V.destructor infestations on the development from capped larvae to emerged bees.展开更多
In this study, a rapid molecular identification method of Tribolium destructor was established with PCR and PCR-RFLP （polymerase chain reaction-restriction fragment length polymorphism） technology. According to the ...In this study, a rapid molecular identification method of Tribolium destructor was established with PCR and PCR-RFLP （polymerase chain reaction-restriction fragment length polymorphism） technology. According to the results, （ 1 ） with PCR method, specific primers were designed based on CO1 gene of T. destructor for PCR amplification, and electrophoresis detection confirmed that PCR method could be used to rapidly and accurately identify T. destructor; （2） with PCR-RFLP method, two pairs of degenerate primers were used to amplify CO1 gene of Tribolium species, PCR products were digested with HindIII and detected by electrophoresis, results indicated that PCR-RFLP method could also be used for rapid identification of T. destructor in quarantine practice.展开更多
Salivary proteins are the initial contact between sedentary insect pests and their host plants. It is expected that one or more salivary proteins mediate the interaction between Hessian fly and wheat, in which a feedi...Salivary proteins are the initial contact between sedentary insect pests and their host plants. It is expected that one or more salivary proteins mediate the interaction between Hessian fly and wheat, in which a feeding site is established to the benefit of the fly. A survey of 52 loci annotated as insect secreted salivary proteins was conducted in 384 individuals evenly distributed among eight biotypes of Hessian fly (B, C, D, E, GP, L, O, and vH9). Amplicons were sequenced with Illumina, and sequence reads were aligned to the reference sequences from which primers had been designed. Positions of consistent base variation (998 in all) were identified and tabulated by biotype. No varying position was associated with biotype-wide virulence to any one of wheat resistance genes H3, H5, H6, H7/H8, H9, H11, H13, and H26. The multiplate pooling strategy utilized in this study is an effective, affordable way to reveal the genotype of hundreds of individuals at tens of genetic loci.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
The Hessian fly, <em>Mayetiola destructor</em>, is a harmful pest of wheat (<em>Triticum aestivum</em>). Pioneer variety 25R78 is putatively tolerant, meaning that the plant can survive success...The Hessian fly, <em>Mayetiola destructor</em>, is a harmful pest of wheat (<em>Triticum aestivum</em>). Pioneer variety 25R78 is putatively tolerant, meaning that the plant can survive successful Hessian fly infestation with reduced growth effects. To understand if Hessian fly-tolerance in wheat results in reduced yield effects and to analyze the economic feasibility of tolerant wheat as a Hessian fly control method, this study focused on analyzing the effect of infestation on tolerant wheat yield. This study analyzed tolerant Pioneer variety 25R78, resistant Pioneer brand variety 25R32, and susceptible Pioneer brand variety 25R47 through harvest. Treated plants were infested using a plastic cover and allowing 1 - 2 female flies to lay eggs for two hours. We measured head, fertile head number and tiller number. Seeds were analyzed by measuring total seed number and weight, as well as average seed number and weight. Tolerant and resistant plants showed no significant effects on yield in comparison to susceptible wheat. The infested tolerant plants were comparable in yield to infested resistant plants. Therefore, we propose that tolerance incorporated into wheat varieties will lower selection pressure on Hessian fly populations and increase the durability of these wheat lines.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
A group of related genes has been isolated and characterized from the gut of Hessian fly larvae [Mayetiola destructor （Say）]. Members in this group appear to encode proteins with secretary signal peptides at the N-t...A group of related genes has been isolated and characterized from the gut of Hessian fly larvae [Mayetiola destructor （Say）]. Members in this group appear to encode proteins with secretary signal peptides at the N-terminals. The mature putative proteins are small, acidic proteins with calculated molecular masses of 14.5 to 15.3 kDa, and isoelectric points from 4.56 to 4.88. Northern blot analysis revealed that these genes are expressed predominantly in the gut of Hessian fly larvae and pupae. Two related genes, GIOK1 and GIOK2, were isolated as tandem repeats. Both genes contain three exons and two introns. The intron/exon boundaries were conserved in terms of amino acid encoding, suggesting that they arose by gene duplication. The fact that the frequency of this group of clones in a gut cDNA library higher than that of total cDNA clones encoding digestive enzymes suggested that this group of proteins may perform an important function in the gut physiology of this insect. However, the exact functions of these proteins are as yet known since no sequence similarity could be identified between these proteins and any known sequences in public databases using standard methods.展开更多
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
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
[Objective] This study aimed to compare the effects of sublimed sulfur and acaricide on controlling bee mites.[Method] Three independent experiments were carried out in the same apiary during 2007-2009.[Results] The r...[Objective] This study aimed to compare the effects of sublimed sulfur and acaricide on controlling bee mites.[Method] Three independent experiments were carried out in the same apiary during 2007-2009.[Results] The results showed that this method is effective in eliminating mites settled on combs or hidden during pupae phase,but not in controlling the mites parasitized on adult bees.The control effect on killing Varroa destructor after treated appeared optimal in the first day and then decreased,and that on killing Tvopilaelaps clareae happened in the second day.The results indicated that the effect would be much better if the bees can be treated 1 time to 2 times again in the following 2-5 days after the first treatment.Back to data pool,we found that the treatment of sublimed sulfur paired with acaricide is effective in controlling V.destructor and T.clareae.[Conclusion] This technique could facilitate the apicultural production in the regions suffered from V.destructor and T.clareae.展开更多
基金supported by the National Natural Science Foundation of China (31760507)the National Key R&D Program of China (2018YFC1706301)。
文摘The potato rot nematode(Ditylenchus destructor) is a very economically important nematode in agronomic and horticultural plants worldwide. In this study, 43 populations of D. destructor were collected from different hosts across China, including 37 populations from Chinese herbal medicine plants. Obtained sequences of ITS-rDNA and D2–D3of 28S-rDNA genes of D. destructor were compared and analyzed. Nine types of significant length variations in ITS sequences were observed among all populations. The differences in ITS1 length were mainly caused by the presence of repetitive elements with substantial base substitutions. Reconstructions of ITS1 secondary structures showed that the minisatellites formed a stem structure. Ten haplotypes were observed in all populations based on mutations and variations of helix H9. Among them, 3 known haplotypes(A–C) were found in 7 populations isolated from potato,sweet potato, and Codonopsis pilosula, and 7 unique haplotypes were found in other 36 populations collected from C. pilosula and Angelica sinensis compared with 7 haplotypes(A–G) according to Subbotin' system. These unique haplotypes were different from haplotypes A–G, and we named them as haplotypes H–N. The present results showed that a total of 14 haplotypes(A–N) of ITS-rDNA have been found in D. destructor. Phylogenetic analyses of ITSrDNA and D2–D3 showed that all populations of D. destructor were clustered into two major clades: one clade only containing haplotype A from sweet potato and the other containing haplotypes B–N from other plants. For further verification, PCR-ITS-RFLP profiles were conducted on 7 new haplotypes. Collectively, our study suggests that D. destructor populations on Chinese medicinal materials are very different from those on other hosts and this work provides a paradigm for relevant researches.
基金supported by the National Natural Science Foundation of China(31760714,31360587)the Academic and Technical Leader Projects of Major Disciplines in Jiangxi Province(20194BCJ22007).
文摘Given recent higher declines in managed Apis mellifera honeybees,which are the most commonly managed bee species around the world(Garibaldi et al.2013),numerous health threats involved in the losses have been received great attention.To date,Varroa destructor mite infestation has become the biggest challenge in commercial beekeeping,which is considered as a thorn stuck in the throat of beekeepers.The Varroa mite threatens bee health by absorbing the fat body and hemolymph of immature and mature bees(Ramsey et al.2019).Varroa mite infestation during the development of worker bees was found to reduce birth weight,influence water content and protein level in hemolymph of newly emerged worker bees,decrease flight performance of drones,change gene expression patterns related to immune system of honeybees,and result in honeybee colony losses(Duay et al.2002;Bowen-Walker and Gunn 2010;Zhang et al.2010;Annoscia et al.2012;Dooremalen et al.2013;Locke 2016).The Varroa mite,as an ectoparasite of the honeybee,prefers living in the sealed brood cells(Bogdanov 2006).Thus,bees are more likely to become hosts of mites in the pupal stage.In this study,we systematically investigated the current impacts of V.destructor infestations on the development from capped larvae to emerged bees.
基金Supported by Science and Technology Project of Jiangsu Entry and Exit Inspection and Quarantine Bureau(2010KJ06)
文摘In this study, a rapid molecular identification method of Tribolium destructor was established with PCR and PCR-RFLP （polymerase chain reaction-restriction fragment length polymorphism） technology. According to the results, （ 1 ） with PCR method, specific primers were designed based on CO1 gene of T. destructor for PCR amplification, and electrophoresis detection confirmed that PCR method could be used to rapidly and accurately identify T. destructor; （2） with PCR-RFLP method, two pairs of degenerate primers were used to amplify CO1 gene of Tribolium species, PCR products were digested with HindIII and detected by electrophoresis, results indicated that PCR-RFLP method could also be used for rapid identification of T. destructor in quarantine practice.
文摘Salivary proteins are the initial contact between sedentary insect pests and their host plants. It is expected that one or more salivary proteins mediate the interaction between Hessian fly and wheat, in which a feeding site is established to the benefit of the fly. A survey of 52 loci annotated as insect secreted salivary proteins was conducted in 384 individuals evenly distributed among eight biotypes of Hessian fly (B, C, D, E, GP, L, O, and vH9). Amplicons were sequenced with Illumina, and sequence reads were aligned to the reference sequences from which primers had been designed. Positions of consistent base variation (998 in all) were identified and tabulated by biotype. No varying position was associated with biotype-wide virulence to any one of wheat resistance genes H3, H5, H6, H7/H8, H9, H11, H13, and H26. The multiplate pooling strategy utilized in this study is an effective, affordable way to reveal the genotype of hundreds of individuals at tens of genetic loci.
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.
文摘The Hessian fly, <em>Mayetiola destructor</em>, is a harmful pest of wheat (<em>Triticum aestivum</em>). Pioneer variety 25R78 is putatively tolerant, meaning that the plant can survive successful Hessian fly infestation with reduced growth effects. To understand if Hessian fly-tolerance in wheat results in reduced yield effects and to analyze the economic feasibility of tolerant wheat as a Hessian fly control method, this study focused on analyzing the effect of infestation on tolerant wheat yield. This study analyzed tolerant Pioneer variety 25R78, resistant Pioneer brand variety 25R32, and susceptible Pioneer brand variety 25R47 through harvest. Treated plants were infested using a plastic cover and allowing 1 - 2 female flies to lay eggs for two hours. We measured head, fertile head number and tiller number. Seeds were analyzed by measuring total seed number and weight, as well as average seed number and weight. Tolerant and resistant plants showed no significant effects on yield in comparison to susceptible wheat. The infested tolerant plants were comparable in yield to infested resistant plants. Therefore, we propose that tolerance incorporated into wheat varieties will lower selection pressure on Hessian fly populations and increase the durability of these wheat lines.
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A group of related genes has been isolated and characterized from the gut of Hessian fly larvae [Mayetiola destructor （Say）]. Members in this group appear to encode proteins with secretary signal peptides at the N-terminals. The mature putative proteins are small, acidic proteins with calculated molecular masses of 14.5 to 15.3 kDa, and isoelectric points from 4.56 to 4.88. Northern blot analysis revealed that these genes are expressed predominantly in the gut of Hessian fly larvae and pupae. Two related genes, GIOK1 and GIOK2, were isolated as tandem repeats. Both genes contain three exons and two introns. The intron/exon boundaries were conserved in terms of amino acid encoding, suggesting that they arose by gene duplication. The fact that the frequency of this group of clones in a gut cDNA library higher than that of total cDNA clones encoding digestive enzymes suggested that this group of proteins may perform an important function in the gut physiology of this insect. However, the exact functions of these proteins are as yet known since no sequence similarity could be identified between these proteins and any known sequences in public databases using standard methods.
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Supported by Special Fund for the Construction of Modern Agricultural Technology System(NYCYTX-43-syz3)~~
文摘[Objective] This study aimed to compare the effects of sublimed sulfur and acaricide on controlling bee mites.[Method] Three independent experiments were carried out in the same apiary during 2007-2009.[Results] The results showed that this method is effective in eliminating mites settled on combs or hidden during pupae phase,but not in controlling the mites parasitized on adult bees.The control effect on killing Varroa destructor after treated appeared optimal in the first day and then decreased,and that on killing Tvopilaelaps clareae happened in the second day.The results indicated that the effect would be much better if the bees can be treated 1 time to 2 times again in the following 2-5 days after the first treatment.Back to data pool,we found that the treatment of sublimed sulfur paired with acaricide is effective in controlling V.destructor and T.clareae.[Conclusion] This technique could facilitate the apicultural production in the regions suffered from V.destructor and T.clareae.
