| As a group of important pollinators,bumblebees(bombus spp.)play a very important role in natural ecology and agricultural production.However,the global diversity of bumblebees has been declining sharply.The spread of parasites and pathogens has been considered to be one of the important factors leading to the decline of bumblebees in many countries and regions.China is the country with the most abundant bumblebee resources in the world,but has the relatively few large-scale investigations on pathogens and parasites.Therefore,this study investigated the current status of pathogens and parasites of 771 bumblebee workers of 22 bumblebee species from the three regions of China(The North China,The South China and The Tibetan Plateau),and analyzed the prevalence of different parasites and pathogens in various regions and bumblebee species.The main results are as follows:The 20 of the total 22 bumblebee species are infested by 9 pathogens expect B.cryptarum and B.armeniacus,namely Apicystis bombi(13.9%),Crithidia bombi(12.4%)and Crithidia expoeki(0.4%),Locustacarus buchneri(19.8%),Black queen cell virus(13.1%),Sacbrood virus(1.9%),Deformed wing virus(0.5%),Acute bee paralysis virus(0.5%)and Israeli acute paralysis virus(0.1%).Apicystis bombi,Crithidia bombi,Locustacarus buchneri and Black queen cell virus are the main pathogens infested the 21 bumblebees.They are widely distributed in The North China,The South China and The Tibetan Plateau,infecting several bumblebee species,Apicystis bombi(11),Crithidia bombi(13),Locustacarus buchneri(12),and Black queen cell virus(12).The prevalence of Apicystis bombi,Crithidia bombi and Black queen cell virus in North China were 35.7%,31.6%,and 22.6%,respectively,which were significantly higher than those in The South China and The Tibetan Plateau(4.2%and 9.5%,χ2=88.797,P<0.05;16.1%and 2.9%,χ2=92.858,P<0.05;12.5%and 9.5%,χ2=18.141,P<0.05);The prevalence of Locustacarus buchneri in The Tibetan Plateau was 28.2%,which was significantly higher than those in The North China and The South China.The types of pathogens carried by bumblebees differed between bumblebee species.The highest prevalence rate of Apicystis bombi(76.7%)and Locustacarus buchneri(96.7%)were in Bombus lantschouensis.B.longipes has the highest prevalence of Crithidia bombi(52.2%)while B.braccatus has the highest prevalence rate of Black queen cell virus(71.4%).On the one hand,different bee species in the same place are infested by different pathogens.In Xinglong,Hebei,the Apicystis bombi and Crithidia bombi prevalence of B.ignitus(66.7%and 4.2%respectively)were significantly higher than B.patagiatus(3.3%and 0%respectively)(P<0.05),and the Black queen cell virus prevalence of B.patagiatus(70.0%)were significantly higher than B.ignitus(25%)(P<0.05).In Aba,Sichuan,the Locustacarus buchneri prevalence of B.friseanus(81.3%)was significantly higher than that of B.keriensis(42.4%)and B.sushkinis s.1.(16.7%)(P<0.05).On the other hand,the prevalence of the same species in different locations is also different.The prevalence of the same species in different locations is also different.In the three different places of Longhua(Hebei),Xinglong(Hebei),and Fangshan(Shanxi),the prevalence of B.patagiatus of the four main pathogens were significantly different.The phenomenon of infestation with multiple parasites and pathogens is widespread.Of the 22 species of bumblebees,15 species totaling 112 samples(14.5%)were simultaneously carrying 2-4 major pathogens(Apicystis bombi,Crithidia bombi,Locustacarus buchneri and Black queen cell virus)The four major pathogens were found in the five bumblebee species at the same time:B.lantschouensis,B.friseanus,B.braccatus,B.ignitus and B.patagiatusApicystis bombi,Crithidia bombi,Locustacarus buchneri and Black queen cell virus infest widely the Chinese bumblebees.The infestation situation differs between regions and bee species.This study lays the foundation for further exploring the relationship between Chinese bumblebees and pathogens. |
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