| Honeybees are the most abundant pollinator in the nature,highly social insect with refined division and resource sharing.Pollination can not only provide bee products with high nutritional value,but also increase the yield and quality of crops,which is of great significance to maintain the balance of the ecosystem.Imidacloprid is the fastest developing new insecticide of neonicotinoid insecticide in recent years.It can control a variety of resistant pests with high efficiency wide spectrum,low poison,low fastness,widely used in agriculture production.Collecting nectar and pollen plant with residue of imidacloprid leads to imidacloprid residues in bees and bee products.This research detects imidacloprid residues in honey and bee pollen from all over by high performance liquid chromatography-tandem mass spectrometry(LC/MS-MS),including Anyi,Wuyuan,Ruichang,Jingdezhen in Jiangxi Province and other provinces after conversion.A total of 30 samples were detected in this experiment,among which only Anyi samples were detected with imidacloprid,the concentration was 1.5906 ng/m L,and the detection rate was 25%.Imidacloprid-olefin were detected in 7 of the 10 regions,among which Anyi had the highest residual amount(27.5289 ng/m L)and Ruichang had the highest detection rate(75%).No imidacloprid or metabolin was detected in the samples collected from Gansu,Yongxin and Wuyuan.In order to investigate the metabolism of imidacloprid in colonies,20 colonies of Apis mellifera L.were divided into four groups with five replicates in each group,including acetone group(group A),10 ppb group(group B),100 ppb group(group C),and 250 ppb group(group D).Bees were fed sugar water containing different doses of imidacloprid on alternate days for one month,then discontinued after one month,and samples of honey and bee volume in the colonies were collected.The residues of imidacloprid and imidacloprid and its metabolites were detected by LC/MS-MS.The imidacloprid-olefin and imidacloprid were detected in all treatment groups,but no imidacloprid and 6-chloronicotinic acid(6-CNA)were detected,and the residues were positively correlated with feeding concentration.In this experiment,a total of 4 combs were extracted from 4 different colonies and placed in an artificial incubator with constant temperature and humidity(34 ℃,RH 75%).According to the concentration,each colony was divided into a group: acetone group,B group: 250 ppb,C group: 400 ppb,with 3 replicates in each group and 100 exocytic bees in each group.By RTq PCR assay,it was observed that Ace1 and Ace2 genes associated with cholinesterase in honeybees showed different expression trends under the influence of pesticides at different stages of development stage.CYP9 Q genes is the main neonicotinoid insecticide detoxification gene of honeybees.CYP9Q1,CYP9Q2 and CYP9Q3 in group C showed A significant upregulation trend at 14 days of age compared with groups A and B.In this experiment,16 S sequencing was conducted on the intestines of bees at different days of age(1d,7d and 14d)under artificial feeding conditions.The results showed that there were significant differences in sobs index,shannon index,simpson index and chao1 index among different treatment groups under the condition of the same day of age.In the analysis of species differences at the genus classification level of honeybees,Snodgrassella,Gilliamella,Bartonella and Bacillus showed significant differences in the 1-day-old of different treatment groups,but only Gilliamella showed significant differences in the intestinal tract of 14-day-old.Under the same treatment conditions,the Snodgrassella,Gilliamella,Bacillus and Lactobacillus of the control group showed significant differences at different age,while the intestinal flora of group B showed no distinct difference.Bartonella and Bifidobacterium in Group C showed significant differences. |
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