| Honeybee plays an important role in agricultural production,ecological balance and scientific research.However,the health of bee colony and the development of apiculture were seriously threatened by Varroa destructor,the use of the acaricide flumethrin in the control of V.destrustor results in its residue in bee colonies,which makes bees exposed to flumethrin stress during development and adult stage.In this study,we take the Western honeybee as the research object,the effects of V.destrustor on the development of bee larvae and the collection ability of adults were studied by artificially infecting V.destrustor.In addition,wokerlarvaes and adults were fed flumethrin sugar solution to study the effects of flumethrin on the development of wokerlarvae and the viability of adult workers.At the same time,the effects of exposure to flumethrin on survival ability of honeybee workers were were studied by contact treatment.The effects of V.destrustor on the development of honeybee larvae from development to emergenc were studied by artificially infecting freshly capped larvae with V.destrustor,and the whole life cycle of honeybee workers was monitored by RFID system.Results showed that the birth weight of treatment group was only 111.96 ± 17.19 mg(Mean ± SD),which was 19.40 mg on averagely lower than the control group,length of wings in treatment group decreased 14.78 μm on averagely than that in control group;the thorax of bees in treatment group also significantly reduced than that in control group.There was no significance on age at onset of foraging of honeybee workers between two groups;In addition,we found that the number of foraging flights per wokerfrom treatment group was significantly lower than that from the control group;Results suggested that either at 1 km or 2 km,there were no significant differences between the control group and treatment group.The larvae of honeybee workers were fed with different doses of flumethrin sugar water(1,0.1,0.01,0 mg/L),and then were fed with the corresponding concentration of flumethrin sugar water after they emerged to explore the effects of flumethrin on the development of wokerlarvae and adults.The experimental results showed that there were no significant differences in pupal weight at the age of 1 day,capping rate and emergence rate among all dosage groups.The birth weight of 1mg/L group was significantly lower than that of 0.01 and 0 mg/L groups.The relative expression levels of memory-related genes Glu RA,Nmdar1 and Tyr1 and detoxification related genes CYP450 and GSTS were significantly lower in the 1 and0.1 mg/L pupal groups than in the control group.The results of 1-day-old honeybee workers showed that the relative expression of Nmdar1 gene in 1mg/L group was significantly lower than that in 0 mg/L group,and Tyr1 gene in 1 and 0.1mg/L groups was significantly lower than that in 0 mg/L group.The results of 7-day-old honeybee workers showed that the relative expression levels of CYP450 gene in 1mg/L group was significantly lower than that in 0 mg/L group.Relative expressions of Defensin1 and Hymenoptaecin in the 1 and 0.1 mg/L groups were significantly lower than those in the 0 mg/L group.The learning and memory ability of 7-day-old honeybee workers in 1 mg/L group was significantly lower than that in 0 mg/L group.In addition,the average life span of honeybee workers in 0.1 and 0.01 mg/L groups was significantly lower than that in 1 and 0 mg/L groups,while there was no significant difference between 1 and 0 mg/L groups.To explore effects of honey bees exposed to different doses of fulumethrin on life span,learning and memory ability,memory,immune and detoxification related gene expression in honeybees,bees of each treatment group received a drop of 1.5 μL flumethrin solution(1/16 LD50,1/8 LD50 和 1/4 LD50)on the thorax respectively,while bees received a drop of solvent as a control.The results show that: with the increase of flumethrin concentration,the average life span of honeybee workers decreased,and the average life span of 1/4 LD50 in the highest dose group was significantly lower than that of 1/8 LD50 and 1/16 LD50 dose groups and the control group,which was about 1/4 lower than that of the control group.The learning success rate of honeybee workers in 1/8 LD50 and 1/4 LD50 dose groups was significantly lower than that in the control group,while there was no significant difference between1/16 LD50 dose group and the control group.The relative expression of learning and memory-related genes Glu RA in 1/4 LD50 and 1/8 LD50 dose groups was significantly lower than that in control group;The relative expression of immune-related genes Defensin1 and Hymenoptaecin in each group was significantly lower than that in the control group.Flumethrin concentration had no significant effect on the relative expression of detoxification related genes CYP450 and GSTS in honeybee workers.The honeybee workers were treated with flumethrin drip(1/4 LD50,1/8 LD50,1/16 LD50,0)in the same way,and then placed into different colonies,the honeybee workers in each treatment group were monitored dynamically for 24 h by RFID equipment.The monitoring results showed that 1/4 LD50 and 1/8 LD50 doses of flumethrin significantly reduced the longevity of honeybee workers,and the average number of collection times and total collection time were significantly lower than1/16 LD50 dose group and control group.With the increase of flumethrin treatment dose,the rest rotation ratio of honeybee workers gradually increased,and the 1/4LD50 group increased 24.62% compared with the control group.That is,bees exposed to 1/8 LD50 or more of flumethrin will shorten their life span,reduce the foraging ability and enthusiasm. |
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