Sublethal Effect Of Sulfoxaflor On Apis Mellifera Ligustica Workers

Bee pollination can not only improve the yield and quality of crops,but also maintain the balance of global biodiversity and ecosystem.In recent years,there has been a large-scale decline of bee population at home and abroad,which is suspected to be caused by a variety of adverse factors alone or interactively,among which pesticide is one of the influencing factors Sulfoxaflor is a sulfonimide insecticide,which acts on the unique binding site of neurotransmitter acetylcholine to kill insects.It is widely used in the control of rape,citrus and other honey powder plant pests.Honeybees are known as "environmental indicators",which are easily affected by sulfoxaflor pesticide residues in nectar plants during the collection of nectar powder.In this study,the survival rate,growth and nutrition of different concentrations of sulfoxaflor on the development stages of Apis mellifera ligustica worker bee were measured.The effects of sublethal stress of sulfoxaflor on detoxification enzyme,immune enzyme system and olfactory learning behavior of Apis mellifera ligustica worker bee were analyzed The main results were as follows1.In this study,1-day-old Apis mellifera ligustica workers bee larvae were exposed to 0.3 mg/L and 5 mg/L sulfoxaflor in the outdoor environment,and 2 ?L pesticide was added into the hole of chaospleen every day for 6 days.The results showed that the intestinal tract of 6-day-old Apis mellifera ligustica workers bee larvae treated with 0.3 mg/L pesticide had no difference with that of the control group,but the development of the intestinal tract was significantly delayed by 5 mg/L pesticide.The midgut was found to be thin and indistinct,in which the intestine and hindgut were isolated.At the same time,the pupation rate and eclosion rate of Apis mellifera ligustica workers bee under the stress of 5 mg/L sulfoxaflor were significantly lower than that of the control,6.69%and 18.4%respectively(P<0.01).At the pupa stage,the contents of fat and free water in the pupa of bees in the two treatment groups were significantly increased,and the contents of glycogen were significantly decreased.The changes in the nutrition of bees were stress responses to the stress of pesticides,so as to reduce the harm to bees,In addition,Compared with the control group,the cat content of honeybee decreased significantly in pupa stage and new house stage.the contents of pepsinase in the 5 mg/L concentration group gradually increased from the stage of larvae to the stage of emergence,indicating that the balance of nutrition and energy in the environment of bees is very important for the maintenance of colony health.Compared with the control group,the T-SOD enzyme activity of bees in the two treatment groups was significantly increased at the stage of honeybee emergence,2.606 ?/mg prot and 1.792 ?/mg prot,respectively,indicating that the immune system of bees in the two treatment groups was activated.2.In this study,48 h acute toxicity test was carried out on the new room 1-day-old adult bees from Apis mellifera ligustica workers by feeding method,and LC50o was measured to be 2.548 mg/L.Subsequently,LC10,LC30 and LC50 concentrations of sulfoxaflor pesticides were selected and subjected to 24 h and 48 h stress treatment on the new room 1-day-old adult bees from Apis mellifera ligustica worker,and the activities of CYP450,CarE and GST enzymes in bees were all affected to some extent.The enzyme activity of CYP450,GST and CarE decreased after 48 h of exposure to LC10,LC 30 in Apis mellifera ligustica worker.CYP450 enzyme activity in Apis mellifera ligustica workers tissues was significantly increased in the LC50 pesticide concentration treatment group(P<0.01),indicating that CYP450 played a major role in the process of metabolic detoxification of bees.In the learning behavior of bees,1.5 mg/L of sulfoxaflor was selected to stress 15-day-old Italian adult bees for up to 7 days through the preliminary test,and the self-made learning equipment was used to carry out odor associative learning experiment on bees.The results showed that the concentration of 1.5 mg/L of sulfoxaflor had no significant lethal toxicity to bees,and there was no significant difference in the learning ability of bees,that is,no effect of sulfoxaflor on the learning behavior of Italian adult bees was found.3.The results of transcriptome analysis of Italian adult's head under sublethal effect of sulfoxaflor showed that:compared with the control group,825 genes(547 down-regulated genes and 278 up-regulated genes)in the bee head of the treatment group changed,Most of the genes,such as immune gene,detoxification metabolism gene,myosin cytoskeleton and sensory neuron related gene,and odor binding protein,were down regulated.qRT-PCR was used to select OBP11,OBP16,OBP18,OBP19,cyp6aq1,sensor neuron,UDP glucuronosyltransferase 2C1,UDP glucuronosyltransferase 1-1 and carbohydrate It was found that the nine functional genes were highly consistent with the transcriptome data,which proved that the sequencing results were very reliable.