Effects Of Fluvalinate On The Development Of Larvae,Survival And Gut Microbiota Of Honey Bee Workers,Apis Mellifera

This study aims to determine the effects of fluvalinate on the development of larvae,survival and gut microbiota of honey bee workers,Apis mellifera,which can be used as healthy reference.The larvae were fed with 2 ?L syrup containing different concentrations of fluvalinate(0,0.5,5 and 50 mg / kg)since the 2nd day of larval stage using a micro sampling syringe injector.Those fed with sugar water with 0.025% acetone were used as control group.The larval capping rate,detoxification enzyme activity and total protein of6-days-old larvae were examined,and the effects of fluvalinate on larval development were analyzed.After the larvae emergence of experimental groups,they were grouped and fed with sugar water containing different concentrations of fluvalinate.After 7 days of feeding,the gut microbes of were collected for metagenome sequencing.Radio frequency identification(RFID)was used to monitor the natural homing and homing ability of workers in each group,and analyzed the effects of fluvalinate on the homing ability of the workers and intestinal colonies.In addition,the effects of fluvalinate on head immunization,detoxification and learning and memory related gene expression in different days group(1 day-old,7 day-old,20 day-old)were analyzed by real-time qPCR.When the concentration of fluvalinate reached 50mg/kg,the capping rate was significantly reduced and the enzyme activity of cytochrome P450 was significantly activated.However,the effects were not statistically significant neither on glutathione-s-transferase GST and carboxylic acid esterase CarE,nor larvae body weight.Over all,with the increasing of fluvalinate concentration,the activity of larvae superoxide dismutase SOD increased gradually,even though the difference was not statistically significant among the four experimental groups.Additionally,the concentration of total protein in larvae exhibited a decreasing trend,following the increasing of fluvalinate concentration.Specifically,the concentration of total protein was significantly lower in 50mg/kg group and 0.5mg/kg group compared to the control group.A significant difference was not observed in emergence rate and birth weight among four dose group.The results of RFID suggest a non-significant difference in the ratio of flying out of the honeycomb for the first time,average life span and survivability among the four treatment groups.However,the average foraging events was significantly lower in50mg/kg group compared to the other three treatment groups.In the 2000 m test,the effect of fluvalinate on the flying ratio and the time taken to fly back to the honeycomb was significant.The expression levels of genes related to immunity,detoxification and memorywere influenced by the level of Fluvalinate concentration.The concentration of 5mg/kg inhibited the expression level of learning and memory related gene including Nmdar1,Nmdar2 and PKA,in 7-day-old and 20-day-old worker bees.Additionally,the concentration of 50mg/kg also inhibited the expression level detoxification and immunity related genes including Nmdar1,Nmdar2 and PKA genes in a 7-day-old and 20-day-old worker bees.Mega-genome sequencing suggest that low dose of tau-fluvalinate facilitated Proteus enrichment,while high doses enriched ascomycota.Based on species phylogenetic clustering,50mg/kg group was clustered into a distinct group.The species gene quantification indicated that the core strains of Snodgrassella ALV were significantly decreased,but Zygosaccharomyces rouxii was significantly increased in 50mg/kg group compared to the other three treatment groups.