Effects Of Nano-graphene Oxide On The Growth And Development Of Fall Armyworm And Its Synergistic Performance On Insecticide

The fall armyworm,scientifically known as Spodoptera frugiperda,poses a significant threat to agricultural production and food security in China.This pest has developed varying degrees of resistance to commonly used chemical insecticides due to their excessive and prolonged use.Nanomaterials possess distinctive physical and chemical properties,and studies have reported their ability to exhibit synergistic effects with pesticides.In this paper,the effects of nano-GDYO on the growth,development and reproduction of S.frugiperda were studied by age-instar bisexual life table method.Based on metagenomic sequencing and transcriptome sequencing,the effects of feeding GDYO feed on the gut microbes and transcriptome of S.frugiperda were analyzed.Finally,the synergistic effect of GDYO on insecticides was determined.The main results are as follows:1 Effects of GDYO on the growth and development of S.frugiperdaThe effects of GDYO on the growth,development and reproduction of S.frugiperda were studied.The study found that the hatching rate of S.frugiperda eggs fed a GDYO diet was significantly lower compared to the control group.Moreover,the developmental duration of the 2nd,3rd,4th,and 5th instar larvae was significantly longer in the experimental group than in the control group.Additionally,the adult stage of the experimental group was significantly shorter,and their total lifespan was also significantly reduced compared to the control group.At the same time,pupal weight and fecundity decreased by 14.12 mg and 266,respectively.The population parameters of intrinsic rate of increase（r）and finite rate of increase（λ）were significantly lower in the experimental group compared to the control group.Additionally,the net reproductive rate（R₀）of the experimental group was drastically lower than the control group,and the average generation period（T）of the experimental group was notably longer than that of the control group.2 Comparative analysis of GDYO on intestinal microbial community composition,function and antibiotic resistance genes of S.frugiperdaThis study showed that the intestinal microbial diversity of S.frugiperda decreased after feeding on GDYO feed.At the phylum level,there was no significant difference in intestinal microbial composition between normal artificial diet and GDYO diet,and Firmicutes was the absolute dominant phylum.At the family level,the top three relative abundances were Enterobacteriaceae,Enterobacteriaceae and Lactobacillus,and the relative abundance of Lactobacillus was significantly lower than that of the control group.Functional annotation analysis showed that the Level1 level had the most functional genes related to metabolism,followed by genetic information processing.Level 2 carbohydrate metabolism is the most abundant,followed by cofactors and vitamin metabolism and other amino acid metabolism.3 Transcriptome sequencing and analysis of S frugiperda feeding with GDYO dietIn this study,a total of 18 differentially expressed genes were obtained by transcriptome sequencing,including 9 up-regulated genes and 9 down-regulated genes.The GO database was used to annotate the function of the differentially expressed genes.A total of 4 differentially expressed genes were compared to the GO database.Among them,the down-regulated 2 differentially expressed genes were annotated to the synaptic cleft and lipase activity,respectively.The up-regulated 2 differentially expressed genes were mainly related to ribosome small subunit,ribosome assembly and lysine methyltransferase activity.4 Study on the synergistic effect of GDYO on insecticidesGDYO had a good synergistic effect on emamectin benzoate and chlorantraniliprole.The LC₅₀ value of emamectin benzoate was 0.045 mg/L,the LC₅₀ value of emamectin benzoate+GDYO was 0.031 mg/L,and the synergistic index of GDYO to emamectin benzoate was 1.45.The LC₅₀ value of chlorantraniliprole was 28.414 mg/L,the LC₅₀ value of chlorantraniliprole+GDYO complex was 10.851 mg/L,and the synergistic index of GDYO to chlorantraniliprole was 2.62.