The Digestive Enzyme Activities And Bacterial Diversity In The Gut Of Hyphantria Cunea(Lepidoptera:Arctiidae)Larvae

The fall webworm,Hyphantria cunea(Lepidoptera:Arctiidae)is a destructive invasive insect pest on forestry and horticultural plants.Its host is very extensive.In this study,the digestive enzyme activities of amylase,lipase and trypsin were determined in the 5th instar larvae of H.cunea fed on 8 spieces of host plants.To clarify the bacterial diversity and differences in the gut of H.cunea larvae on different diets,the 16S rDNA genes of the bacteria in the gut of H.cunea larvae fed on 3 different diets was sequenced by Illumina MiSeq techniques.The results and conclusions were as follows:1.In this study,the digestive enzyme activities of amylase,lipase and trypsin were determined in the 5th instar larvae of H.cunea fed on 8 spieces of host plants.The order of the gut amylase activity from high to low was the samples fed on Ailanthus altissima,Salix babylonica,Platanus occidentalis,Ulmus pumila,Populus X Canadensis,Forsythia suspense,Fraxinus chinensis and Morus alba,respectively.The order of the gut lipase activity from high to low was the samples fed on Ailanthus altissima,Salix babylonica,Populus X Canadensis,Fraxinus chinensis,Ulmus pumila,Platanus occidentalis,Forsythia suspense and Morus alba,respectively.The order of the gut trypsin activity from high to low was the samples fed on Salix babylonica,Populus X Canadensis,Ulmus pumila,Ailanthus altissima,Morus alba,Forsythia suspensa,Platanus occidentalis and Fraxinus chinensis,respectively.There were significant differences in the three digestive enzyme activities of the larvae fed on 8 spieces of host plants(P<0.05).2.The V3-V4 regions of the 16S rDNA genes of the bacteria in the gut of H.cunea larvae fed on artificial diet,Morus alba and Salix babylonica was sequenced by Illumina MiSeq techniques.All reads of H.cunea larvae on three diets were obtained and clustered into 5247 OTUs.These OTUs were annotated into 23 phyla,60 classes,90 orders,143 families,196 genera and 58 species.At phyla level,the dominant phyla of the bacteria in the gut of H.cunea larvae fed on three diets were Proteobacteria and Firmicutes.At class level,the dominant class of the bacteria in the gut of H.cunea larvae fed on artificial diet was ?-Proteobacteria,but the dominant class of the bacteria in the gut of H.cunea larvae fed on Morus alba and Salix babylonica was a-Proteobacteria.At order level,the dominant order of the bacteria in the gut of H.cunea larvae fed on artificial diet was Oceanospirillales,but the dominant order of the bacteria in the gut of H.cunea larvae fed on Morus alba and Salix babylonica was Rickettsiales.At family level,the dominant family of the bacteria in the gut of H.cunea larvae fed on artificial diet was Halomonadaceae,but the dominant family of the bacteria in the gut of H.cunea larvae fed on Morus alba and Salix babylonica was Mitochondria.At genus level,the dominant genera of the bacteria in the gut of H.cunea larvae from artificial diet,Morus alba and Salix babylonica were Shewanella.Staphylococcus and Bacillus,respectively.At species level,the dominant specie of the bacteria in the gut of H.cunea larvae fed on artificial diet and Salix babylonica was Shewanella algae,but the dominant specie of the bacteria in the gut of H.cunea larvae fed on Morus alba was Staphylococcus sciuri.3.Alpha diversity index and OTUs Rank curve of the gut bacteria showed that the gut bacterial community of H.cunea larvae fed on three diets have higher richness and diversity.Venn analysis of OTUs,abundance distribution heatmap,PCA,Beta diversity index heatmap of the gut bacteria showed that the gut bacterial community of H.cunea larvae fed on three diets have have some differences.