Influence of Host Plants on the Diversity of Gut Microbiota Communities of Fall Armyworm Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae)

Abstract The gut bacteria of insects influence their host physiology positively, although their mechanism is not yet understood. This study characterized the microbiome of the gut of Spodoptera frugiperda larvae fed with nine different host plants; sugar cane (M1), maize (M2), onion (M3), cucumber (R1), tomato (R2), sweet potato (R3), cabbage L1), green amaranth (L2), and celocia (L3) by sequencing the theV3-V4 hypervariable region of the 16S rRNA gene using Illumina PE250 NovaSeq system. The results revealed that gut bacterial composition varied among larvae samples fed on different host plants. Three alpha diversity indices revealed highly significant differences on the gut bacterial diversity of S. frugiperda fed with different host plants.. Analysis of Molecular Variance (AMOVA) and Analysis of Similarity (ANOSIM) also revealed significant variations on the bacterial communities among the various host plants. Five bacteria phyla (Firmicutes, Proteobacteria, Cyanobacteria, Actinobacteria and Bacteroidetes) were prevalent across the larvae samples. Firmicutes (44.1%) was the most dominant phylum followed by Proteobacteria (28.5%). Linear discriminant analysis effect size (LEfSe) analyses showed that S. frugiperda larvae were enriched by diverse bacteria groups. Celocia (L3) and sweet potato (R3) were enriched in phylum Firmicutes by 15.1% and 14.2 % respectively while green amaranth (L2) and sugar cane (M1) were enriched in proteobacteria by 18.5% and 14.3% respectively. Genus Enterococcus was predominant and mostly enhanced by L3 with 21.7% incidence. Mann-Whitney’ test revealed highly significant differences (p<0.001) on OTUs number among larvae samples. Our findings indicate that host plant is a major driver shaping insect gut microbiota.