Abstract: 【Aim】 Springtails make a significant contribution to the soil ecosystem. This study aims to investigate the gut microbial structure and diversity and their potential functions in three springtail species, Sinella (Coecobrya) oligoseta, Proisotoma minuta and Tomocerus missus. 【Methods】 Microbes in the adult intestinal contents of the three springtail species were analyzed and compared by 16S rDNA amplicon sequencing, and the function prediction of gut microbial genes was conducted using Tax4Fun method. 【Results】Among the three springtail species, T. missus showed the highest adult gut microbial diversity, while S. (C.) oligoseta showed the lowest adult gut microbial diversity. At the phylum level, Proteobacteria, Firmicutes and Bacteroidetes were the most predominant microbes in the adult gut microbiota of the three springtail species, followed by Actinobacteria. At the genus level, the abundance of Pseudomonas in the gut of S. (C.) oligoseta (16.21%) was significantly higher than those in the guts of P. minuta (0.87%) and T. missus (1.37%). The abundance of Vibrio in the gut of P. minuta (25.81%) was significantly higher than that in the gut of S. (C.) oligoseta (3.35%) and T. missus (0.004%). Additionally, based on KEGG pathway annotations, we predicted that the genes in adult gut microbiota of the three springtail species may be involved in the metabolism of carbohydrates and amino acids, infectious diseases and drug resistance. 【Conclusion】 In the intestines of the three springtail species, S. (C.) oligoseta, P. minuta and T. missus, the core microbiota are the same at the phylum level, but obviously different at the genus level. The influencing factors should include the genetic traits and the abundance and diversity of microbes in the habitat of each species. Actinomycetes in springtail guts are conducive to the discovery of new strains and the application of their metabolites. Drug-resistant and pathogenic bacteria likely exist in the intestines of the three springtail species, implying new directions of functional studies on gut microbiota in springtails.

Key words: Springtails, gut microbiota, species diversity, 16S rDNA, species annotation; function prediction