Gut microbiota differences between female and male adults of Dolycoris baccarum

Abstract:

Insects have a mutually dependent symbiotic relationship with their gut microbiota, which plays an important role in the insect metabolism, immunity, development, and pesticide resistance. Gut microbiota is influenced by factors such as diet, sex, and rearing environment. Currently, little is known about the gut microbiota differences between males and females of the phytophagous insect Dolycoris baccarum.Objective To study the effects of sex on the composition and abundance of gut microbiota in D. baccarum, explore sex-related microorganisms, and provide a basis for utilizing different sex-associated strains in the biocontrol of D. baccarum.Methods The PacBio platform was used for third-generation 16S rRNA gene amplicon sequencing and the bioinformatics analysis was performed to reveal the diversity and composition of gut microbiota in male and female D. baccarum. The bacterial isolation and culture method was employed to obtain gut microbiota strains from D. baccarum, which were then identified by morphological analysis and 16S rRNA gene sequencing.Results The gut microbiota of D. baccarum was diverse, including a total of 165 genera belonging to 109 families, 60 orders, 29 classes of 14 phyla. The gut microbiota was analyzed at six taxonomic levels (phylum, class, order, family, genus, and species). Only the phylum Deinococcota and the class Deinococci were specific to males, while the phyla Chloroflexi, Desulfobacterota, and Cyanobacteria, the class Cyanobacteriia, the genus Lacticaseibacillus, and the species Glutamicibacter creatinolyticus, Acinetobacter, and Lacticaseibacillus paracasei were specific to females. The relative abundance of Serratia marcescens was significantly higher in males than in females. In the guts of females and males, the relative abundance of Gammaproteobacteria, Enterobacterales, Yersiniaceae, Serratia, and S. marcescens was 51.223% and 95.512%, 49.784% and 95.492%, 2.385% and 10.377%, 2.383% and 10.372%, and 2.310% and 10.375%, respectively. All 28 strains isolated in vitro and identified based on morphological characteristics and 16S rRNA sequences belonged to Serratia.Conclusion There are significant differences in the gut microbiota composition between male and female D. baccarum. The diversity of gut microbiota in male adults of D. baccarum is significantly higher than that in female adults. All strains isolated belong to Serratia. This study provides theoretical support for investigating the potential functions of gut microbiota in male and female D. baccarum as well as for the biocontrol of D. baccarum.