Disentangling Gut Bacterial Community Patterns in Cryptocercus punctulatus and Comparing Their Metagenomes with Other Xylophagous Dyctioptera Insects

Gut microbiota enable wood-feeding insects to digest recalcitrant diets. Two DNA-based analyses were performed. Amplicon sequencing of gut microbiota samples from <i>Cryptocercus punctulatus</i> showed inter-individual heterogeneity with visually distinct ordination patterns; however, no statistically significant differences were detected. Shotgun metagenomics was used to compare the taxonomic and functional profiles of <i>C. punctulatus</i> gut microbiota with those of other xylophagous Dictyoptera. Despite taxonomic differences, <i>C. punctulatus</i> microbiota revealed functional convergence with termites (<i>Mastotermes darwiniensis</i> and <i>Nasutitermes</i> sp.). Carbohydrate metabolism was performed by different bacterial phyla across all insects. All insect species possessed metabolic potential for cellulose, hemicellulose, pectin, and starch digestion, but lignin degradation capabilities were not detected. Termites showed higher abundance of chitin and xylan degradation pathways and nitrogen fixation genes, though nitrogen fixation was also present in <i>Cryptocercus</i> cockroaches. Genes for oxidative stress tolerance were present across all species but were most abundant in cockroaches, particularly, <i>Cryptocercus</i>. All insects harbored antibiotic resistance genes, with highest levels found in cockroaches. These findings indicate that metabolic requirements for wood digestion shape gut microbial community assembly across xylophagous insects, with distinct microbial taxa contributing to cellulose and hemicellulose breakdown. Moreover, the widespread presence of antibiotic resistance genes raises concerns about the potential transmission of antibiotic resistance within insect-associated microbiomes.