Metabolomics and microbiome provide new insights into mechanisms of the variations between the larva and adult stages of the Model Beetle Tribolium castaneum (Herbst)

Tribolium castaneum (Herbst) is a pest that threatens global grain and cereal production. Previous studies have shown that insect metabolism can be influenced by the gut microbiome. However, comprehensive research on the gut microbial population and dominant bacterial flora in T. castaneum is lacking. This study aims to examine the gut microbiota of T. castaneum using microbiome analysis and analyze its impact on the insect's metabolism through metabolome analysis. The microbiota diversity in adult T. castaneum was found to be higher than that in the larva group. Functional analysis revealed that the gut bacterial community is associated with metabolic pathways such as alanine, glutamine and glutamate, arginine and proline, tyrosine, and carbohydrate metabolism based on Tax4fun prediction. Meanwhile, metabolomics analysis of T. castaneum adults and larvae identified 141 differentially abundant metabolites (DAMs), including 126 up-regulated and 15 down-regulated metabolites. These DAMs were enriched in pathways including the tricarboxylic acid (TCA) cycle, arginine biosynthesis, alanine, aspartate and glutamate metabolism, and tyrosine metabolism. Additionally, correlation analysis showed significant relationships between the gut microbiota and metabolites. These findings enhance our understanding of the gut microbiota in T. castaneum and provide insights for the development of more effective strategies in controlling stored-product insect pests.