Characterization of the microbiota and mycobiota of Tenebrio molitor: implications for pathogen management in insect mass-rearing systems

Insect farming for food and feed offers a sustainable protein source with significant environmental advantages. This study focuses on the characterization of the microbiota and mycobiota of Tenebrio molitor to identify potential pathogens affecting insect colonies. A systematic review of the literature was conducted, followed by an experimental metabarcoding approach comparing microbial differences between developmental stages, rearing colonies, and treatments in larvae and adults: (i) whole, non-disinfected individuals; (ii) disinfected individuals without intestines; (iii) isolated intestines from disinfected individuals; and (iv) frass collected from rearing containers. Among the pathogens identified were bacteria such as Serratia marcescens and Pseudomonas aeruginosa , and fungi including Mucor circinelloides . Firmicutes and Proteobacteria were the dominant bacterial phyla, while Ascomycota and Basidiomycota dominated the fungal community. Diversity indices revealed significant variation between groups and treatments. These findings provide valuable insights for addressing disease challenges in insect mass-rearing systems and emphasise the need for further research on microbial shifts across life stages and rearing conditions to improve management strategies.