Synergistic role of egg-associated bacteria in promoting egg hatching of black soldier fly (Hermetia illucens L.).

The black soldier fly (Hermetia illucens L.) is a critical species for organic waste bioconversion, yet the microbial ecology regulating its embryonic development remains obscure. This study investigated the diversity, temporal dynamics, and functional role of the egg-associated microbiota in black soldier fly hatching. Surface sterilization experiments revealed that the presence of surface microbes significantly facilitates hatching, as sterilization reduced hatching rates from 77.06% to 33.72%. Notably, this reduction was substantially reversed by re-inoculation with native egg-derived bacteria. High-throughput 16S rRNA gene sequencing demonstrated dynamic temporal shifts within the bacterial community during the 72 h incubation period, which was consistently dominated by the phyla Proteobacteria and Firmicutes. Functional prediction via PICRUSt indicated that the abundance of genes encoding chorion-degrading enzymes, including chitinases and proteases, fluctuated synchronously with critical hatching stages. Furthermore, culture-dependent screening identified Bacillus and Staphylococcus as key hatching promoters. Co-inoculation of these two strains resulted in synergistic improvements in hatching success compared to single-strain treatments. These findings suggest that specific members of the egg-associated microbiota function cooperatively to assist hatching, likely through enzymatic modification of the chorion. This study provides new insights into early-stage insect-microbe interactions and offers a potential microbial management strategy for optimizing black soldier fly mass rearing.