The natural history of the black soldier fly, Hermetia illucens: insights from complete mitochondrial genome sequences

The Black Soldier Fly (BSF) Hermetia illucens is a cosmopolitan fly heavily used by industrial companies to reduce biowaste and produce protein and fat for poultry and aquaculture feed. However, the natural history and the genetic diversity of the BSF is poorly known. In this study, we analysed 677 CO1 sequences derived from samples found all over the five continents leading us to the discovery of 52 haplotypes including 10 major haplotypes. We refined the definition of these haplotypes by sequencing 59 mitochondrial genomes. We could derive an estimate of the separation events of the different haplotypes at more than two million years for the oldest branches. This worldwide cryptic genetic and genomic diversity is mirrored at local scale in France in which we found five major haplotypes sometimes in sympatry. Our data resolve the phylogenetic relationships between the major lineages and give insights into the dispersal and the numbers of BSF neo-introduction at global and local scales. Our results indicate that the genetic and genomic diversity of commercial BSF stock is very low and these brood stock participated in the dissemination of the BSF in the wild. Taken together these results call for a better understanding of the genomic diversity of the BSF to unravel possible specific adaptations of the different lineages for industrial needs and to initiate the selection process.