Comparative untargeted metabolic analysis of natural- and laboratory-reared larvae of black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae)

Abstract

In the present study, we examined the metabolic composition of black soldier fly (BSF) larvae from natural populations (Ruhama: R and She'ar Yashuv: S) and from a laboratory-reared colony (C) using untargeted metabolomics analysis. The results revealed significant over-accumulation of metabolites from phenylalanine and purine metabolism and biosynthesis of phenylalanine, tyrosine and tryptophan, and arginine in both natural populations, and enriched pathway analysis, compared to the laboratory-reared colony. In addition, we found accumulation of glutathione metabolism and aminoacyl tRNA biosynthesis related metabolites in R, and linoleic acid and tryptophan metabolism related metabolites in S. Moreover, we found down-accumulation of metabolites belonging to alanine, aspartate and glutamate metabolism in both natural populations: amino sugar and nucleotide sugar metabolism only in the R population and aminoacyl-tRNA biosynthesis, glyoxylate and dicarboxylate metabolism only in the S population. Overall, the results suggest that the naturally growing larvae require large quantities of metabolites from aromatic amino acids (phenylalanine, tyrosine and tryptophan) for defense against pathogens under natural conditions e.g., melanization. In addition, glutathione metabolites help the BSF to survive under oxidative stress. Further study of the functional metabolomics of naturally growing and laboratory-reared larvae could provide a platform for better understanding of BSF larval survival mechanisms in complex environments.

Keywords: Hermetia illucens; Immunity; Liquid chromatography-mass spectrometry; Natural conditions; Vitamins.