Glycerophospholipid Profiles of Allomyrina dichotoma Larvae at Different Instars Based on Lipidomics and Transcriptomics Suggest a Promising Lipid Source.

The farming of insects has emerged as a novel source of proteins and lipids. The larvae of Allomyrina dichotoma, an important source insect, contain large concentrations of lipids; however, the constituents of these lipids are unknown. We used lipidomics and transcriptomics to analyze the deposition of glycerophospholipids in A. dichotoma larvae at different instars. A total of eight subclasses of 833 glycerophospholipid molecules were identified in A. dichotoma larvae. The results showed the lipid with the highest levels in A. dichotoma larvae was phosphatidylethanolamine (PE) followed by phosphatidylcholine (PC), and phosphatidylglycerol (PG). Glycerophospholipids in A. dichotoma larvae at three instars were clearly differentiated. Large amounts of PE and PC were deposited in Stage 3 larvae, and cardiolipin (CL), phosphatidylinositol (PI), phosphatidylserine (PS), and phosphatidic acids (PAs) showed a similar pattern. However, PG and phosphatidylinositol diphosphate (PIP) decreased in Stage 3 larvae. Furthermore, the metabolic pathways and the key genes related to glycerophospholipid synthesis were identified based on transcriptomes for A. dichotoma larvae. These results revealed the composition of glycerophospholipids. We also explored the molecular mechanism for deposition of glycerophospholipids during the developmental stages of A. dichotoma larvae. Our results provide insights for using A. dichotoma larvae to produce lipids.